spi: stm32: use dma_get_slave_caps prior to configuring dma channel

First check the dma channel capabilities (max burst) before
configuring the dma channel.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://msgid.link/r/20231218155721.359198-2-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index f48e4dc..af0c27d 100644 (file)
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1157,15 +1157,19 @@ static void stm32_spi_dma_rx_cb(void *data)
  * stm32_spi_dma_config - configure dma slave channel depending on current
  *                       transfer bits_per_word.
  * @spi: pointer to the spi controller data structure
+ * @dma_chan: pointer to the DMA channel
  * @dma_conf: pointer to the dma_slave_config structure
  * @dir: direction of the dma transfer
  */
 static void stm32_spi_dma_config(struct stm32_spi *spi,
+                                struct dma_chan *dma_chan,
                                 struct dma_slave_config *dma_conf,
                                 enum dma_transfer_direction dir)
 {
        enum dma_slave_buswidth buswidth;
+       struct dma_slave_caps caps;
        u32 maxburst;
+       int ret;
 
        if (spi->cur_bpw <= 8)
                buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE;
@@ -1184,6 +1188,11 @@ static void stm32_spi_dma_config(struct stm32_spi *spi,
                maxburst = 1;
        }
 
+       /* Get the DMA channel caps, and adjust maxburst if possible */
+       ret = dma_get_slave_caps(dma_chan, &caps);
+       if (!ret)
+               maxburst = min(maxburst, caps.max_burst);
+
        memset(dma_conf, 0, sizeof(struct dma_slave_config));
        dma_conf->direction = dir;
        if (dma_conf->direction == DMA_DEV_TO_MEM) { /* RX */
@@ -1366,7 +1375,7 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
 
        rx_dma_desc = NULL;
        if (spi->rx_buf && spi->dma_rx) {
-               stm32_spi_dma_config(spi, &rx_dma_conf, DMA_DEV_TO_MEM);
+               stm32_spi_dma_config(spi, spi->dma_rx, &rx_dma_conf, DMA_DEV_TO_MEM);
                dmaengine_slave_config(spi->dma_rx, &rx_dma_conf);
 
                /* Enable Rx DMA request */
@@ -1382,7 +1391,7 @@ static int stm32_spi_transfer_one_dma(struct stm32_spi *spi,
 
        tx_dma_desc = NULL;
        if (spi->tx_buf && spi->dma_tx) {
-               stm32_spi_dma_config(spi, &tx_dma_conf, DMA_MEM_TO_DEV);
+               stm32_spi_dma_config(spi, spi->dma_tx, &tx_dma_conf, DMA_MEM_TO_DEV);
                dmaengine_slave_config(spi->dma_tx, &tx_dma_conf);
 
                tx_dma_desc = dmaengine_prep_slave_sg(