adi_v5_swd.c

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// SPDX-License-Identifier: GPL-2.0-or-later
 
/***************************************************************************
 *
 *   Copyright (C) 2010 by David Brownell
 ***************************************************************************/
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
 
#include "arm.h"
#include "arm_adi_v5.h"
#include <helper/time_support.h>
 
#include <transport/transport.h>
#include <jtag/interface.h>
 
#include <jtag/swd.h>
 
/* for debug, set do_sync to true to force synchronous transfers */
static bool do_sync;
 
static struct adiv5_dap *swd_multidrop_selected_dap;
 
 
static int swd_queue_dp_write_inner(struct adiv5_dap *dap, unsigned int reg,
        uint32_t data);
 
 
static int swd_send_sequence(struct adiv5_dap *dap, enum swd_special_seq seq)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    return swd->switch_seq(seq);
}
 
static void swd_finish_read(struct adiv5_dap *dap)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    if (dap->last_read) {
        swd->read_reg(swd_cmd(true, false, DP_RDBUFF), dap->last_read, 0);
        dap->last_read = NULL;
    }
}
 
static void swd_clear_sticky_errors(struct adiv5_dap *dap)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    swd->write_reg(swd_cmd(false, false, DP_ABORT),
        STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
}
 
static int swd_run_inner(struct adiv5_dap *dap)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    int retval;
 
    retval = swd->run();
 
    if (retval != ERROR_OK) {
        /* fault response */
        dap->do_reconnect = true;
    }
 
    return retval;
}
 
static inline int check_sync(struct adiv5_dap *dap)
{
    return do_sync ? swd_run_inner(dap) : ERROR_OK;
}
 
static int swd_queue_dp_bankselect(struct adiv5_dap *dap, unsigned int reg)
{
    /* Only register address 0 and 4 are banked. */
    if ((reg & 0xf) > 4)
        return ERROR_OK;
 
    uint64_t sel = (reg & 0x000000F0) >> 4;
    if (dap->select != DP_SELECT_INVALID)
        sel |= dap->select & ~0xfULL;
 
    if (sel == dap->select)
        return ERROR_OK;
 
    dap->select = sel;
 
    int retval = swd_queue_dp_write_inner(dap, DP_SELECT, (uint32_t)sel);
    if (retval != ERROR_OK)
        dap->select = DP_SELECT_INVALID;
 
    return retval;
}
 
static int swd_queue_dp_read_inner(struct adiv5_dap *dap, unsigned int reg,
        uint32_t *data)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    int retval = swd_queue_dp_bankselect(dap, reg);
    if (retval != ERROR_OK)
        return retval;
 
    swd->read_reg(swd_cmd(true, false, reg), data, 0);
 
    return check_sync(dap);
}
 
static int swd_queue_dp_write_inner(struct adiv5_dap *dap, unsigned int reg,
        uint32_t data)
{
    int retval;
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    swd_finish_read(dap);
 
    if (reg == DP_SELECT) {
        dap->select = data & (DP_SELECT_APSEL | DP_SELECT_APBANK | DP_SELECT_DPBANK);
 
        swd->write_reg(swd_cmd(false, false, reg), data, 0);
 
        retval = check_sync(dap);
        if (retval != ERROR_OK)
            dap->select = DP_SELECT_INVALID;
 
        return retval;
    }
 
    retval = swd_queue_dp_bankselect(dap, reg);
    if (retval != ERROR_OK)
        return retval;
 
    swd->write_reg(swd_cmd(false, false, reg), data, 0);
 
    return check_sync(dap);
}
 
 
static int swd_multidrop_select_inner(struct adiv5_dap *dap, uint32_t *dpidr_ptr,
        uint32_t *dlpidr_ptr, bool clear_sticky)
{
    int retval;
    uint32_t dpidr, dlpidr;
 
    assert(dap_is_multidrop(dap));
 
    swd_send_sequence(dap, LINE_RESET);
    /* From ARM IHI 0074C ADIv6.0, chapter B4.3.3 "Connection and line reset
     * sequence":
     * - line reset sets DP_SELECT_DPBANK to zero;
     * - read of DP_DPIDR takes the connection out of reset;
     * - write of DP_TARGETSEL keeps the connection in reset;
     * - other accesses return protocol error (SWDIO not driven by target).
     *
     * Read DP_DPIDR to get out of reset. Initialize dap->select to zero to
     * skip the write to DP_SELECT, avoiding the protocol error. Set again
     * dap->select to DP_SELECT_INVALID because the rest of the register is
     * unknown after line reset.
     */
    dap->select = 0;
 
    retval = swd_queue_dp_write_inner(dap, DP_TARGETSEL, dap->multidrop_targetsel);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_queue_dp_read_inner(dap, DP_DPIDR, &dpidr);
    if (retval != ERROR_OK)
        return retval;
 
    if (clear_sticky) {
        /* Clear all sticky errors (including ORUN) */
        swd_clear_sticky_errors(dap);
    } else {
        /* Ideally just clear ORUN flag which is set by reset */
        retval = swd_queue_dp_write_inner(dap, DP_ABORT, ORUNERRCLR);
        if (retval != ERROR_OK)
            return retval;
    }
 
    dap->select = DP_SELECT_INVALID;
 
    retval = swd_queue_dp_read_inner(dap, DP_DLPIDR, &dlpidr);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_run_inner(dap);
    if (retval != ERROR_OK)
        return retval;
 
    if ((dpidr & DP_DPIDR_VERSION_MASK) < (2UL << DP_DPIDR_VERSION_SHIFT)) {
        LOG_INFO("Read DPIDR 0x%08" PRIx32
                 " has version < 2. A non multidrop capable device connected?",
                 dpidr);
        return ERROR_FAIL;
    }
 
    /* TODO: check TARGETID if DLIPDR is same for more than one DP */
    uint32_t expected_dlpidr = DP_DLPIDR_PROTVSN |
            (dap->multidrop_targetsel & DP_TARGETSEL_INSTANCEID_MASK);
    if (dlpidr != expected_dlpidr) {
        LOG_INFO("Read incorrect DLPIDR 0x%08" PRIx32
                 " (possibly CTRL/STAT value)",
                 dlpidr);
        return ERROR_FAIL;
    }
 
    LOG_DEBUG_IO("Selected DP_TARGETSEL 0x%08" PRIx32, dap->multidrop_targetsel);
    swd_multidrop_selected_dap = dap;
 
    if (dpidr_ptr)
        *dpidr_ptr = dpidr;
 
    if (dlpidr_ptr)
        *dlpidr_ptr = dlpidr;
 
    return retval;
}
 
static int swd_multidrop_select(struct adiv5_dap *dap)
{
    if (!dap_is_multidrop(dap))
        return ERROR_OK;
 
    if (swd_multidrop_selected_dap == dap)
        return ERROR_OK;
 
    int retval = ERROR_OK;
    for (unsigned int retry = 0; ; retry++) {
        bool clear_sticky = retry > 0;
 
        retval = swd_multidrop_select_inner(dap, NULL, NULL, clear_sticky);
        if (retval == ERROR_OK)
            break;
 
        swd_multidrop_selected_dap = NULL;
        if (retry > 3) {
            LOG_ERROR("Failed to select multidrop %s", adiv5_dap_name(dap));
            return retval;
        }
 
        LOG_DEBUG("Failed to select multidrop %s, retrying...",
                  adiv5_dap_name(dap));
        /* we going to retry localy, do not ask for full reconnect */
        dap->do_reconnect = false;
    }
 
    return retval;
}
 
static int swd_connect_multidrop(struct adiv5_dap *dap)
{
    int retval;
    uint32_t dpidr = 0xdeadbeef;
    uint32_t dlpidr = 0xdeadbeef;
    int64_t timeout = timeval_ms() + 500;
 
    do {
        swd_send_sequence(dap, JTAG_TO_DORMANT);
        swd_send_sequence(dap, DORMANT_TO_SWD);
 
        /* Clear link state, including the SELECT cache. */
        dap->do_reconnect = false;
        dap_invalidate_cache(dap);
        swd_multidrop_selected_dap = NULL;
 
        retval = swd_multidrop_select_inner(dap, &dpidr, &dlpidr, true);
        if (retval == ERROR_OK)
            break;
 
        alive_sleep(1);
 
    } while (timeval_ms() < timeout);
 
    if (retval != ERROR_OK) {
        swd_multidrop_selected_dap = NULL;
        LOG_ERROR("Failed to connect multidrop %s", adiv5_dap_name(dap));
        return retval;
    }
 
    LOG_INFO("SWD DPIDR 0x%08" PRIx32 ", DLPIDR 0x%08" PRIx32,
              dpidr, dlpidr);
 
    return retval;
}
 
static int swd_connect_single(struct adiv5_dap *dap)
{
    int retval;
    uint32_t dpidr = 0xdeadbeef;
    int64_t timeout = timeval_ms() + 500;
 
    do {
        if (dap->switch_through_dormant) {
            swd_send_sequence(dap, JTAG_TO_DORMANT);
            swd_send_sequence(dap, DORMANT_TO_SWD);
        } else {
            swd_send_sequence(dap, JTAG_TO_SWD);
        }
 
        /* Clear link state, including the SELECT cache. */
        dap->do_reconnect = false;
        dap_invalidate_cache(dap);
 
        /* The sequences to enter in SWD (JTAG_TO_SWD and DORMANT_TO_SWD) end
         * with a SWD line reset sequence (50 clk with SWDIO high).
         * From ARM IHI 0074C ADIv6.0, chapter B4.3.3 "Connection and line reset
         * sequence":
         * - line reset sets DP_SELECT_DPBANK to zero;
         * - read of DP_DPIDR takes the connection out of reset;
         * - write of DP_TARGETSEL keeps the connection in reset;
         * - other accesses return protocol error (SWDIO not driven by target).
         *
         * Read DP_DPIDR to get out of reset. Initialize dap->select to zero to
         * skip the write to DP_SELECT, avoiding the protocol error. Set again
         * dap->select to DP_SELECT_INVALID because the rest of the register is
         * unknown after line reset.
         */
        dap->select = 0;
        retval = swd_queue_dp_read_inner(dap, DP_DPIDR, &dpidr);
        if (retval == ERROR_OK) {
            retval = swd_run_inner(dap);
            if (retval == ERROR_OK)
                break;
        }
 
        alive_sleep(1);
 
        dap->switch_through_dormant = !dap->switch_through_dormant;
    } while (timeval_ms() < timeout);
 
    dap->select = DP_SELECT_INVALID;
 
    if (retval != ERROR_OK) {
        LOG_ERROR("Error connecting DP: cannot read IDR");
        return retval;
    }
 
    LOG_INFO("SWD DPIDR 0x%08" PRIx32, dpidr);
 
    do {
        dap->do_reconnect = false;
 
        /* force clear all sticky faults */
        swd_clear_sticky_errors(dap);
 
        retval = swd_run_inner(dap);
        if (retval != ERROR_WAIT)
            break;
 
        alive_sleep(10);
 
    } while (timeval_ms() < timeout);
 
    return retval;
}
 
static int swd_connect(struct adiv5_dap *dap)
{
    int status;
 
    /* FIXME validate transport config ... is the
     * configured DAP present (check IDCODE)?
     */
 
    /* Check if we should reset srst already when connecting, but not if reconnecting. */
    if (!dap->do_reconnect) {
        enum reset_types jtag_reset_config = jtag_get_reset_config();
 
        if (jtag_reset_config & RESET_CNCT_UNDER_SRST) {
            if (jtag_reset_config & RESET_SRST_NO_GATING)
                adapter_assert_reset();
            else
                LOG_WARNING("\'srst_nogate\' reset_config option is required");
        }
    }
 
    if (dap_is_multidrop(dap))
        status = swd_connect_multidrop(dap);
    else
        status = swd_connect_single(dap);
 
    /* IHI 0031E B4.3.2:
     * "A WAIT response must not be issued to the ...
     * ... writes to the ABORT register"
     * swd_clear_sticky_errors() writes to the ABORT register only.
     *
     * Unfortunately at least Microchip SAMD51/E53/E54 returns WAIT
     * in a corner case. Just try if ABORT resolves the problem.
     */
    if (status == ERROR_WAIT) {
        LOG_WARNING("Connecting DP: stalled AP operation, issuing ABORT");
 
        dap->do_reconnect = false;
 
        status = swd_queue_dp_write_inner(dap, DP_ABORT,
            DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR);
 
        if (status == ERROR_OK)
            status = swd_run_inner(dap);
    }
 
    if (status == ERROR_OK)
        status = dap_dp_init(dap);
 
    return status;
}
 
static int swd_check_reconnect(struct adiv5_dap *dap)
{
    if (dap->do_reconnect)
        return swd_connect(dap);
 
    return ERROR_OK;
}
 
static int swd_queue_ap_abort(struct adiv5_dap *dap, uint8_t *ack)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    /* TODO: Send DAPABORT in swd_multidrop_select_inner()
     * in the case the multidrop dap is not selected?
     * swd_queue_ap_abort() is not currently used anyway...
     */
    int retval = swd_multidrop_select(dap);
    if (retval != ERROR_OK)
        return retval;
 
    swd->write_reg(swd_cmd(false, false, DP_ABORT),
        DAPABORT | STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
    return check_sync(dap);
}
 
static int swd_queue_dp_read(struct adiv5_dap *dap, unsigned reg,
        uint32_t *data)
{
    int retval = swd_check_reconnect(dap);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_multidrop_select(dap);
    if (retval != ERROR_OK)
        return retval;
 
    return swd_queue_dp_read_inner(dap, reg, data);
}
 
static int swd_queue_dp_write(struct adiv5_dap *dap, unsigned reg,
        uint32_t data)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    int retval = swd_check_reconnect(dap);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_multidrop_select(dap);
    if (retval != ERROR_OK)
        return retval;
 
    return swd_queue_dp_write_inner(dap, reg, data);
}
 
static int swd_queue_ap_bankselect(struct adiv5_ap *ap, unsigned reg)
{
    int retval;
    struct adiv5_dap *dap = ap->dap;
    uint64_t sel;
 
    if (is_adiv6(dap)) {
        sel = ap->ap_num | (reg & 0x00000FF0);
        if (sel == (dap->select & ~0xfULL))
            return ERROR_OK;
 
        if (dap->select != DP_SELECT_INVALID)
            sel |= dap->select & 0xf;
        dap->select = sel;
        LOG_DEBUG("AP BANKSEL: %" PRIx64, sel);
 
        retval = swd_queue_dp_write(dap, DP_SELECT, (uint32_t)sel);
 
        if (retval == ERROR_OK && dap->asize > 32)
            retval = swd_queue_dp_write(dap, DP_SELECT1, (uint32_t)(sel >> 32));
 
        if (retval != ERROR_OK)
            dap->select = DP_SELECT_INVALID;
 
        return retval;
    }
 
    /* ADIv5 */
    sel = (ap->ap_num << 24) | (reg & 0x000000F0);
    if (dap->select != DP_SELECT_INVALID)
        sel |= dap->select & DP_SELECT_DPBANK;
 
    if (sel == dap->select)
        return ERROR_OK;
 
    dap->select = sel;
 
    retval = swd_queue_dp_write_inner(dap, DP_SELECT, sel);
    if (retval != ERROR_OK)
        dap->select = DP_SELECT_INVALID;
 
    return retval;
}
 
static int swd_queue_ap_read(struct adiv5_ap *ap, unsigned reg,
        uint32_t *data)
{
    struct adiv5_dap *dap = ap->dap;
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    int retval = swd_check_reconnect(dap);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_multidrop_select(dap);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_queue_ap_bankselect(ap, reg);
    if (retval != ERROR_OK)
        return retval;
 
    swd->read_reg(swd_cmd(true, true, reg), dap->last_read, ap->memaccess_tck);
    dap->last_read = data;
 
    return check_sync(dap);
}
 
static int swd_queue_ap_write(struct adiv5_ap *ap, unsigned reg,
        uint32_t data)
{
    struct adiv5_dap *dap = ap->dap;
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    assert(swd);
 
    int retval = swd_check_reconnect(dap);
    if (retval != ERROR_OK)
        return retval;
 
    retval = swd_multidrop_select(dap);
    if (retval != ERROR_OK)
        return retval;
 
    swd_finish_read(dap);
 
    retval = swd_queue_ap_bankselect(ap, reg);
    if (retval != ERROR_OK)
        return retval;
 
    swd->write_reg(swd_cmd(false, true, reg), data, ap->memaccess_tck);
 
    return check_sync(dap);
}
 
static int swd_run(struct adiv5_dap *dap)
{
    int retval = swd_multidrop_select(dap);
    if (retval != ERROR_OK)
        return retval;
 
    swd_finish_read(dap);
 
    return swd_run_inner(dap);
}
 
static void swd_quit(struct adiv5_dap *dap)
{
    const struct swd_driver *swd = adiv5_dap_swd_driver(dap);
    static bool done;
 
    /* There is no difference if the sequence is sent at the last
     * or the first swd_quit() call, send it just once */
    if (done)
        return;
 
    done = true;
    if (dap_is_multidrop(dap)) {
        swd->switch_seq(SWD_TO_DORMANT);
        /* Revisit!
         * Leaving DPs in dormant state was tested and offers some safety
         * against DPs mismatch in case of unintentional use of non-multidrop SWD.
         * To put SWJ-DPs to power-on state issue
         * swd->switch_seq(DORMANT_TO_JTAG);
         */
    } else {
        if (dap->switch_through_dormant) {
            swd->switch_seq(SWD_TO_DORMANT);
            swd->switch_seq(DORMANT_TO_JTAG);
        } else {
            swd->switch_seq(SWD_TO_JTAG);
        }
    }
 
    /* flush the queue to shift out the sequence before exit */
    swd->run();
}
 
const struct dap_ops swd_dap_ops = {
    .connect = swd_connect,
    .send_sequence = swd_send_sequence,
    .queue_dp_read = swd_queue_dp_read,
    .queue_dp_write = swd_queue_dp_write,
    .queue_ap_read = swd_queue_ap_read,
    .queue_ap_write = swd_queue_ap_write,
    .queue_ap_abort = swd_queue_ap_abort,
    .run = swd_run,
    .quit = swd_quit,
};
 
static const struct command_registration swd_commands[] = {
    {
        /*
         * Set up SWD and JTAG targets identically, unless/until
         * infrastructure improves ...  meanwhile, ignore all
         * JTAG-specific stuff like IR length for SWD.
         *
         * REVISIT can we verify "just one SWD DAP" here/early?
         */
        .name = "newdap",
        .jim_handler = jim_jtag_newtap,
        .mode = COMMAND_CONFIG,
        .help = "declare a new SWD DAP"
    },
    COMMAND_REGISTRATION_DONE
};
 
static const struct command_registration swd_handlers[] = {
    {
        .name = "swd",
        .mode = COMMAND_ANY,
        .help = "SWD command group",
        .chain = swd_commands,
        .usage = "",
    },
    COMMAND_REGISTRATION_DONE
};
 
static int swd_select(struct command_context *ctx)
{
    /* FIXME: only place where global 'adapter_driver' is still needed */
    extern struct adapter_driver *adapter_driver;
    const struct swd_driver *swd = adapter_driver->swd_ops;
    int retval;
 
    retval = register_commands(ctx, NULL, swd_handlers);
    if (retval != ERROR_OK)
        return retval;
 
     /* be sure driver is in SWD mode; start
      * with hardware default TRN (1), it can be changed later
      */
    if (!swd || !swd->read_reg || !swd->write_reg || !swd->init) {
        LOG_DEBUG("no SWD driver?");
        return ERROR_FAIL;
    }
 
    retval = swd->init();
    if (retval != ERROR_OK) {
        LOG_DEBUG("can't init SWD driver");
        return retval;
    }
 
    return retval;
}
 
static int swd_init(struct command_context *ctx)
{
    /* nothing done here, SWD is initialized
     * together with the DAP */
    return ERROR_OK;
}
 
static struct transport swd_transport = {
    .name = "swd",
    .select = swd_select,
    .init = swd_init,
};
 
static void swd_constructor(void) __attribute__((constructor));
static void swd_constructor(void)
{
    transport_register(&swd_transport);
}
 
bool transport_is_swd(void)
{
    return get_current_transport() == &swd_transport;
}