swo.c

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/*
 * This file is part of the libjaylink project.
 *
 * Copyright (C) 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_SWO         0xeb

#define SWO_CMD_START       0x64
#define SWO_CMD_STOP        0x65
#define SWO_CMD_READ        0x66
#define SWO_CMD_GET_SPEEDS  0x6e

#define SWO_PARAM_MODE      0x01
#define SWO_PARAM_BAUDRATE  0x02
#define SWO_PARAM_READ_SIZE 0x03
#define SWO_PARAM_BUFFER_SIZE   0x04

#define SWO_ERR         0x80000000

JAYLINK_API int jaylink_swo_start(struct jaylink_device_handle *devh,
        enum jaylink_swo_mode mode, uint32_t baudrate, uint32_t size)
{
    int ret;
    struct jaylink_context *ctx;
    uint8_t buf[32];
    uint32_t status;

    if (!devh || !baudrate || !size)
        return JAYLINK_ERR_ARG;

    if (mode != JAYLINK_SWO_MODE_UART)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;
    ret = transport_start_write_read(devh, 21, 4, true);

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

    buf[0] = CMD_SWO;
    buf[1] = SWO_CMD_START;

    buf[2] = 0x04;
    buf[3] = SWO_PARAM_MODE;
    buffer_set_u32(buf, mode, 4);

    buf[8] = 0x04;
    buf[9] = SWO_PARAM_BAUDRATE;
    buffer_set_u32(buf, baudrate, 10);

    buf[14] = 0x04;
    buf[15] = SWO_PARAM_BUFFER_SIZE;
    buffer_set_u32(buf, size, 16);

    buf[20] = 0x00;

    ret = transport_write(devh, buf, 21);

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

    ret = transport_read(devh, buf, 4);

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

    status = buffer_get_u32(buf, 0);

    if (status > 0) {
        log_err(ctx, "Failed to start capture: 0x%x.", status);
        return JAYLINK_ERR_DEV;
    }

    return JAYLINK_OK;
}

JAYLINK_API int jaylink_swo_stop(struct jaylink_device_handle *devh)
{
    int ret;
    struct jaylink_context *ctx;
    uint8_t buf[4];
    uint32_t status;

    if (!devh)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;
    ret = transport_start_write_read(devh, 3, 4, true);

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

    buf[0] = CMD_SWO;
    buf[1] = SWO_CMD_STOP;
    buf[2] = 0x00;

    ret = transport_write(devh, buf, 3);

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

    ret = transport_read(devh, buf, 4);

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

    status = buffer_get_u32(buf, 0);

    if (status > 0) {
        log_err(ctx, "Failed to stop capture: 0x%x.", status);
        return JAYLINK_ERR_DEV;
    }

    return JAYLINK_OK;
}

JAYLINK_API int jaylink_swo_read(struct jaylink_device_handle *devh,
        uint8_t *buffer, uint32_t *length)
{
    int ret;
    struct jaylink_context *ctx;
    uint8_t buf[32];
    uint32_t status;
    uint32_t tmp;

    if (!devh || !buffer || !length)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;
    ret = transport_start_write_read(devh, 9, 8, true);

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

    buf[0] = CMD_SWO;
    buf[1] = SWO_CMD_READ;

    buf[2] = 0x04;
    buf[3] = SWO_PARAM_READ_SIZE;
    buffer_set_u32(buf, *length, 4);

    buf[8] = 0x00;

    ret = transport_write(devh, buf, 9);

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

    ret = transport_read(devh, buf, 8);

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

    status = buffer_get_u32(buf, 0);
    tmp = buffer_get_u32(buf, 4);

    if (tmp > *length) {
        log_err(ctx, "Received %u bytes but only %u bytes were "
            "requested.", tmp, *length);
        return JAYLINK_ERR_PROTO;
    }

    *length = tmp;

    if (tmp > 0) {
        ret = transport_start_read(devh, tmp);

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

        ret = transport_read(devh, buffer, tmp);

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

    if (status > 0) {
        log_err(ctx, "Failed to read data: 0x%x.", status);
        return JAYLINK_ERR_DEV;
    }

    return JAYLINK_OK;
}

JAYLINK_API int jaylink_swo_get_speeds(struct jaylink_device_handle *devh,
        enum jaylink_swo_mode mode, struct jaylink_swo_speed *speed)
{
    int ret;
    struct jaylink_context *ctx;
    uint8_t buf[24];
    uint32_t tmp;
    uint32_t length;

    if (!devh || !speed)
        return JAYLINK_ERR_ARG;

    if (mode != JAYLINK_SWO_MODE_UART)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;
    ret = transport_start_write_read(devh, 9, 4, true);

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

    buf[0] = CMD_SWO;
    buf[1] = SWO_CMD_GET_SPEEDS;

    buf[2] = 0x04;
    buf[3] = SWO_PARAM_MODE;
    buffer_set_u32(buf, mode, 4);

    buf[8] = 0x00;

    ret = transport_write(devh, buf, 9);

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

    ret = transport_read(devh, buf, 4);

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

    tmp = buffer_get_u32(buf, 0);

    if (tmp & SWO_ERR) {
        log_err(ctx, "Failed to retrieve speed information: 0x%x.",
            tmp);
        return JAYLINK_ERR_DEV;
    }

    length = tmp;

    if (length != 28) {
        log_err(ctx, "Unexpected number of bytes received: %u.",
            length);
        return JAYLINK_ERR_PROTO;
    }

    length = length - 4;
    ret = transport_start_read(devh, length);

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

    ret = transport_read(devh, buf, length);

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

    speed->freq = buffer_get_u32(buf, 4);
    speed->min_div = buffer_get_u32(buf, 8);

    if (!speed->min_div) {
        log_err(ctx, "Minimum frequency divider is zero.");
        return JAYLINK_ERR_PROTO;
    }

    speed->max_div = buffer_get_u32(buf, 12);

    if (speed->max_div < speed->min_div) {
        log_err(ctx, "Maximum frequency divider is less than minimum "
            "frequency divider.");
        return JAYLINK_ERR_PROTO;
    }

    speed->min_prescaler = buffer_get_u32(buf, 16);
    speed->max_prescaler = buffer_get_u32(buf, 20);

    if (speed->max_prescaler < speed->min_prescaler) {
        log_err(ctx, "Maximum prescaler is less than minimum "
            "prescaler.");
        return JAYLINK_ERR_PROTO;
    }

    return JAYLINK_OK;
}