openwrt/target/linux/layerscape/patches-5.4/806-dma-0021-MLK-21443-dmaengine-fsl-edma-v3-clear-pending-irq-be.patch

From 63c3fd953a620873c722494355a345643607c0a2 Mon Sep 17 00:00:00 2001
From: Robin Gong <yibin.gong@nxp.com>
Date: Thu, 11 Apr 2019 14:36:37 +0800
Subject: [PATCH] MLK-21443: dmaengine: fsl-edma-v3: clear pending irq before
 request irq

edma interrupt maybe happened during reboot or watchdog reset, meanwhile
gic never power down on i.mx8QM/QXP, thus the unexpect irq will come in
once edma driver request irq at probe phase. Unfortunately, at that time
that edma channel's power domain which power-up by customer driver such
as audio/uart driver may not be ready, so kernel panic triggered once
touch such edma registers which still not power up in interrupt handler.
Move request irq from probe to alloc dma channel so that edma channel's
power domain has already been powered, besides, clear meaningless
interrupt before request irq.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Acked-by: Fugang Duan <fugang.duan@nxp.com>
(cherry picked from commit 0a0d8f8b944094342fda18f23f3ac13b8a73871d)
---
 drivers/dma/fsl-edma-v3.c | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

--- a/drivers/dma/fsl-edma-v3.c
+++ b/drivers/dma/fsl-edma-v3.c
@@ -162,7 +162,8 @@ struct fsl_edma3_chan {
 	int				is_dfifo;
 	struct dma_pool			*tcd_pool;
 	u32				chn_real_count;
-	char				txirq_name[32];
+	char                            txirq_name[32];
+	struct platform_device		*pdev;
 };
 
 struct fsl_edma3_desc {
@@ -180,6 +181,7 @@ struct fsl_edma3_reg_save {
 
 struct fsl_edma3_engine {
 	struct dma_device	dma_dev;
+	unsigned long		irqflag;
 	struct mutex		fsl_edma3_mutex;
 	u32			n_chans;
 	int			errirq;
@@ -790,10 +792,23 @@ static struct dma_chan *fsl_edma3_xlate(
 static int fsl_edma3_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct fsl_edma3_chan *fsl_chan = to_fsl_edma3_chan(chan);
+	struct platform_device *pdev = fsl_chan->pdev;
+	int ret;
 
 	fsl_chan->tcd_pool = dma_pool_create("tcd_pool", chan->device->dev,
 				sizeof(struct fsl_edma3_hw_tcd),
 				32, 0);
+	/* clear meaningless pending irq anyway */
+	writel(1, fsl_chan->membase + EDMA_CH_INT);
+	ret = devm_request_irq(&pdev->dev, fsl_chan->txirq,
+			fsl_edma3_tx_handler, fsl_chan->edma3->irqflag,
+			fsl_chan->txirq_name, fsl_chan);
+	if (ret) {
+		dev_err(&pdev->dev, "Can't register %s IRQ.\n",
+			fsl_chan->txirq_name);
+		return ret;
+	}
+
 	return 0;
 }
 
@@ -803,6 +818,8 @@ static void fsl_edma3_free_chan_resource
 	unsigned long flags;
 	LIST_HEAD(head);
 
+	devm_free_irq(&fsl_chan->pdev->dev, fsl_chan->txirq, fsl_chan);
+
 	spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
 	fsl_edma3_disable_request(fsl_chan);
 	fsl_chan->edesc = NULL;
@@ -830,7 +847,6 @@ static int fsl_edma3_probe(struct platfo
 	struct resource *res;
 	int len, chans;
 	int ret, i;
-	unsigned long irqflag = 0;
 
 	ret = of_property_read_u32(np, "dma-channels", &chans);
 	if (ret) {
@@ -845,7 +861,7 @@ static int fsl_edma3_probe(struct platfo
 
 	/* Audio edma rx/tx channel shared interrupt */
 	if (of_property_read_bool(np, "shared-interrupt"))
-		irqflag = IRQF_SHARED;
+		fsl_edma3->irqflag = IRQF_SHARED;
 
 	fsl_edma3->swap = of_device_is_compatible(np, "fsl,imx8qm-adma");
 	fsl_edma3->n_chans = chans;
@@ -853,12 +869,13 @@ static int fsl_edma3_probe(struct platfo
 	INIT_LIST_HEAD(&fsl_edma3->dma_dev.channels);
 	for (i = 0; i < fsl_edma3->n_chans; i++) {
 		struct fsl_edma3_chan *fsl_chan = &fsl_edma3->chans[i];
-		const char *txirq_name = fsl_chan->txirq_name;
+		const char *txirq_name;
 		char chanid[3], id_len = 0;
 		char *p = chanid;
 		unsigned long val;
 
 		fsl_chan->edma3 = fsl_edma3;
+		fsl_chan->pdev = pdev;
 		fsl_chan->pm_state = RUNNING;
 		fsl_chan->idle = true;
 		/* Get per channel membase */
@@ -904,14 +921,7 @@ static int fsl_edma3_probe(struct platfo
 			return fsl_chan->txirq;
 		}
 
-		ret = devm_request_irq(&pdev->dev, fsl_chan->txirq,
-				fsl_edma3_tx_handler, irqflag, txirq_name,
-				fsl_chan);
-		if (ret) {
-			dev_err(&pdev->dev, "Can't register %s IRQ.\n",
-				txirq_name);
-			return ret;
-		}
+		memcpy(fsl_chan->txirq_name, txirq_name, strlen(txirq_name));
 
 		fsl_chan->vchan.desc_free = fsl_edma3_free_desc;
 		vchan_init(&fsl_chan->vchan, &fsl_edma3->dma_dev);