linux-kernel - [PATCH] omap: dma: Clear status registers on enable/disable irq.

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Message-ID: <1334954578-10478-1-git-send-email-oleg.matcovschi@ti.com>
Date:	Fri, 20 Apr 2012 13:42:58 -0700
From:	Oleg Matcovschi <oleg.matcovschi@...com>
To:	<linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>
CC:	<tony@...mide.com>, <linux@....linux.org.uk>,
	Oleg Matcovschi <oleg.matcovschi@...com>
Subject: [PATCH] omap: dma: Clear status registers on enable/disable irq.

Use omap_disable_channel_irq() function instead of directly accessing CICR.
The omap_disable_chanel_irq() function clears pending interrupts
and disables interrupt on channel.
Functions omap2_enable_irq_lch()/omap2_disable_irq_lch() clear interrupt
status register.

Signed-off-by: Oleg Matcovschi <oleg.matcovschi@...com>
---
 arch/arm/plat-omap/dma.c |   57 +++++++++++++++++++++------------------------
 1 files changed, 27 insertions(+), 30 deletions(-)

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index 3ec7ec5..d420b7f 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -563,11 +563,9 @@ EXPORT_SYMBOL(omap_set_dma_dest_burst_mode);
 
 static inline void omap_enable_channel_irq(int lch)
 {
-	u32 status;
-
 	/* Clear CSR */
 	if (cpu_class_is_omap1())
-		status = p->dma_read(CSR, lch);
+		p->dma_read(CSR, lch);
 	else if (cpu_class_is_omap2())
 		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
 
@@ -575,10 +573,15 @@ static inline void omap_enable_channel_irq(int lch)
 	p->dma_write(dma_chan[lch].enabled_irqs, CICR, lch);
 }
 
-static void omap_disable_channel_irq(int lch)
+static inline void omap_disable_channel_irq(int lch)
 {
-	if (cpu_class_is_omap2())
-		p->dma_write(0, CICR, lch);
+	/* disable channel interrupts */
+	p->dma_write(0, CICR, lch);
+	/* Clear CSR */
+	if (cpu_class_is_omap1())
+		p->dma_read(CSR, lch);
+	else if (cpu_class_is_omap2())
+		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
 }
 
 void omap_enable_dma_irq(int lch, u16 bits)
@@ -622,14 +625,14 @@ static inline void disable_lnk(int lch)
 	l = p->dma_read(CLNK_CTRL, lch);
 
 	/* Disable interrupts */
+	omap_disable_channel_irq(lch);
+
 	if (cpu_class_is_omap1()) {
-		p->dma_write(0, CICR, lch);
 		/* Set the STOP_LNK bit */
 		l |= 1 << 14;
 	}
 
 	if (cpu_class_is_omap2()) {
-		omap_disable_channel_irq(lch);
 		/* Clear the ENABLE_LNK bit */
 		l &= ~(1 << 15);
 	}
@@ -647,6 +650,9 @@ static inline void omap2_enable_irq_lch(int lch)
 		return;
 
 	spin_lock_irqsave(&dma_chan_lock, flags);
+	/* clear IRQ STATUS */
+	p->dma_write(1 << lch, IRQSTATUS_L0, lch);
+	/* Enable interrupt */
 	val = p->dma_read(IRQENABLE_L0, lch);
 	val |= 1 << lch;
 	p->dma_write(val, IRQENABLE_L0, lch);
@@ -662,9 +668,12 @@ static inline void omap2_disable_irq_lch(int lch)
 		return;
 
 	spin_lock_irqsave(&dma_chan_lock, flags);
+	/* Disable interrupt */
 	val = p->dma_read(IRQENABLE_L0, lch);
 	val &= ~(1 << lch);
 	p->dma_write(val, IRQENABLE_L0, lch);
+	/* clear IRQ STATUS */
+	p->dma_write(1 << lch, IRQSTATUS_L0, lch);
 	spin_unlock_irqrestore(&dma_chan_lock, flags);
 }
 
@@ -735,11 +744,8 @@ int omap_request_dma(int dev_id, const char *dev_name,
 	}
 
 	if (cpu_class_is_omap2()) {
-		omap2_enable_irq_lch(free_ch);
 		omap_enable_channel_irq(free_ch);
-		/* Clear the CSR register and IRQ status register */
-		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, free_ch);
-		p->dma_write(1 << free_ch, IRQSTATUS_L0, 0);
+		omap2_enable_irq_lch(free_ch);
 	}
 
 	*dma_ch_out = free_ch;
@@ -758,27 +764,19 @@ void omap_free_dma(int lch)
 		return;
 	}
 
-	if (cpu_class_is_omap1()) {
-		/* Disable all DMA interrupts for the channel. */
-		p->dma_write(0, CICR, lch);
-		/* Make sure the DMA transfer is stopped. */
-		p->dma_write(0, CCR, lch);
-	}
-
-	if (cpu_class_is_omap2()) {
+	/* Disable interrupt for logical channel */
+	if (cpu_class_is_omap2())
 		omap2_disable_irq_lch(lch);
 
-		/* Clear the CSR register and IRQ status register */
-		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
-		p->dma_write(1 << lch, IRQSTATUS_L0, lch);
+	/* Disable all DMA interrupts for the channel. */
+	omap_disable_channel_irq(lch);
 
-		/* Disable all DMA interrupts for the channel. */
-		p->dma_write(0, CICR, lch);
+	/* Make sure the DMA transfer is stopped. */
+	p->dma_write(0, CCR, lch);
 
-		/* Make sure the DMA transfer is stopped. */
-		p->dma_write(0, CCR, lch);
+	/* Clear registers */
+	if (cpu_class_is_omap2())
 		omap_clear_dma(lch);
-	}
 
 	spin_lock_irqsave(&dma_chan_lock, flags);
 	dma_chan[lch].dev_id = -1;
@@ -926,8 +924,7 @@ void omap_stop_dma(int lch)
 	u32 l;
 
 	/* Disable all interrupts on the channel */
-	if (cpu_class_is_omap1())
-		p->dma_write(0, CICR, lch);
+	omap_disable_channel_irq(lch);
 
 	l = p->dma_read(CCR, lch);
 	if (IS_DMA_ERRATA(DMA_ERRATA_i541) &&
-- 
1.7.4.1

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