ENGR00132607 MX50: Fix ePxP crash issue

It can be reproduced by loop-running epdc rotation test.
The crash reason is the timing to disable ePxP clocks is critical, which
was not met before. This issue is fixed by disabling clocks only when
ePxP is inactive and no more task is on the wait queue.

Signed-off-by: Robby Cai <R63905@freescale.com>

1 files changed, 22 insertions, 11 deletions

diff --git a/drivers/dma/pxp/pxp_dma.c b/drivers/dma/pxp/pxp_dma.c
index 73b3fcadddd4..e798e1c5e188 100644
--- a/drivers/dma/pxp/pxp_dma.c
+++ b/drivers/dma/pxp/pxp_dma.c
@@ -52,10 +52,10 @@ struct pxps {
 	int irq;		/* PXP IRQ to the CPU */
 
 	spinlock_t lock;
-	struct mutex mutex_clk;
 	int clk_stat;
 #define	CLK_STAT_OFF		0
 #define	CLK_STAT_ON		1
+	int pxp_ongoing;
 
 	struct device *dev;
 	struct pxp_dma pxp_dma;
@@ -596,39 +596,44 @@ static int pxp_config(struct pxps *pxp, struct pxp_channel *pxp_chan)
 
 static void pxp_clk_enable(struct pxps *pxp)
 {
-	mutex_lock(&pxp->mutex_clk);
+	unsigned long flags;
+	spin_lock_irqsave(&pxp->lock, flags);
 
 	if (pxp->clk_stat == CLK_STAT_ON) {
-		mutex_unlock(&pxp->mutex_clk);
+		spin_unlock_irqrestore(&pxp->lock, flags);
 		return;
 	}
 
 	clk_enable(pxp->clk);
 	pxp->clk_stat = CLK_STAT_ON;
 
-	mutex_unlock(&pxp->mutex_clk);
+	spin_unlock_irqrestore(&pxp->lock, flags);
 }
 
 static void pxp_clk_disable(struct pxps *pxp)
 {
-	mutex_lock(&pxp->mutex_clk);
+	unsigned long flags;
+	spin_lock_irqsave(&pxp->lock, flags);
 
 	if (pxp->clk_stat == CLK_STAT_OFF) {
-		mutex_unlock(&pxp->mutex_clk);
+		spin_unlock_irqrestore(&pxp->lock, flags);
 		return;
 	}
 
 	clk_disable(pxp->clk);
 	pxp->clk_stat = CLK_STAT_OFF;
 
-	mutex_unlock(&pxp->mutex_clk);
+	spin_unlock_irqrestore(&pxp->lock, flags);
 }
 
 static void pxp_clkoff_timer(unsigned long arg)
 {
 	struct pxps *pxp = (struct pxps *)arg;
 
-	pxp_clk_disable(pxp);
+	if ((pxp->pxp_ongoing == 0) && list_empty(&head))
+		pxp_clk_disable(pxp);
+	else
+		mod_timer(&pxp->clk_timer, jiffies + msecs_to_jiffies(4000));
 }
 
 static struct pxp_tx_desc *pxpdma_first_active(struct pxp_channel *pxp_chan)
@@ -692,6 +697,7 @@ static void pxpdma_dostart_work(struct pxps *pxp)
 
 	spin_lock_irqsave(&pxp->lock, flags);
 	if (list_empty(&head)) {
+		pxp->pxp_ongoing = 0;
 		spin_unlock_irqrestore(&pxp->lock, flags);
 		return;
 	}
@@ -712,6 +718,8 @@ static void pxpdma_dostart_work(struct pxps *pxp)
 
 	pxp_start(pxp);
 
+	mod_timer(&pxp->clk_timer, jiffies + msecs_to_jiffies(4000));
+
 	spin_unlock_irqrestore(&pxp->lock, flags);
 }
 
@@ -857,11 +865,10 @@ static irqreturn_t pxp_irq(int irq, void *dev_id)
 
 	__raw_writel(BM_PXP_STAT_IRQ, pxp->base + HW_PXP_STAT_CLR);
 
-	mod_timer(&pxp->clk_timer, jiffies + msecs_to_jiffies(4000));
-
 	spin_lock_irqsave(&pxp->lock, flags);
 
 	if (list_empty(&head)) {
+		pxp->pxp_ongoing = 0;
 		spin_unlock_irqrestore(&pxp->lock, flags);
 		return IRQ_NONE;
 	}
@@ -872,6 +879,7 @@ static irqreturn_t pxp_irq(int irq, void *dev_id)
 	if (list_empty(&pxp_chan->active_list)) {
 		pr_debug("PXP_IRQ pxp_chan->active_list empty. chan_id %d\n",
 			 pxp_chan->dma_chan.chan_id);
+		pxp->pxp_ongoing = 0;
 		spin_unlock_irqrestore(&pxp->lock, flags);
 		return IRQ_NONE;
 	}
@@ -898,6 +906,7 @@ static irqreturn_t pxp_irq(int irq, void *dev_id)
 	list_del(&pxp_chan->list);
 
 	wake_up(&pxp->done);
+	pxp->pxp_ongoing = 0;
 
 	spin_unlock_irqrestore(&pxp->lock, flags);
 
@@ -1034,6 +1043,7 @@ static void pxp_issue_pending(struct dma_chan *chan)
 		return;
 	}
 
+	pxp->pxp_ongoing = 1;
 	pxpdma_dostart_work(pxp);
 }
 
@@ -1312,8 +1322,9 @@ static int pxp_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, pxp);
 	pxp->irq = irq;
 
+	pxp->pxp_ongoing = 0;
+
 	spin_lock_init(&pxp->lock);
-	mutex_init(&pxp->mutex_clk);
 
 	if (!request_mem_region(res->start, resource_size(res), "pxp-mem")) {
 		err = -EBUSY;