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HAL_ChibiOS: implement UART port locking

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This commit is contained in:
Andrew Tridgell 2018-04-02 16:00:36 +10:00
parent 85ae6f60a8
commit e448b5d069
2 changed files with 47 additions and 4 deletions
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40
libraries/AP_HAL_ChibiOS/UARTDriver.cpp
View File

@ -447,8 +447,8 @@ int16_t UARTDriver::read()
/* Empty implementations of Print virtual methods */
size_t UARTDriver::write(uint8_t c)
{
if (!chMtxTryLock(&_write_mutex)) {
return -1;
if (lock_key != 0 || !chMtxTryLock(&_write_mutex)) {
return 0;
}
if (!_initialised) {
@ -473,12 +473,12 @@ size_t UARTDriver::write(uint8_t c)
size_t UARTDriver::write(const uint8_t *buffer, size_t size)
{
if (!_initialised) {
if (!_initialised || lock_key != 0) {
return 0;
}
if (!chMtxTryLock(&_write_mutex)) {
return -1;
return 0;
}
if (_blocking_writes && !unbuffered_writes) {
@ -502,6 +502,38 @@ size_t UARTDriver::write(const uint8_t *buffer, size_t size)
return ret;
}
/*
lock the uart for exclusive use by write_locked() with the right key
*/
bool UARTDriver::lock_port(uint32_t key)
{
if (lock_key && key != lock_key && key != 0) {
// someone else is using it
return false;
}
lock_key = key;
return true;
}
/*
write to a locked port. If port is locked and key is not correct then 0 is returned
and write is discarded. All writes are non-blocking
*/
size_t UARTDriver::write_locked(const uint8_t *buffer, size_t size, uint32_t key)
{
if (lock_key != 0 && key != lock_key) {
return 0;
}
if (!chMtxTryLock(&_write_mutex)) {
return 0;
}
size_t ret = _writebuf.write(buffer, size);
chMtxUnlock(&_write_mutex);
return ret;
}
/*
wait for data to arrive, or a timeout. Return true if data has
arrived, false on timeout

11
libraries/AP_HAL_ChibiOS/UARTDriver.h
View File

@ -46,6 +46,14 @@ public:
size_t write(uint8_t c);
size_t write(const uint8_t *buffer, size_t size);
// lock a port for exclusive use. Use a key of 0 to unlock
bool lock_port(uint32_t key) override;
// write to a locked port. If port is locked and key is not correct then 0 is returned
// and write is discarded
size_t write_locked(const uint8_t *buffer, size_t size, uint32_t key) override;
struct SerialDef {
BaseSequentialStream* serial;
bool is_usb;
@ -87,6 +95,9 @@ private:
// index into uart_drivers table
uint8_t serial_num;
// key for a locked port
uint32_t lock_key;
uint32_t _baudrate;
uint16_t tx_len;