spi_slave: fix the issue rx dma get broken by master unexpected transaction

components/driver/include/driver/spi_common.h

@@ -180,6 +180,26 @@ void spicommon_setup_dma_desc_links(lldesc_t *dmadesc, int len, const uint8_t *d
  */
 spi_dev_t *spicommon_hw_for_host(spi_host_device_t host);
 
+
+/** Temporarily connect CS signal input to high to avoid slave detecting unexpected transactions.
+ *
+ * @note Don't use this in the application.
+ *
+ * @param host The spi host.
+ */
+void spicommon_freeze_cs(spi_host_device_t host);
+
+/** Use this function instead of cs_initial to avoid overwrite the output config
+ *  This is used in test by internal gpio matrix connections
+ *
+ * @note Don't use this in the application.
+ *
+ * @param host The spi host.
+ * @param cs_io_num GPIO number of the CS pin.
+ * @param iomux The peripheral is using iomux pins.
+ */
+void spicommon_restore_cs(spi_host_device_t host, int cs_io_num, bool iomux);
+
 /**
  * @brief Get the IRQ source for a specific SPI host
  *

components/driver/spi_common.c

@@ -371,6 +371,26 @@ void IRAM_ATTR spicommon_setup_dma_desc_links(lldesc_t *dmadesc, int len, const
     dmadesc[n - 1].qe.stqe_next = NULL;
 }
 
+void spicommon_freeze_cs(spi_host_device_t host)
+{
+    gpio_matrix_in(0x38, io_signal[host].spics_in, false);
+}
+
+static void IOMUX_IN(uint32_t gpio, uint32_t signal_idx)
+{
+    GPIO.func_in_sel_cfg[signal_idx].sig_in_sel = 0;
+    PIN_INPUT_ENABLE(GPIO_PIN_MUX_REG[gpio]);
+}
+
+void spicommon_restore_cs(spi_host_device_t host, int cs_io_num, bool iomux)
+{
+    if (iomux) {
+        IOMUX_IN(cs_io_num, io_signal[host].spics_in);
+    } else {
+        gpio_matrix_in(cs_io_num, io_signal[host].spics_in, false);
+    }
+}
+
 
 /*
 Code for workaround for DMA issue in ESP32 v0/v1 silicon

components/driver/spi_slave.c

@@ -50,6 +50,7 @@ static const char *SPI_TAG = "spi_slave";
 #define VALID_HOST(x) (x>SPI_HOST && x<=VSPI_HOST)
 
 typedef struct {
+    int id;
     spi_slave_interface_config_t cfg;
     intr_handle_t intr;
     spi_dev_t *hw;
@@ -92,10 +93,13 @@ esp_err_t spi_slave_initialize(spi_host_device_t host, const spi_bus_config_t *b
     if (spihost[host] == NULL) goto nomem;
     memset(spihost[host], 0, sizeof(spi_slave_t));
     memcpy(&spihost[host]->cfg, slave_config, sizeof(spi_slave_interface_config_t));
+    spihost[host]->id = host;
 
     spicommon_bus_initialize_io(host, bus_config, dma_chan, SPICOMMON_BUSFLAG_SLAVE, &native);
     gpio_set_direction(slave_config->spics_io_num, GPIO_MODE_INPUT);
     spicommon_cs_initialize(host, slave_config->spics_io_num, 0, native==false);
+    // The slave DMA suffers from unexpected transactions. Forbid reading if DMA is enabled by disabling the CS line.
+    if (dma_chan != 0) spicommon_freeze_cs(host);
     spihost[host]->no_gpio_matrix = native;
     spihost[host]->dma_chan = dma_chan;
     if (dma_chan != 0) {
@@ -325,6 +329,9 @@ static void IRAM_ATTR spi_intr(void *arg)
     if (!host->hw->slave.trans_done) return;
 
     if (host->cur_trans) {
+        // When DMA is enabled, the slave rx dma suffers from unexpected transactions. Forbid reading until transaction ready.
+        if (host->dma_chan != 0) spicommon_freeze_cs(host->id);
+
         //when data of cur_trans->length are all sent, the slv_rdata_bit
         //will be the length sent-1 (i.e. cur_trans->length-1 ), otherwise
         //the length sent.
@@ -433,6 +440,9 @@ static void IRAM_ATTR spi_intr(void *arg)
         host->hw->user.usr_mosi = (trans->tx_buffer == NULL) ? 0 : 1;
         host->hw->user.usr_miso = (trans->rx_buffer == NULL) ? 0 : 1;
 
+        //The slave rx dma get disturbed by unexpected transaction. Only connect the CS when slave is ready.
+        if (host->dma_chan != 0) spicommon_restore_cs(host->id, host->cfg.spics_io_num, host->no_gpio_matrix);
+
         //Kick off transfer
         host->hw->cmd.usr = 1;
         if (host->cfg.post_setup_cb) host->cfg.post_setup_cb(trans);