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sdmmc: fill as many DMA descriptors as possible

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This commit is contained in:
Ivan Grokhotkov 2018-03-06 17:18:05 +08:00
parent 20a8c3318a
commit 5f97e6bebb
1 changed files with 25 additions and 1 deletions
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26
components/driver/sdmmc_transaction.c
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@ -78,6 +78,7 @@ static esp_err_t handle_event(sdmmc_command_t* cmd, sdmmc_req_state_t* pstate);
static esp_err_t process_events(sdmmc_event_t evt, sdmmc_command_t* cmd, sdmmc_req_state_t* pstate);
static void process_command_response(uint32_t status, sdmmc_command_t* cmd);
static void fill_dma_descriptors(size_t num_desc);
static size_t get_free_descriptors_count();
esp_err_t sdmmc_host_transaction_handler_init()
{
@ -167,6 +168,28 @@ esp_err_t sdmmc_host_do_transaction(int slot, sdmmc_command_t* cmdinfo)
return ret;
}
static size_t get_free_descriptors_count()
{
const size_t next = s_cur_transfer.next_desc;
size_t count = 0;
/* Starting with the current DMA descriptor, count the number of
* descriptors which have 'owned_by_idmac' set to 0. These are the
* descriptors already processed by the DMA engine.
*/
for (size_t i = 0; i < SDMMC_DMA_DESC_CNT; ++i) {
sdmmc_desc_t* desc = &s_dma_desc[(next + i) % SDMMC_DMA_DESC_CNT];
if (desc->owned_by_idmac) {
break;
}
++count;
if (desc->next_desc_ptr == NULL) {
/* final descriptor in the chain */
break;
}
}
return count;
}
static void fill_dma_descriptors(size_t num_desc)
{
for (size_t i = 0; i < num_desc; ++i) {
@ -376,7 +399,8 @@ static esp_err_t process_events(sdmmc_event_t evt, sdmmc_command_t* cmd, sdmmc_r
if (mask_check_and_clear(&evt.dma_status, SDMMC_DMA_DONE_MASK)) {
s_cur_transfer.desc_remaining--;
if (s_cur_transfer.size_remaining) {
fill_dma_descriptors(1);
int desc_to_fill = get_free_descriptors_count();
fill_dma_descriptors(desc_to_fill);
sdmmc_host_dma_resume();
}
if (s_cur_transfer.desc_remaining == 0) {