xscale.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2006, 2007 by Dominic Rath                              *
 *   Dominic.Rath@gmx.de                                                   *
 *                                                                         *
 *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
 *   oyvind.harboe@zylin.com                                               *
 *                                                                         *
 *   Copyright (C) 2009 Michael Schwingen                                  *
 *   michael@schwingen.org                                                 *
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "breakpoints.h"
#include "xscale.h"
#include "target_type.h"
#include "arm_jtag.h"
#include "arm_simulator.h"
#include "arm_disassembler.h"
#include <helper/time_support.h>
#include "register.h"
#include "image.h"
#include "arm_opcodes.h"
#include "armv4_5.h"
 
/*
 * Important XScale documents available as of October 2009 include:
 *
 *  Intel XScale® Core Developer’s Manual, January 2004
 *      Order Number: 273473-002
 *  This has a chapter detailing debug facilities, and punts some
 *  details to chip-specific microarchitecture documents.
 *
 *  Hot-Debug for Intel XScale® Core Debug White Paper, May 2005
 *      Document Number: 273539-005
 *  Less detailed than the developer's manual, but summarizes those
 *  missing details (for most XScales) and gives LOTS of notes about
 *  debugger/handler interaction issues.  Presents a simpler reset
 *  and load-handler sequence than the arch doc.  (Note, OpenOCD
 *  doesn't currently support "Hot-Debug" as defined there.)
 *
 * Chip-specific microarchitecture documents may also be useful.
 */
 
/* forward declarations */
static int xscale_resume(struct target *, int current,
    target_addr_t address, int handle_breakpoints, int debug_execution);
static int xscale_debug_entry(struct target *);
static int xscale_restore_banked(struct target *);
static int xscale_get_reg(struct reg *reg);
static int xscale_set_reg(struct reg *reg, uint8_t *buf);
static int xscale_set_breakpoint(struct target *, struct breakpoint *);
static int xscale_set_watchpoint(struct target *, struct watchpoint *);
static int xscale_unset_breakpoint(struct target *, struct breakpoint *);
static int xscale_read_trace(struct target *);
 
/* This XScale "debug handler" is loaded into the processor's
 * mini-ICache, which is 2K of code writable only via JTAG.
 */
static const uint8_t xscale_debug_handler[] = {
#include "../../contrib/loaders/debug/xscale/debug_handler.inc"
};
 
static const char *const xscale_reg_list[] = {
    "XSCALE_MAINID",        /* 0 */
    "XSCALE_CACHETYPE",
    "XSCALE_CTRL",
    "XSCALE_AUXCTRL",
    "XSCALE_TTB",
    "XSCALE_DAC",
    "XSCALE_FSR",
    "XSCALE_FAR",
    "XSCALE_PID",
    "XSCALE_CPACCESS",
    "XSCALE_IBCR0",         /* 10 */
    "XSCALE_IBCR1",
    "XSCALE_DBR0",
    "XSCALE_DBR1",
    "XSCALE_DBCON",
    "XSCALE_TBREG",
    "XSCALE_CHKPT0",
    "XSCALE_CHKPT1",
    "XSCALE_DCSR",
    "XSCALE_TX",
    "XSCALE_RX",            /* 20 */
    "XSCALE_TXRXCTRL",
};
 
static const struct xscale_reg xscale_reg_arch_info[] = {
    {XSCALE_MAINID, NULL},
    {XSCALE_CACHETYPE, NULL},
    {XSCALE_CTRL, NULL},
    {XSCALE_AUXCTRL, NULL},
    {XSCALE_TTB, NULL},
    {XSCALE_DAC, NULL},
    {XSCALE_FSR, NULL},
    {XSCALE_FAR, NULL},
    {XSCALE_PID, NULL},
    {XSCALE_CPACCESS, NULL},
    {XSCALE_IBCR0, NULL},
    {XSCALE_IBCR1, NULL},
    {XSCALE_DBR0, NULL},
    {XSCALE_DBR1, NULL},
    {XSCALE_DBCON, NULL},
    {XSCALE_TBREG, NULL},
    {XSCALE_CHKPT0, NULL},
    {XSCALE_CHKPT1, NULL},
    {XSCALE_DCSR, NULL},    /* DCSR accessed via JTAG or SW */
    {-1, NULL}, /* TX accessed via JTAG */
    {-1, NULL}, /* RX accessed via JTAG */
    {-1, NULL}, /* TXRXCTRL implicit access via JTAG */
};
 
/* convenience wrapper to access XScale specific registers */
static int xscale_set_reg_u32(struct reg *reg, uint32_t value)
{
    uint8_t buf[4] = { 0 };
 
    buf_set_u32(buf, 0, 32, value);
 
    return xscale_set_reg(reg, buf);
}
 
static const char xscale_not[] = "target is not an XScale";
 
static int xscale_verify_pointer(struct command_invocation *cmd,
    struct xscale_common *xscale)
{
    if (xscale->common_magic != XSCALE_COMMON_MAGIC) {
        command_print(cmd, xscale_not);
        return ERROR_TARGET_INVALID;
    }
    return ERROR_OK;
}
 
static int xscale_jtag_set_instr(struct jtag_tap *tap, uint32_t new_instr, tap_state_t end_state)
{
    assert(tap);
 
    if (buf_get_u32(tap->cur_instr, 0, tap->ir_length) != new_instr) {
        struct scan_field field;
        uint8_t scratch[4] = { 0 };
 
        memset(&field, 0, sizeof(field));
        field.num_bits = tap->ir_length;
        field.out_value = scratch;
        buf_set_u32(scratch, 0, field.num_bits, new_instr);
 
        jtag_add_ir_scan(tap, &field, end_state);
    }
 
    return ERROR_OK;
}
 
static int xscale_read_dcsr(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
    struct scan_field fields[3];
    uint8_t field0 = 0x0;
    uint8_t field0_check_value = 0x2;
    uint8_t field0_check_mask = 0x7;
    uint8_t field2 = 0x0;
    uint8_t field2_check_value = 0x0;
    uint8_t field2_check_mask = 0x1;
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_SELDCSR << xscale->xscale_variant,
        TAP_DRPAUSE);
 
    buf_set_u32(&field0, 1, 1, xscale->hold_rst);
    buf_set_u32(&field0, 2, 1, xscale->external_debug_break);
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 3;
    fields[0].out_value = &field0;
    uint8_t tmp;
    fields[0].in_value = &tmp;
 
    fields[1].num_bits = 32;
    fields[1].in_value = xscale->reg_cache->reg_list[XSCALE_DCSR].value;
 
    fields[2].num_bits = 1;
    fields[2].out_value = &field2;
    uint8_t tmp2;
    fields[2].in_value = &tmp2;
 
    jtag_add_dr_scan(target->tap, 3, fields, TAP_DRPAUSE);
 
    jtag_check_value_mask(fields + 0, &field0_check_value, &field0_check_mask);
    jtag_check_value_mask(fields + 2, &field2_check_value, &field2_check_mask);
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK) {
        LOG_ERROR("JTAG error while reading DCSR");
        return retval;
    }
 
    xscale->reg_cache->reg_list[XSCALE_DCSR].dirty = false;
    xscale->reg_cache->reg_list[XSCALE_DCSR].valid = true;
 
    /* write the register with the value we just read
     * on this second pass, only the first bit of field0 is guaranteed to be 0)
     */
    field0_check_mask = 0x1;
    fields[1].out_value = xscale->reg_cache->reg_list[XSCALE_DCSR].value;
    fields[1].in_value = NULL;
 
    jtag_add_dr_scan(target->tap, 3, fields, TAP_DRPAUSE);
 
    /* DANGER!!! this must be here. It will make sure that the arguments
     * to jtag_set_check_value() does not go out of scope! */
    return jtag_execute_queue();
}
 
 
static void xscale_getbuf(jtag_callback_data_t arg)
{
    uint8_t *in = (uint8_t *)arg;
    *((uint32_t *)arg) = buf_get_u32(in, 0, 32);
}
 
static int xscale_receive(struct target *target, uint32_t *buffer, int num_words)
{
    if (num_words == 0)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    struct xscale_common *xscale = target_to_xscale(target);
    int retval = ERROR_OK;
    tap_state_t path[3];
    struct scan_field fields[3];
    uint8_t *field0 = malloc(num_words * 1);
    uint8_t field0_check_value = 0x2;
    uint8_t field0_check_mask = 0x6;
    uint32_t *field1 = malloc(num_words * 4);
    uint8_t field2_check_value = 0x0;
    uint8_t field2_check_mask = 0x1;
    int words_done = 0;
    int words_scheduled = 0;
    int i;
 
    path[0] = TAP_DRSELECT;
    path[1] = TAP_DRCAPTURE;
    path[2] = TAP_DRSHIFT;
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 3;
    uint8_t tmp;
    fields[0].in_value = &tmp;
    fields[0].check_value = &field0_check_value;
    fields[0].check_mask = &field0_check_mask;
 
    fields[1].num_bits = 32;
 
    fields[2].num_bits = 1;
    uint8_t tmp2;
    fields[2].in_value = &tmp2;
    fields[2].check_value = &field2_check_value;
    fields[2].check_mask = &field2_check_mask;
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_DBGTX << xscale->xscale_variant,
        TAP_IDLE);
    jtag_add_runtest(1, TAP_IDLE);  /* ensures that we're in the TAP_IDLE state as the above
                     *could be a no-op */
 
    /* repeat until all words have been collected */
    int attempts = 0;
    while (words_done < num_words) {
        /* schedule reads */
        words_scheduled = 0;
        for (i = words_done; i < num_words; i++) {
            fields[0].in_value = &field0[i];
 
            jtag_add_pathmove(3, path);
 
            fields[1].in_value = (uint8_t *)(field1 + i);
 
            jtag_add_dr_scan_check(target->tap, 3, fields, TAP_IDLE);
 
            jtag_add_callback(xscale_getbuf, (jtag_callback_data_t)(field1 + i));
 
            words_scheduled++;
        }
 
        retval = jtag_execute_queue();
        if (retval != ERROR_OK) {
            LOG_ERROR("JTAG error while receiving data from debug handler");
            break;
        }
 
        /* examine results */
        for (i = words_done; i < num_words; i++) {
            if (!(field0[i] & 1)) {
                /* move backwards if necessary */
                int j;
                for (j = i; j < num_words - 1; j++) {
                    field0[j] = field0[j + 1];
                    field1[j] = field1[j + 1];
                }
                words_scheduled--;
            }
        }
        if (words_scheduled == 0) {
            if (attempts++ == 1000) {
                LOG_ERROR(
                    "Failed to receiving data from debug handler after 1000 attempts");
                retval = ERROR_TARGET_TIMEOUT;
                break;
            }
        }
 
        words_done += words_scheduled;
    }
 
    for (i = 0; i < num_words; i++)
        *(buffer++) = buf_get_u32((uint8_t *)&field1[i], 0, 32);
 
    free(field1);
 
    return retval;
}
 
static int xscale_read_tx(struct target *target, int consume)
{
    struct xscale_common *xscale = target_to_xscale(target);
    tap_state_t path[3];
    tap_state_t noconsume_path[6];
    int retval;
    struct timeval timeout, now;
    struct scan_field fields[3];
    uint8_t field0_in = 0x0;
    uint8_t field0_check_value = 0x2;
    uint8_t field0_check_mask = 0x6;
    uint8_t field2_check_value = 0x0;
    uint8_t field2_check_mask = 0x1;
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_DBGTX << xscale->xscale_variant,
        TAP_IDLE);
 
    path[0] = TAP_DRSELECT;
    path[1] = TAP_DRCAPTURE;
    path[2] = TAP_DRSHIFT;
 
    noconsume_path[0] = TAP_DRSELECT;
    noconsume_path[1] = TAP_DRCAPTURE;
    noconsume_path[2] = TAP_DREXIT1;
    noconsume_path[3] = TAP_DRPAUSE;
    noconsume_path[4] = TAP_DREXIT2;
    noconsume_path[5] = TAP_DRSHIFT;
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 3;
    fields[0].in_value = &field0_in;
 
    fields[1].num_bits = 32;
    fields[1].in_value = xscale->reg_cache->reg_list[XSCALE_TX].value;
 
    fields[2].num_bits = 1;
    uint8_t tmp;
    fields[2].in_value = &tmp;
 
    gettimeofday(&timeout, NULL);
    timeval_add_time(&timeout, 1, 0);
 
    for (;; ) {
        /* if we want to consume the register content (i.e. clear TX_READY),
         * we have to go straight from Capture-DR to Shift-DR
         * otherwise, we go from Capture-DR to Exit1-DR to Pause-DR
        */
        if (consume)
            jtag_add_pathmove(3, path);
        else
            jtag_add_pathmove(ARRAY_SIZE(noconsume_path), noconsume_path);
 
        jtag_add_dr_scan(target->tap, 3, fields, TAP_IDLE);
 
        jtag_check_value_mask(fields + 0, &field0_check_value, &field0_check_mask);
        jtag_check_value_mask(fields + 2, &field2_check_value, &field2_check_mask);
 
        retval = jtag_execute_queue();
        if (retval != ERROR_OK) {
            LOG_ERROR("JTAG error while reading TX");
            return ERROR_TARGET_TIMEOUT;
        }
 
        gettimeofday(&now, NULL);
        if (timeval_compare(&now, &timeout) > 0) {
            LOG_ERROR("time out reading TX register");
            return ERROR_TARGET_TIMEOUT;
        }
        if (!((!(field0_in & 1)) && consume))
            goto done;
        if (debug_level >= 3) {
            LOG_DEBUG("waiting 100ms");
            alive_sleep(100);   /* avoid flooding the logs */
        } else
            keep_alive();
    }
done:
 
    if (!(field0_in & 1))
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 
    return ERROR_OK;
}
 
static int xscale_write_rx(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
    struct timeval timeout, now;
    struct scan_field fields[3];
    uint8_t field0_out = 0x0;
    uint8_t field0_in = 0x0;
    uint8_t field0_check_value = 0x2;
    uint8_t field0_check_mask = 0x6;
    uint8_t field2 = 0x0;
    uint8_t field2_check_value = 0x0;
    uint8_t field2_check_mask = 0x1;
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_DBGRX << xscale->xscale_variant,
        TAP_IDLE);
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 3;
    fields[0].out_value = &field0_out;
    fields[0].in_value = &field0_in;
 
    fields[1].num_bits = 32;
    fields[1].out_value = xscale->reg_cache->reg_list[XSCALE_RX].value;
 
    fields[2].num_bits = 1;
    fields[2].out_value = &field2;
    uint8_t tmp;
    fields[2].in_value = &tmp;
 
    gettimeofday(&timeout, NULL);
    timeval_add_time(&timeout, 1, 0);
 
    /* poll until rx_read is low */
    LOG_DEBUG("polling RX");
    for (;;) {
        jtag_add_dr_scan(target->tap, 3, fields, TAP_IDLE);
 
        jtag_check_value_mask(fields + 0, &field0_check_value, &field0_check_mask);
        jtag_check_value_mask(fields + 2, &field2_check_value, &field2_check_mask);
 
        retval = jtag_execute_queue();
        if (retval != ERROR_OK) {
            LOG_ERROR("JTAG error while writing RX");
            return retval;
        }
 
        gettimeofday(&now, NULL);
        if ((now.tv_sec > timeout.tv_sec) ||
            ((now.tv_sec == timeout.tv_sec) && (now.tv_usec > timeout.tv_usec))) {
            LOG_ERROR("time out writing RX register");
            return ERROR_TARGET_TIMEOUT;
        }
        if (!(field0_in & 1))
            goto done;
        if (debug_level >= 3) {
            LOG_DEBUG("waiting 100ms");
            alive_sleep(100);   /* avoid flooding the logs */
        } else
            keep_alive();
    }
done:
 
    /* set rx_valid */
    field2 = 0x1;
    jtag_add_dr_scan(target->tap, 3, fields, TAP_IDLE);
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK) {
        LOG_ERROR("JTAG error while writing RX");
        return retval;
    }
 
    return ERROR_OK;
}
 
/* send count elements of size byte to the debug handler */
static int xscale_send(struct target *target, const uint8_t *buffer, int count, int size)
{
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
    int done_count = 0;
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_DBGRX << xscale->xscale_variant,
        TAP_IDLE);
 
    static const uint8_t t0;
    uint8_t t1[4] = { 0 };
    static const uint8_t t2 = 1;
    struct scan_field fields[3] = {
            { .num_bits = 3, .out_value = &t0 },
            { .num_bits = 32, .out_value = t1 },
            { .num_bits = 1, .out_value = &t2 },
    };
 
    int endianness = target->endianness;
    while (done_count++ < count) {
        uint32_t t;
 
        switch (size) {
            case 4:
                if (endianness == TARGET_LITTLE_ENDIAN)
                    t = le_to_h_u32(buffer);
                else
                    t = be_to_h_u32(buffer);
                break;
            case 2:
                if (endianness == TARGET_LITTLE_ENDIAN)
                    t = le_to_h_u16(buffer);
                else
                    t = be_to_h_u16(buffer);
                break;
            case 1:
                t = buffer[0];
                break;
            default:
                LOG_ERROR("BUG: size neither 4, 2 nor 1");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
 
        buf_set_u32(t1, 0, 32, t);
 
        jtag_add_dr_scan(target->tap,
            3,
            fields,
            TAP_IDLE);
        buffer += size;
    }
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK) {
        LOG_ERROR("JTAG error while sending data to debug handler");
        return retval;
    }
 
    return ERROR_OK;
}
 
static int xscale_send_u32(struct target *target, uint32_t value)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    buf_set_u32(xscale->reg_cache->reg_list[XSCALE_RX].value, 0, 32, value);
    return xscale_write_rx(target);
}
 
static int xscale_write_dcsr(struct target *target, int hold_rst, int ext_dbg_brk)
{
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
    struct scan_field fields[3];
    uint8_t field0 = 0x0;
    uint8_t field0_check_value = 0x2;
    uint8_t field0_check_mask = 0x7;
    uint8_t field2 = 0x0;
    uint8_t field2_check_value = 0x0;
    uint8_t field2_check_mask = 0x1;
 
    if (hold_rst != -1)
        xscale->hold_rst = hold_rst;
 
    if (ext_dbg_brk != -1)
        xscale->external_debug_break = ext_dbg_brk;
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_SELDCSR << xscale->xscale_variant,
        TAP_IDLE);
 
    buf_set_u32(&field0, 1, 1, xscale->hold_rst);
    buf_set_u32(&field0, 2, 1, xscale->external_debug_break);
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 3;
    fields[0].out_value = &field0;
    uint8_t tmp;
    fields[0].in_value = &tmp;
 
    fields[1].num_bits = 32;
    fields[1].out_value = xscale->reg_cache->reg_list[XSCALE_DCSR].value;
 
    fields[2].num_bits = 1;
    fields[2].out_value = &field2;
    uint8_t tmp2;
    fields[2].in_value = &tmp2;
 
    jtag_add_dr_scan(target->tap, 3, fields, TAP_IDLE);
 
    jtag_check_value_mask(fields + 0, &field0_check_value, &field0_check_mask);
    jtag_check_value_mask(fields + 2, &field2_check_value, &field2_check_mask);
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK) {
        LOG_ERROR("JTAG error while writing DCSR");
        return retval;
    }
 
    xscale->reg_cache->reg_list[XSCALE_DCSR].dirty = false;
    xscale->reg_cache->reg_list[XSCALE_DCSR].valid = true;
 
    return ERROR_OK;
}
 
/* parity of the number of bits 0 if even; 1 if odd. for 32 bit words */
static unsigned int parity(unsigned int v)
{
    /* unsigned int ov = v; */
    v ^= v >> 16;
    v ^= v >> 8;
    v ^= v >> 4;
    v &= 0xf;
    /* LOG_DEBUG("parity of 0x%x is %i", ov, (0x6996 >> v) & 1); */
    return (0x6996 >> v) & 1;
}
 
static int xscale_load_ic(struct target *target, uint32_t va, uint32_t buffer[8])
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint8_t packet[4] = { 0 };
    uint8_t cmd = 0;
    int word;
    struct scan_field fields[2];
 
    LOG_DEBUG("loading miniIC at 0x%8.8" PRIx32 "", va);
 
    /* LDIC into IR */
    xscale_jtag_set_instr(target->tap,
        XSCALE_LDIC << xscale->xscale_variant,
        TAP_IDLE);
 
    /* CMD is b011 to load a cacheline into the Mini ICache.
     * Loading into the main ICache is deprecated, and unused.
     * It's followed by three zero bits, and 27 address bits.
     */
    buf_set_u32(&cmd, 0, 6, 0x3);
 
    /* virtual address of desired cache line */
    buf_set_u32(packet, 0, 27, va >> 5);
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 6;
    fields[0].out_value = &cmd;
 
    fields[1].num_bits = 27;
    fields[1].out_value = packet;
 
    jtag_add_dr_scan(target->tap, 2, fields, TAP_IDLE);
 
    /* rest of packet is a cacheline: 8 instructions, with parity */
    fields[0].num_bits = 32;
    fields[0].out_value = packet;
 
    fields[1].num_bits = 1;
    fields[1].out_value = &cmd;
 
    for (word = 0; word < 8; word++) {
        buf_set_u32(packet, 0, 32, buffer[word]);
 
        uint32_t value;
        memcpy(&value, packet, sizeof(uint32_t));
        cmd = parity(value);
 
        jtag_add_dr_scan(target->tap, 2, fields, TAP_IDLE);
    }
 
    return jtag_execute_queue();
}
 
static int xscale_invalidate_ic_line(struct target *target, uint32_t va)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint8_t packet[4] = { 0 };
    uint8_t cmd = 0;
    struct scan_field fields[2];
 
    xscale_jtag_set_instr(target->tap,
        XSCALE_LDIC << xscale->xscale_variant,
        TAP_IDLE);
 
    /* CMD for invalidate IC line b000, bits [6:4] b000 */
    buf_set_u32(&cmd, 0, 6, 0x0);
 
    /* virtual address of desired cache line */
    buf_set_u32(packet, 0, 27, va >> 5);
 
    memset(&fields, 0, sizeof(fields));
 
    fields[0].num_bits = 6;
    fields[0].out_value = &cmd;
 
    fields[1].num_bits = 27;
    fields[1].out_value = packet;
 
    jtag_add_dr_scan(target->tap, 2, fields, TAP_IDLE);
 
    return ERROR_OK;
}
 
static int xscale_update_vectors(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    int i;
    int retval;
 
    uint32_t low_reset_branch, high_reset_branch;
 
    for (i = 1; i < 8; i++) {
        /* if there's a static vector specified for this exception, override */
        if (xscale->static_high_vectors_set & (1 << i))
            xscale->high_vectors[i] = xscale->static_high_vectors[i];
        else {
            retval = target_read_u32(target, 0xffff0000 + 4*i, &xscale->high_vectors[i]);
            if (retval == ERROR_TARGET_TIMEOUT)
                return retval;
            if (retval != ERROR_OK) {
                /* Some of these reads will fail as part of normal execution */
                xscale->high_vectors[i] = ARMV4_5_B(0xfffffe, 0);
            }
        }
    }
 
    for (i = 1; i < 8; i++) {
        if (xscale->static_low_vectors_set & (1 << i))
            xscale->low_vectors[i] = xscale->static_low_vectors[i];
        else {
            retval = target_read_u32(target, 0x0 + 4*i, &xscale->low_vectors[i]);
            if (retval == ERROR_TARGET_TIMEOUT)
                return retval;
            if (retval != ERROR_OK) {
                /* Some of these reads will fail as part of normal execution */
                xscale->low_vectors[i] = ARMV4_5_B(0xfffffe, 0);
            }
        }
    }
 
    /* calculate branches to debug handler */
    low_reset_branch = (xscale->handler_address + 0x20 - 0x0 - 0x8) >> 2;
    high_reset_branch = (xscale->handler_address + 0x20 - 0xffff0000 - 0x8) >> 2;
 
    xscale->low_vectors[0] = ARMV4_5_B((low_reset_branch & 0xffffff), 0);
    xscale->high_vectors[0] = ARMV4_5_B((high_reset_branch & 0xffffff), 0);
 
    /* invalidate and load exception vectors in mini i-cache */
    xscale_invalidate_ic_line(target, 0x0);
    xscale_invalidate_ic_line(target, 0xffff0000);
 
    xscale_load_ic(target, 0x0, xscale->low_vectors);
    xscale_load_ic(target, 0xffff0000, xscale->high_vectors);
 
    return ERROR_OK;
}
 
static int xscale_arch_state(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct arm *arm = &xscale->arm;
 
    static const char *state[] = {
        "disabled", "enabled"
    };
 
    static const char *arch_dbg_reason[] = {
        "", "\n(processor reset)", "\n(trace buffer full)"
    };
 
    if (arm->common_magic != ARM_COMMON_MAGIC) {
        LOG_ERROR("BUG: called for a non-ARMv4/5 target");
        return ERROR_COMMAND_SYNTAX_ERROR;
    }
 
    arm_arch_state(target);
    LOG_USER("MMU: %s, D-Cache: %s, I-Cache: %s%s",
        state[xscale->armv4_5_mmu.mmu_enabled],
        state[xscale->armv4_5_mmu.armv4_5_cache.d_u_cache_enabled],
        state[xscale->armv4_5_mmu.armv4_5_cache.i_cache_enabled],
        arch_dbg_reason[xscale->arch_debug_reason]);
 
    return ERROR_OK;
}
 
static int xscale_poll(struct target *target)
{
    int retval = ERROR_OK;
 
    if ((target->state == TARGET_RUNNING) || (target->state == TARGET_DEBUG_RUNNING)) {
        enum target_state previous_state = target->state;
        retval = xscale_read_tx(target, 0);
        if (retval == ERROR_OK) {
 
            /* there's data to read from the tx register, we entered debug state */
            target->state = TARGET_HALTED;
 
            /* process debug entry, fetching current mode regs */
            retval = xscale_debug_entry(target);
        } else if (retval != ERROR_TARGET_RESOURCE_NOT_AVAILABLE) {
            LOG_USER("error while polling TX register, reset CPU");
            /* here we "lie" so GDB won't get stuck and a reset can be performed */
            target->state = TARGET_HALTED;
        }
 
        /* debug_entry could have overwritten target state (i.e. immediate resume)
         * don't signal event handlers in that case
         */
        if (target->state != TARGET_HALTED)
            return ERROR_OK;
 
        /* if target was running, signal that we halted
         * otherwise we reentered from debug execution */
        if (previous_state == TARGET_RUNNING)
            target_call_event_callbacks(target, TARGET_EVENT_HALTED);
        else
            target_call_event_callbacks(target, TARGET_EVENT_DEBUG_HALTED);
    }
 
    return retval;
}
 
static int xscale_debug_entry(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct arm *arm = &xscale->arm;
    uint32_t pc;
    uint32_t buffer[10];
    unsigned i;
    int retval;
    uint32_t moe;
 
    /* clear external dbg break (will be written on next DCSR read) */
    xscale->external_debug_break = 0;
    retval = xscale_read_dcsr(target);
    if (retval != ERROR_OK)
        return retval;
 
    /* get r0, pc, r1 to r7 and cpsr */
    retval = xscale_receive(target, buffer, 10);
    if (retval != ERROR_OK)
        return retval;
 
    /* move r0 from buffer to register cache */
    buf_set_u32(arm->core_cache->reg_list[0].value, 0, 32, buffer[0]);
    arm->core_cache->reg_list[0].dirty = true;
    arm->core_cache->reg_list[0].valid = true;
    LOG_DEBUG("r0: 0x%8.8" PRIx32 "", buffer[0]);
 
    /* move pc from buffer to register cache */
    buf_set_u32(arm->pc->value, 0, 32, buffer[1]);
    arm->pc->dirty = true;
    arm->pc->valid = true;
    LOG_DEBUG("pc: 0x%8.8" PRIx32 "", buffer[1]);
 
    /* move data from buffer to register cache */
    for (i = 1; i <= 7; i++) {
        buf_set_u32(arm->core_cache->reg_list[i].value, 0, 32, buffer[1 + i]);
        arm->core_cache->reg_list[i].dirty = true;
        arm->core_cache->reg_list[i].valid = true;
        LOG_DEBUG("r%i: 0x%8.8" PRIx32 "", i, buffer[i + 1]);
    }
 
    arm_set_cpsr(arm, buffer[9]);
    LOG_DEBUG("cpsr: 0x%8.8" PRIx32 "", buffer[9]);
 
    if (!is_arm_mode(arm->core_mode)) {
        target->state = TARGET_UNKNOWN;
        LOG_ERROR("cpsr contains invalid mode value - communication failure");
        return ERROR_TARGET_FAILURE;
    }
    LOG_DEBUG("target entered debug state in %s mode",
        arm_mode_name(arm->core_mode));
 
    /* get banked registers, r8 to r14, and spsr if not in USR/SYS mode */
    if (arm->spsr) {
        xscale_receive(target, buffer, 8);
        buf_set_u32(arm->spsr->value, 0, 32, buffer[7]);
        arm->spsr->dirty = false;
        arm->spsr->valid = true;
    } else {
        /* r8 to r14, but no spsr */
        xscale_receive(target, buffer, 7);
    }
 
    /* move data from buffer to right banked register in cache */
    for (i = 8; i <= 14; i++) {
        struct reg *r = arm_reg_current(arm, i);
 
        buf_set_u32(r->value, 0, 32, buffer[i - 8]);
        r->dirty = false;
        r->valid = true;
    }
 
    /* mark xscale regs invalid to ensure they are retrieved from the
     * debug handler if requested  */
    for (i = 0; i < xscale->reg_cache->num_regs; i++)
        xscale->reg_cache->reg_list[i].valid = false;
 
    /* examine debug reason */
    xscale_read_dcsr(target);
    moe = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 2, 3);
 
    /* stored PC (for calculating fixup) */
    pc = buf_get_u32(arm->pc->value, 0, 32);
 
    switch (moe) {
        case 0x0:   /* Processor reset */
            target->debug_reason = DBG_REASON_DBGRQ;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_RESET;
            pc -= 4;
            break;
        case 0x1:   /* Instruction breakpoint hit */
            target->debug_reason = DBG_REASON_BREAKPOINT;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_GENERIC;
            pc -= 4;
            break;
        case 0x2:   /* Data breakpoint hit */
            target->debug_reason = DBG_REASON_WATCHPOINT;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_GENERIC;
            pc -= 4;
            break;
        case 0x3:   /* BKPT instruction executed */
            target->debug_reason = DBG_REASON_BREAKPOINT;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_GENERIC;
            pc -= 4;
            break;
        case 0x4:   /* Ext. debug event */
            target->debug_reason = DBG_REASON_DBGRQ;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_GENERIC;
            pc -= 4;
            break;
        case 0x5:   /* Vector trap occurred */
            target->debug_reason = DBG_REASON_BREAKPOINT;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_GENERIC;
            pc -= 4;
            break;
        case 0x6:   /* Trace buffer full break */
            target->debug_reason = DBG_REASON_DBGRQ;
            xscale->arch_debug_reason = XSCALE_DBG_REASON_TB_FULL;
            pc -= 4;
            break;
        case 0x7:   /* Reserved (may flag Hot-Debug support) */
        default:
            LOG_ERROR("Method of Entry is 'Reserved'");
            exit(-1);
            break;
    }
 
    /* apply PC fixup */
    buf_set_u32(arm->pc->value, 0, 32, pc);
 
    /* on the first debug entry, identify cache type */
    if (xscale->armv4_5_mmu.armv4_5_cache.ctype == -1) {
        uint32_t cache_type_reg;
 
        /* read cp15 cache type register */
        xscale_get_reg(&xscale->reg_cache->reg_list[XSCALE_CACHETYPE]);
        cache_type_reg = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_CACHETYPE].value,
                0,
                32);
 
        armv4_5_identify_cache(cache_type_reg, &xscale->armv4_5_mmu.armv4_5_cache);
    }
 
    /* examine MMU and Cache settings
     * read cp15 control register */
    xscale_get_reg(&xscale->reg_cache->reg_list[XSCALE_CTRL]);
    xscale->cp15_control_reg =
        buf_get_u32(xscale->reg_cache->reg_list[XSCALE_CTRL].value, 0, 32);
    xscale->armv4_5_mmu.mmu_enabled = (xscale->cp15_control_reg & 0x1U) ? 1 : 0;
    xscale->armv4_5_mmu.armv4_5_cache.d_u_cache_enabled =
        (xscale->cp15_control_reg & 0x4U) ? 1 : 0;
    xscale->armv4_5_mmu.armv4_5_cache.i_cache_enabled =
        (xscale->cp15_control_reg & 0x1000U) ? 1 : 0;
 
    /* tracing enabled, read collected trace data */
    if (xscale->trace.mode != XSCALE_TRACE_DISABLED) {
        xscale_read_trace(target);
 
        /* Resume if entered debug due to buffer fill and we're still collecting
         * trace data.  Note that a debug exception due to trace buffer full
         * can only happen in fill mode. */
        if (xscale->arch_debug_reason == XSCALE_DBG_REASON_TB_FULL) {
            if (--xscale->trace.fill_counter > 0)
                xscale_resume(target, 1, 0x0, 1, 0);
        } else  /* entered debug for other reason; reset counter */
            xscale->trace.fill_counter = 0;
    }
 
    return ERROR_OK;
}
 
static int xscale_halt(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    LOG_DEBUG("target->state: %s",
        target_state_name(target));
 
    if (target->state == TARGET_HALTED) {
        LOG_DEBUG("target was already halted");
        return ERROR_OK;
    } else if (target->state == TARGET_UNKNOWN) {
        /* this must not happen for a xscale target */
        LOG_ERROR("target was in unknown state when halt was requested");
        return ERROR_TARGET_INVALID;
    } else if (target->state == TARGET_RESET)
        LOG_DEBUG("target->state == TARGET_RESET");
    else {
        /* assert external dbg break */
        xscale->external_debug_break = 1;
        xscale_read_dcsr(target);
 
        target->debug_reason = DBG_REASON_DBGRQ;
    }
 
    return ERROR_OK;
}
 
static int xscale_enable_single_step(struct target *target, uint32_t next_pc)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct reg *ibcr0 = &xscale->reg_cache->reg_list[XSCALE_IBCR0];
    int retval;
 
    if (xscale->ibcr0_used) {
        struct breakpoint *ibcr0_bp =
            breakpoint_find(target, buf_get_u32(ibcr0->value, 0, 32) & 0xfffffffe);
 
        if (ibcr0_bp)
            xscale_unset_breakpoint(target, ibcr0_bp);
        else {
            LOG_ERROR(
                "BUG: xscale->ibcr0_used is set, but no breakpoint with that address found");
            exit(-1);
        }
    }
 
    retval = xscale_set_reg_u32(ibcr0, next_pc | 0x1);
    if (retval != ERROR_OK)
        return retval;
 
    return ERROR_OK;
}
 
static int xscale_disable_single_step(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct reg *ibcr0 = &xscale->reg_cache->reg_list[XSCALE_IBCR0];
    int retval;
 
    retval = xscale_set_reg_u32(ibcr0, 0x0);
    if (retval != ERROR_OK)
        return retval;
 
    return ERROR_OK;
}
 
static void xscale_enable_watchpoints(struct target *target)
{
    struct watchpoint *watchpoint = target->watchpoints;
 
    while (watchpoint) {
        if (!watchpoint->is_set)
            xscale_set_watchpoint(target, watchpoint);
        watchpoint = watchpoint->next;
    }
}
 
static void xscale_enable_breakpoints(struct target *target)
{
    struct breakpoint *breakpoint = target->breakpoints;
 
    /* set any pending breakpoints */
    while (breakpoint) {
        if (!breakpoint->is_set)
            xscale_set_breakpoint(target, breakpoint);
        breakpoint = breakpoint->next;
    }
}
 
static void xscale_free_trace_data(struct xscale_common *xscale)
{
    struct xscale_trace_data *td = xscale->trace.data;
    while (td) {
        struct xscale_trace_data *next_td = td->next;
        free(td->entries);
        free(td);
        td = next_td;
    }
    xscale->trace.data = NULL;
}
 
static int xscale_resume(struct target *target, int current,
    target_addr_t address, int handle_breakpoints, int debug_execution)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct arm *arm = &xscale->arm;
    uint32_t current_pc;
    int retval;
    int i;
 
    LOG_DEBUG("-");
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (!debug_execution)
        target_free_all_working_areas(target);
 
    /* update vector tables */
    retval = xscale_update_vectors(target);
    if (retval != ERROR_OK)
        return retval;
 
    /* current = 1: continue on current pc, otherwise continue at <address> */
    if (!current)
        buf_set_u32(arm->pc->value, 0, 32, address);
 
    current_pc = buf_get_u32(arm->pc->value, 0, 32);
 
    /* if we're at the reset vector, we have to simulate the branch */
    if (current_pc == 0x0) {
        arm_simulate_step(target, NULL);
        current_pc = buf_get_u32(arm->pc->value, 0, 32);
    }
 
    /* the front-end may request us not to handle breakpoints */
    if (handle_breakpoints) {
        struct breakpoint *breakpoint;
        breakpoint = breakpoint_find(target,
                buf_get_u32(arm->pc->value, 0, 32));
        if (breakpoint) {
            uint32_t next_pc;
            enum trace_mode saved_trace_mode;
 
            /* there's a breakpoint at the current PC, we have to step over it */
            LOG_DEBUG("unset breakpoint at " TARGET_ADDR_FMT "",
                breakpoint->address);
            xscale_unset_breakpoint(target, breakpoint);
 
            /* calculate PC of next instruction */
            retval = arm_simulate_step(target, &next_pc);
            if (retval != ERROR_OK) {
                uint32_t current_opcode;
                target_read_u32(target, current_pc, &current_opcode);
                LOG_ERROR(
                    "BUG: couldn't calculate PC of next instruction, current opcode was 0x%8.8" PRIx32 "",
                    current_opcode);
            }
 
            LOG_DEBUG("enable single-step");
            xscale_enable_single_step(target, next_pc);
 
            /* restore banked registers */
            retval = xscale_restore_banked(target);
            if (retval != ERROR_OK)
                return retval;
 
            /* send resume request */
            xscale_send_u32(target, 0x30);
 
            /* send CPSR */
            xscale_send_u32(target,
                buf_get_u32(arm->cpsr->value, 0, 32));
            LOG_DEBUG("writing cpsr with value 0x%8.8" PRIx32,
                buf_get_u32(arm->cpsr->value, 0, 32));
 
            for (i = 7; i >= 0; i--) {
                /* send register */
                xscale_send_u32(target,
                    buf_get_u32(arm->core_cache->reg_list[i].value, 0, 32));
                LOG_DEBUG("writing r%i with value 0x%8.8" PRIx32 "",
                    i, buf_get_u32(arm->core_cache->reg_list[i].value, 0, 32));
            }
 
            /* send PC */
            xscale_send_u32(target,
                buf_get_u32(arm->pc->value, 0, 32));
            LOG_DEBUG("writing PC with value 0x%8.8" PRIx32,
                buf_get_u32(arm->pc->value, 0, 32));
 
            /* disable trace data collection in xscale_debug_entry() */
            saved_trace_mode = xscale->trace.mode;
            xscale->trace.mode = XSCALE_TRACE_DISABLED;
 
            /* wait for and process debug entry */
            xscale_debug_entry(target);
 
            /* re-enable trace buffer, if enabled previously */
            xscale->trace.mode = saved_trace_mode;
 
            LOG_DEBUG("disable single-step");
            xscale_disable_single_step(target);
 
            LOG_DEBUG("set breakpoint at " TARGET_ADDR_FMT "",
                breakpoint->address);
            xscale_set_breakpoint(target, breakpoint);
        }
    }
 
    /* enable any pending breakpoints and watchpoints */
    xscale_enable_breakpoints(target);
    xscale_enable_watchpoints(target);
 
    /* restore banked registers */
    retval = xscale_restore_banked(target);
    if (retval != ERROR_OK)
        return retval;
 
    /* send resume request (command 0x30 or 0x31)
     * clean the trace buffer if it is to be enabled (0x62) */
    if (xscale->trace.mode != XSCALE_TRACE_DISABLED) {
        if (xscale->trace.mode == XSCALE_TRACE_FILL) {
            /* If trace enabled in fill mode and starting collection of new set
                 * of buffers, initialize buffer counter and free previous buffers */
            if (xscale->trace.fill_counter == 0) {
                xscale->trace.fill_counter = xscale->trace.buffer_fill;
                xscale_free_trace_data(xscale);
            }
        } else  /* wrap mode; free previous buffer */
            xscale_free_trace_data(xscale);
 
        xscale_send_u32(target, 0x62);
        xscale_send_u32(target, 0x31);
    } else
        xscale_send_u32(target, 0x30);
 
    /* send CPSR */
    xscale_send_u32(target, buf_get_u32(arm->cpsr->value, 0, 32));
    LOG_DEBUG("writing cpsr with value 0x%8.8" PRIx32,
        buf_get_u32(arm->cpsr->value, 0, 32));
 
    for (i = 7; i >= 0; i--) {
        /* send register */
        xscale_send_u32(target, buf_get_u32(arm->core_cache->reg_list[i].value, 0, 32));
        LOG_DEBUG("writing r%i with value 0x%8.8" PRIx32 "",
            i, buf_get_u32(arm->core_cache->reg_list[i].value, 0, 32));
    }
 
    /* send PC */
    xscale_send_u32(target, buf_get_u32(arm->pc->value, 0, 32));
    LOG_DEBUG("wrote PC with value 0x%8.8" PRIx32,
        buf_get_u32(arm->pc->value, 0, 32));
 
    target->debug_reason = DBG_REASON_NOTHALTED;
 
    if (!debug_execution) {
        /* registers are now invalid */
        register_cache_invalidate(arm->core_cache);
        target->state = TARGET_RUNNING;
        target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
    } else {
        target->state = TARGET_DEBUG_RUNNING;
        target_call_event_callbacks(target, TARGET_EVENT_DEBUG_RESUMED);
    }
 
    LOG_DEBUG("target resumed");
 
    return ERROR_OK;
}
 
static int xscale_step_inner(struct target *target, int current,
    uint32_t address, int handle_breakpoints)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct arm *arm = &xscale->arm;
    uint32_t next_pc;
    int retval;
    int i;
 
    target->debug_reason = DBG_REASON_SINGLESTEP;
 
    /* calculate PC of next instruction */
    retval = arm_simulate_step(target, &next_pc);
    if (retval != ERROR_OK) {
        uint32_t current_opcode, current_pc;
        current_pc = buf_get_u32(arm->pc->value, 0, 32);
 
        target_read_u32(target, current_pc, &current_opcode);
        LOG_ERROR(
            "BUG: couldn't calculate PC of next instruction, current opcode was 0x%8.8" PRIx32 "",
            current_opcode);
        return retval;
    }
 
    LOG_DEBUG("enable single-step");
    retval = xscale_enable_single_step(target, next_pc);
    if (retval != ERROR_OK)
        return retval;
 
    /* restore banked registers */
    retval = xscale_restore_banked(target);
    if (retval != ERROR_OK)
        return retval;
 
    /* send resume request (command 0x30 or 0x31)
     * clean the trace buffer if it is to be enabled (0x62) */
    if (xscale->trace.mode != XSCALE_TRACE_DISABLED) {
        retval = xscale_send_u32(target, 0x62);
        if (retval != ERROR_OK)
            return retval;
        retval = xscale_send_u32(target, 0x31);
        if (retval != ERROR_OK)
            return retval;
    } else {
        retval = xscale_send_u32(target, 0x30);
        if (retval != ERROR_OK)
            return retval;
    }
 
    /* send CPSR */
    retval = xscale_send_u32(target,
            buf_get_u32(arm->cpsr->value, 0, 32));
    if (retval != ERROR_OK)
        return retval;
    LOG_DEBUG("writing cpsr with value 0x%8.8" PRIx32,
        buf_get_u32(arm->cpsr->value, 0, 32));
 
    for (i = 7; i >= 0; i--) {
        /* send register */
        retval = xscale_send_u32(target,
                buf_get_u32(arm->core_cache->reg_list[i].value, 0, 32));
        if (retval != ERROR_OK)
            return retval;
        LOG_DEBUG("writing r%i with value 0x%8.8" PRIx32 "", i,
            buf_get_u32(arm->core_cache->reg_list[i].value, 0, 32));
    }
 
    /* send PC */
    retval = xscale_send_u32(target,
            buf_get_u32(arm->pc->value, 0, 32));
    if (retval != ERROR_OK)
        return retval;
    LOG_DEBUG("wrote PC with value 0x%8.8" PRIx32,
        buf_get_u32(arm->pc->value, 0, 32));
 
    target_call_event_callbacks(target, TARGET_EVENT_RESUMED);
 
    /* registers are now invalid */
    register_cache_invalidate(arm->core_cache);
 
    /* wait for and process debug entry */
    retval = xscale_debug_entry(target);
    if (retval != ERROR_OK)
        return retval;
 
    LOG_DEBUG("disable single-step");
    retval = xscale_disable_single_step(target);
    if (retval != ERROR_OK)
        return retval;
 
    target_call_event_callbacks(target, TARGET_EVENT_HALTED);
 
    return ERROR_OK;
}
 
static int xscale_step(struct target *target, int current,
    target_addr_t address, int handle_breakpoints)
{
    struct arm *arm = target_to_arm(target);
    struct breakpoint *breakpoint = NULL;
 
    uint32_t current_pc;
    int retval;
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* current = 1: continue on current pc, otherwise continue at <address> */
    if (!current)
        buf_set_u32(arm->pc->value, 0, 32, address);
 
    current_pc = buf_get_u32(arm->pc->value, 0, 32);
 
    /* if we're at the reset vector, we have to simulate the step */
    if (current_pc == 0x0) {
        retval = arm_simulate_step(target, NULL);
        if (retval != ERROR_OK)
            return retval;
        current_pc = buf_get_u32(arm->pc->value, 0, 32);
        LOG_DEBUG("current pc %" PRIx32, current_pc);
 
        target->debug_reason = DBG_REASON_SINGLESTEP;
        target_call_event_callbacks(target, TARGET_EVENT_HALTED);
 
        return ERROR_OK;
    }
 
    /* the front-end may request us not to handle breakpoints */
    if (handle_breakpoints)
        breakpoint = breakpoint_find(target,
                buf_get_u32(arm->pc->value, 0, 32));
    if (breakpoint) {
        retval = xscale_unset_breakpoint(target, breakpoint);
        if (retval != ERROR_OK)
            return retval;
    }
 
    retval = xscale_step_inner(target, current, address, handle_breakpoints);
    if (retval != ERROR_OK)
        return retval;
 
    if (breakpoint)
        xscale_set_breakpoint(target, breakpoint);
 
    LOG_DEBUG("target stepped");
 
    return ERROR_OK;
 
}
 
static int xscale_assert_reset(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    /* TODO: apply hw reset signal in not examined state */
    if (!(target_was_examined(target))) {
        LOG_WARNING("Reset is not asserted because the target is not examined.");
        LOG_WARNING("Use a reset button or power cycle the target.");
        return ERROR_TARGET_NOT_EXAMINED;
    }
 
    LOG_DEBUG("target->state: %s",
        target_state_name(target));
 
    /* assert reset */
    jtag_add_reset(0, 1);
 
    /* sleep 1ms, to be sure we fulfill any requirements */
    jtag_add_sleep(1000);
    jtag_execute_queue();
 
    /* select DCSR instruction (set endstate to R-T-I to ensure we don't
     * end up in T-L-R, which would reset JTAG
     */
    xscale_jtag_set_instr(target->tap,
        XSCALE_SELDCSR << xscale->xscale_variant,
        TAP_IDLE);
 
    /* set Hold reset, Halt mode and Trap Reset */
    buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 30, 1, 0x1);
    buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 16, 1, 0x1);
    xscale_write_dcsr(target, 1, 0);
 
    /* select BYPASS, because having DCSR selected caused problems on the PXA27x */
    xscale_jtag_set_instr(target->tap, ~0, TAP_IDLE);
    jtag_execute_queue();
 
    target->state = TARGET_RESET;
 
    if (target->reset_halt) {
        int retval = target_halt(target);
        if (retval != ERROR_OK)
            return retval;
    }
 
    return ERROR_OK;
}
 
static int xscale_deassert_reset(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct breakpoint *breakpoint = target->breakpoints;
 
    LOG_DEBUG("-");
 
    xscale->ibcr_available = 2;
    xscale->ibcr0_used = 0;
    xscale->ibcr1_used = 0;
 
    xscale->dbr_available = 2;
    xscale->dbr0_used = 0;
    xscale->dbr1_used = 0;
 
    /* mark all hardware breakpoints as unset */
    while (breakpoint) {
        if (breakpoint->type == BKPT_HARD)
            breakpoint->is_set = false;
        breakpoint = breakpoint->next;
    }
 
    xscale->trace.mode = XSCALE_TRACE_DISABLED;
    xscale_free_trace_data(xscale);
 
    register_cache_invalidate(xscale->arm.core_cache);
 
    /* FIXME mark hardware watchpoints got unset too.  Also,
     * at least some of the XScale registers are invalid...
     */
 
    /*
     * REVISIT:  *assumes* we had a SRST+TRST reset so the mini-icache
     * contents got invalidated.  Safer to force that, so writing new
     * contents can't ever fail..
     */
    {
        uint32_t address;
        unsigned buf_cnt;
        const uint8_t *buffer = xscale_debug_handler;
        int retval;
 
        /* release SRST */
        jtag_add_reset(0, 0);
 
        /* wait 300ms; 150 and 100ms were not enough */
        jtag_add_sleep(300*1000);
 
        jtag_add_runtest(2030, TAP_IDLE);
        jtag_execute_queue();
 
        /* set Hold reset, Halt mode and Trap Reset */
        buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 30, 1, 0x1);
        buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 16, 1, 0x1);
        xscale_write_dcsr(target, 1, 0);
 
        /* Load the debug handler into the mini-icache.  Since
         * it's using halt mode (not monitor mode), it runs in
         * "Special Debug State" for access to registers, memory,
         * coprocessors, trace data, etc.
         */
        address = xscale->handler_address;
        for (unsigned binary_size = sizeof(xscale_debug_handler);
            binary_size > 0;
            binary_size -= buf_cnt, buffer += buf_cnt) {
            uint32_t cache_line[8];
            unsigned i;
 
            buf_cnt = binary_size;
            if (buf_cnt > 32)
                buf_cnt = 32;
 
            for (i = 0; i < buf_cnt; i += 4) {
                /* convert LE buffer to host-endian uint32_t */
                cache_line[i / 4] = le_to_h_u32(&buffer[i]);
            }
 
            for (; i < 32; i += 4)
                cache_line[i / 4] = 0xe1a08008;
 
            /* only load addresses other than the reset vectors */
            if ((address % 0x400) != 0x0) {
                retval = xscale_load_ic(target, address,
                        cache_line);
                if (retval != ERROR_OK)
                    return retval;
            }
 
            address += buf_cnt;
        }
 
        retval = xscale_load_ic(target, 0x0,
                xscale->low_vectors);
        if (retval != ERROR_OK)
            return retval;
        retval = xscale_load_ic(target, 0xffff0000,
                xscale->high_vectors);
        if (retval != ERROR_OK)
            return retval;
 
        jtag_add_runtest(30, TAP_IDLE);
 
        jtag_add_sleep(100000);
 
        /* set Hold reset, Halt mode and Trap Reset */
        buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 30, 1, 0x1);
        buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 16, 1, 0x1);
        xscale_write_dcsr(target, 1, 0);
 
        /* clear Hold reset to let the target run (should enter debug handler) */
        xscale_write_dcsr(target, 0, 1);
        target->state = TARGET_RUNNING;
 
        if (!target->reset_halt) {
            jtag_add_sleep(10000);
 
            /* we should have entered debug now */
            xscale_debug_entry(target);
            target->state = TARGET_HALTED;
 
            /* resume the target */
            xscale_resume(target, 1, 0x0, 1, 0);
        }
    }
 
    return ERROR_OK;
}
 
static int xscale_read_core_reg(struct target *target, struct reg *r,
    int num, enum arm_mode mode)
{
    LOG_ERROR("not implemented");
    return ERROR_OK;
}
 
static int xscale_write_core_reg(struct target *target, struct reg *r,
    int num, enum arm_mode mode, uint8_t *value)
{
    LOG_ERROR("not implemented");
    return ERROR_OK;
}
 
static int xscale_full_context(struct target *target)
{
    struct arm *arm = target_to_arm(target);
 
    uint32_t *buffer;
 
    int i, j;
 
    LOG_DEBUG("-");
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    buffer = malloc(4 * 8);
 
    /* iterate through processor modes (FIQ, IRQ, SVC, ABT, UND and SYS)
     * we can't enter User mode on an XScale (unpredictable),
     * but User shares registers with SYS
     */
    for (i = 1; i < 7; i++) {
        enum arm_mode mode = armv4_5_number_to_mode(i);
        bool valid = true;
        struct reg *r;
 
        if (mode == ARM_MODE_USR)
            continue;
 
        /* check if there are invalid registers in the current mode
         */
        for (j = 0; valid && j <= 16; j++) {
            if (!ARMV4_5_CORE_REG_MODE(arm->core_cache,
                mode, j).valid)
                valid = false;
        }
        if (valid)
            continue;
 
        /* request banked registers */
        xscale_send_u32(target, 0x0);
 
        /* send CPSR for desired bank mode */
        xscale_send_u32(target, mode | 0xc0 /* I/F bits */);
 
        /* get banked registers:  r8 to r14; and SPSR
         * except in USR/SYS mode
         */
        if (mode != ARM_MODE_SYS) {
            /* SPSR */
            r = &ARMV4_5_CORE_REG_MODE(arm->core_cache,
                    mode, 16);
 
            xscale_receive(target, buffer, 8);
 
            buf_set_u32(r->value, 0, 32, buffer[7]);
            r->dirty = false;
            r->valid = true;
        } else
            xscale_receive(target, buffer, 7);
 
        /* move data from buffer to register cache */
        for (j = 8; j <= 14; j++) {
            r = &ARMV4_5_CORE_REG_MODE(arm->core_cache,
                    mode, j);
 
            buf_set_u32(r->value, 0, 32, buffer[j - 8]);
            r->dirty = false;
            r->valid = true;
        }
    }
 
    free(buffer);
 
    return ERROR_OK;
}
 
static int xscale_restore_banked(struct target *target)
{
    struct arm *arm = target_to_arm(target);
 
    int i, j;
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* iterate through processor modes (FIQ, IRQ, SVC, ABT, UND and SYS)
     * and check if any banked registers need to be written.  Ignore
     * USR mode (number 0) in favor of SYS; we can't enter User mode on
     * an XScale (unpredictable), but they share all registers.
     */
    for (i = 1; i < 7; i++) {
        enum arm_mode mode = armv4_5_number_to_mode(i);
        struct reg *r;
 
        if (mode == ARM_MODE_USR)
            continue;
 
        /* check if there are dirty registers in this mode */
        for (j = 8; j <= 14; j++) {
            if (ARMV4_5_CORE_REG_MODE(arm->core_cache,
                mode, j).dirty)
                goto dirty;
        }
 
        /* if not USR/SYS, check if the SPSR needs to be written */
        if (mode != ARM_MODE_SYS) {
            if (ARMV4_5_CORE_REG_MODE(arm->core_cache,
                mode, 16).dirty)
                goto dirty;
        }
 
        /* there's nothing to flush for this mode */
        continue;
 
dirty:
        /* command 0x1:  "send banked registers" */
        xscale_send_u32(target, 0x1);
 
        /* send CPSR for desired mode */
        xscale_send_u32(target, mode | 0xc0 /* I/F bits */);
 
        /* send r8 to r14/lr ... only FIQ needs more than r13..r14,
         * but this protocol doesn't understand that nuance.
         */
        for (j = 8; j <= 14; j++) {
            r = &ARMV4_5_CORE_REG_MODE(arm->core_cache,
                    mode, j);
            xscale_send_u32(target, buf_get_u32(r->value, 0, 32));
            r->dirty = false;
        }
 
        /* send spsr if not in USR/SYS mode */
        if (mode != ARM_MODE_SYS) {
            r = &ARMV4_5_CORE_REG_MODE(arm->core_cache,
                    mode, 16);
            xscale_send_u32(target, buf_get_u32(r->value, 0, 32));
            r->dirty = false;
        }
    }
 
    return ERROR_OK;
}
 
static int xscale_read_memory(struct target *target, target_addr_t address,
    uint32_t size, uint32_t count, uint8_t *buffer)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t *buf32;
    uint32_t i;
    int retval;
 
    LOG_DEBUG("address: " TARGET_ADDR_FMT ", size: 0x%8.8" PRIx32 ", count: 0x%8.8" PRIx32,
        address,
        size,
        count);
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* sanitize arguments */
    if (((size != 4) && (size != 2) && (size != 1)) || (count == 0) || !(buffer))
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (((size == 4) && (address & 0x3u)) || ((size == 2) && (address & 0x1u)))
        return ERROR_TARGET_UNALIGNED_ACCESS;
 
    /* send memory read request (command 0x1n, n: access size) */
    retval = xscale_send_u32(target, 0x10 | size);
    if (retval != ERROR_OK)
        return retval;
 
    /* send base address for read request */
    retval = xscale_send_u32(target, address);
    if (retval != ERROR_OK)
        return retval;
 
    /* send number of requested data words */
    retval = xscale_send_u32(target, count);
    if (retval != ERROR_OK)
        return retval;
 
    /* receive data from target (count times 32-bit words in host endianness) */
    buf32 = malloc(4 * count);
    retval = xscale_receive(target, buf32, count);
    if (retval != ERROR_OK) {
        free(buf32);
        return retval;
    }
 
    /* extract data from host-endian buffer into byte stream */
    for (i = 0; i < count; i++) {
        switch (size) {
            case 4:
                target_buffer_set_u32(target, buffer, buf32[i]);
                buffer += 4;
                break;
            case 2:
                target_buffer_set_u16(target, buffer, buf32[i] & 0xffff);
                buffer += 2;
                break;
            case 1:
                *buffer++ = buf32[i] & 0xff;
                break;
            default:
                LOG_ERROR("invalid read size");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
    }
 
    free(buf32);
 
    /* examine DCSR, to see if Sticky Abort (SA) got set */
    retval = xscale_read_dcsr(target);
    if (retval != ERROR_OK)
        return retval;
    if (buf_get_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 5, 1) == 1) {
        /* clear SA bit */
        retval = xscale_send_u32(target, 0x60);
        if (retval != ERROR_OK)
            return retval;
 
        return ERROR_TARGET_DATA_ABORT;
    }
 
    return ERROR_OK;
}
 
static int xscale_read_phys_memory(struct target *target, target_addr_t address,
    uint32_t size, uint32_t count, uint8_t *buffer)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    /* with MMU inactive, there are only physical addresses */
    if (!xscale->armv4_5_mmu.mmu_enabled)
        return xscale_read_memory(target, address, size, count, buffer);
 
    LOG_ERROR("%s: %s is not implemented.  Disable MMU?",
        target_name(target), __func__);
    return ERROR_FAIL;
}
 
static int xscale_write_memory(struct target *target, target_addr_t address,
    uint32_t size, uint32_t count, const uint8_t *buffer)
{
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
 
    LOG_DEBUG("address: " TARGET_ADDR_FMT ", size: 0x%8.8" PRIx32 ", count: 0x%8.8" PRIx32,
        address,
        size,
        count);
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* sanitize arguments */
    if (((size != 4) && (size != 2) && (size != 1)) || (count == 0) || !(buffer))
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    if (((size == 4) && (address & 0x3u)) || ((size == 2) && (address & 0x1u)))
        return ERROR_TARGET_UNALIGNED_ACCESS;
 
    /* send memory write request (command 0x2n, n: access size) */
    retval = xscale_send_u32(target, 0x20 | size);
    if (retval != ERROR_OK)
        return retval;
 
    /* send base address for read request */
    retval = xscale_send_u32(target, address);
    if (retval != ERROR_OK)
        return retval;
 
    /* send number of requested data words to be written*/
    retval = xscale_send_u32(target, count);
    if (retval != ERROR_OK)
        return retval;
 
    /* extract data from host-endian buffer into byte stream */
#if 0
    for (i = 0; i < count; i++) {
        switch (size) {
            case 4:
                value = target_buffer_get_u32(target, buffer);
                xscale_send_u32(target, value);
                buffer += 4;
                break;
            case 2:
                value = target_buffer_get_u16(target, buffer);
                xscale_send_u32(target, value);
                buffer += 2;
                break;
            case 1:
                value = *buffer;
                xscale_send_u32(target, value);
                buffer += 1;
                break;
            default:
                LOG_ERROR("should never get here");
                exit(-1);
        }
    }
#endif
    retval = xscale_send(target, buffer, count, size);
    if (retval != ERROR_OK)
        return retval;
 
    /* examine DCSR, to see if Sticky Abort (SA) got set */
    retval = xscale_read_dcsr(target);
    if (retval != ERROR_OK)
        return retval;
    if (buf_get_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 5, 1) == 1) {
        /* clear SA bit */
        retval = xscale_send_u32(target, 0x60);
        if (retval != ERROR_OK)
            return retval;
 
        LOG_ERROR("data abort writing memory");
        return ERROR_TARGET_DATA_ABORT;
    }
 
    return ERROR_OK;
}
 
static int xscale_write_phys_memory(struct target *target, target_addr_t address,
    uint32_t size, uint32_t count, const uint8_t *buffer)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    /* with MMU inactive, there are only physical addresses */
    if (!xscale->armv4_5_mmu.mmu_enabled)
        return xscale_write_memory(target, address, size, count, buffer);
 
    LOG_ERROR("%s: %s is not implemented.  Disable MMU?",
        target_name(target), __func__);
    return ERROR_FAIL;
}
 
static int xscale_get_ttb(struct target *target, uint32_t *result)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t ttb;
    int retval;
 
    retval = xscale_get_reg(&xscale->reg_cache->reg_list[XSCALE_TTB]);
    if (retval != ERROR_OK)
        return retval;
    ttb = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_TTB].value, 0, 32);
 
    *result = ttb;
 
    return ERROR_OK;
}
 
static int xscale_disable_mmu_caches(struct target *target, int mmu,
    int d_u_cache, int i_cache)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t cp15_control;
    int retval;
 
    /* read cp15 control register */
    retval = xscale_get_reg(&xscale->reg_cache->reg_list[XSCALE_CTRL]);
    if (retval != ERROR_OK)
        return retval;
    cp15_control = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_CTRL].value, 0, 32);
 
    if (mmu)
        cp15_control &= ~0x1U;
 
    if (d_u_cache) {
        /* clean DCache */
        retval = xscale_send_u32(target, 0x50);
        if (retval != ERROR_OK)
            return retval;
        retval = xscale_send_u32(target, xscale->cache_clean_address);
        if (retval != ERROR_OK)
            return retval;
 
        /* invalidate DCache */
        retval = xscale_send_u32(target, 0x51);
        if (retval != ERROR_OK)
            return retval;
 
        cp15_control &= ~0x4U;
    }
 
    if (i_cache) {
        /* invalidate ICache */
        retval = xscale_send_u32(target, 0x52);
        if (retval != ERROR_OK)
            return retval;
        cp15_control &= ~0x1000U;
    }
 
    /* write new cp15 control register */
    retval = xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_CTRL], cp15_control);
    if (retval != ERROR_OK)
        return retval;
 
    /* execute cpwait to ensure outstanding operations complete */
    retval = xscale_send_u32(target, 0x53);
    return retval;
}
 
static int xscale_enable_mmu_caches(struct target *target, int mmu,
    int d_u_cache, int i_cache)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t cp15_control;
    int retval;
 
    /* read cp15 control register */
    retval = xscale_get_reg(&xscale->reg_cache->reg_list[XSCALE_CTRL]);
    if (retval != ERROR_OK)
        return retval;
    cp15_control = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_CTRL].value, 0, 32);
 
    if (mmu)
        cp15_control |= 0x1U;
 
    if (d_u_cache)
        cp15_control |= 0x4U;
 
    if (i_cache)
        cp15_control |= 0x1000U;
 
    /* write new cp15 control register */
    retval = xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_CTRL], cp15_control);
    if (retval != ERROR_OK)
        return retval;
 
    /* execute cpwait to ensure outstanding operations complete */
    retval = xscale_send_u32(target, 0x53);
    return retval;
}
 
static int xscale_set_breakpoint(struct target *target,
    struct breakpoint *breakpoint)
{
    int retval;
    struct xscale_common *xscale = target_to_xscale(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (breakpoint->is_set) {
        LOG_WARNING("breakpoint already set");
        return ERROR_OK;
    }
 
    if (breakpoint->type == BKPT_HARD) {
        uint32_t value = breakpoint->address | 1;
        if (!xscale->ibcr0_used) {
            xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_IBCR0], value);
            xscale->ibcr0_used = 1;
            /* breakpoint set on first breakpoint register */
            breakpoint_hw_set(breakpoint, 0);
        } else if (!xscale->ibcr1_used) {
            xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_IBCR1], value);
            xscale->ibcr1_used = 1;
            /* breakpoint set on second breakpoint register */
            breakpoint_hw_set(breakpoint, 1);
        } else {/* bug: availability previously verified in xscale_add_breakpoint() */
            LOG_ERROR("BUG: no hardware comparator available");
            return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
    } else if (breakpoint->type == BKPT_SOFT) {
        if (breakpoint->length == 4) {
            /* keep the original instruction in target endianness */
            retval = target_read_memory(target, breakpoint->address, 4, 1,
                    breakpoint->orig_instr);
            if (retval != ERROR_OK)
                return retval;
            /* write the bkpt instruction in target endianness
             *(arm7_9->arm_bkpt is host endian) */
            retval = target_write_u32(target, breakpoint->address,
                    xscale->arm_bkpt);
            if (retval != ERROR_OK)
                return retval;
        } else {
            /* keep the original instruction in target endianness */
            retval = target_read_memory(target, breakpoint->address, 2, 1,
                    breakpoint->orig_instr);
            if (retval != ERROR_OK)
                return retval;
            /* write the bkpt instruction in target endianness
             *(arm7_9->arm_bkpt is host endian) */
            retval = target_write_u16(target, breakpoint->address,
                    xscale->thumb_bkpt);
            if (retval != ERROR_OK)
                return retval;
        }
        breakpoint->is_set = true;
 
        xscale_send_u32(target, 0x50);  /* clean dcache */
        xscale_send_u32(target, xscale->cache_clean_address);
        xscale_send_u32(target, 0x51);  /* invalidate dcache */
        xscale_send_u32(target, 0x52);  /* invalidate icache and flush fetch buffers */
    }
 
    return ERROR_OK;
}
 
static int xscale_add_breakpoint(struct target *target,
    struct breakpoint *breakpoint)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    if ((breakpoint->type == BKPT_HARD) && (xscale->ibcr_available < 1)) {
        LOG_ERROR("no breakpoint unit available for hardware breakpoint");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    if ((breakpoint->length != 2) && (breakpoint->length != 4)) {
        LOG_ERROR("only breakpoints of two (Thumb) or four (ARM) bytes length supported");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    if (breakpoint->type == BKPT_HARD)
        xscale->ibcr_available--;
 
    return xscale_set_breakpoint(target, breakpoint);
}
 
static int xscale_unset_breakpoint(struct target *target,
    struct breakpoint *breakpoint)
{
    int retval;
    struct xscale_common *xscale = target_to_xscale(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (!breakpoint->is_set) {
        LOG_WARNING("breakpoint not set");
        return ERROR_OK;
    }
 
    if (breakpoint->type == BKPT_HARD) {
        if (breakpoint->number == 0) {
            xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_IBCR0], 0x0);
            xscale->ibcr0_used = 0;
        } else if (breakpoint->number == 1) {
            xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_IBCR1], 0x0);
            xscale->ibcr1_used = 0;
        }
        breakpoint->is_set = false;
    } else {
        /* restore original instruction (kept in target endianness) */
        if (breakpoint->length == 4) {
            retval = target_write_memory(target, breakpoint->address, 4, 1,
                    breakpoint->orig_instr);
            if (retval != ERROR_OK)
                return retval;
        } else {
            retval = target_write_memory(target, breakpoint->address, 2, 1,
                    breakpoint->orig_instr);
            if (retval != ERROR_OK)
                return retval;
        }
        breakpoint->is_set = false;
 
        xscale_send_u32(target, 0x50);  /* clean dcache */
        xscale_send_u32(target, xscale->cache_clean_address);
        xscale_send_u32(target, 0x51);  /* invalidate dcache */
        xscale_send_u32(target, 0x52);  /* invalidate icache and flush fetch buffers */
    }
 
    return ERROR_OK;
}
 
static int xscale_remove_breakpoint(struct target *target, struct breakpoint *breakpoint)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (breakpoint->is_set)
        xscale_unset_breakpoint(target, breakpoint);
 
    if (breakpoint->type == BKPT_HARD)
        xscale->ibcr_available++;
 
    return ERROR_OK;
}
 
static int xscale_set_watchpoint(struct target *target,
    struct watchpoint *watchpoint)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t enable = 0;
    struct reg *dbcon = &xscale->reg_cache->reg_list[XSCALE_DBCON];
    uint32_t dbcon_value = buf_get_u32(dbcon->value, 0, 32);
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    switch (watchpoint->rw) {
        case WPT_READ:
            enable = 0x3;
            break;
        case WPT_ACCESS:
            enable = 0x2;
            break;
        case WPT_WRITE:
            enable = 0x1;
            break;
        default:
            LOG_ERROR("BUG: watchpoint->rw neither read, write nor access");
    }
 
    /* For watchpoint across more than one word, both DBR registers must
       be enlisted, with the second used as a mask. */
    if (watchpoint->length > 4) {
        if (xscale->dbr0_used || xscale->dbr1_used) {
            LOG_ERROR("BUG: sufficient hardware comparators unavailable");
            return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
        }
 
        /* Write mask value to DBR1, based on the length argument.
         * Address bits ignored by the comparator are those set in mask. */
        xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_DBR1],
            watchpoint->length - 1);
        xscale->dbr1_used = 1;
        enable |= 0x100;        /* DBCON[M] */
    }
 
    if (!xscale->dbr0_used) {
        xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_DBR0], watchpoint->address);
        dbcon_value |= enable;
        xscale_set_reg_u32(dbcon, dbcon_value);
        watchpoint_set(watchpoint, 0);
        xscale->dbr0_used = 1;
    } else if (!xscale->dbr1_used) {
        xscale_set_reg_u32(&xscale->reg_cache->reg_list[XSCALE_DBR1], watchpoint->address);
        dbcon_value |= enable << 2;
        xscale_set_reg_u32(dbcon, dbcon_value);
        watchpoint_set(watchpoint, 1);
        xscale->dbr1_used = 1;
    } else {
        LOG_ERROR("BUG: no hardware comparator available");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    return ERROR_OK;
}
 
static int xscale_add_watchpoint(struct target *target,
    struct watchpoint *watchpoint)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    if (xscale->dbr_available < 1) {
        LOG_ERROR("no more watchpoint registers available");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    if (watchpoint->value)
        LOG_WARNING("xscale does not support value, mask arguments; ignoring");
 
    /* check that length is a power of two */
    for (uint32_t len = watchpoint->length; len != 1; len /= 2) {
        if (len % 2) {
            LOG_ERROR("xscale requires that watchpoint length is a power of two");
            return ERROR_COMMAND_ARGUMENT_INVALID;
        }
    }
 
    if (watchpoint->length == 4) {  /* single word watchpoint */
        xscale->dbr_available--;/* one DBR reg used */
        return ERROR_OK;
    }
 
    /* watchpoints across multiple words require both DBR registers */
    if (xscale->dbr_available < 2) {
        LOG_ERROR("insufficient watchpoint registers available");
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
    }
 
    if (watchpoint->length > watchpoint->address) {
        LOG_ERROR("xscale does not support watchpoints with length "
            "greater than address");
        return ERROR_COMMAND_ARGUMENT_INVALID;
    }
 
    xscale->dbr_available = 0;
    return ERROR_OK;
}
 
static int xscale_unset_watchpoint(struct target *target,
    struct watchpoint *watchpoint)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct reg *dbcon = &xscale->reg_cache->reg_list[XSCALE_DBCON];
    uint32_t dbcon_value = buf_get_u32(dbcon->value, 0, 32);
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (!watchpoint->is_set) {
        LOG_WARNING("breakpoint not set");
        return ERROR_OK;
    }
 
    if (watchpoint->number == 0) {
        if (watchpoint->length > 4) {
            dbcon_value &= ~0x103;  /* clear DBCON[M] as well */
            xscale->dbr1_used = 0;  /* DBR1 was used for mask */
        } else
            dbcon_value &= ~0x3;
 
        xscale_set_reg_u32(dbcon, dbcon_value);
        xscale->dbr0_used = 0;
    } else if (watchpoint->number == 1) {
        dbcon_value &= ~0xc;
        xscale_set_reg_u32(dbcon, dbcon_value);
        xscale->dbr1_used = 0;
    }
    watchpoint->is_set = false;
 
    return ERROR_OK;
}
 
static int xscale_remove_watchpoint(struct target *target, struct watchpoint *watchpoint)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("target not halted");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    if (watchpoint->is_set)
        xscale_unset_watchpoint(target, watchpoint);
 
    if (watchpoint->length > 4)
        xscale->dbr_available++;/* both DBR regs now available */
 
    xscale->dbr_available++;
 
    return ERROR_OK;
}
 
static int xscale_get_reg(struct reg *reg)
{
    struct xscale_reg *arch_info = reg->arch_info;
    struct target *target = arch_info->target;
    struct xscale_common *xscale = target_to_xscale(target);
 
    /* DCSR, TX and RX are accessible via JTAG */
    if (strcmp(reg->name, "XSCALE_DCSR") == 0)
        return xscale_read_dcsr(arch_info->target);
    else if (strcmp(reg->name, "XSCALE_TX") == 0) {
        /* 1 = consume register content */
        return xscale_read_tx(arch_info->target, 1);
    } else if (strcmp(reg->name, "XSCALE_RX") == 0) {
        /* can't read from RX register (host -> debug handler) */
        return ERROR_OK;
    } else if (strcmp(reg->name, "XSCALE_TXRXCTRL") == 0) {
        /* can't (explicitly) read from TXRXCTRL register */
        return ERROR_OK;
    } else {/* Other DBG registers have to be transferred by the debug handler
         * send CP read request (command 0x40) */
        xscale_send_u32(target, 0x40);
 
        /* send CP register number */
        xscale_send_u32(target, arch_info->dbg_handler_number);
 
        /* read register value */
        xscale_read_tx(target, 1);
        buf_cpy(xscale->reg_cache->reg_list[XSCALE_TX].value, reg->value, 32);
 
        reg->dirty = false;
        reg->valid = true;
    }
 
    return ERROR_OK;
}
 
static int xscale_set_reg(struct reg *reg, uint8_t *buf)
{
    struct xscale_reg *arch_info = reg->arch_info;
    struct target *target = arch_info->target;
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t value = buf_get_u32(buf, 0, 32);
 
    /* DCSR, TX and RX are accessible via JTAG */
    if (strcmp(reg->name, "XSCALE_DCSR") == 0) {
        buf_set_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 0, 32, value);
        return xscale_write_dcsr(arch_info->target, -1, -1);
    } else if (strcmp(reg->name, "XSCALE_RX") == 0) {
        buf_set_u32(xscale->reg_cache->reg_list[XSCALE_RX].value, 0, 32, value);
        return xscale_write_rx(arch_info->target);
    } else if (strcmp(reg->name, "XSCALE_TX") == 0) {
        /* can't write to TX register (debug-handler -> host) */
        return ERROR_OK;
    } else if (strcmp(reg->name, "XSCALE_TXRXCTRL") == 0) {
        /* can't (explicitly) write to TXRXCTRL register */
        return ERROR_OK;
    } else {/* Other DBG registers have to be transferred by the debug handler
         * send CP write request (command 0x41) */
        xscale_send_u32(target, 0x41);
 
        /* send CP register number */
        xscale_send_u32(target, arch_info->dbg_handler_number);
 
        /* send CP register value */
        xscale_send_u32(target, value);
        buf_set_u32(reg->value, 0, 32, value);
    }
 
    return ERROR_OK;
}
 
static int xscale_write_dcsr_sw(struct target *target, uint32_t value)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct reg *dcsr = &xscale->reg_cache->reg_list[XSCALE_DCSR];
    struct xscale_reg *dcsr_arch_info = dcsr->arch_info;
 
    /* send CP write request (command 0x41) */
    xscale_send_u32(target, 0x41);
 
    /* send CP register number */
    xscale_send_u32(target, dcsr_arch_info->dbg_handler_number);
 
    /* send CP register value */
    xscale_send_u32(target, value);
    buf_set_u32(dcsr->value, 0, 32, value);
 
    return ERROR_OK;
}
 
static int xscale_read_trace(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct arm *arm = &xscale->arm;
    struct xscale_trace_data **trace_data_p;
 
    /* 258 words from debug handler
     * 256 trace buffer entries
     * 2 checkpoint addresses
     */
    uint32_t trace_buffer[258];
    int is_address[256];
    int i, j;
    unsigned int num_checkpoints = 0;
 
    if (target->state != TARGET_HALTED) {
        LOG_WARNING("target must be stopped to read trace data");
        return ERROR_TARGET_NOT_HALTED;
    }
 
    /* send read trace buffer command (command 0x61) */
    xscale_send_u32(target, 0x61);
 
    /* receive trace buffer content */
    xscale_receive(target, trace_buffer, 258);
 
    /* parse buffer backwards to identify address entries */
    for (i = 255; i >= 0; i--) {
        /* also count number of checkpointed entries */
        if ((trace_buffer[i] & 0xe0) == 0xc0)
            num_checkpoints++;
 
        is_address[i] = 0;
        if (((trace_buffer[i] & 0xf0) == 0x90) ||
            ((trace_buffer[i] & 0xf0) == 0xd0)) {
            if (i > 0)
                is_address[--i] = 1;
            if (i > 0)
                is_address[--i] = 1;
            if (i > 0)
                is_address[--i] = 1;
            if (i > 0)
                is_address[--i] = 1;
        }
    }
 
 
    /* search first non-zero entry that is not part of an address */
    for (j = 0; (j < 256) && (trace_buffer[j] == 0) && (!is_address[j]); j++)
        ;
 
    if (j == 256) {
        LOG_DEBUG("no trace data collected");
        return ERROR_XSCALE_NO_TRACE_DATA;
    }
 
    /* account for possible partial address at buffer start (wrap mode only) */
    if (is_address[0]) {    /* first entry is address; complete set of 4? */
        i = 1;
        while (i < 4)
            if (!is_address[i++])
                break;
        if (i < 4)
            j += i;     /* partial address; can't use it */
    }
 
    /* if first valid entry is indirect branch, can't use that either (no address) */
    if (((trace_buffer[j] & 0xf0) == 0x90) || ((trace_buffer[j] & 0xf0) == 0xd0))
        j++;
 
    /* walk linked list to terminating entry */
    for (trace_data_p = &xscale->trace.data; *trace_data_p;
        trace_data_p = &(*trace_data_p)->next)
        ;
 
    *trace_data_p = malloc(sizeof(struct xscale_trace_data));
    (*trace_data_p)->next = NULL;
    (*trace_data_p)->chkpt0 = trace_buffer[256];
    (*trace_data_p)->chkpt1 = trace_buffer[257];
    (*trace_data_p)->last_instruction = buf_get_u32(arm->pc->value, 0, 32);
    (*trace_data_p)->entries = malloc(sizeof(struct xscale_trace_entry) * (256 - j));
    (*trace_data_p)->depth = 256 - j;
    (*trace_data_p)->num_checkpoints = num_checkpoints;
 
    for (i = j; i < 256; i++) {
        (*trace_data_p)->entries[i - j].data = trace_buffer[i];
        if (is_address[i])
            (*trace_data_p)->entries[i - j].type = XSCALE_TRACE_ADDRESS;
        else
            (*trace_data_p)->entries[i - j].type = XSCALE_TRACE_MESSAGE;
    }
 
    return ERROR_OK;
}
 
static int xscale_read_instruction(struct target *target, uint32_t pc,
    struct arm_instruction *instruction)
{
    struct xscale_common *const xscale = target_to_xscale(target);
    int section = -1;
    size_t size_read;
    uint32_t opcode;
    int retval;
 
    if (!xscale->trace.image)
        return ERROR_TRACE_IMAGE_UNAVAILABLE;
 
    /* search for the section the current instruction belongs to */
    for (unsigned int i = 0; i < xscale->trace.image->num_sections; i++) {
        if ((xscale->trace.image->sections[i].base_address <= pc) &&
            (xscale->trace.image->sections[i].base_address +
            xscale->trace.image->sections[i].size > pc)) {
            section = i;
            break;
        }
    }
 
    if (section == -1) {
        /* current instruction couldn't be found in the image */
        return ERROR_TRACE_INSTRUCTION_UNAVAILABLE;
    }
 
    if (xscale->trace.core_state == ARM_STATE_ARM) {
        uint8_t buf[4];
        retval = image_read_section(xscale->trace.image, section,
                pc - xscale->trace.image->sections[section].base_address,
                4, buf, &size_read);
        if (retval != ERROR_OK) {
            LOG_ERROR("error while reading instruction");
            return ERROR_TRACE_INSTRUCTION_UNAVAILABLE;
        }
        opcode = target_buffer_get_u32(target, buf);
        arm_evaluate_opcode(opcode, pc, instruction);
    } else if (xscale->trace.core_state == ARM_STATE_THUMB) {
        uint8_t buf[2];
        retval = image_read_section(xscale->trace.image, section,
                pc - xscale->trace.image->sections[section].base_address,
                2, buf, &size_read);
        if (retval != ERROR_OK) {
            LOG_ERROR("error while reading instruction");
            return ERROR_TRACE_INSTRUCTION_UNAVAILABLE;
        }
        opcode = target_buffer_get_u16(target, buf);
        thumb_evaluate_opcode(opcode, pc, instruction);
    } else {
        LOG_ERROR("BUG: unknown core state encountered");
        exit(-1);
    }
 
    return ERROR_OK;
}
 
/* Extract address encoded into trace data.
 * Write result to address referenced by argument 'target', or 0 if incomplete.  */
static inline void xscale_branch_address(struct xscale_trace_data *trace_data,
    int i, uint32_t *target)
{
    /* if there are less than four entries prior to the indirect branch message
     * we can't extract the address */
    if (i < 4)
        *target = 0;
    else {
        *target = (trace_data->entries[i-1].data) | (trace_data->entries[i-2].data << 8) |
            (trace_data->entries[i-3].data << 16) | (trace_data->entries[i-4].data << 24);
    }
}
 
static inline void xscale_display_instruction(struct target *target, uint32_t pc,
    struct arm_instruction *instruction,
    struct command_invocation *cmd)
{
    int retval = xscale_read_instruction(target, pc, instruction);
    if (retval == ERROR_OK)
        command_print(cmd, "%s", instruction->text);
    else
        command_print(cmd, "0x%8.8" PRIx32 "\t<not found in image>", pc);
}
 
static int xscale_analyze_trace(struct target *target, struct command_invocation *cmd)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct xscale_trace_data *trace_data = xscale->trace.data;
    int i, retval;
    uint32_t breakpoint_pc = 0;
    struct arm_instruction instruction;
    uint32_t current_pc = 0;/* initialized when address determined */
 
    if (!xscale->trace.image)
        LOG_WARNING("No trace image loaded; use 'xscale trace_image'");
 
    /* loop for each trace buffer that was loaded from target */
    while (trace_data) {
        int chkpt = 0;  /* incremented as checkpointed entries found */
        int j;
 
        /* FIXME: set this to correct mode when trace buffer is first enabled */
        xscale->trace.core_state = ARM_STATE_ARM;
 
        /* loop for each entry in this trace buffer */
        for (i = 0; i < trace_data->depth; i++) {
            int exception = 0;
            uint32_t chkpt_reg = 0x0;
            uint32_t branch_target = 0;
            int count;
 
            /* trace entry type is upper nybble of 'message byte' */
            int trace_msg_type = (trace_data->entries[i].data & 0xf0) >> 4;
 
            /* Target addresses of indirect branches are written into buffer
             * before the message byte representing the branch. Skip past it */
            if (trace_data->entries[i].type == XSCALE_TRACE_ADDRESS)
                continue;
 
            switch (trace_msg_type) {
                case 0: /* Exceptions */
                case 1:
                case 2:
                case 3:
                case 4:
                case 5:
                case 6:
                case 7:
                    exception = (trace_data->entries[i].data & 0x70) >> 4;
 
                    /* FIXME: vector table may be at ffff0000 */
                    branch_target = (trace_data->entries[i].data & 0xf0) >> 2;
                    break;
 
                case 8: /* Direct Branch */
                    break;
 
                case 9: /* Indirect Branch */
                    xscale_branch_address(trace_data, i, &branch_target);
                    break;
 
                case 13:    /* Checkpointed Indirect Branch */
                    xscale_branch_address(trace_data, i, &branch_target);
                    if ((trace_data->num_checkpoints == 2) && (chkpt == 0))
                        chkpt_reg = trace_data->chkpt1; /* 2 chkpts, this is
                                         *oldest */
                    else
                        chkpt_reg = trace_data->chkpt0; /* 1 chkpt, or 2 and
                                         *newest */
 
                    chkpt++;
                    break;
 
                case 12:    /* Checkpointed Direct Branch */
                    if ((trace_data->num_checkpoints == 2) && (chkpt == 0))
                        chkpt_reg = trace_data->chkpt1; /* 2 chkpts, this is
                                         *oldest */
                    else
                        chkpt_reg = trace_data->chkpt0; /* 1 chkpt, or 2 and
                                         *newest */
 
                    /* if no current_pc, checkpoint will be starting point */
                    if (current_pc == 0)
                        branch_target = chkpt_reg;
 
                    chkpt++;
                    break;
 
                case 15:/* Roll-over */
                    break;
 
                default:/* Reserved */
                    LOG_WARNING("trace is suspect: invalid trace message byte");
                    continue;
 
            }
 
            /* If we don't have the current_pc yet, but we did get the branch target
             * (either from the trace buffer on indirect branch, or from a checkpoint reg),
             * then we can start displaying instructions at the next iteration, with
             * branch_target as the starting point.
             */
            if (current_pc == 0) {
                current_pc = branch_target; /* remains 0 unless branch_target *obtained */
                continue;
            }
 
            /* We have current_pc.  Read and display the instructions from the image.
             * First, display count instructions (lower nybble of message byte). */
            count = trace_data->entries[i].data & 0x0f;
            for (j = 0; j < count; j++) {
                xscale_display_instruction(target, current_pc, &instruction,
                    cmd);
                current_pc += xscale->trace.core_state == ARM_STATE_ARM ? 4 : 2;
            }
 
            /* An additional instruction is implicitly added to count for
             * rollover and some exceptions: undef, swi, prefetch abort. */
            if ((trace_msg_type == 15) || (exception > 0 && exception < 4)) {
                xscale_display_instruction(target, current_pc, &instruction,
                    cmd);
                current_pc += xscale->trace.core_state == ARM_STATE_ARM ? 4 : 2;
            }
 
            if (trace_msg_type == 15)   /* rollover */
                continue;
 
            if (exception) {
                command_print(cmd, "--- exception %i ---", exception);
                continue;
            }
 
            /* not exception or rollover; next instruction is a branch and is
             * not included in the count */
            xscale_display_instruction(target, current_pc, &instruction, cmd);
 
            /* for direct branches, extract branch destination from instruction */
            if ((trace_msg_type == 8) || (trace_msg_type == 12)) {
                retval = xscale_read_instruction(target, current_pc, &instruction);
                if (retval == ERROR_OK)
                    current_pc = instruction.info.b_bl_bx_blx.target_address;
                else
                    current_pc = 0; /* branch destination unknown */
 
                /* direct branch w/ checkpoint; can also get from checkpoint reg */
                if (trace_msg_type == 12) {
                    if (current_pc == 0)
                        current_pc = chkpt_reg;
                    else if (current_pc != chkpt_reg)   /* sanity check */
                        LOG_WARNING("trace is suspect: checkpoint register "
                            "inconsistent with address from image");
                }
 
                if (current_pc == 0)
                    command_print(cmd, "address unknown");
 
                continue;
            }
 
            /* indirect branch; the branch destination was read from trace buffer */
            if ((trace_msg_type == 9) || (trace_msg_type == 13)) {
                current_pc = branch_target;
 
                /* sanity check (checkpoint reg is redundant) */
                if ((trace_msg_type == 13) && (chkpt_reg != branch_target))
                    LOG_WARNING("trace is suspect: checkpoint register "
                        "inconsistent with address from trace buffer");
            }
 
        }   /* END: for (i = 0; i < trace_data->depth; i++) */
 
        breakpoint_pc = trace_data->last_instruction;   /* used below */
        trace_data = trace_data->next;
 
    }   /* END: while (trace_data) */
 
    /* Finally... display all instructions up to the value of the pc when the
     * debug break occurred (saved when trace data was collected from target).
     * This is necessary because the trace only records execution branches and 16
     * consecutive instructions (rollovers), so last few typically missed.
     */
    if (current_pc == 0)
        return ERROR_OK;/* current_pc was never found */
 
    /* how many instructions remaining? */
    int gap_count = (breakpoint_pc - current_pc) /
        (xscale->trace.core_state == ARM_STATE_ARM ? 4 : 2);
 
    /* should never be negative or over 16, but verify */
    if (gap_count < 0 || gap_count > 16) {
        LOG_WARNING("trace is suspect: excessive gap at end of trace");
        return ERROR_OK;/* bail; large number or negative value no good */
    }
 
    /* display remaining instructions */
    for (i = 0; i < gap_count; i++) {
        xscale_display_instruction(target, current_pc, &instruction, cmd);
        current_pc += xscale->trace.core_state == ARM_STATE_ARM ? 4 : 2;
    }
 
    return ERROR_OK;
}
 
static const struct reg_arch_type xscale_reg_type = {
    .get = xscale_get_reg,
    .set = xscale_set_reg,
};
 
static void xscale_build_reg_cache(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct arm *arm = &xscale->arm;
    struct reg_cache **cache_p = register_get_last_cache_p(&target->reg_cache);
    struct xscale_reg *arch_info = malloc(sizeof(xscale_reg_arch_info));
    int i;
    int num_regs = ARRAY_SIZE(xscale_reg_arch_info);
 
    (*cache_p) = arm_build_reg_cache(target, arm);
 
    (*cache_p)->next = malloc(sizeof(struct reg_cache));
    cache_p = &(*cache_p)->next;
 
    /* fill in values for the xscale reg cache */
    (*cache_p)->name = "XScale registers";
    (*cache_p)->next = NULL;
    (*cache_p)->reg_list = calloc(num_regs, sizeof(struct reg));
    (*cache_p)->num_regs = num_regs;
 
    for (i = 0; i < num_regs; i++) {
        (*cache_p)->reg_list[i].name = xscale_reg_list[i];
        (*cache_p)->reg_list[i].value = calloc(4, 1);
        (*cache_p)->reg_list[i].dirty = false;
        (*cache_p)->reg_list[i].valid = false;
        (*cache_p)->reg_list[i].size = 32;
        (*cache_p)->reg_list[i].arch_info = &arch_info[i];
        (*cache_p)->reg_list[i].type = &xscale_reg_type;
        (*cache_p)->reg_list[i].exist = true;
        arch_info[i] = xscale_reg_arch_info[i];
        arch_info[i].target = target;
    }
 
    xscale->reg_cache = (*cache_p);
}
 
static void xscale_free_reg_cache(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
    struct reg_cache *cache = xscale->reg_cache;
 
    for (unsigned int i = 0; i < ARRAY_SIZE(xscale_reg_arch_info); i++)
        free(cache->reg_list[i].value);
 
    free(cache->reg_list[0].arch_info);
    free(cache->reg_list);
    free(cache);
 
    arm_free_reg_cache(&xscale->arm);
}
 
static int xscale_init_target(struct command_context *cmd_ctx,
    struct target *target)
{
    xscale_build_reg_cache(target);
    return ERROR_OK;
}
 
static void xscale_deinit_target(struct target *target)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    xscale_free_reg_cache(target);
    free(xscale);
}
 
static int xscale_init_arch_info(struct target *target,
    struct xscale_common *xscale, struct jtag_tap *tap)
{
    struct arm *arm;
    uint32_t high_reset_branch, low_reset_branch;
    int i;
 
    arm = &xscale->arm;
 
    /* store architecture specific data */
    xscale->common_magic = XSCALE_COMMON_MAGIC;
 
    /* PXA3xx with 11 bit IR shifts the JTAG instructions */
    if (tap->ir_length == 11)
        xscale->xscale_variant = XSCALE_PXA3XX;
    else
        xscale->xscale_variant = XSCALE_IXP4XX_PXA2XX;
 
    /* the debug handler isn't installed (and thus not running) at this time */
    xscale->handler_address = 0xfe000800;
 
    /* clear the vectors we keep locally for reference */
    memset(xscale->low_vectors, 0, sizeof(xscale->low_vectors));
    memset(xscale->high_vectors, 0, sizeof(xscale->high_vectors));
 
    /* no user-specified vectors have been configured yet */
    xscale->static_low_vectors_set = 0x0;
    xscale->static_high_vectors_set = 0x0;
 
    /* calculate branches to debug handler */
    low_reset_branch = (xscale->handler_address + 0x20 - 0x0 - 0x8) >> 2;
    high_reset_branch = (xscale->handler_address + 0x20 - 0xffff0000 - 0x8) >> 2;
 
    xscale->low_vectors[0] = ARMV4_5_B((low_reset_branch & 0xffffff), 0);
    xscale->high_vectors[0] = ARMV4_5_B((high_reset_branch & 0xffffff), 0);
 
    for (i = 1; i <= 7; i++) {
        xscale->low_vectors[i] = ARMV4_5_B(0xfffffe, 0);
        xscale->high_vectors[i] = ARMV4_5_B(0xfffffe, 0);
    }
 
    /* 64kB aligned region used for DCache cleaning */
    xscale->cache_clean_address = 0xfffe0000;
 
    xscale->hold_rst = 0;
    xscale->external_debug_break = 0;
 
    xscale->ibcr_available = 2;
    xscale->ibcr0_used = 0;
    xscale->ibcr1_used = 0;
 
    xscale->dbr_available = 2;
    xscale->dbr0_used = 0;
    xscale->dbr1_used = 0;
 
    LOG_INFO("%s: hardware has 2 breakpoints and 2 watchpoints",
        target_name(target));
 
    xscale->arm_bkpt = ARMV5_BKPT(0x0);
    xscale->thumb_bkpt = ARMV5_T_BKPT(0x0) & 0xffff;
 
    xscale->vector_catch = 0x1;
 
    xscale->trace.data = NULL;
    xscale->trace.image = NULL;
    xscale->trace.mode = XSCALE_TRACE_DISABLED;
    xscale->trace.buffer_fill = 0;
    xscale->trace.fill_counter = 0;
 
    /* prepare ARMv4/5 specific information */
    arm->arch_info = xscale;
    arm->core_type = ARM_CORE_TYPE_STD;
    arm->read_core_reg = xscale_read_core_reg;
    arm->write_core_reg = xscale_write_core_reg;
    arm->full_context = xscale_full_context;
 
    arm_init_arch_info(target, arm);
 
    xscale->armv4_5_mmu.armv4_5_cache.ctype = -1;
    xscale->armv4_5_mmu.get_ttb = xscale_get_ttb;
    xscale->armv4_5_mmu.read_memory = xscale_read_memory;
    xscale->armv4_5_mmu.write_memory = xscale_write_memory;
    xscale->armv4_5_mmu.disable_mmu_caches = xscale_disable_mmu_caches;
    xscale->armv4_5_mmu.enable_mmu_caches = xscale_enable_mmu_caches;
    xscale->armv4_5_mmu.has_tiny_pages = 1;
    xscale->armv4_5_mmu.mmu_enabled = 0;
 
    return ERROR_OK;
}
 
static int xscale_target_create(struct target *target, Jim_Interp *interp)
{
    struct xscale_common *xscale;
 
    if (sizeof(xscale_debug_handler) > 0x800) {
        LOG_ERROR("debug_handler.bin: larger than 2kb");
        return ERROR_FAIL;
    }
 
    xscale = calloc(1, sizeof(*xscale));
    if (!xscale)
        return ERROR_FAIL;
 
    return xscale_init_arch_info(target, xscale, target->tap);
}
 
COMMAND_HANDLER(xscale_handle_debug_handler_command)
{
    struct target *target = NULL;
    struct xscale_common *xscale;
    int retval;
    uint32_t handler_address;
 
    if (CMD_ARGC < 2)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    target = get_target(CMD_ARGV[0]);
    if (!target) {
        LOG_ERROR("target '%s' not defined", CMD_ARGV[0]);
        return ERROR_FAIL;
    }
 
    xscale = target_to_xscale(target);
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], handler_address);
 
    if (((handler_address >= 0x800) && (handler_address <= 0x1fef800)) ||
        ((handler_address >= 0xfe000800) && (handler_address <= 0xfffff800)))
        xscale->handler_address = handler_address;
    else {
        LOG_ERROR(
            "xscale debug_handler <address> must be between 0x800 and 0x1fef800 or between 0xfe000800 and 0xfffff800");
        return ERROR_FAIL;
    }
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_cache_clean_address_command)
{
    struct target *target = NULL;
    struct xscale_common *xscale;
    int retval;
    uint32_t cache_clean_address;
 
    if (CMD_ARGC < 2)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    target = get_target(CMD_ARGV[0]);
    if (!target) {
        LOG_ERROR("target '%s' not defined", CMD_ARGV[0]);
        return ERROR_FAIL;
    }
    xscale = target_to_xscale(target);
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], cache_clean_address);
 
    if (cache_clean_address & 0xffff)
        LOG_ERROR("xscale cache_clean_address <address> must be 64kb aligned");
    else
        xscale->cache_clean_address = cache_clean_address;
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_cache_info_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    return armv4_5_handle_cache_info_command(CMD, &xscale->armv4_5_mmu.armv4_5_cache);
}
 
static int xscale_virt2phys(struct target *target,
    target_addr_t virtual, target_addr_t *physical)
{
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t cb;
 
    if (xscale->common_magic != XSCALE_COMMON_MAGIC) {
        LOG_ERROR(xscale_not);
        return ERROR_TARGET_INVALID;
    }
 
    uint32_t ret;
    int retval = armv4_5_mmu_translate_va(target, &xscale->armv4_5_mmu,
            virtual, &cb, &ret);
    if (retval != ERROR_OK)
        return retval;
    *physical = ret;
    return ERROR_OK;
}
 
static int xscale_mmu(struct target *target, int *enabled)
{
    struct xscale_common *xscale = target_to_xscale(target);
 
    if (target->state != TARGET_HALTED) {
        LOG_ERROR("Target not halted");
        return ERROR_TARGET_INVALID;
    }
    *enabled = xscale->armv4_5_mmu.mmu_enabled;
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_mmu_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (target->state != TARGET_HALTED) {
        command_print(CMD, "target must be stopped for \"%s\" command", CMD_NAME);
        return ERROR_OK;
    }
 
    if (CMD_ARGC >= 1) {
        bool enable;
        COMMAND_PARSE_ENABLE(CMD_ARGV[0], enable);
        if (enable)
            xscale_enable_mmu_caches(target, 1, 0, 0);
        else
            xscale_disable_mmu_caches(target, 1, 0, 0);
        xscale->armv4_5_mmu.mmu_enabled = enable;
    }
 
    command_print(CMD, "mmu %s",
        (xscale->armv4_5_mmu.mmu_enabled) ? "enabled" : "disabled");
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_idcache_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
 
    int retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (target->state != TARGET_HALTED) {
        command_print(CMD, "target must be stopped for \"%s\" command", CMD_NAME);
        return ERROR_OK;
    }
 
    bool icache = false;
    if (strcmp(CMD_NAME, "icache") == 0)
        icache = true;
    if (CMD_ARGC >= 1) {
        bool enable;
        COMMAND_PARSE_ENABLE(CMD_ARGV[0], enable);
        if (icache) {
            xscale->armv4_5_mmu.armv4_5_cache.i_cache_enabled = enable;
            if (enable)
                xscale_enable_mmu_caches(target, 0, 0, 1);
            else
                xscale_disable_mmu_caches(target, 0, 0, 1);
        } else {
            xscale->armv4_5_mmu.armv4_5_cache.d_u_cache_enabled = enable;
            if (enable)
                xscale_enable_mmu_caches(target, 0, 1, 0);
            else
                xscale_disable_mmu_caches(target, 0, 1, 0);
        }
    }
 
    bool enabled = icache ?
        xscale->armv4_5_mmu.armv4_5_cache.i_cache_enabled :
        xscale->armv4_5_mmu.armv4_5_cache.d_u_cache_enabled;
    const char *msg = enabled ? "enabled" : "disabled";
    command_print(CMD, "%s %s", CMD_NAME, msg);
 
    return ERROR_OK;
}
 
static const struct {
    char name[15];
    unsigned mask;
} vec_ids[] = {
    { "fiq",        DCSR_TF, },
    { "irq",        DCSR_TI, },
    { "dabt",       DCSR_TD, },
    { "pabt",       DCSR_TA, },
    { "swi",        DCSR_TS, },
    { "undef",      DCSR_TU, },
    { "reset",      DCSR_TR, },
};
 
COMMAND_HANDLER(xscale_handle_vector_catch_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
    uint32_t dcsr_value;
    uint32_t catch = 0;
    struct reg *dcsr_reg = &xscale->reg_cache->reg_list[XSCALE_DCSR];
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (CMD_ARGC > 0) {
        if (CMD_ARGC == 1) {
            if (strcmp(CMD_ARGV[0], "all") == 0) {
                catch = DCSR_TRAP_MASK;
                CMD_ARGC--;
            } else if (strcmp(CMD_ARGV[0], "none") == 0) {
                catch = 0;
                CMD_ARGC--;
            }
        }
        while (CMD_ARGC-- > 0) {
            unsigned i;
            for (i = 0; i < ARRAY_SIZE(vec_ids); i++) {
                if (strcmp(CMD_ARGV[CMD_ARGC], vec_ids[i].name))
                    continue;
                catch |= vec_ids[i].mask;
                break;
            }
            if (i == ARRAY_SIZE(vec_ids)) {
                LOG_ERROR("No vector '%s'", CMD_ARGV[CMD_ARGC]);
                return ERROR_COMMAND_SYNTAX_ERROR;
            }
        }
        buf_set_u32(dcsr_reg->value, 0, 32,
                (buf_get_u32(dcsr_reg->value, 0, 32) & ~DCSR_TRAP_MASK) | catch);
        xscale_write_dcsr(target, -1, -1);
    }
 
    dcsr_value = buf_get_u32(dcsr_reg->value, 0, 32);
    for (unsigned i = 0; i < ARRAY_SIZE(vec_ids); i++) {
        command_print(CMD, "%15s: %s", vec_ids[i].name,
            (dcsr_value & vec_ids[i].mask) ? "catch" : "ignore");
    }
 
    return ERROR_OK;
}
 
 
COMMAND_HANDLER(xscale_handle_vector_table_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int err = 0;
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (CMD_ARGC == 0) {    /* print current settings */
        int idx;
 
        command_print(CMD, "active user-set static vectors:");
        for (idx = 1; idx < 8; idx++)
            if (xscale->static_low_vectors_set & (1 << idx))
                command_print(CMD,
                    "low  %d: 0x%" PRIx32,
                    idx,
                    xscale->static_low_vectors[idx]);
        for (idx = 1; idx < 8; idx++)
            if (xscale->static_high_vectors_set & (1 << idx))
                command_print(CMD,
                    "high %d: 0x%" PRIx32,
                    idx,
                    xscale->static_high_vectors[idx]);
        return ERROR_OK;
    }
 
    if (CMD_ARGC != 3)
        err = 1;
    else {
        int idx;
        COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], idx);
        uint32_t vec;
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[2], vec);
 
        if (idx < 1 || idx >= 8)
            err = 1;
 
        if (!err && strcmp(CMD_ARGV[0], "low") == 0) {
            xscale->static_low_vectors_set |= (1<<idx);
            xscale->static_low_vectors[idx] = vec;
        } else if (!err && (strcmp(CMD_ARGV[0], "high") == 0)) {
            xscale->static_high_vectors_set |= (1<<idx);
            xscale->static_high_vectors[idx] = vec;
        } else
            err = 1;
    }
 
    if (err)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    return ERROR_OK;
}
 
 
COMMAND_HANDLER(xscale_handle_trace_buffer_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    uint32_t dcsr_value;
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (target->state != TARGET_HALTED) {
        command_print(CMD, "target must be stopped for \"%s\" command", CMD_NAME);
        return ERROR_OK;
    }
 
    if (CMD_ARGC >= 1) {
        if (strcmp("enable", CMD_ARGV[0]) == 0)
            xscale->trace.mode = XSCALE_TRACE_WRAP; /* default */
        else if (strcmp("disable", CMD_ARGV[0]) == 0)
            xscale->trace.mode = XSCALE_TRACE_DISABLED;
        else
            return ERROR_COMMAND_SYNTAX_ERROR;
    }
 
    if (CMD_ARGC >= 2 && xscale->trace.mode != XSCALE_TRACE_DISABLED) {
        if (strcmp("fill", CMD_ARGV[1]) == 0) {
            int buffcount = 1;      /* default */
            if (CMD_ARGC >= 3)
                COMMAND_PARSE_NUMBER(int, CMD_ARGV[2], buffcount);
            if (buffcount < 1) {        /* invalid */
                command_print(CMD, "fill buffer count must be > 0");
                xscale->trace.mode = XSCALE_TRACE_DISABLED;
                return ERROR_COMMAND_SYNTAX_ERROR;
            }
            xscale->trace.buffer_fill = buffcount;
            xscale->trace.mode = XSCALE_TRACE_FILL;
        } else if (strcmp("wrap", CMD_ARGV[1]) == 0)
            xscale->trace.mode = XSCALE_TRACE_WRAP;
        else {
            xscale->trace.mode = XSCALE_TRACE_DISABLED;
            return ERROR_COMMAND_SYNTAX_ERROR;
        }
    }
 
    if (xscale->trace.mode != XSCALE_TRACE_DISABLED) {
        char fill_string[12];
        sprintf(fill_string, "fill %d", xscale->trace.buffer_fill);
        command_print(CMD, "trace buffer enabled (%s)",
            (xscale->trace.mode == XSCALE_TRACE_FILL)
            ? fill_string : "wrap");
    } else
        command_print(CMD, "trace buffer disabled");
 
    dcsr_value = buf_get_u32(xscale->reg_cache->reg_list[XSCALE_DCSR].value, 0, 32);
    if (xscale->trace.mode == XSCALE_TRACE_FILL)
        xscale_write_dcsr_sw(target, (dcsr_value & 0xfffffffc) | 2);
    else
        xscale_write_dcsr_sw(target, dcsr_value & 0xfffffffc);
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_trace_image_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
 
    if (CMD_ARGC < 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (xscale->trace.image) {
        image_close(xscale->trace.image);
        free(xscale->trace.image);
        command_print(CMD, "previously loaded image found and closed");
    }
 
    xscale->trace.image = malloc(sizeof(struct image));
    xscale->trace.image->base_address_set = false;
    xscale->trace.image->start_address_set = false;
 
    /* a base address isn't always necessary, default to 0x0 (i.e. don't relocate) */
    if (CMD_ARGC >= 2) {
        xscale->trace.image->base_address_set = true;
        COMMAND_PARSE_NUMBER(llong, CMD_ARGV[1], xscale->trace.image->base_address);
    } else
        xscale->trace.image->base_address_set = false;
 
    if (image_open(xscale->trace.image, CMD_ARGV[0],
        (CMD_ARGC >= 3) ? CMD_ARGV[2] : NULL) != ERROR_OK) {
        free(xscale->trace.image);
        xscale->trace.image = NULL;
        return ERROR_OK;
    }
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_dump_trace_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    struct xscale_trace_data *trace_data;
    struct fileio *file;
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (target->state != TARGET_HALTED) {
        command_print(CMD, "target must be stopped for \"%s\" command", CMD_NAME);
        return ERROR_OK;
    }
 
    if (CMD_ARGC < 1)
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    trace_data = xscale->trace.data;
 
    if (!trace_data) {
        command_print(CMD, "no trace data collected");
        return ERROR_OK;
    }
 
    if (fileio_open(&file, CMD_ARGV[0], FILEIO_WRITE, FILEIO_BINARY) != ERROR_OK)
        return ERROR_OK;
 
    while (trace_data) {
        int i;
 
        fileio_write_u32(file, trace_data->chkpt0);
        fileio_write_u32(file, trace_data->chkpt1);
        fileio_write_u32(file, trace_data->last_instruction);
        fileio_write_u32(file, trace_data->depth);
 
        for (i = 0; i < trace_data->depth; i++)
            fileio_write_u32(file, trace_data->entries[i].data |
                ((trace_data->entries[i].type & 0xffff) << 16));
 
        trace_data = trace_data->next;
    }
 
    fileio_close(file);
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_analyze_trace_buffer_command)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    xscale_analyze_trace(target, CMD);
 
    return ERROR_OK;
}
 
COMMAND_HANDLER(xscale_handle_cp15)
{
    struct target *target = get_current_target(CMD_CTX);
    struct xscale_common *xscale = target_to_xscale(target);
    int retval;
 
    retval = xscale_verify_pointer(CMD, xscale);
    if (retval != ERROR_OK)
        return retval;
 
    if (target->state != TARGET_HALTED) {
        command_print(CMD, "target must be stopped for \"%s\" command", CMD_NAME);
        return ERROR_OK;
    }
    uint32_t reg_no = 0;
    struct reg *reg = NULL;
    if (CMD_ARGC > 0) {
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], reg_no);
        /*translate from xscale cp15 register no to openocd register*/
        switch (reg_no) {
            case 0:
                reg_no = XSCALE_MAINID;
                break;
            case 1:
                reg_no = XSCALE_CTRL;
                break;
            case 2:
                reg_no = XSCALE_TTB;
                break;
            case 3:
                reg_no = XSCALE_DAC;
                break;
            case 5:
                reg_no = XSCALE_FSR;
                break;
            case 6:
                reg_no = XSCALE_FAR;
                break;
            case 13:
                reg_no = XSCALE_PID;
                break;
            case 15:
                reg_no = XSCALE_CPACCESS;
                break;
            default:
                command_print(CMD, "invalid register number");
                return ERROR_COMMAND_SYNTAX_ERROR;
        }
        reg = &xscale->reg_cache->reg_list[reg_no];
 
    }
    if (CMD_ARGC == 1) {
        uint32_t value;
 
        /* read cp15 control register */
        xscale_get_reg(reg);
        value = buf_get_u32(reg->value, 0, 32);
        command_print(CMD, "%s (/%i): 0x%" PRIx32 "", reg->name, (int)(reg->size),
            value);
    } else if (CMD_ARGC == 2) {
        uint32_t value;
        COMMAND_PARSE_NUMBER(u32, CMD_ARGV[1], value);
 
        /* send CP write request (command 0x41) */
        xscale_send_u32(target, 0x41);
 
        /* send CP register number */
        xscale_send_u32(target, reg_no);
 
        /* send CP register value */
        xscale_send_u32(target, value);
 
        /* execute cpwait to ensure outstanding operations complete */
        xscale_send_u32(target, 0x53);
    } else
        return ERROR_COMMAND_SYNTAX_ERROR;
 
    return ERROR_OK;
}
 
static const struct command_registration xscale_exec_command_handlers[] = {
    {
        .name = "cache_info",
        .handler = xscale_handle_cache_info_command,
        .mode = COMMAND_EXEC,
        .help = "display information about CPU caches",
        .usage = "",
    },
    {
        .name = "mmu",
        .handler = xscale_handle_mmu_command,
        .mode = COMMAND_EXEC,
        .help = "enable or disable the MMU",
        .usage = "['enable'|'disable']",
    },
    {
        .name = "icache",
        .handler = xscale_handle_idcache_command,
        .mode = COMMAND_EXEC,
        .help = "display ICache state, optionally enabling or "
            "disabling it",
        .usage = "['enable'|'disable']",
    },
    {
        .name = "dcache",
        .handler = xscale_handle_idcache_command,
        .mode = COMMAND_EXEC,
        .help = "display DCache state, optionally enabling or "
            "disabling it",
        .usage = "['enable'|'disable']",
    },
    {
        .name = "vector_catch",
        .handler = xscale_handle_vector_catch_command,
        .mode = COMMAND_EXEC,
        .help = "set or display mask of vectors "
            "that should trigger debug entry",
        .usage = "['all'|'none'|'fiq'|'irq'|'dabt'|'pabt'|'swi'|'undef'|'reset']",
    },
    {
        .name = "vector_table",
        .handler = xscale_handle_vector_table_command,
        .mode = COMMAND_EXEC,
        .help = "set vector table entry in mini-ICache, "
            "or display current tables",
        .usage = "[('high'|'low') index code]",
    },
    {
        .name = "trace_buffer",
        .handler = xscale_handle_trace_buffer_command,
        .mode = COMMAND_EXEC,
        .help = "display trace buffer status, enable or disable "
            "tracing, and optionally reconfigure trace mode",
        .usage = "['enable'|'disable' ['fill' [number]|'wrap']]",
    },
    {
        .name = "dump_trace",
        .handler = xscale_handle_dump_trace_command,
        .mode = COMMAND_EXEC,
        .help = "dump content of trace buffer to file",
        .usage = "filename",
    },
    {
        .name = "analyze_trace",
        .handler = xscale_handle_analyze_trace_buffer_command,
        .mode = COMMAND_EXEC,
        .help = "analyze content of trace buffer",
        .usage = "",
    },
    {
        .name = "trace_image",
        .handler = xscale_handle_trace_image_command,
        .mode = COMMAND_EXEC,
        .help = "load image from file to address (default 0)",
        .usage = "filename [offset [filetype]]",
    },
    {
        .name = "cp15",
        .handler = xscale_handle_cp15,
        .mode = COMMAND_EXEC,
        .help = "Read or write coprocessor 15 register.",
        .usage = "register [value]",
    },
    COMMAND_REGISTRATION_DONE
};
static const struct command_registration xscale_any_command_handlers[] = {
    {
        .name = "debug_handler",
        .handler = xscale_handle_debug_handler_command,
        .mode = COMMAND_ANY,
        .help = "Change address used for debug handler.",
        .usage = "<target> <address>",
    },
    {
        .name = "cache_clean_address",
        .handler = xscale_handle_cache_clean_address_command,
        .mode = COMMAND_ANY,
        .help = "Change address used for cleaning data cache.",
        .usage = "address",
    },
    {
        .chain = xscale_exec_command_handlers,
    },
    COMMAND_REGISTRATION_DONE
};
static const struct command_registration xscale_command_handlers[] = {
    {
        .chain = arm_command_handlers,
    },
    {
        .name = "xscale",
        .mode = COMMAND_ANY,
        .help = "xscale command group",
        .usage = "",
        .chain = xscale_any_command_handlers,
    },
    COMMAND_REGISTRATION_DONE
};
 
struct target_type xscale_target = {
    .name = "xscale",
 
    .poll = xscale_poll,
    .arch_state = xscale_arch_state,
 
    .halt = xscale_halt,
    .resume = xscale_resume,
    .step = xscale_step,
 
    .assert_reset = xscale_assert_reset,
    .deassert_reset = xscale_deassert_reset,
 
    /* REVISIT on some cores, allow exporting iwmmxt registers ... */
    .get_gdb_arch = arm_get_gdb_arch,
    .get_gdb_reg_list = arm_get_gdb_reg_list,
 
    .read_memory = xscale_read_memory,
    .read_phys_memory = xscale_read_phys_memory,
    .write_memory = xscale_write_memory,
    .write_phys_memory = xscale_write_phys_memory,
 
    .checksum_memory = arm_checksum_memory,
    .blank_check_memory = arm_blank_check_memory,
 
    .run_algorithm = armv4_5_run_algorithm,
 
    .add_breakpoint = xscale_add_breakpoint,
    .remove_breakpoint = xscale_remove_breakpoint,
    .add_watchpoint = xscale_add_watchpoint,
    .remove_watchpoint = xscale_remove_watchpoint,
 
    .commands = xscale_command_handlers,
    .target_create = xscale_target_create,
    .init_target = xscale_init_target,
    .deinit_target = xscale_deinit_target,
 
    .virt2phys = xscale_virt2phys,
    .mmu = xscale_mmu
};