ARM: OMAP: dma: Clear status registers on enable/disable irq

Use omap_disable_channel_irq() function instead of directly accessing CICR
register in various functions.

The omap_disable_chanel_irq() function now 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@ti.com>
Tested-by: Jarkko Nikula <jarkko.nikula@bitmer.com>
[tony@atomide.com: updated comments to clarify CICR access]
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/plat-omap/dma.c

@@ -573,22 +573,25 @@ 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);
-	else if (cpu_class_is_omap2())
+		p->dma_read(CSR, lch);
+	else
 		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
 
 	/* Enable some nice interrupts. */
 	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())
+	/* disable channel interrupts */
 	p->dma_write(0, CICR, lch);
+	/* Clear CSR */
+	if (cpu_class_is_omap1())
+		p->dma_read(CSR, lch);
+	else
+		p->dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR, lch);
 }
 
 void omap_enable_dma_irq(int lch, u16 bits)
@@ -632,14 +635,14 @@ 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);
 	}
@@ -657,6 +660,9 @@ 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);
@@ -672,9 +678,12 @@ 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);
 }
 
@@ -745,11 +754,8 @@ 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;
@@ -768,27 +774,19 @@ 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. */
-		p->dma_write(0, CICR, lch);
+	omap_disable_channel_irq(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;
@@ -943,8 +941,7 @@ 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) &&