X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=arch%2Farm%2Fplat-omap%2Fdma.c;h=78f45defcd26461dbc1c32a3ef6ddae069936f9e;hb=d63ff34838f434f99056ab6be25a5b55920283f0;hp=002fb4d96bbc7020b6158b469040faf29c72b891;hpb=81e0a6ed9888d145d25b7ccece6e1016626bc3c2;p=pandora-kernel.git

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index 002fb4d96bbc..78f45defcd26 100644
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -563,22 +563,25 @@ 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())
-		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
+		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;
@@ -915,6 +913,13 @@ void omap_start_dma(int lch)
 			l |= OMAP_DMA_CCR_BUFFERING_DISABLE;
 	l |= OMAP_DMA_CCR_EN;
 
+	/*
+	 * As dma_write() uses IO accessors which are weakly ordered, there
+	 * is no guarantee that data in coherent DMA memory will be visible
+	 * to the DMA device.  Add a memory barrier here to ensure that any
+	 * such data is visible prior to enabling DMA.
+	 */
+	mb();
 	p->dma_write(l, CCR, lch);
 
 	dma_chan[lch].flags |= OMAP_DMA_ACTIVE;
@@ -926,8 +931,7 @@ 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) &&
@@ -964,6 +968,13 @@ void omap_stop_dma(int lch)
 		p->dma_write(l, CCR, lch);
 	}
 
+	/*
+	 * Ensure that data transferred by DMA is visible to any access
+	 * after DMA has been disabled.  This is important for coherent
+	 * DMA regions.
+	 */
+	mb();
+
 	if (!omap_dma_in_1510_mode() && dma_chan[lch].next_lch != -1) {
 		int next_lch, cur_lch = lch;
 		char dma_chan_link_map[dma_lch_count];