spi: spi-s3c64xx: Check return values

Check return values in prepare_dma() and s3c64xx_spi_config() and
propagate errors upwards.

Fixes: 788437273f ("spi: s3c64xx: move to generic dmaengine API")
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Łukasz Stelmach <l.stelmach@samsung.com>
Link: https://lore.kernel.org/r/20201002122243.26849-4-l.stelmach@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-s3c64xx.c

@@ -122,6 +122,7 @@
 
 struct s3c64xx_spi_dma_data {
 	struct dma_chan *ch;
+	dma_cookie_t cookie;
 	enum dma_transfer_direction direction;
 };
 
@@ -271,12 +272,13 @@ static void s3c64xx_spi_dmacb(void *data)
 	spin_unlock_irqrestore(&sdd->lock, flags);
 }
 
-static void prepare_dma(struct s3c64xx_spi_dma_data *dma,
+static int prepare_dma(struct s3c64xx_spi_dma_data *dma,
 			struct sg_table *sgt)
 {
 	struct s3c64xx_spi_driver_data *sdd;
 	struct dma_slave_config config;
 	struct dma_async_tx_descriptor *desc;
+	int ret;
 
 	memset(&config, 0, sizeof(config));
 
@@ -300,12 +302,24 @@ static void prepare_dma(struct s3c64xx_spi_dma_data *dma,
 
 	desc = dmaengine_prep_slave_sg(dma->ch, sgt->sgl, sgt->nents,
 				       dma->direction, DMA_PREP_INTERRUPT);
+	if (!desc) {
+		dev_err(&sdd->pdev->dev, "unable to prepare %s scatterlist",
+			dma->direction == DMA_DEV_TO_MEM ? "rx" : "tx");
+		return -ENOMEM;
+	}
 
 	desc->callback = s3c64xx_spi_dmacb;
 	desc->callback_param = dma;
 
-	dmaengine_submit(desc);
+	dma->cookie = dmaengine_submit(desc);
+	ret = dma_submit_error(dma->cookie);
+	if (ret) {
+		dev_err(&sdd->pdev->dev, "DMA submission failed");
+		return -EIO;
+	}
+
 	dma_async_issue_pending(dma->ch);
+	return 0;
 }
 
 static void s3c64xx_spi_set_cs(struct spi_device *spi, bool enable)
@@ -355,11 +369,12 @@ static bool s3c64xx_spi_can_dma(struct spi_master *master,
 	return xfer->len > (FIFO_LVL_MASK(sdd) >> 1) + 1;
 }
 
-static void s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
+static int s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 				    struct spi_transfer *xfer, int dma_mode)
 {
 	void __iomem *regs = sdd->regs;
 	u32 modecfg, chcfg;
+	int ret = 0;
 
 	modecfg = readl(regs + S3C64XX_SPI_MODE_CFG);
 	modecfg &= ~(S3C64XX_SPI_MODE_TXDMA_ON | S3C64XX_SPI_MODE_RXDMA_ON);
@@ -385,7 +400,7 @@ static void s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 		chcfg |= S3C64XX_SPI_CH_TXCH_ON;
 		if (dma_mode) {
 			modecfg |= S3C64XX_SPI_MODE_TXDMA_ON;
-			prepare_dma(&sdd->tx_dma, &xfer->tx_sg);
+			ret = prepare_dma(&sdd->tx_dma, &xfer->tx_sg);
 		} else {
 			switch (sdd->cur_bpw) {
 			case 32:
@@ -417,12 +432,17 @@ static void s3c64xx_enable_datapath(struct s3c64xx_spi_driver_data *sdd,
 			writel(((xfer->len * 8 / sdd->cur_bpw) & 0xffff)
 					| S3C64XX_SPI_PACKET_CNT_EN,
 					regs + S3C64XX_SPI_PACKET_CNT);
-			prepare_dma(&sdd->rx_dma, &xfer->rx_sg);
+			ret = prepare_dma(&sdd->rx_dma, &xfer->rx_sg);
 		}
 	}
 
+	if (ret)
+		return ret;
+
 	writel(modecfg, regs + S3C64XX_SPI_MODE_CFG);
 	writel(chcfg, regs + S3C64XX_SPI_CH_CFG);
+
+	return 0;
 }
 
 static u32 s3c64xx_spi_wait_for_timeout(struct s3c64xx_spi_driver_data *sdd,
@@ -555,9 +575,10 @@ static int s3c64xx_wait_for_pio(struct s3c64xx_spi_driver_data *sdd,
 	return 0;
 }
 
-static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
+static int s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
 {
 	void __iomem *regs = sdd->regs;
+	int ret;
 	u32 val;
 
 	/* Disable Clock */
@@ -605,7 +626,9 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
 
 	if (sdd->port_conf->clk_from_cmu) {
 		/* The src_clk clock is divided internally by 2 */
-		clk_set_rate(sdd->src_clk, sdd->cur_speed * 2);
+		ret = clk_set_rate(sdd->src_clk, sdd->cur_speed * 2);
+		if (ret)
+			return ret;
 	} else {
 		/* Configure Clock */
 		val = readl(regs + S3C64XX_SPI_CLK_CFG);
@@ -619,6 +642,8 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
 		val |= S3C64XX_SPI_ENCLK_ENABLE;
 		writel(val, regs + S3C64XX_SPI_CLK_CFG);
 	}
+
+	return 0;
 }
 
 #define XFER_DMAADDR_INVALID DMA_BIT_MASK(32)
@@ -661,7 +686,9 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
 		sdd->cur_bpw = bpw;
 		sdd->cur_speed = speed;
 		sdd->cur_mode = spi->mode;
-		s3c64xx_spi_config(sdd);
+		status = s3c64xx_spi_config(sdd);
+		if (status)
+			return status;
 	}
 
 	if (!is_polling(sdd) && (xfer->len > fifo_len) &&
@@ -688,10 +715,15 @@ static int s3c64xx_spi_transfer_one(struct spi_master *master,
 		/* Start the signals */
 		s3c64xx_spi_set_cs(spi, true);
 
-		s3c64xx_enable_datapath(sdd, xfer, use_dma);
+		status = s3c64xx_enable_datapath(sdd, xfer, use_dma);
 
 		spin_unlock_irqrestore(&sdd->lock, flags);
 
+		if (status) {
+			dev_err(&spi->dev, "failed to enable data path for transfer: %d\n", status);
+			break;
+		}
+
 		if (use_dma)
 			status = s3c64xx_wait_for_dma(sdd, xfer);
 		else