Fix race condition in omap_request_dma()

Commit Message

HU TAO-TGHK48 Oct. 30, 2009, 9:33 p.m. UTC

None

Patch

diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
index cd53b28..5767899 100755
--- a/arch/arm/plat-omap/dma.c
+++ b/arch/arm/plat-omap/dma.c
@@ -673,13 +673,16 @@  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,
@@ -788,10 +791,13 @@  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));