linux-kernel - [PATCH 7/8] dmaengine: fsl-edma: wait until no hardware request is in progress

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Message-ID: <20241216075819.2066772-8-larisa.grigore@oss.nxp.com>
Date: Mon, 16 Dec 2024 09:58:17 +0200
From: Larisa Grigore <larisa.grigore@....nxp.com>
To: Frank.Li@....com
Cc: dmaengine@...r.kernel.org,
	imx@...ts.linux.dev,
	linux-kernel@...r.kernel.org,
	s32@....com,
	Christophe Lizzi <clizzi@...hat.com>,
	Alberto Ruiz <aruizrui@...hat.com>,
	Enric Balletbo <eballetb@...hat.com>,
	Larisa Grigore <larisa.grigore@....nxp.com>
Subject: [PATCH 7/8] dmaengine: fsl-edma: wait until no hardware request is in progress

Wait DMA hardware complete cleanup work by checking HRS bit before
disabling the channel to make sure trail data is already written to
memory.

Fixes: 72f5801a4e2b7 ("dmaengine: fsl-edma: integrate v3 support")
Signed-off-by: Larisa Grigore <larisa.grigore@....nxp.com>
---
 drivers/dma/fsl-edma-common.c | 9 +++++++++
 drivers/dma/fsl-edma-common.h | 4 ++++
 2 files changed, 13 insertions(+)

diff --git a/drivers/dma/fsl-edma-common.c b/drivers/dma/fsl-edma-common.c
index 62d51b269e54..d364514f21be 100644
--- a/drivers/dma/fsl-edma-common.c
+++ b/drivers/dma/fsl-edma-common.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
+#include <linux/iopoll.h>
 #include <linux/pm_runtime.h>
 #include <linux/pm_domain.h>
 
@@ -127,11 +128,19 @@ static void fsl_edma_enable_request(struct fsl_edma_chan *fsl_chan)
 
 static void fsl_edma3_disable_request(struct fsl_edma_chan *fsl_chan)
 {
+	struct fsl_edma_engine *fsl_edma = fsl_chan->edma;
+	struct edma_regs *regs = &fsl_chan->edma->regs;
 	u32 val = edma_readl_chreg(fsl_chan, ch_csr);
+	u32 ch = fsl_chan->vchan.chan.chan_id;
 	u32 flags;
 
 	flags = fsl_edma_drvflags(fsl_chan);
 
+	/* Make sure there is no hardware request in progress. */
+	read_poll_timeout(edma_readl, val, !(val & EDMA_V3_MP_HRS_CH(ch)),
+			  EDMA_USEC_POLL, EDMA_USEC_TIMEOUT, false, fsl_edma,
+			  regs->v3.hrs);
+
 	if (flags & FSL_EDMA_DRV_HAS_CHMUX)
 		edma_writel(fsl_chan->edma, 0, fsl_chan->mux_addr);
 
diff --git a/drivers/dma/fsl-edma-common.h b/drivers/dma/fsl-edma-common.h
index 63e908fc3575..ed210bd71681 100644
--- a/drivers/dma/fsl-edma-common.h
+++ b/drivers/dma/fsl-edma-common.h
@@ -70,6 +70,10 @@
 #define EDMA_V3_CH_CSR_ACTIVE      BIT(31)
 #define EDMA_V3_CH_ES_ERR          BIT(31)
 #define EDMA_V3_MP_ES_VLD          BIT(31)
+#define EDMA_V3_MP_HRS_CH(ch)      BIT(ch)
+
+#define EDMA_USEC_POLL		10
+#define EDMA_USEC_TIMEOUT	10000
 
 enum fsl_edma_pm_state {
 	RUNNING = 0,
-- 
2.47.0