mips32_pracc.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *   Copyright (C) 2008 by Spencer Oliver                                  *
 *   spen@spen-soft.co.uk                                                  *
 *                                                                         *
 *   Copyright (C) 2008 by David T.L. Wong                                 *
 *                                                                         *
 *   Copyright (C) 2009 by David N. Claffey <dnclaffey@gmail.com>          *
 *                                                                         *
 *   Copyright (C) 2011 by Drasko DRASKOVIC                                *
 *   drasko.draskovic@gmail.com                                            *
 ***************************************************************************/
 
/*
 * This version has optimized assembly routines for 32 bit operations:
 * - read word
 * - write word
 * - write array of words
 *
 * One thing to be aware of is that the MIPS32 cpu will execute the
 * instruction after a branch instruction (one delay slot).
 *
 * For example:
 *  LW $2, ($5 +10)
 *  B foo
 *  LW $1, ($2 +100)
 *
 * The LW $1, ($2 +100) instruction is also executed. If this is
 * not wanted a NOP can be inserted:
 *
 *  LW $2, ($5 +10)
 *  B foo
 *  NOP
 *  LW $1, ($2 +100)
 *
 * or the code can be changed to:
 *
 *  B foo
 *  LW $2, ($5 +10)
 *  LW $1, ($2 +100)
 *
 * The original code contained NOPs. I have removed these and moved
 * the branches.
 *
 * These changes result in a 35% speed increase when programming an
 * external flash.
 *
 * More improvement could be gained if the registers do no need
 * to be preserved but in that case the routines should be aware
 * OpenOCD is used as a flash programmer or as a debug tool.
 *
 * Nico Coesel
 */
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include <helper/align.h>
#include <helper/time_support.h>
#include <jtag/adapter.h>
 
#include "mips32.h"
#include "mips32_pracc.h"
 
static int wait_for_pracc_rw(struct mips_ejtag *ejtag_info)
{
    int64_t then = timeval_ms();
 
    /* wait for the PrAcc to become "1" */
    mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
 
    while (1) {
        ejtag_info->pa_ctrl = ejtag_info->ejtag_ctrl;
        int retval = mips_ejtag_drscan_32(ejtag_info, &ejtag_info->pa_ctrl);
        if (retval != ERROR_OK)
            return retval;
 
        if (ejtag_info->pa_ctrl & EJTAG_CTRL_PRACC)
            break;
 
        int64_t timeout = timeval_ms() - then;
        if (timeout > 1000) {
            LOG_DEBUG("DEBUGMODULE: No memory access in progress!");
            return ERROR_JTAG_DEVICE_ERROR;
        }
    }
 
    return ERROR_OK;
}
 
/* Shift in control and address for a new processor access, save them in ejtag_info */
static int mips32_pracc_read_ctrl_addr(struct mips_ejtag *ejtag_info)
{
    int retval = wait_for_pracc_rw(ejtag_info);
    if (retval != ERROR_OK)
        return retval;
 
    mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ADDRESS);
 
    ejtag_info->pa_addr = 0;
    return  mips_ejtag_drscan_32(ejtag_info, &ejtag_info->pa_addr);
}
 
/* Finish processor access */
static void mips32_pracc_finish(struct mips_ejtag *ejtag_info)
{
    uint32_t ctrl = ejtag_info->ejtag_ctrl & ~EJTAG_CTRL_PRACC;
    mips_ejtag_set_instr(ejtag_info, EJTAG_INST_CONTROL);
    mips_ejtag_drscan_32_out(ejtag_info, ctrl);
}
 
static int mips32_pracc_clean_text_jump(struct mips_ejtag *ejtag_info)
{
    uint32_t jt_code = MIPS32_J(ejtag_info->isa, MIPS32_PRACC_TEXT);
    pracc_swap16_array(ejtag_info, &jt_code, 1);
    /* do 3 0/nops to clean pipeline before a jump to pracc text, NOP in delay slot */
    for (int i = 0; i != 5; i++) {
        /* Wait for pracc */
        int retval = wait_for_pracc_rw(ejtag_info);
        if (retval != ERROR_OK)
            return retval;
 
        /* Data or instruction out */
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA);
        uint32_t data = (i == 3) ? jt_code : MIPS32_NOP;
        mips_ejtag_drscan_32_out(ejtag_info, data);
 
        /* finish pa */
        mips32_pracc_finish(ejtag_info);
    }
 
    if (ejtag_info->mode != 0)  /* async mode support only for MIPS ... */
        return ERROR_OK;
 
    for (int i = 0; i != 2; i++) {
        int retval = mips32_pracc_read_ctrl_addr(ejtag_info);
        if (retval != ERROR_OK)
            return retval;
 
        if (ejtag_info->pa_addr != MIPS32_PRACC_TEXT) { /* LEXRA/BMIPS ?, shift out another NOP, max 2 */
            mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA);
            mips_ejtag_drscan_32_out(ejtag_info, MIPS32_NOP);
            mips32_pracc_finish(ejtag_info);
        } else
            break;
    }
 
    return ERROR_OK;
}
 
static int mips32_pracc_exec(struct mips_ejtag *ejtag_info, struct pracc_queue_info *ctx,
                    uint32_t *param_out, bool check_last)
{
    int code_count = 0;
    int store_pending = 0;      /* increases with every store instr at dmseg, decreases with every store pa */
    uint32_t max_store_addr = 0;    /* for store pa address testing */
    bool restart = 0;       /* restarting control */
    int restart_count = 0;
    uint32_t instr = 0;
    bool final_check = 0;       /* set to 1 if in final checks after function code shifted out */
    bool pass = 0;          /* to check the pass through pracc text after function code sent */
    int retval;
 
    while (1) {
        if (restart) {
            if (restart_count < 3) {                    /* max 3 restarts allowed */
                retval = mips32_pracc_clean_text_jump(ejtag_info);
                if (retval != ERROR_OK)
                    return retval;
            } else
                return ERROR_JTAG_DEVICE_ERROR;
            restart_count++;
            restart = 0;
            code_count = 0;
            LOG_DEBUG("restarting code");
        }
 
        retval = mips32_pracc_read_ctrl_addr(ejtag_info); /* update current pa info: control and address */
        if (retval != ERROR_OK)
            return retval;
 
        /* Check for read or write access */
        if (ejtag_info->pa_ctrl & EJTAG_CTRL_PRNW) {                /* write/store access */
            /* Check for pending store from a previous store instruction at dmseg */
            if (store_pending == 0) {
                LOG_DEBUG("unexpected write at address %" PRIx32, ejtag_info->pa_addr);
                if (code_count < 2) {   /* allow for restart */
                    restart = 1;
                    continue;
                } else
                    return ERROR_JTAG_DEVICE_ERROR;
            } else {
                /* check address */
                if (ejtag_info->pa_addr < MIPS32_PRACC_PARAM_OUT ||
                        ejtag_info->pa_addr > max_store_addr) {
                    LOG_DEBUG("writing at unexpected address %" PRIx32, ejtag_info->pa_addr);
                    return ERROR_JTAG_DEVICE_ERROR;
                }
            }
            /* read data */
            uint32_t data = 0;
            mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA);
            retval = mips_ejtag_drscan_32(ejtag_info, &data);
            if (retval != ERROR_OK)
                return retval;
 
            /* store data at param out, address based offset */
            param_out[(ejtag_info->pa_addr - MIPS32_PRACC_PARAM_OUT) / 4] = data;
            store_pending--;
 
        } else {                    /* read/fetch access */
             if (!final_check) {            /* executing function code */
                /* check address */
                if (ejtag_info->pa_addr != (MIPS32_PRACC_TEXT + code_count * 4)) {
                    LOG_DEBUG("reading at unexpected address %" PRIx32 ", expected %x",
                            ejtag_info->pa_addr, MIPS32_PRACC_TEXT + code_count * 4);
 
                    /* restart code execution only in some cases */
                    if (code_count == 1 && ejtag_info->pa_addr == MIPS32_PRACC_TEXT &&
                                        restart_count == 0) {
                        LOG_DEBUG("restarting, without clean jump");
                        restart_count++;
                        code_count = 0;
                        continue;
                    } else if (code_count < 2) {
                        restart = 1;
                        continue;
                    }
                    return ERROR_JTAG_DEVICE_ERROR;
                }
                /* check for store instruction at dmseg */
                uint32_t store_addr = ctx->pracc_list[code_count].addr;
                if (store_addr != 0) {
                    if (store_addr > max_store_addr)
                        max_store_addr = store_addr;
                    store_pending++;
                }
 
                instr = ctx->pracc_list[code_count++].instr;
                if (code_count == ctx->code_count)  /* last instruction, start final check */
                    final_check = 1;
 
             } else {   /* final check after function code shifted out */
                    /* check address */
                if (ejtag_info->pa_addr == MIPS32_PRACC_TEXT) {
                    if (!pass) {    /* first pass through pracc text */
                        if (store_pending == 0)     /* done, normal exit */
                            return ERROR_OK;
                        pass = 1;       /* pracc text passed */
                        code_count = 0;     /* restart code count */
                    } else {
                        LOG_DEBUG("unexpected second pass through pracc text");
                        return ERROR_JTAG_DEVICE_ERROR;
                    }
                } else {
                    if (ejtag_info->pa_addr != (MIPS32_PRACC_TEXT + code_count * 4)) {
                        LOG_DEBUG("unexpected read address in final check: %"
                            PRIx32 ", expected: %x", ejtag_info->pa_addr,
                            MIPS32_PRACC_TEXT + code_count * 4);
                        return ERROR_JTAG_DEVICE_ERROR;
                    }
                }
                if (!pass) {
                    if ((code_count - ctx->code_count) > 1) { /* allow max 2 instr delay slot */
                        LOG_DEBUG("failed to jump back to pracc text");
                        return ERROR_JTAG_DEVICE_ERROR;
                    }
                } else
                    if (code_count > 10) {      /* enough, abandon */
                        LOG_DEBUG("execution abandoned, store pending: %d", store_pending);
                        return ERROR_JTAG_DEVICE_ERROR;
                    }
                instr = MIPS32_NOP; /* shift out NOPs instructions */
                code_count++;
             }
 
            /* Send instruction out */
            mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA);
            mips_ejtag_drscan_32_out(ejtag_info, instr);
        }
        /* finish processor access, let the processor eat! */
        mips32_pracc_finish(ejtag_info);
 
        if (final_check && !check_last)         /* last instr, don't check, execute and exit */
            return jtag_execute_queue();
 
        if (store_pending == 0 && pass) {   /* store access done, but after passing pracc text */
            LOG_DEBUG("warning: store access pass pracc text");
            return ERROR_OK;
        }
    }
}
 
inline void pracc_queue_init(struct pracc_queue_info *ctx)
{
    ctx->retval = ERROR_OK;
    ctx->code_count = 0;
    ctx->store_count = 0;
    ctx->max_code = 0;
    ctx->pracc_list = NULL;
    ctx->isa = ctx->ejtag_info->isa ? 1 : 0;
}
 
void pracc_add(struct pracc_queue_info *ctx, uint32_t addr, uint32_t instr)
{
    if (ctx->retval != ERROR_OK)    /* On previous out of memory, return */
        return;
    if (ctx->code_count == ctx->max_code) {
        void *p = realloc(ctx->pracc_list, sizeof(struct pa_list) * (ctx->max_code + PRACC_BLOCK));
        if (p) {
            ctx->max_code += PRACC_BLOCK;
            ctx->pracc_list = p;
        } else {
            ctx->retval = ERROR_FAIL;   /* Out of memory */
            return;
        }
    }
    ctx->pracc_list[ctx->code_count].instr = instr;
    ctx->pracc_list[ctx->code_count++].addr = addr;
    if (addr)
        ctx->store_count++;
}
 
static void pracc_add_li32(struct pracc_queue_info *ctx, uint32_t reg_num, uint32_t data, bool optimize)
{
    if (LOWER16(data) == 0 && optimize)
        pracc_add(ctx, 0, MIPS32_LUI(ctx->isa, reg_num, UPPER16(data)));    /* load only upper value */
    else if (UPPER16(data) == 0 && optimize)
        pracc_add(ctx, 0, MIPS32_ORI(ctx->isa, reg_num, 0, LOWER16(data))); /* load only lower */
    else {
        pracc_add(ctx, 0, MIPS32_LUI(ctx->isa, reg_num, UPPER16(data)));    /* load upper and lower */
        pracc_add(ctx, 0, MIPS32_ORI(ctx->isa, reg_num, reg_num, LOWER16(data)));
    }
}
 
inline void pracc_queue_free(struct pracc_queue_info *ctx)
{
    free(ctx->pracc_list);
}
 
int mips32_pracc_queue_exec(struct mips_ejtag *ejtag_info, struct pracc_queue_info *ctx,
                    uint32_t *buf, bool check_last)
{
    if (ctx->retval != ERROR_OK) {
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
 
    if (ejtag_info->isa && ejtag_info->endianness)
        for (int i = 0; i != ctx->code_count; i++)
            ctx->pracc_list[i].instr = SWAP16(ctx->pracc_list[i].instr);
 
    if (ejtag_info->mode == 0)
        return mips32_pracc_exec(ejtag_info, ctx, buf, check_last);
 
    union scan_in {
        uint8_t scan_96[12];
        struct {
            uint8_t ctrl[4];
            uint8_t data[4];
            uint8_t addr[4];
        } scan_32;
 
    } *scan_in = malloc(sizeof(union scan_in) * (ctx->code_count + ctx->store_count));
    if (!scan_in) {
        LOG_ERROR("Out of memory");
        return ERROR_FAIL;
    }
 
    unsigned num_clocks =
        ((uint64_t)(ejtag_info->scan_delay) * adapter_get_speed_khz() + 500000) / 1000000;
 
    uint32_t ejtag_ctrl = ejtag_info->ejtag_ctrl & ~EJTAG_CTRL_PRACC;
    mips_ejtag_set_instr(ejtag_info, EJTAG_INST_ALL);
 
    int scan_count = 0;
    for (int i = 0; i != ctx->code_count; i++) {
        jtag_add_clocks(num_clocks);
        mips_ejtag_add_scan_96(ejtag_info, ejtag_ctrl, ctx->pracc_list[i].instr,
                       scan_in[scan_count++].scan_96);
 
        /* Check store address from previous instruction, if not the first */
        if (i > 0 && ctx->pracc_list[i - 1].addr) {
            jtag_add_clocks(num_clocks);
            mips_ejtag_add_scan_96(ejtag_info, ejtag_ctrl, 0, scan_in[scan_count++].scan_96);
        }
    }
 
    int retval = jtag_execute_queue();      /* execute queued scans */
    if (retval != ERROR_OK)
        goto exit;
 
    uint32_t fetch_addr = MIPS32_PRACC_TEXT;        /* start address */
    scan_count = 0;
    for (int i = 0; i != ctx->code_count; i++) {                /* verify every pracc access */
        /* check pracc bit */
        ejtag_ctrl = buf_get_u32(scan_in[scan_count].scan_32.ctrl, 0, 32);
        uint32_t addr = buf_get_u32(scan_in[scan_count].scan_32.addr, 0, 32);
        if (!(ejtag_ctrl & EJTAG_CTRL_PRACC)) {
            LOG_ERROR("Error: access not pending  count: %d", scan_count);
            retval = ERROR_FAIL;
            goto exit;
        }
        if (ejtag_ctrl & EJTAG_CTRL_PRNW) {
            LOG_ERROR("Not a fetch/read access, count: %d", scan_count);
            retval = ERROR_FAIL;
            goto exit;
        }
        if (addr != fetch_addr) {
            LOG_ERROR("Fetch addr mismatch, read: %" PRIx32 " expected: %" PRIx32 " count: %d",
                      addr, fetch_addr, scan_count);
            retval = ERROR_FAIL;
            goto exit;
        }
        fetch_addr += 4;
        scan_count++;
 
        /* check if previous instruction is a store instruction at dmesg */
        if (i > 0 && ctx->pracc_list[i - 1].addr) {
            uint32_t store_addr = ctx->pracc_list[i - 1].addr;
            ejtag_ctrl = buf_get_u32(scan_in[scan_count].scan_32.ctrl, 0, 32);
            addr = buf_get_u32(scan_in[scan_count].scan_32.addr, 0, 32);
 
            if (!(ejtag_ctrl & EJTAG_CTRL_PRNW)) {
                LOG_ERROR("Not a store/write access, count: %d", scan_count);
                retval = ERROR_FAIL;
                goto exit;
            }
            if (addr != store_addr) {
                LOG_ERROR("Store address mismatch, read: %" PRIx32 " expected: %" PRIx32 " count: %d",
                                  addr, store_addr, scan_count);
                retval = ERROR_FAIL;
                goto exit;
            }
            int buf_index = (addr - MIPS32_PRACC_PARAM_OUT) / 4;
            buf[buf_index] = buf_get_u32(scan_in[scan_count].scan_32.data, 0, 32);
            scan_count++;
        }
    }
exit:
    free(scan_in);
    return retval;
}
 
static int mips32_pracc_read_u32(struct mips_ejtag *ejtag_info, uint32_t addr, uint32_t *buf)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, PRACC_UPPER_BASE_ADDR)); /* $15 = MIPS32_PRACC_BASE_ADDR */
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 8, UPPER16((addr + 0x8000)))); /* load  $8 with modified upper addr */
    pracc_add(&ctx, 0, MIPS32_LW(ctx.isa, 8, LOWER16(addr), 8));            /* lw $8, LOWER16(addr)($8) */
    pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT,
                MIPS32_SW(ctx.isa, 8, PRACC_OUT_OFFSET, 15));   /* sw $8,PRACC_OUT_OFFSET($15) */
    pracc_add_li32(&ctx, 8, ejtag_info->reg8, 0);               /* restore $8 */
    pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));      /* jump to start */
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));                /* move COP0 DeSave to $15 */
 
    ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, buf, 1);
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
int mips32_pracc_read_mem(struct mips_ejtag *ejtag_info, uint32_t addr, int size, int count, void *buf)
{
    if (count == 1 && size == 4)
        return mips32_pracc_read_u32(ejtag_info, addr, (uint32_t *)buf);
 
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    uint32_t *data = NULL;
    if (size != 4) {
        data = malloc(256 * sizeof(uint32_t));
        if (!data) {
            LOG_ERROR("Out of memory");
            goto exit;
        }
    }
 
    uint32_t *buf32 = buf;
    uint16_t *buf16 = buf;
    uint8_t *buf8 = buf;
 
    while (count) {
        ctx.code_count = 0;
        ctx.store_count = 0;
 
        int this_round_count = (count > 256) ? 256 : count;
        uint32_t last_upper_base_addr = UPPER16((addr + 0x8000));
 
        pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, PRACC_UPPER_BASE_ADDR)); /* $15 = MIPS32_PRACC_BASE_ADDR */
        pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 9, last_upper_base_addr));   /* upper memory addr to $9 */
 
        for (int i = 0; i != this_round_count; i++) {           /* Main code loop */
            uint32_t upper_base_addr = UPPER16((addr + 0x8000));
            if (last_upper_base_addr != upper_base_addr) {  /* if needed, change upper addr in $9 */
                pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 9, upper_base_addr));
                last_upper_base_addr = upper_base_addr;
            }
 
            if (size == 4)              /* load from memory to $8 */
                pracc_add(&ctx, 0, MIPS32_LW(ctx.isa, 8, LOWER16(addr), 9));
            else if (size == 2)
                pracc_add(&ctx, 0, MIPS32_LHU(ctx.isa, 8, LOWER16(addr), 9));
            else
                pracc_add(&ctx, 0, MIPS32_LBU(ctx.isa, 8, LOWER16(addr), 9));
 
            pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT + i * 4,         /* store $8 at param out */
                      MIPS32_SW(ctx.isa, 8, PRACC_OUT_OFFSET + i * 4, 15));
            addr += size;
        }
        pracc_add_li32(&ctx, 8, ejtag_info->reg8, 0);               /* restore $8 */
        pracc_add_li32(&ctx, 9, ejtag_info->reg9, 0);               /* restore $9 */
 
        pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));  /* jump to start */
        pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));            /* restore $15 from DeSave */
 
        if (size == 4) {
            ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, buf32, 1);
            if (ctx.retval != ERROR_OK)
                goto exit;
            buf32 += this_round_count;
        } else {
            ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, data, 1);
            if (ctx.retval != ERROR_OK)
                goto exit;
 
            uint32_t *data_p = data;
            for (int i = 0; i != this_round_count; i++) {
                if (size == 2)
                    *buf16++ = *data_p++;
                else
                    *buf8++ = *data_p++;
            }
        }
        count -= this_round_count;
    }
exit:
    pracc_queue_free(&ctx);
    free(data);
    return ctx.retval;
}
 
int mips32_cp0_read(struct mips_ejtag *ejtag_info, uint32_t *val, uint32_t cp0_reg, uint32_t cp0_sel)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, PRACC_UPPER_BASE_ADDR)); /* $15 = MIPS32_PRACC_BASE_ADDR */
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 8, cp0_reg, cp0_sel));      /* move cp0 reg / sel to $8 */
    pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT,
                MIPS32_SW(ctx.isa, 8, PRACC_OUT_OFFSET, 15));   /* store $8 to pracc_out */
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));                /* restore $15 from DeSave */
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 8, UPPER16(ejtag_info->reg8)));  /* restore upper 16 bits  of $8 */
    pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));      /* jump to start */
    pracc_add(&ctx, 0, MIPS32_ORI(ctx.isa, 8, 8, LOWER16(ejtag_info->reg8))); /* restore lower 16 bits of $8 */
 
    ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, val, 1);
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
int mips32_cp0_write(struct mips_ejtag *ejtag_info, uint32_t val, uint32_t cp0_reg, uint32_t cp0_sel)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    pracc_add_li32(&ctx, 15, val, 0);               /* Load val to $15 */
 
    pracc_add(&ctx, 0, MIPS32_MTC0(ctx.isa, 15, cp0_reg, cp0_sel));     /* write $15 to cp0 reg / sel */
    pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));      /* jump to start */
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));            /* restore $15 from DeSave */
 
    ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 1);
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
static int mips32_pracc_synchronize_cache(struct mips_ejtag *ejtag_info,
                     uint32_t start_addr, uint32_t end_addr, int cached, int rel)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    uint32_t clsiz;
    if (rel) {  /* Release 2 (rel = 1) */
        pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, PRACC_UPPER_BASE_ADDR)); /* $15 = MIPS32_PRACC_BASE_ADDR */
 
        pracc_add(&ctx, 0, MIPS32_RDHWR(ctx.isa, 8, MIPS32_SYNCI_STEP)); /* load synci_step value to $8 */
 
        pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT,
                MIPS32_SW(ctx.isa, 8, PRACC_OUT_OFFSET, 15));       /* store $8 to pracc_out */
 
        pracc_add_li32(&ctx, 8, ejtag_info->reg8, 0);               /* restore $8 */
 
        pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));  /* jump to start */
        pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));            /* restore $15 from DeSave */
 
        ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, &clsiz, 1);
        if (ctx.retval != ERROR_OK)
            goto exit;
 
    } else {            /* Release 1 (rel = 0) */
        uint32_t conf;
        ctx.retval = mips32_cp0_read(ejtag_info, &conf, 16, 1);
        if (ctx.retval != ERROR_OK)
            goto exit;
 
        uint32_t dl = (conf & MIPS32_CONFIG1_DL_MASK) >> MIPS32_CONFIG1_DL_SHIFT;
 
        /* dl encoding : dl=1 => 4 bytes, dl=2 => 8 bytes, etc... max dl=6 => 128 bytes cache line size */
        clsiz = 0x2 << dl;
        if (dl == 0)
            clsiz = 0;
    }
 
    if (clsiz == 0)
        goto exit;  /* Nothing to do */
 
    /* make sure clsiz is power of 2 */
    if (!IS_PWR_OF_2(clsiz)) {
        LOG_DEBUG("clsiz must be power of 2");
        ctx.retval = ERROR_FAIL;
        goto exit;
    }
 
    /* make sure start_addr and end_addr have the same offset inside de cache line */
    start_addr |= clsiz - 1;
    end_addr |= clsiz - 1;
 
    ctx.code_count = 0;
    ctx.store_count = 0;
 
    int count = 0;
    uint32_t last_upper_base_addr = UPPER16((start_addr + 0x8000));
 
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, last_upper_base_addr)); /* load upper memory base addr to $15 */
 
    while (start_addr <= end_addr) {                        /* main loop */
        uint32_t upper_base_addr = UPPER16((start_addr + 0x8000));
        if (last_upper_base_addr != upper_base_addr) {      /* if needed, change upper addr in $15 */
            pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, upper_base_addr));
            last_upper_base_addr = upper_base_addr;
        }
        if (rel)            /* synci instruction, offset($15) */
            pracc_add(&ctx, 0, MIPS32_SYNCI(ctx.isa, LOWER16(start_addr), 15));
 
        else {
            if (cached == 3)    /* cache Hit_Writeback_D, offset($15) */
                pracc_add(&ctx, 0, MIPS32_CACHE(ctx.isa, MIPS32_CACHE_D_HIT_WRITEBACK,
                            LOWER16(start_addr), 15));
            /* cache Hit_Invalidate_I, offset($15) */
            pracc_add(&ctx, 0, MIPS32_CACHE(ctx.isa, MIPS32_CACHE_I_HIT_INVALIDATE,
                            LOWER16(start_addr), 15));
        }
        start_addr += clsiz;
        count++;
        if (count == 256 && start_addr <= end_addr) {           /* more ?, then execute code list */
            pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));  /* to start */
            pracc_add(&ctx, 0, MIPS32_NOP);                 /* nop in delay slot */
 
            ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 1);
            if (ctx.retval != ERROR_OK)
                goto exit;
 
            ctx.code_count = 0; /* reset counters for another loop */
            ctx.store_count = 0;
            count = 0;
        }
    }
    pracc_add(&ctx, 0, MIPS32_SYNC(ctx.isa));
    pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));      /* jump to start */
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));                /* restore $15 from DeSave*/
 
    ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 1);
exit:
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
static int mips32_pracc_write_mem_generic(struct mips_ejtag *ejtag_info,
        uint32_t addr, int size, int count, const void *buf)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    const uint32_t *buf32 = buf;
    const uint16_t *buf16 = buf;
    const uint8_t *buf8 = buf;
 
    while (count) {
        ctx.code_count = 0;
        ctx.store_count = 0;
 
        int this_round_count = (count > 128) ? 128 : count;
        uint32_t last_upper_base_addr = UPPER16((addr + 0x8000));
                  /* load $15 with memory base address */
        pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, last_upper_base_addr));
 
        for (int i = 0; i != this_round_count; i++) {
            uint32_t upper_base_addr = UPPER16((addr + 0x8000));
            if (last_upper_base_addr != upper_base_addr) {  /* if needed, change upper address in $15*/
                pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 15, upper_base_addr));
                last_upper_base_addr = upper_base_addr;
            }
 
            if (size == 4) {
                pracc_add_li32(&ctx, 8, *buf32, 1);     /* load with li32, optimize */
                pracc_add(&ctx, 0, MIPS32_SW(ctx.isa, 8, LOWER16(addr), 15)); /* store word to mem */
                buf32++;
 
            } else if (size == 2) {
                pracc_add(&ctx, 0, MIPS32_ORI(ctx.isa, 8, 0, *buf16));      /* load lower value */
                pracc_add(&ctx, 0, MIPS32_SH(ctx.isa, 8, LOWER16(addr), 15)); /* store half word */
                buf16++;
 
            } else {
                pracc_add(&ctx, 0, MIPS32_ORI(ctx.isa, 8, 0, *buf8));       /* load lower value */
                pracc_add(&ctx, 0, MIPS32_SB(ctx.isa, 8, LOWER16(addr), 15));   /* store byte */
                buf8++;
            }
            addr += size;
        }
 
        pracc_add_li32(&ctx, 8, ejtag_info->reg8, 0);               /* restore $8 */
 
        pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));  /* jump to start */
        pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 15, 31, 0));            /* restore $15 from DeSave */
 
        ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 1);
        if (ctx.retval != ERROR_OK)
            goto exit;
        count -= this_round_count;
    }
exit:
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
int mips32_pracc_write_mem(struct mips_ejtag *ejtag_info, uint32_t addr, int size, int count, const void *buf)
{
    int retval = mips32_pracc_write_mem_generic(ejtag_info, addr, size, count, buf);
    if (retval != ERROR_OK)
        return retval;
 
    uint32_t conf = 0;
    int cached = 0;
 
    if ((KSEGX(addr) == KSEG1) || ((addr >= 0xff200000) && (addr <= 0xff3fffff)))
        return retval; /*Nothing to do*/
 
    mips32_cp0_read(ejtag_info, &conf, 16, 0);
 
    switch (KSEGX(addr)) {
        case KUSEG:
            cached = (conf & MIPS32_CONFIG0_KU_MASK) >> MIPS32_CONFIG0_KU_SHIFT;
            break;
        case KSEG0:
            cached = (conf & MIPS32_CONFIG0_K0_MASK) >> MIPS32_CONFIG0_K0_SHIFT;
            break;
        case KSEG2:
        case KSEG3:
            cached = (conf & MIPS32_CONFIG0_K23_MASK) >> MIPS32_CONFIG0_K23_SHIFT;
            break;
        default:
            /* what ? */
            break;
    }
 
    if (cached == 3 || cached == 0) {       /* Write back cache or write through cache */
        uint32_t start_addr = addr;
        uint32_t end_addr = addr + count * size;
        uint32_t rel = (conf & MIPS32_CONFIG0_AR_MASK) >> MIPS32_CONFIG0_AR_SHIFT;
        if (rel > 1) {
            LOG_DEBUG("Unknown release in cache code");
            return ERROR_FAIL;
        }
        retval = mips32_pracc_synchronize_cache(ejtag_info, start_addr, end_addr, cached, rel);
    }
 
    return retval;
}
 
int mips32_pracc_write_regs(struct mips_ejtag *ejtag_info, uint32_t *regs)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    uint32_t cp0_write_code[] = {
        MIPS32_MTC0(ctx.isa, 1, 12, 0),                 /* move $1 to status */
        MIPS32_MTLO(ctx.isa, 1),                        /* move $1 to lo */
        MIPS32_MTHI(ctx.isa, 1),                        /* move $1 to hi */
        MIPS32_MTC0(ctx.isa, 1, 8, 0),                  /* move $1 to badvaddr */
        MIPS32_MTC0(ctx.isa, 1, 13, 0),                 /* move $1 to cause*/
        MIPS32_MTC0(ctx.isa, 1, 24, 0),                 /* move $1 to depc (pc) */
    };
 
    /* load registers 2 to 31 with li32, optimize */
    for (int i = 2; i < 32; i++)
        pracc_add_li32(&ctx, i, regs[i], 1);
 
    for (int i = 0; i != 6; i++) {
        pracc_add_li32(&ctx, 1, regs[i + 32], 0);   /* load CPO value in $1 */
        pracc_add(&ctx, 0, cp0_write_code[i]);          /* write value from $1 to CPO register */
    }
    pracc_add(&ctx, 0, MIPS32_MTC0(ctx.isa, 15, 31, 0));                /* load $15 in DeSave */
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 1, UPPER16((regs[1]))));     /* load upper half word in $1 */
    pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));      /* jump to start */
    pracc_add(&ctx, 0, MIPS32_ORI(ctx.isa, 1, 1, LOWER16((regs[1]))));  /* load lower half word in $1 */
 
    ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, NULL, 1);
 
    ejtag_info->reg8 = regs[8];
    ejtag_info->reg9 = regs[9];
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
int mips32_pracc_read_regs(struct mips_ejtag *ejtag_info, uint32_t *regs)
{
    struct pracc_queue_info ctx = {.ejtag_info = ejtag_info};
    pracc_queue_init(&ctx);
 
    uint32_t cp0_read_code[] = {
        MIPS32_MFC0(ctx.isa, 8, 12, 0),                 /* move status to $8 */
        MIPS32_MFLO(ctx.isa, 8),                        /* move lo to $8 */
        MIPS32_MFHI(ctx.isa, 8),                        /* move hi to $8 */
        MIPS32_MFC0(ctx.isa, 8, 8, 0),                  /* move badvaddr to $8 */
        MIPS32_MFC0(ctx.isa, 8, 13, 0),                 /* move cause to $8 */
        MIPS32_MFC0(ctx.isa, 8, 24, 0),                 /* move depc (pc) to $8 */
    };
 
    pracc_add(&ctx, 0, MIPS32_MTC0(ctx.isa, 1, 31, 0));             /* move $1 to COP0 DeSave */
    pracc_add(&ctx, 0, MIPS32_LUI(ctx.isa, 1, PRACC_UPPER_BASE_ADDR));  /* $1 = MIP32_PRACC_BASE_ADDR */
 
    for (int i = 2; i != 32; i++)                   /* store GPR's 2 to 31 */
        pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT + (i * 4),
                  MIPS32_SW(ctx.isa, i, PRACC_OUT_OFFSET + (i * 4), 1));
 
    for (int i = 0; i != 6; i++) {
        pracc_add(&ctx, 0, cp0_read_code[i]);               /* load COP0 needed registers to $8 */
        pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT + (i + 32) * 4,          /* store $8 at PARAM OUT */
                  MIPS32_SW(ctx.isa, 8, PRACC_OUT_OFFSET + (i + 32) * 4, 1));
    }
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 8, 31, 0));         /* move DeSave to $8, reg1 value */
    pracc_add(&ctx, MIPS32_PRACC_PARAM_OUT + 4,         /* store reg1 value from $8 to param out */
              MIPS32_SW(ctx.isa, 8, PRACC_OUT_OFFSET + 4, 1));
 
    pracc_add(&ctx, 0, MIPS32_MFC0(ctx.isa, 1, 31, 0));     /* move COP0 DeSave to $1, restore reg1 */
    pracc_add(&ctx, 0, MIPS32_B(ctx.isa, NEG16((ctx.code_count + 1) << ctx.isa)));      /* jump to start */
    pracc_add(&ctx, 0, MIPS32_MTC0(ctx.isa, 15, 31, 0));                /* load $15 in DeSave */
 
    ctx.retval = mips32_pracc_queue_exec(ejtag_info, &ctx, regs, 1);
 
    ejtag_info->reg8 = regs[8]; /* reg8 is saved but not restored, next called function should restore it */
    ejtag_info->reg9 = regs[9];
    pracc_queue_free(&ctx);
    return ctx.retval;
}
 
/* fastdata upload/download requires an initialized working area
 * to load the download code; it should not be called otherwise
 * fetch order from the fastdata area
 * 1. start addr
 * 2. end addr
 * 3. data ...
 */
int mips32_pracc_fastdata_xfer(struct mips_ejtag *ejtag_info, struct working_area *source,
        int write_t, uint32_t addr, int count, uint32_t *buf)
{
    uint32_t isa = ejtag_info->isa ? 1 : 0;
    uint32_t handler_code[] = {
        /* r15 points to the start of this code */
        MIPS32_SW(isa, 8, MIPS32_FASTDATA_HANDLER_SIZE - 4, 15),
        MIPS32_SW(isa, 9, MIPS32_FASTDATA_HANDLER_SIZE - 8, 15),
        MIPS32_SW(isa, 10, MIPS32_FASTDATA_HANDLER_SIZE - 12, 15),
        MIPS32_SW(isa, 11, MIPS32_FASTDATA_HANDLER_SIZE - 16, 15),
        /* start of fastdata area in t0 */
        MIPS32_LUI(isa, 8, UPPER16(MIPS32_PRACC_FASTDATA_AREA)),
        MIPS32_ORI(isa, 8, 8, LOWER16(MIPS32_PRACC_FASTDATA_AREA)),
        MIPS32_LW(isa, 9, 0, 8),                        /* start addr in t1 */
        MIPS32_LW(isa, 10, 0, 8),                       /* end addr to t2 */
                    /* loop: */
        write_t ? MIPS32_LW(isa, 11, 0, 8) : MIPS32_LW(isa, 11, 0, 9),  /* from xfer area : from memory */
        write_t ? MIPS32_SW(isa, 11, 0, 9) : MIPS32_SW(isa, 11, 0, 8),  /* to memory      : to xfer area */
 
        MIPS32_BNE(isa, 10, 9, NEG16(3 << isa)),            /* bne $t2,t1,loop */
        MIPS32_ADDI(isa, 9, 9, 4),                  /* addi t1,t1,4 */
 
        MIPS32_LW(isa, 8, MIPS32_FASTDATA_HANDLER_SIZE - 4, 15),
        MIPS32_LW(isa, 9, MIPS32_FASTDATA_HANDLER_SIZE - 8, 15),
        MIPS32_LW(isa, 10, MIPS32_FASTDATA_HANDLER_SIZE - 12, 15),
        MIPS32_LW(isa, 11, MIPS32_FASTDATA_HANDLER_SIZE - 16, 15),
 
        MIPS32_LUI(isa, 15, UPPER16(MIPS32_PRACC_TEXT)),
        MIPS32_ORI(isa, 15, 15, LOWER16(MIPS32_PRACC_TEXT) | isa),  /* isa bit for JR instr */
        MIPS32_JR(isa, 15),                             /* jr start */
        MIPS32_MFC0(isa, 15, 31, 0),                    /* move COP0 DeSave to $15 */
    };
 
    if (source->size < MIPS32_FASTDATA_HANDLER_SIZE)
        return ERROR_TARGET_RESOURCE_NOT_AVAILABLE;
 
    pracc_swap16_array(ejtag_info, handler_code, ARRAY_SIZE(handler_code));
        /* write program into RAM */
    if (write_t != ejtag_info->fast_access_save) {
        mips32_pracc_write_mem(ejtag_info, source->address, 4, ARRAY_SIZE(handler_code), handler_code);
        /* save previous operation to speed to any consecutive read/writes */
        ejtag_info->fast_access_save = write_t;
    }
 
    LOG_DEBUG("%s using 0x%.8" TARGET_PRIxADDR " for write handler", __func__, source->address);
 
    uint32_t jmp_code[] = {
        MIPS32_LUI(isa, 15, UPPER16(source->address)),          /* load addr of jump in $15 */
        MIPS32_ORI(isa, 15, 15, LOWER16(source->address) | isa),    /* isa bit for JR instr */
        MIPS32_JR(isa, 15),                     /* jump to ram program */
        isa ? MIPS32_XORI(isa, 15, 15, 1) : MIPS32_NOP, /* drop isa bit, needed for LW/SW instructions */
    };
 
    pracc_swap16_array(ejtag_info, jmp_code, ARRAY_SIZE(jmp_code));
 
    /* execute jump code, with no address check */
    for (unsigned i = 0; i < ARRAY_SIZE(jmp_code); i++) {
        int retval = wait_for_pracc_rw(ejtag_info);
        if (retval != ERROR_OK)
            return retval;
 
        mips_ejtag_set_instr(ejtag_info, EJTAG_INST_DATA);
        mips_ejtag_drscan_32_out(ejtag_info, jmp_code[i]);
 
        /* Clear the access pending bit (let the processor eat!) */
        mips32_pracc_finish(ejtag_info);
    }
 
    /* wait PrAcc pending bit for FASTDATA write, read address */
    int retval = mips32_pracc_read_ctrl_addr(ejtag_info);
    if (retval != ERROR_OK)
        return retval;
 
    /* next fetch to dmseg should be in FASTDATA_AREA, check */
    if (ejtag_info->pa_addr != MIPS32_PRACC_FASTDATA_AREA)
        return ERROR_FAIL;
 
    /* Send the load start address */
    uint32_t val = addr;
    mips_ejtag_set_instr(ejtag_info, EJTAG_INST_FASTDATA);
    mips_ejtag_fastdata_scan(ejtag_info, 1, &val);
 
    retval = wait_for_pracc_rw(ejtag_info);
    if (retval != ERROR_OK)
        return retval;
 
    /* Send the load end address */
    val = addr + (count - 1) * 4;
    mips_ejtag_set_instr(ejtag_info, EJTAG_INST_FASTDATA);
    mips_ejtag_fastdata_scan(ejtag_info, 1, &val);
 
    unsigned num_clocks = 0;    /* like in legacy code */
    if (ejtag_info->mode != 0)
        num_clocks = ((uint64_t)(ejtag_info->scan_delay) * adapter_get_speed_khz() + 500000) / 1000000;
 
    for (int i = 0; i < count; i++) {
        jtag_add_clocks(num_clocks);
        mips_ejtag_fastdata_scan(ejtag_info, write_t, buf++);
    }
 
    retval = jtag_execute_queue();
    if (retval != ERROR_OK) {
        LOG_ERROR("fastdata load failed");
        return retval;
    }
 
    retval = mips32_pracc_read_ctrl_addr(ejtag_info);
    if (retval != ERROR_OK)
        return retval;
 
    if (ejtag_info->pa_addr != MIPS32_PRACC_TEXT)
        LOG_ERROR("mini program did not return to start");
 
    return retval;
}