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| author | Tao Hu <taohu@motorola.com> | 2009-11-10 18:55:17 -0800 |
|---|---|---|
| committer | Tony Lindgren <tony@atomide.com> | 2009-11-10 18:55:17 -0800 |
| commit | ee90732456fe8e75406fdd3cd136a4bfb7ce31f5 (patch) | |
| tree | 0c0f49d8240d595e8162fbc02939266e3c268a9e | |
| parent | b419148e567728f6af0c3b01965c1cc141e3e13a (diff) | |
| download | linux-ee90732456fe8e75406fdd3cd136a4bfb7ce31f5.tar.gz linux-ee90732456fe8e75406fdd3cd136a4bfb7ce31f5.tar.bz2 linux-ee90732456fe8e75406fdd3cd136a4bfb7ce31f5.zip | |
omap: Fix race condition in omap dma driver
The bug could cause irq enable bit of one DMA channel is
cleared/set unexpectedly when 2 (or more) drivers are calling
omap_request_dma()/omap_free_dma() simultaneously
Signed-off-by: Fei Yang <AFY095@motorola.com>
Signed-off-by: Tao Hu <taohu@motorola.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
| -rw-r--r-- | arch/arm/plat-omap/dma.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c index b53125f41293..02ed94526aa3 100644 --- a/arch/arm/plat-omap/dma.c +++ b/arch/arm/plat-omap/dma.c @@ -691,13 +691,16 @@ static inline void disable_lnk(int lch) static inline void omap2_enable_irq_lch(int lch) { u32 val; + unsigned long flags; if (!cpu_class_is_omap2()) return; + spin_lock_irqsave(&dma_chan_lock, flags); val = dma_read(IRQENABLE_L0); val |= 1 << lch; dma_write(val, IRQENABLE_L0); + spin_unlock_irqrestore(&dma_chan_lock, flags); } int omap_request_dma(int dev_id, const char *dev_name, @@ -799,10 +802,13 @@ void omap_free_dma(int lch) if (cpu_class_is_omap2()) { u32 val; + + spin_lock_irqsave(&dma_chan_lock, flags); /* Disable interrupts */ val = dma_read(IRQENABLE_L0); val &= ~(1 << lch); dma_write(val, IRQENABLE_L0); + spin_unlock_irqrestore(&dma_chan_lock, flags); /* Clear the CSR register and IRQ status register */ dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(lch)); |