diff options
| -rw-r--r-- | ports/stm32/spi.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/ports/stm32/spi.c b/ports/stm32/spi.c index 3cd470ccb..2b5bdb038 100644 --- a/ports/stm32/spi.c +++ b/ports/stm32/spi.c @@ -404,11 +404,16 @@ void spi_deinit(SPI_HandleTypeDef *spi) { } STATIC HAL_StatusTypeDef spi_wait_dma_finished(SPI_HandleTypeDef *spi, uint32_t timeout) { - // Note: we can't use WFI to idle in this loop because the DMA completion - // interrupt may occur before the WFI. Hence we miss it and have to wait - // until the next sys-tick (up to 1ms). uint32_t start = HAL_GetTick(); - while (HAL_SPI_GetState(spi) != HAL_SPI_STATE_READY) { + for (;;) { + // Do an atomic check of the state; WFI will exit even if IRQs are disabled + uint32_t irq_state = disable_irq(); + if (spi->State == HAL_SPI_STATE_READY) { + enable_irq(irq_state); + return HAL_OK; + } + __WFI(); + enable_irq(irq_state); if (HAL_GetTick() - start >= timeout) { return HAL_TIMEOUT; } |