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stm32/sdcard: Fully reset SDMMC periph before calling HAL DMA functions. 

The HAL DMA functions enable SDMMC interrupts before fully resetting the
peripheral, and this can lead to a DTIMEOUT IRQ during the initialisation
of the DMA transfer, which then clears out the DMA state and leads to the
read/write not working at all.  The DTIMEOUT is there from previous SDMMC
DMA transfers, even those that succeeded, and is of duration ~180 seconds,
which is 0xffffffff / 24MHz (default DTIMER value, and clock of
peripheral).

To work around this issue, fully reset the SDMMC peripheral before calling
the HAL SD DMA functions.

Fixes issue #4110.
This commit is contained in:
Damien George 2018-09-12 16:55:46 +10:00
parent e6a6ded74e
commit 9fb1f18cf4
1 changed files with 12 additions and 0 deletions
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12
ports/stm32/sdcard.c
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@ -266,6 +266,16 @@ void SDMMC2_IRQHandler(void) {
}
#endif
STATIC void sdcard_reset_periph(void) {
// Fully reset the SDMMC peripheral before calling HAL SD DMA functions.
// (There could be an outstanding DTIMEOUT event from a previous call and the
// HAL function enables IRQs before fully configuring the SDMMC peripheral.)
sd_handle.Instance->DTIMER = 0;
sd_handle.Instance->DLEN = 0;
sd_handle.Instance->DCTRL = 0;
sd_handle.Instance->ICR = SDMMC_STATIC_FLAGS;
}
STATIC HAL_StatusTypeDef sdcard_wait_finished(SD_HandleTypeDef *sd, uint32_t timeout) {
// Wait for HAL driver to be ready (eg for DMA to finish)
uint32_t start = HAL_GetTick();
@ -340,6 +350,7 @@ mp_uint_t sdcard_read_blocks(uint8_t *dest, uint32_t block_num, uint32_t num_blo
// from reading the peripheral the CPU then reads the new data
MP_HAL_CLEANINVALIDATE_DCACHE(dest, num_blocks * SDCARD_BLOCK_SIZE);
sdcard_reset_periph();
err = HAL_SD_ReadBlocks_DMA(&sd_handle, dest, block_num, num_blocks);
if (err == HAL_OK) {
err = sdcard_wait_finished(&sd_handle, 60000);
@ -406,6 +417,7 @@ mp_uint_t sdcard_write_blocks(const uint8_t *src, uint32_t block_num, uint32_t n
// make sure cache is flushed to RAM so the DMA can read the correct data
MP_HAL_CLEAN_DCACHE(src, num_blocks * SDCARD_BLOCK_SIZE);
sdcard_reset_periph();
err = HAL_SD_WriteBlocks_DMA(&sd_handle, (uint8_t*)src, block_num, num_blocks);
if (err == HAL_OK) {
err = sdcard_wait_finished(&sd_handle, 60000);