From: Juha Yrjölä <juha.yrjola@solidboot.com>
Date: Wed, 21 Jan 2009 17:24:09 +0000 (+0200)
Subject: ARM OMAP: Fix race in OMAP2/3 DMA IRQ handling
X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=340986de702bffd457d5e039dc7d40e5cc32091c

ARM OMAP: Fix race in OMAP2/3 DMA IRQ handling

CSR must be cleared before invoking the callback.

If the callback function starts a new, fast DMA transfer on the same
channel, the completion status might lost if CSR is cleared after
the callback invocation.

Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
old mode 100644
new mode 100755
index 922985ef32b..9b697a41d77
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -1889,11 +1889,11 @@ static int omap2_dma_handle_ch(int ch)
 		status = dma_read(CSR(ch));
 	}
 
+	dma_write(status, CSR(ch));
+
 	if (likely(dma_chan[ch].callback != NULL))
 		dma_chan[ch].callback(ch, status, dma_chan[ch].data);
 
-	dma_write(status, CSR(ch));
-
 	return 0;
 }