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fix(sdmmc): Add a better handling of devices accessing PSRAM through DMA

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Closes https://github.com/espressif/esp-idf/issues/18412
This commit is contained in:
Adam Múdry
2026-07-21 15:03:07 +02:00
parent 406ac81a03
commit d52b12fe11
9 changed files with 182 additions and 36 deletions
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components/sdmmc/sdmmc_cmd.c
+18 -16
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@@ -23,6 +23,20 @@ static inline size_t get_chunk_size(const sdmmc_card_t *card)
return (chunk_size != 0) ? chunk_size : 1;
}
/**
* @brief Whether the host can transfer the user buffer directly, without an
* intermediate DMA-capable buffer.
*
* The protocol layer does not need to reason about DMA or PSRAM: it simply asks
* the host driver whether the buffer is usable as-is. The driver accounts for
* alignment and any hardware-specific reachability constraints (e.g. whether the
* peripheral's DMA can reach PSRAM).
*/
static inline bool sdmmc_buffer_directly_usable(const sdmmc_card_t *card, const void *buf, size_t size)
{
return card->host.check_buffer_alignment(card->host.slot, buf, size);
}
static esp_err_t allocate_dma_buf(size_t* actual_size, size_t block_size, void **buf)
{
if (actual_size == NULL || buf == NULL) {
@@ -486,16 +500,10 @@ esp_err_t sdmmc_write_sectors(sdmmc_card_t* card, const void* src,
esp_err_t err = ESP_OK;
size_t block_size = card->csd.sector_size;
bool is_aligned = card->host.check_buffer_alignment(card->host.slot, src, block_size * block_count);
if (is_aligned
#if !SOC_SDMMC_PSRAM_DMA_CAPABLE
&& !esp_ptr_external_ram(src)
#endif
) {
if (sdmmc_buffer_directly_usable(card, src, block_size * block_count)) {
err = sdmmc_write_sectors_dma(card, src, start_block, block_count, block_size * block_count);
} else {
// SDMMC peripheral needs DMA-capable buffers. Split the write into
// The host cannot transfer this buffer directly. Split the write into
// separate (multi) block writes, if needed, and allocate a temporary
// DMA-capable buffer.
size_t chunk_size = get_chunk_size(card);
@@ -649,16 +657,10 @@ esp_err_t sdmmc_read_sectors(sdmmc_card_t* card, void* dst,
esp_err_t err = ESP_OK;
size_t block_size = card->csd.sector_size;
bool is_aligned = card->host.check_buffer_alignment(card->host.slot, dst, block_size * block_count);
if (is_aligned
#if !SOC_SDMMC_PSRAM_DMA_CAPABLE
&& !esp_ptr_external_ram(dst)
#endif
) {
if (sdmmc_buffer_directly_usable(card, dst, block_size * block_count)) {
err = sdmmc_read_sectors_dma(card, dst, start_block, block_count, block_size * block_count);
} else {
// SDMMC peripheral needs DMA-capable buffers. Split the read into
// The host cannot transfer this buffer directly. Split the read into
// separate (multi) block reads, if needed, and allocate a temporary
// DMA-capable buffer.
size_t chunk_size = get_chunk_size(card);