[PATCH v2 1/1] dmaengine: fsl-dma: fix DMA error when enabling sg if 'DONE' bit is set

[PATCH v2 1/1] dmaengine: fsl-dma: fix DMA error when enabling sg if 'DONE' bit is set

[Frank Li]

In eDMAv3, clearing 'DONE' bit (bit 30) of CHn_CSR is required when
enabling scatter-gather (SG). eDMAv4 does not require this change.

Cc: <stable@vger.kernel.org>
Fixes: 72f5801a4e2b ("dmaengine: fsl-edma: integrate v3 support")
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---

Notes:
    Change from v1 to v2
    - Fixed sparse warning
    
    sparse warnings: (new ones prefixed by >>)
    >> drivers/dma/fsl-edma-common.c:463:21: sparse: sparse: restricted __le16 degrades to integer
       drivers/dma/fsl-edma-common.c:465:21: sparse: sparse: restricted __le16 degrades to integer

 drivers/dma/fsl-edma-common.c | 15 ++++++++++++++-
 drivers/dma/fsl-edma-common.h | 14 +++++++++++++-
 drivers/dma/fsl-edma-main.c   |  2 +-
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
index 70e24e76d73b6..598e72be54097 100644
--- a/drivers/dma/fsl-edma-common.c
+++ b/drivers/dma/fsl-edma-common.c
@@ -454,12 +454,25 @@ static void fsl_edma_set_tcd_regs(struct fsl_edma_chan *fsl_chan,
 
 	edma_write_tcdreg(fsl_chan, tcd->dlast_sga, dlast_sga);
 
+	csr = le16_to_cpu(tcd->csr);
+
 	if (fsl_chan->is_sw) {
-		csr = le16_to_cpu(tcd->csr);
 		csr |= EDMA_TCD_CSR_START;
 		tcd->csr = cpu_to_le16(csr);
 	}
 
+	/*
+	 * Must clear CHn_CSR[DONE] bit before enable TCDn_CSR[ESG] at EDMAv3
+	 * eDMAv4 have not such requirement.
+	 * Change MLINK need clear CHn_CSR[DONE] for both eDMAv3 and eDMAv4.
+	 */
+	if (((fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_CLEAR_DONE_E_SG) &&
+		(csr & EDMA_TCD_CSR_E_SG)) ||
+	    ((fsl_edma_drvflags(fsl_chan) & FSL_EDMA_DRV_CLEAR_DONE_E_LINK) &&
+		(csr & EDMA_TCD_CSR_E_LINK)))
+		edma_writel_chreg(fsl_chan, edma_readl_chreg(fsl_chan, ch_csr), ch_csr);
+
+
 	edma_write_tcdreg(fsl_chan, tcd->csr, csr);
 }
 
diff --git a/drivers/dma/fsl-edma-common.h b/drivers/dma/fsl-edma-common.h
index 453c997d0119a..fc0bdf6d16a96 100644
--- a/drivers/dma/fsl-edma-common.h
+++ b/drivers/dma/fsl-edma-common.h
@@ -183,11 +183,23 @@ struct fsl_edma_desc {
 #define FSL_EDMA_DRV_BUS_8BYTE		BIT(10)
 #define FSL_EDMA_DRV_DEV_TO_DEV		BIT(11)
 #define FSL_EDMA_DRV_ALIGN_64BYTE	BIT(12)
+/* Need clean CHn_CSR DONE before enable TCD's ESG */
+#define FSL_EDMA_DRV_CLEAR_DONE_E_SG	BIT(13)
+/* Need clean CHn_CSR DONE before enable TCD's MAJORELINK */
+#define FSL_EDMA_DRV_CLEAR_DONE_E_LINK	BIT(14)
 
 #define FSL_EDMA_DRV_EDMA3	(FSL_EDMA_DRV_SPLIT_REG |	\
 				 FSL_EDMA_DRV_BUS_8BYTE |	\
 				 FSL_EDMA_DRV_DEV_TO_DEV |	\
-				 FSL_EDMA_DRV_ALIGN_64BYTE)
+				 FSL_EDMA_DRV_ALIGN_64BYTE |	\
+				 FSL_EDMA_DRV_CLEAR_DONE_E_SG |	\
+				 FSL_EDMA_DRV_CLEAR_DONE_E_LINK)
+
+#define FSL_EDMA_DRV_EDMA4	(FSL_EDMA_DRV_SPLIT_REG |	\
+				 FSL_EDMA_DRV_BUS_8BYTE |	\
+				 FSL_EDMA_DRV_DEV_TO_DEV |	\
+				 FSL_EDMA_DRV_ALIGN_64BYTE |	\
+				 FSL_EDMA_DRV_CLEAR_DONE_E_LINK)
 
 struct fsl_edma_drvdata {
 	u32			dmamuxs; /* only used before v3 */
diff --git a/drivers/dma/fsl-edma-main.c b/drivers/dma/fsl-edma-main.c
index 2c20460e53aa9..4f8312b64f144 100644
--- a/drivers/dma/fsl-edma-main.c
+++ b/drivers/dma/fsl-edma-main.c
@@ -357,7 +357,7 @@ static struct fsl_edma_drvdata imx93_data3 = {
 };
 
 static struct fsl_edma_drvdata imx93_data4 = {
-	.flags = FSL_EDMA_DRV_HAS_CHMUX | FSL_EDMA_DRV_HAS_DMACLK | FSL_EDMA_DRV_EDMA3,
+	.flags = FSL_EDMA_DRV_HAS_CHMUX | FSL_EDMA_DRV_HAS_DMACLK | FSL_EDMA_DRV_EDMA4,
 	.chreg_space_sz = 0x8000,
 	.chreg_off = 0x10000,
 	.setup_irq = fsl_edma3_irq_init,
-- 
2.34.1

Re: [PATCH v2 1/1] dmaengine: fsl-dma: fix DMA error when enabling sg if 'DONE' bit is set

[Vinod Koul]

On Thu, 21 Sep 2023 10:46:52 -0400, Frank Li wrote:
> In eDMAv3, clearing 'DONE' bit (bit 30) of CHn_CSR is required when
> enabling scatter-gather (SG). eDMAv4 does not require this change.
> 
> 

Applied, thanks!

[1/1] dmaengine: fsl-dma: fix DMA error when enabling sg if 'DONE' bit is set
      commit: 3c67c5236fbf7a58c1a26d57da4465ea5fb25537

Best regards,
-- 
~Vinod