[PATCH v2 2/2] spi: imx: add fallback feature

From: Robin Gong
Date: Tue Jun 16 2020 - 10:42:57 EST


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@xxxxxxx>
---
drivers/spi/spi-imx.c | 35 ++++++++++++++---------------------
1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index b7a85e3..2b8d339 100644
--- 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);
}
--
2.7.4