ardupilot/libraries/GCS_MAVLink/GCS_DeviceOp.cpp

/*
   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 3 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/>.
 */
/*
  handle device operations over MAVLink
 */

#include "GCS_config.h"

#if AP_MAVLINK_MSG_DEVICE_OP_ENABLED

#include <AP_HAL/AP_HAL.h>
#include <AP_HAL/Device.h>
#include <AP_HAL/I2CDevice.h>
#include "GCS.h"
#include <stdio.h>

extern const AP_HAL::HAL& hal;

/*
  handle DEVICE_OP_READ message
 */
void GCS_MAVLINK::handle_device_op_read(const mavlink_message_t &msg)
{
    mavlink_device_op_read_t packet;
    mavlink_msg_device_op_read_decode(&msg, &packet);
    AP_HAL::Device *dev = nullptr;
    uint8_t retcode = 0;
    uint8_t data[sizeof(mavlink_device_op_read_reply_t::data)] {};
    bool ret = false;
    uint8_t regstart = packet.regstart;

    if (packet.bustype == DEVICE_OP_BUSTYPE_I2C) {
        dev = hal.i2c_mgr->get_device_ptr(packet.bus, packet.address);
    } else if (packet.bustype == DEVICE_OP_BUSTYPE_SPI) {
        dev = hal.spi->get_device_ptr(packet.busname);
    } else {
        retcode = 1;
        goto fail;
    }
    if (!dev) {
        retcode = 2;
        goto fail;
    }
    if (packet.count > sizeof(data)) {
        retcode = 5;
        goto fail;
    }
    if (!dev->get_semaphore()->take(10)) {
        retcode = 3;
        goto fail;        
    }
    if (regstart == 0xff) {
        // assume raw transfer, non-register interface
        ret = dev->transfer_bank(packet.bank, nullptr, 0, data, packet.count);
        // reply using register start 0 for display purposes
        regstart = 0;
    } else {
        ret = dev->read_bank_registers(packet.bank, packet.regstart, data, packet.count);
    }
    dev->get_semaphore()->give();
    if (!ret) {
        retcode = 4;
        goto fail;
    }
    mavlink_msg_device_op_read_reply_send(
        chan,
        packet.request_id,
        retcode,
        regstart,
        packet.count,
        data,
        packet.bank);
    delete dev;
    return;

fail:
    mavlink_msg_device_op_read_reply_send(
        chan,
        packet.request_id,
        retcode,
        packet.regstart,
        0,
        nullptr,
        packet.bank);
    delete dev;
}

/*
  handle DEVICE_OP_WRITE message
 */
void GCS_MAVLINK::handle_device_op_write(const mavlink_message_t &msg)
{
    mavlink_device_op_write_t packet;
    mavlink_msg_device_op_write_decode(&msg, &packet);
    AP_HAL::Device *dev = nullptr;
    uint8_t retcode = 0;
    
    if (packet.bustype == DEVICE_OP_BUSTYPE_I2C) {
        dev = hal.i2c_mgr->get_device_ptr(packet.bus, packet.address);
    } else if (packet.bustype == DEVICE_OP_BUSTYPE_SPI) {
        dev = hal.spi->get_device_ptr(packet.busname);
    } else {
        retcode = 1;
        goto fail;
    }
    if (!dev) {
        retcode = 2;
        goto fail;
    }
    if (packet.count > sizeof(packet.data)) {
        // bound count against the payload buffer to prevent OOB read
        // from packet.data[i] in the register write loop and OOB read
        // in the raw transfer_bank() path below.
        retcode = 5;
        goto fail;
    }
    if (!dev->get_semaphore()->take(10)) {
        retcode = 3;
        goto fail;        
    }
    if (packet.regstart == 0xff) {
        // assume raw transfer, non-register interface
        if (!dev->transfer_bank(packet.bank, packet.data, packet.count, nullptr, 0)) {
            retcode = 4;
        }
    } else {
        for (uint8_t i=0; i<packet.count; i++) {
            if (!dev->write_bank_register(packet.bank, packet.regstart+i, packet.data[i])) {
                retcode = 4;
                break;
            }
        }
    }
    dev->get_semaphore()->give();

fail:
    mavlink_msg_device_op_write_reply_send(
        chan,
        packet.request_id,
        retcode);

    delete dev;
}

#endif  // AP_MAVLINK_MSG_DEVICE_OP_ENABLED