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Code Issues Releases Activity

PIOS SPI: Add a second claim bus method for use in ISR. This has no timeout

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and uses an ISR safe queue claiming method.  This avoids deadlocks when ISR
blocks other tasks from freeing the bus.
This commit is contained in:
James Cotton 2012-01-21 09:07:06 -06:00
parent ec903449cd
commit ff0bd87f4e
2 changed files with 22 additions and 0 deletions
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21
flight/PiOS/STM32F4xx/pios_spi.c
View File

@ -247,6 +247,27 @@ int32_t PIOS_SPI_ClaimBus(uint32_t spi_id)
return 0;
}
/**
* Claim the SPI bus semaphore from an ISR. Has no timeout.
* \param[in] spi SPI number (0 or 1)
* \return 0 if no error
* \return -1 if timeout before claiming semaphore
*/
int32_t PIOS_SPI_ClaimBusISR(uint32_t spi_id)
{
#if defined(PIOS_INCLUDE_FREERTOS)
struct pios_spi_dev * spi_dev = (struct pios_spi_dev *)spi_id;
bool valid = PIOS_SPI_validate(spi_dev);
PIOS_Assert(valid)
if (xQueueGenericReceive(( xQueueHandle ) spi_dev->busy, NULL, 0x0000 , pdFALSE ) != pdTRUE)
return -1;
#endif
return 0;
}
/**
* Release the SPI bus semaphore. Calling the SPI functions does not require this
* \param[in] spi SPI number (0 or 1)

1
flight/PiOS/inc/pios_spi.h
View File

@ -54,6 +54,7 @@ extern int32_t PIOS_SPI_TransferByte(uint32_t spi_id, uint8_t b);
extern int32_t PIOS_SPI_TransferBlock(uint32_t spi_id, const uint8_t *send_buffer, uint8_t *receive_buffer, uint16_t len, void *callback);
extern int32_t PIOS_SPI_Busy(uint32_t spi_id);
extern int32_t PIOS_SPI_ClaimBus(uint32_t spi_id);
extern int32_t PIOS_SPI_ClaimBusISR(uint32_t spi_id);
extern int32_t PIOS_SPI_ReleaseBus(uint32_t spi_id);
extern void PIOS_SPI_IRQ_Handler(uint32_t spi_id);
extern void PIOS_SPI_SetPrescalar(uint32_t spi_id, uint32_t prescalar);