diff options
| author | Huang Shijie <b32955@freescale.com> | 2010-09-09 13:15:11 +0800 |
|---|---|---|
| committer | Huang Shijie <b32955@freescale.com> | 2010-09-09 17:17:48 +0800 |
| commit | c68ef5cee2731d11ed32958aa77ae86c7120b603 (patch) | |
| tree | ceb6188e2bf1b11227c7775868ed95cd6ae602c6 | |
| parent | fcd3a416c29587d10ca125a801964c508ff72f96 (diff) | |
ENGR00127105 DMA:remove mutex when enable/disable DMA channel
These two functions can be called in IRQ context, but mutex may
cause the schedule. So remove the mutex lock, the spinlock of each
channel is enough.
Signed-off-by: Huang Shijie <b32955@freescale.com>
| -rw-r--r-- | arch/arm/plat-mxs/dmaengine.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/arm/plat-mxs/dmaengine.c b/arch/arm/plat-mxs/dmaengine.c index 52330d3ea9e3..0c2485b18506 100644 --- a/arch/arm/plat-mxs/dmaengine.c +++ b/arch/arm/plat-mxs/dmaengine.c @@ -127,14 +127,16 @@ int mxs_dma_enable(int channel) if (!(pchan->flags & MXS_DMA_FLAGS_ALLOCATED)) return -EINVAL; + /* + * neednot mutex lock, this function will be called in irq context. + * The mutex may cause process schedule. + */ pdma = pchan->dma; - mutex_lock(&mxs_dma_mutex); spin_lock_irqsave(&pchan->lock, flags); if (pchan->pending_num && pdma->enable) ret = pdma->enable(pchan, channel - pdma->chan_base); pchan->flags |= MXS_DMA_FLAGS_BUSY; spin_unlock_irqrestore(&pchan->lock, flags); - mutex_unlock(&mxs_dma_mutex); return ret; } EXPORT_SYMBOL(mxs_dma_enable); @@ -151,8 +153,11 @@ void mxs_dma_disable(int channel) return; if (!(pchan->flags & MXS_DMA_FLAGS_BUSY)) return; + /* + * neednot mutex lock, this function will be called in irq context. + * The mutex may cause process schedule. + */ pdma = pchan->dma; - mutex_lock(&mxs_dma_mutex); spin_lock_irqsave(&pchan->lock, flags); if (pdma->disable) pdma->disable(pchan, channel - pdma->chan_base); @@ -161,7 +166,6 @@ void mxs_dma_disable(int channel) pchan->pending_num = 0; list_splice_init(&pchan->active, &pchan->done); spin_unlock_irqrestore(&pchan->lock, flags); - mutex_unlock(&mxs_dma_mutex); } EXPORT_SYMBOL(mxs_dma_disable); |