>From a36dac7ee6140ffa23f0adc024964aaf3e266e5f Mon Sep 17 00:00:00 2001
From: Tao Hu <taohu@xxxxxxxxxxxx>
Date: Thu, 29 Oct 2009 17:17:21 -0500
Subject: [PATCH] Fix race condition in omap_request_dma()
The bug could cause irq enable bit of one DMA channel is
cleared unexpectedly when 2 (or more) drivers are calling
omap_request_dma() simultaneously
Signed-off-by: Fei Yang <AFY095@xxxxxxxxxxxx>
Signed-off-by: Tao Hu <taohu@xxxxxxxxxxxx>
---
arch/arm/plat-omap/dma.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index cd53b28..6895484 100755
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -749,11 +749,13 @@ int omap_request_dma(int dev_id, const char
*dev_name,
}
if (cpu_class_is_omap2()) {
+ spin_lock_irqsave(&dma_chan_lock, flags);
omap2_enable_irq_lch(free_ch);
omap_enable_channel_irq(free_ch);
/* Clear the CSR register and IRQ status register */
dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(free_ch));
dma_write(1 << free_ch, IRQSTATUS_L0);
+ spin_unlock_irqrestore(&dma_chan_lock, flags);
}
*dma_ch_out = free_ch;
--
1.5.4.3
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