[PATCH v9 05/14] spi: imx: fallback to PIO if dma setup failure

[Robin Gong]

Fallback to PIO in case dma setup failed. For example, sdma firmware not
updated but ERR009165 workaroud added in kernel.

Signed-off-by: Robin Gong <yibin.gong@xxxxxxx>
Acked-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
 drivers/spi/spi-imx.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index f4f28a4..b7a85e3 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -71,6 +71,7 @@ struct spi_imx_devtype_data {
 	void (*reset)(struct spi_imx_data *);
 	void (*setup_wml)(struct spi_imx_data *);
 	void (*disable)(struct spi_imx_data *);
+	void (*disable_dma)(struct spi_imx_data *);
 	bool has_dmamode;
 	bool has_slavemode;
 	unsigned int fifo_size;
@@ -485,6 +486,11 @@ static void mx51_ecspi_trigger(struct spi_imx_data *spi_imx)
 	writel(reg, spi_imx->base + MX51_ECSPI_CTRL);
 }
 
+static void mx51_disable_dma(struct spi_imx_data *spi_imx)
+{
+	writel(0, spi_imx->base + MX51_ECSPI_DMA);
+}
+
 static void mx51_ecspi_disable(struct spi_imx_data *spi_imx)
 {
 	u32 ctrl;
@@ -987,6 +993,7 @@ static struct spi_imx_devtype_data imx51_ecspi_devtype_data = {
 	.rx_available = mx51_ecspi_rx_available,
 	.reset = mx51_ecspi_reset,
 	.setup_wml = mx51_setup_wml,
+	.disable_dma = mx51_disable_dma,
 	.fifo_size = 64,
 	.has_dmamode = true,
 	.dynamic_burst = true,
@@ -1001,6 +1008,7 @@ static struct spi_imx_devtype_data imx53_ecspi_devtype_data = {
 	.prepare_transfer = mx51_ecspi_prepare_transfer,
 	.trigger = mx51_ecspi_trigger,
 	.rx_available = mx51_ecspi_rx_available,
+	.disable_dma = mx51_disable_dma,
 	.reset = mx51_ecspi_reset,
 	.fifo_size = 64,
 	.has_dmamode = true,
@@ -1385,6 +1393,7 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
 				DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 	if (!desc_tx) {
 		dmaengine_terminate_all(master->dma_tx);
+		dmaengine_terminate_all(master->dma_rx);
 		return -EINVAL;
 	}
 
@@ -1498,6 +1507,7 @@ 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))
@@ -1506,10 +1516,23 @@ static int spi_imx_transfer(struct spi_device *spi,
 	if (spi_imx->slave_mode)
 		return spi_imx_pio_transfer_slave(spi, transfer);
 
-	if (spi_imx->usedma)
-		return spi_imx_dma_transfer(spi_imx, transfer);
-	else
-		return spi_imx_pio_transfer(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");
+	}
+
+	return spi_imx_pio_transfer(spi, transfer);
 }
 
 static int spi_imx_setup(struct spi_device *spi)
-- 
2.7.4