spi: add dma channel auto-alloc feature on esp32

components/driver/include/driver/spi_common.h

@@ -105,11 +105,11 @@ typedef struct {
  *
  * @param host_id SPI peripheral that controls this bus
  * @param bus_config Pointer to a spi_bus_config_t struct specifying how the host should be initialized
- * @param dma_chan Either channel 1 or 2, or 0 in the case when no DMA is required. Selecting a DMA channel
- *                 for a SPI bus allows transfers on the bus to have sizes only limited by the amount of
- *                 internal memory. Selecting no DMA channel (by passing the value 0) limits the amount of
- *                 bytes transfered to a maximum of 64. Set to 0 if only the SPI flash uses
- *                 this bus.
+ * @param dma_chan -1: auto dma allocate mode; 0: non-dma mode; 1 or 2: assign a specific DMA channel;
+ *                 Selecting a DMA channel for an SPI bus allows transfers on the bus to have sizes only
+ *                 limited by the amount of internal memory. Selecting no DMA channel (by passing the
+ *                 value 0) limits the amount of bytes transfered to a maximum of 64. Set to 0 if only
+ *                 the SPI flash uses this bus. Set -1 to let the driver to allocate the DMA channel.
  *
  * @warning If a DMA channel is selected, any transmit and receive buffer used should be allocated in
  *          DMA-capable memory.
@@ -120,7 +120,7 @@ typedef struct {
  *
  * @return
  *         - ESP_ERR_INVALID_ARG   if configuration is invalid
- *         - ESP_ERR_INVALID_STATE if host already is in use
+ *         - ESP_ERR_INVALID_STATE if host already is in use or DMA channel is not available
  *         - ESP_ERR_NO_MEM        if out of memory
  *         - ESP_OK                on success
  */

components/driver/include/driver/spi_common_internal.h

@@ -115,19 +115,6 @@ bool spicommon_periph_in_use(spi_host_device_t host);
  */
 bool spicommon_periph_free(spi_host_device_t host);
 
-/**
- * @brief Try to claim a SPI DMA channel
- *
- *  Call this if your driver wants to use SPI with a DMA channnel.
- *
- * @param dma_chan channel to claim
- *
- * @note This public API is deprecated.
- *
- * @return True if success; false otherwise.
- */
-bool spicommon_dma_chan_claim(int dma_chan);
-
 /**
  * @brief Check whether the spi DMA channel is in use.
  *
@@ -151,12 +138,13 @@ bool spicommon_dma_chan_in_use(int dma_chan);
 bool spicommon_dma_chan_free(int dma_chan);
 
 /**
- * @brief Connect SPI and DMA peripherals
+ * @brief Try to claim a SPI DMA channel and connect it with SPI peripherals
  *
- * @param host     SPI peripheral
- * @param dma_chan DMA channel
+ * @param host_id                   SPI host ID
+ * @param dma_chan                  -1: auto dma allocate mode; 0: non-dma mode; 1 or 2: assign a specific DMA channel;
+ * @param[out] out_actual_dma_chan  Actual DMA channel (if you choose to assign a specific DMA channel, this will be the channel you assigned before)
  */
-void spicommon_connect_spi_and_dma(spi_host_device_t host, int dma_chan);
+esp_err_t spicommon_alloc_dma(spi_host_device_t host_id, int dma_chan, uint32_t *out_actual_dma_chan);
 
 /**
  * @brief Connect a SPI peripheral to GPIO pins

components/driver/include/driver/spi_slave.h

@@ -93,9 +93,11 @@ struct spi_slave_transaction_t {
  * @param host SPI peripheral to use as a SPI slave interface
  * @param bus_config Pointer to a spi_bus_config_t struct specifying how the host should be initialized
  * @param slave_config Pointer to a spi_slave_interface_config_t struct specifying the details for the slave interface
- * @param dma_chan Either 1 or 2. A SPI bus used by this driver must have a DMA channel associated with
- *                 it. The SPI hardware has two DMA channels to share. This parameter indicates which
- *                 one to use.
+ * @param dma_chan -1: auto dma allocate mode; 0: non-dma mode; 1 or 2: assign a specific DMA channel;
+ *                 Selecting a DMA channel for an SPI bus allows transfers on the bus to have sizes only
+ *                 limited by the amount of internal memory. Selecting no DMA channel (by passing the
+ *                 value 0) limits the amount of bytes transfered to a maximum of 64. Set to 0 if only
+ *                 the SPI flash uses this bus. Set -1 to let the driver to allocate the DMA channel.
  *
  * @warning If a DMA channel is selected, any transmit and receive buffer used should be allocated in
  *          DMA-capable memory.
@@ -106,7 +108,7 @@ struct spi_slave_transaction_t {
  *
  * @return
  *         - ESP_ERR_INVALID_ARG   if configuration is invalid
- *         - ESP_ERR_INVALID_STATE if host already is in use
+ *         - ESP_ERR_INVALID_STATE if host already is in use or DMA channel is not available
  *         - ESP_ERR_NO_MEM        if out of memory
  *         - ESP_OK                on success
  */

components/driver/include/driver/spi_slave_hd.h

@@ -86,7 +86,7 @@ typedef struct {
     uint32_t address_bits;                      ///< address field bits, multiples of 8 and at least 8.
     uint32_t dummy_bits;                        ///< dummy field bits, multiples of 8 and at least 8.
     uint32_t queue_size;                        ///< Transaction queue size. This sets how many transactions can be 'in the air' (queued using spi_slave_hd_queue_trans but not yet finished using spi_slave_hd_get_trans_result) at the same time
-    uint32_t dma_chan;                          ///< DMA channel used
+    uint32_t dma_chan;                          ///< DMA channel used. -1: auto dma allocate mode; 0: non-dma mode; 1 or 2: assign a specific DMA channel;
     spi_slave_hd_callback_config_t cb_config;   ///< Callback configuration
 } spi_slave_hd_slot_config_t;