[PATCH v4] dmaengine: Extend NXP QDMA driver to check transmission errors

["Koehrer Mathias (ETAS/EES-SL)" <mathias.koehrer@etas.com>]

Extend NXP QDMA driver to check transmission errors

The NXP QDMA driver (fsl-qdma.c) does not check the status bits
that indicate if a DMA transfer has been completed successfully.
This patch extends the driver to do exactly this.

Signed-off-by: Mathias Koehrer <mathias.koehrer@etas.com>

---
Changelog v2:
- Fix patch format

Changelog v3:
- Fix missing parentheses

Changelog v4:
- Adapt source code formatting

---
Index: linux-5.4/drivers/dma/fsl-qdma.c
===================================================================
--- linux-5.4.orig/drivers/dma/fsl-qdma.c
+++ linux-5.4/drivers/dma/fsl-qdma.c
@@ -56,7 +56,7 @@
 
 /* Registers for bit and genmask */
 #define FSL_QDMA_CQIDR_SQT		BIT(15)
-#define QDMA_CCDF_FOTMAT		BIT(29)
+#define QDMA_CCDF_FORMAT		BIT(29)
 #define QDMA_CCDF_SER			BIT(30)
 #define QDMA_SG_FIN			BIT(30)
 #define QDMA_SG_LEN_MASK		GENMASK(29, 0)
@@ -110,8 +110,19 @@
 #define FSL_QDMA_CMD_DSEN_OFFSET	19
 #define FSL_QDMA_CMD_LWC_OFFSET		16
 
+/* Field definition for Descriptor status */
+#define QDMA_CCDF_STATUS_RTE		BIT(5)
+#define QDMA_CCDF_STATUS_WTE		BIT(4)
+#define QDMA_CCDF_STATUS_CDE		BIT(2)
+#define QDMA_CCDF_STATUS_SDE		BIT(1)
+#define QDMA_CCDF_STATUS_DDE		BIT(0)
+#define QDMA_CCDF_STATUS_MASK		(QDMA_CCDF_STATUS_RTE | \
+					QDMA_CCDF_STATUS_WTE | \
+					QDMA_CCDF_STATUS_CDE | \
+					QDMA_CCDF_STATUS_SDE | \
+					QDMA_CCDF_STATUS_DDE)
+
 /* Field definition for Descriptor offset */
-#define QDMA_CCDF_STATUS		20
 #define QDMA_CCDF_OFFSET		20
 #define QDMA_SDDF_CMD(x)		(((u64)(x)) << 32)
 
@@ -243,13 +254,14 @@ qdma_ccdf_get_offset(const struct fsl_qd
 static inline void
 qdma_ccdf_set_format(struct fsl_qdma_format *ccdf, int offset)
 {
-	ccdf->cfg = cpu_to_le32(QDMA_CCDF_FOTMAT | offset);
+	ccdf->cfg = cpu_to_le32(QDMA_CCDF_FORMAT |
+				(offset << QDMA_CCDF_OFFSET));
 }
 
 static inline int
 qdma_ccdf_get_status(const struct fsl_qdma_format *ccdf)
 {
-	return (le32_to_cpu(ccdf->status) & QDMA_CCDF_MASK) >> QDMA_CCDF_STATUS;
+	return (le32_to_cpu(ccdf->status) & QDMA_CCDF_STATUS_MASK);
 }
 
 static inline void
@@ -618,6 +630,7 @@ fsl_qdma_queue_transfer_complete(struct
 {
 	bool duplicate;
 	u32 reg, i, count;
+	u8 completion_status;
 	struct fsl_qdma_queue *temp_queue;
 	struct fsl_qdma_format *status_addr;
 	struct fsl_qdma_comp *fsl_comp = NULL;
@@ -677,6 +690,8 @@ fsl_qdma_queue_transfer_complete(struct
 		}
 		list_del(&fsl_comp->list);
 
+		completion_status = qdma_ccdf_get_status(status_addr);
+
 		reg = qdma_readl(fsl_qdma, block + FSL_QDMA_BSQMR);
 		reg |= FSL_QDMA_BSQMR_DI;
 		qdma_desc_addr_set64(status_addr, 0x0);
@@ -686,6 +701,31 @@ fsl_qdma_queue_transfer_complete(struct
 		qdma_writel(fsl_qdma, reg, block + FSL_QDMA_BSQMR);
 		spin_unlock(&temp_queue->queue_lock);
 
+		/* The completion_status is evaluated here
+		 * (outside of spin lock)
+		 */
+		if (completion_status) {
+			/* A completion error occurred! */
+			if (completion_status & QDMA_CCDF_STATUS_WTE) {
+				/* Write transaction error */
+				fsl_comp->vdesc.tx_result.result =
+					DMA_TRANS_WRITE_FAILED;
+			} else if (completion_status & QDMA_CCDF_STATUS_RTE) {
+				/* Read transaction error */
+				fsl_comp->vdesc.tx_result.result =
+					DMA_TRANS_READ_FAILED;
+			} else {
+				/* Command/source/destination
+				 * description error
+				 */
+				fsl_comp->vdesc.tx_result.result =
+					DMA_TRANS_ABORTED;
+				dev_err(fsl_qdma->dma_dev.dev,
+					"DMA status descriptor error %x\n",
+					completion_status);
+			}
+		}
+
 		spin_lock(&fsl_comp->qchan->vchan.lock);
 		vchan_cookie_complete(&fsl_comp->vdesc);
 		fsl_comp->qchan->status = DMA_COMPLETE;
@@ -700,11 +740,22 @@ static irqreturn_t fsl_qdma_error_handle
 	unsigned int intr;
 	struct fsl_qdma_engine *fsl_qdma = dev_id;
 	void __iomem *status = fsl_qdma->status_base;
+	unsigned int decfdw0r;
+	unsigned int decfdw1r;
+	unsigned int decfdw2r;
+	unsigned int decfdw3r;
 
 	intr = qdma_readl(fsl_qdma, status + FSL_QDMA_DEDR);
 
-	if (intr)
-		dev_err(fsl_qdma->dma_dev.dev, "DMA transaction error!\n");
+	if (intr) {
+		decfdw0r = qdma_readl(fsl_qdma, status + FSL_QDMA_DECFDW0R);
+		decfdw1r = qdma_readl(fsl_qdma, status + FSL_QDMA_DECFDW1R);
+		decfdw2r = qdma_readl(fsl_qdma, status + FSL_QDMA_DECFDW2R);
+		decfdw3r = qdma_readl(fsl_qdma, status + FSL_QDMA_DECFDW3R);
+		dev_err(fsl_qdma->dma_dev.dev,
+			"DMA transaction error! (%x: %x-%x-%x-%x)\n",
+			intr, decfdw0r, decfdw1r, decfdw2r, decfdw3r);
+	}
 
 	qdma_writel(fsl_qdma, FSL_QDMA_DEDR_CLEAR, status + FSL_QDMA_DEDR);
 	return IRQ_HANDLED;