sdmmc: read/write/erase return early on sector count == 0

Closes https://github.com/espressif/esp-idf/issues/10593

components/sdmmc/include/sdmmc_cmd.h

@@ -58,7 +58,7 @@ esp_err_t sdmmc_get_status(sdmmc_card_t* card);
  * @param start_sector  sector where to start writing
  * @param sector_count  number of sectors to write
  * @return
- *      - ESP_OK on success
+ *      - ESP_OK on success or sector_count equal to 0
  *      - One of the error codes from SDMMC host controller
  */
 esp_err_t sdmmc_write_sectors(sdmmc_card_t* card, const void* src,
@@ -74,7 +74,7 @@ esp_err_t sdmmc_write_sectors(sdmmc_card_t* card, const void* src,
  * @param start_sector  sector where to start reading
  * @param sector_count  number of sectors to read
  * @return
- *      - ESP_OK on success
+ *      - ESP_OK on success or sector_count equal to 0
  *      - One of the error codes from SDMMC host controller
  */
 esp_err_t sdmmc_read_sectors(sdmmc_card_t* card, void* dst,
@@ -92,7 +92,7 @@ esp_err_t sdmmc_read_sectors(sdmmc_card_t* card, void* dst,
  * @param sector_count  number of sectors to erase
  * @param arg  erase command (CMD38) argument
  * @return
- *      - ESP_OK on success
+ *      - ESP_OK on success or sector_count equal to 0
  *      - One of the error codes from SDMMC host controller
  */
 esp_err_t sdmmc_erase_sectors(sdmmc_card_t* card, size_t start_sector,

components/sdmmc/sdmmc_cmd.c

@@ -359,6 +359,10 @@ esp_err_t sdmmc_send_cmd_send_status(sdmmc_card_t* card, uint32_t* out_status)
 esp_err_t sdmmc_write_sectors(sdmmc_card_t* card, const void* src,
         size_t start_block, size_t block_count)
 {
+    if (block_count == 0) {
+        return ESP_OK;
+    }
+
     esp_err_t err = ESP_OK;
     size_t block_size = card->csd.sector_size;
     if (esp_ptr_dma_capable(src) && (intptr_t)src % 4 == 0) {
@@ -456,6 +460,10 @@ esp_err_t sdmmc_write_sectors_dma(sdmmc_card_t* card, const void* src,
 esp_err_t sdmmc_read_sectors(sdmmc_card_t* card, void* dst,
         size_t start_block, size_t block_count)
 {
+    if (block_count == 0) {
+        return ESP_OK;
+    }
+
     esp_err_t err = ESP_OK;
     size_t block_size = card->csd.sector_size;
     if (esp_ptr_dma_capable(dst) && (intptr_t)dst % 4 == 0) {
@@ -530,6 +538,10 @@ esp_err_t sdmmc_read_sectors_dma(sdmmc_card_t* card, void* dst,
 esp_err_t sdmmc_erase_sectors(sdmmc_card_t* card, size_t start_sector,
         size_t sector_count, sdmmc_erase_arg_t arg)
 {
+    if (sector_count == 0) {
+        return ESP_OK;
+    }
+
     if (start_sector + sector_count > card->csd.capacity) {
         return ESP_ERR_INVALID_SIZE;
     }

components/sdmmc/test/test_sd.c

@@ -1035,6 +1035,29 @@ TEST_CASE("SDMMC discard test (SD slot 1, 4 line)", "[sd][test_env=UT_T1_SDMODE]
 }
 #endif //WITH_SD_TEST
 
+#if WITH_SD_TEST
+TEST_CASE("sdmmc read/write/erase sector shoud return ESP_OK with sector count == 0", "[sd][test_env=UT_T1_SDMODE]")
+{
+    sd_test_board_power_on();
+    sdmmc_host_t config = SDMMC_HOST_DEFAULT();
+    sdmmc_slot_config_t slot_config = SDMMC_SLOT_CONFIG_DEFAULT();
+    TEST_ESP_OK(sdmmc_host_init());
+
+    TEST_ESP_OK(sdmmc_host_init_slot(SDMMC_HOST_SLOT_1, &slot_config));
+    sdmmc_card_t* card = malloc(sizeof(sdmmc_card_t));
+    TEST_ASSERT_NOT_NULL(card);
+    TEST_ESP_OK(sdmmc_card_init(&config, card));
+
+    TEST_ESP_OK(sdmmc_write_sectors(card, NULL, 0, 0));
+    TEST_ESP_OK(sdmmc_read_sectors(card, NULL, 0, 0));
+    TEST_ESP_OK(sdmmc_erase_sectors(card, 0, 0, SDMMC_ERASE_ARG));
+
+    free(card);
+    TEST_ESP_OK(sdmmc_host_deinit());
+    sd_test_board_power_off();
+}
+#endif //WITH_SD_TEST
+
 #if WITH_EMMC_TEST
 static void test_mmc_sanitize_blocks(sdmmc_card_t* card)
 {