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Commit 823588c1 authored by Kevin Hilman's avatar Kevin Hilman Committed by Russell King
Browse files

[ARM] 3537/1: Rework DMA-bounce locking for finer granularity 



Patch from Kevin Hilman

This time with IRQ versions of locks.

Rework also enables compatability with realtime-preemption patch.
With the current locking via interrupt disabling, under RT,
potentially sleeping functions can be called with interrupts
disabled.

Signed-off-by: default avatarKevin Hilman <khilman@mvista.com>
Signed-off-by: default avatarDeepak Saxena <dsaxena@plexity.net>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent fa3e686a

arch/arm/common/dmabounce.c

+21 −46
Original line number Diff line number Diff line
@@ -77,6 +77,8 @@ struct dmabounce_device_info { 
#endif

	struct dmabounce_pool	small;

	struct dmabounce_pool	large;



	rwlock_t lock;

};



static LIST_HEAD(dmabounce_devs);
@@ -116,6 +118,7 @@ alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, 
	struct safe_buffer *buf;

	struct dmabounce_pool *pool;

	struct device *dev = device_info->dev;

	unsigned long flags;



	dev_dbg(dev, "%s(ptr=%p, size=%d, dir=%d)\n",

		__func__, ptr, size, dir);
@@ -163,8 +166,12 @@ alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, 
		print_alloc_stats(device_info);

#endif



	write_lock_irqsave(&device_info->lock, flags);



	list_add(&buf->node, &device_info->safe_buffers);



	write_unlock_irqrestore(&device_info->lock, flags);



	return buf;

}
@@ -172,22 +179,32 @@ alloc_safe_buffer(struct dmabounce_device_info *device_info, void *ptr, 
static inline struct safe_buffer *

find_safe_buffer(struct dmabounce_device_info *device_info, dma_addr_t safe_dma_addr)

{

	struct safe_buffer *b;

	struct safe_buffer *b = NULL;

	unsigned long flags;



	read_lock_irqsave(&device_info->lock, flags);



	list_for_each_entry(b, &device_info->safe_buffers, node)

		if (b->safe_dma_addr == safe_dma_addr)

			return b;

			break;



	return NULL;

	read_unlock_irqrestore(&device_info->lock, flags);

	return b;

}



static inline void

free_safe_buffer(struct dmabounce_device_info *device_info, struct safe_buffer *buf)

{

	unsigned long flags;



	dev_dbg(device_info->dev, "%s(buf=%p)\n", __func__, buf);



	write_lock_irqsave(&device_info->lock, flags);



	list_del(&buf->node);



	write_unlock_irqrestore(&device_info->lock, flags);



	if (buf->pool)

		dma_pool_free(buf->pool->pool, buf->safe, buf->safe_dma_addr);

	else
@@ -396,7 +413,6 @@ dma_addr_t 
dma_map_single(struct device *dev, void *ptr, size_t size,

		enum dma_data_direction dir)

{

	unsigned long flags;

	dma_addr_t dma_addr;



	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",
@@ -404,12 +420,8 @@ dma_map_single(struct device *dev, void *ptr, size_t size, 


	BUG_ON(dir == DMA_NONE);



	local_irq_save(flags);



	dma_addr = map_single(dev, ptr, size, dir);



	local_irq_restore(flags);



	return dma_addr;

}
@@ -424,25 +436,18 @@ void 
dma_unmap_single(struct device *dev, dma_addr_t dma_addr, size_t size,

			enum dma_data_direction dir)

{

	unsigned long flags;



	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",

		__func__, (void *) dma_addr, size, dir);



	BUG_ON(dir == DMA_NONE);



	local_irq_save(flags);



	unmap_single(dev, dma_addr, size, dir);



	local_irq_restore(flags);

}



int

dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,

		enum dma_data_direction dir)

{

	unsigned long flags;

	int i;



	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
@@ -450,8 +455,6 @@ dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, 


	BUG_ON(dir == DMA_NONE);



	local_irq_save(flags);



	for (i = 0; i < nents; i++, sg++) {

		struct page *page = sg->page;

		unsigned int offset = sg->offset;
@@ -462,8 +465,6 @@ dma_map_sg(struct device *dev, struct scatterlist *sg, int nents, 
			map_single(dev, ptr, length, dir);

	}



	local_irq_restore(flags);



	return nents;

}
@@ -471,7 +472,6 @@ void 
dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents,

		enum dma_data_direction dir)

{

	unsigned long flags;

	int i;



	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
@@ -479,55 +479,38 @@ dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nents, 


	BUG_ON(dir == DMA_NONE);



	local_irq_save(flags);



	for (i = 0; i < nents; i++, sg++) {

		dma_addr_t dma_addr = sg->dma_address;

		unsigned int length = sg->length;



		unmap_single(dev, dma_addr, length, dir);

	}



	local_irq_restore(flags);

}



void

dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_addr, size_t size,

				enum dma_data_direction dir)

{

	unsigned long flags;



	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",

		__func__, (void *) dma_addr, size, dir);



	local_irq_save(flags);



	sync_single(dev, dma_addr, size, dir);



	local_irq_restore(flags);

}



void

dma_sync_single_for_device(struct device *dev, dma_addr_t dma_addr, size_t size,

				enum dma_data_direction dir)

{

	unsigned long flags;



	dev_dbg(dev, "%s(ptr=%p,size=%d,dir=%x)\n",

		__func__, (void *) dma_addr, size, dir);



	local_irq_save(flags);



	sync_single(dev, dma_addr, size, dir);



	local_irq_restore(flags);

}



void

dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents,

			enum dma_data_direction dir)

{

	unsigned long flags;

	int i;



	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
@@ -535,23 +518,18 @@ dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg, int nents, 


	BUG_ON(dir == DMA_NONE);



	local_irq_save(flags);



	for (i = 0; i < nents; i++, sg++) {

		dma_addr_t dma_addr = sg->dma_address;

		unsigned int length = sg->length;



		sync_single(dev, dma_addr, length, dir);

	}



	local_irq_restore(flags);

}



void

dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents,

			enum dma_data_direction dir)

{

	unsigned long flags;

	int i;



	dev_dbg(dev, "%s(sg=%p,nents=%d,dir=%x)\n",
@@ -559,16 +537,12 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg, int nents, 


	BUG_ON(dir == DMA_NONE);



	local_irq_save(flags);



	for (i = 0; i < nents; i++, sg++) {

		dma_addr_t dma_addr = sg->dma_address;

		unsigned int length = sg->length;



		sync_single(dev, dma_addr, length, dir);

	}



	local_irq_restore(flags);

}



static int
@@ -622,6 +596,7 @@ dmabounce_register_dev(struct device *dev, unsigned long small_buffer_size, 


	device_info->dev = dev;

	INIT_LIST_HEAD(&device_info->safe_buffers);

	rwlock_init(&device_info->lock);



#ifdef STATS

	device_info->total_allocs = 0;