spi: imx: add fallback feature

Add fallback pio feature in case  dma transfer failed before start.
Besides, another whole pio transfer including setup_transfer will be
issued by spi core, no need to restore jobs like commit bcd8e7761ec9 ("spi:
imx: fallback to PIO if dma setup failure").

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Link: https://lore.kernel.org/r/1592347329-28363-3-git-send-email-yibin.gong@nxp.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index b7a85e3..2b8d339 100644 (file)
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -224,7 +224,7 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
 {
        struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
 
-       if (!use_dma)
+       if (!use_dma || master->fallback)
                return false;
 
        if (!master->dma_rx)
@@ -1364,11 +1364,12 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 
        ret = spi_imx_dma_configure(master);
        if (ret)
-               return ret;
+               goto dma_failure_no_start;
 
        if (!spi_imx->devtype_data->setup_wml) {
                dev_err(spi_imx->dev, "No setup_wml()?\n");
-               return -EINVAL;
+               ret = -EINVAL;
+               goto dma_failure_no_start;
        }
        spi_imx->devtype_data->setup_wml(spi_imx);
 
@@ -1379,8 +1380,10 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
        desc_rx = dmaengine_prep_slave_sg(master->dma_rx,
                                rx->sgl, rx->nents, DMA_DEV_TO_MEM,
                                DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
-       if (!desc_rx)
-               return -EINVAL;
+       if (!desc_rx) {
+               ret = -EINVAL;
+               goto dma_failure_no_start;
+       }
 
        desc_rx->callback = spi_imx_dma_rx_callback;
        desc_rx->callback_param = (void *)spi_imx;
@@ -1425,6 +1428,10 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
        }
 
        return transfer->len;
+/* fallback to pio */
+dma_failure_no_start:
+       transfer->error |= SPI_TRANS_FAIL_NO_START;
+       return ret;
 }
 
 static int spi_imx_pio_transfer(struct spi_device *spi,
@@ -1507,7 +1514,6 @@ static int spi_imx_transfer(struct spi_device *spi,
                                struct spi_transfer *transfer)
 {
        struct spi_imx_data *spi_imx = spi_master_get_devdata(spi->master);
-       int ret;
 
        /* flush rxfifo before transfer */
        while (spi_imx->devtype_data->rx_available(spi_imx))
@@ -1516,21 +1522,8 @@ static int spi_imx_transfer(struct spi_device *spi,
        if (spi_imx->slave_mode)
                return spi_imx_pio_transfer_slave(spi, transfer);
 
-       /*
-        * fallback PIO mode if dma setup error happen, for example sdma
-        * firmware may not be updated as ERR009165 required.
-        */
-       if (spi_imx->usedma) {
-               ret = spi_imx_dma_transfer(spi_imx, transfer);
-               if (ret != -EINVAL)
-                       return ret;
-
-               spi_imx->devtype_data->disable_dma(spi_imx);
-
-               spi_imx->usedma = false;
-               spi_imx->dynamic_burst = spi_imx->devtype_data->dynamic_burst;
-               dev_dbg(&spi->dev, "Fallback to PIO mode\n");
-       }
+       if (spi_imx->usedma)
+               return spi_imx_dma_transfer(spi_imx, transfer);
 
        return spi_imx_pio_transfer(spi, transfer);
 }