swd.c

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/*
 * This file is part of the libjaylink project.
 *
 * Copyright (C) 2014-2015 Marc Schink <jaylink-dev@marcschink.de>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdint.h>
#include <stdbool.h>

#include "libjaylink.h"
#include "libjaylink-internal.h"

#define CMD_SWD_IO 0xcf

#define SWD_IO_ERR_NO_MEMORY    0x06

JAYLINK_API int jaylink_swd_io(struct jaylink_device_handle *devh,
        const uint8_t *direction, const uint8_t *out, uint8_t *in,
        uint16_t length)
{
    int ret;
    struct jaylink_context *ctx;
    uint16_t num_bytes;
    uint8_t buf[4];
    uint8_t status;

    if (!devh || !direction || !out || !in || !length)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;
    num_bytes = (length + 7) / 8;

    ret = transport_start_write_read(devh, 4 + 2 * num_bytes,
        num_bytes + 1, true);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "transport_start_write_read() failed: %s.",
            jaylink_strerror(ret));
        return ret;
    }

    buf[0] = CMD_SWD_IO;
    buf[1] = 0x00;
    buffer_set_u16(buf, length, 2);

    ret = transport_write(devh, buf, 4);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "transport_write() failed: %s.",
            jaylink_strerror(ret));
        return ret;
    }

    ret = transport_write(devh, direction, num_bytes);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "transport_write() failed: %s.",
            jaylink_strerror(ret));
        return ret;
    }

    ret = transport_write(devh, out, num_bytes);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "transport_write() failed: %s.",
            jaylink_strerror(ret));
        return ret;
    }

    ret = transport_read(devh, in, num_bytes);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "transport_read() failed: %s.",
            jaylink_strerror(ret));
        return ret;
    }

    ret = transport_read(devh, &status, 1);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "transport_read() failed: %s.",
            jaylink_strerror(ret));
        return ret;
    }

    if (status == SWD_IO_ERR_NO_MEMORY) {
        return JAYLINK_ERR_DEV_NO_MEMORY;
    } else if (status > 0) {
        log_err(ctx, "SWD I/O operation failed: 0x%x.", status);
        return JAYLINK_ERR_DEV;
    }

    return JAYLINK_OK;
}