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Commit 93228b44 authored by Vladimir Murzin's avatar Vladimir Murzin Committed by Christoph Hellwig
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drivers: dma-coherent: Introduce default DMA pool 



This patch introduces default coherent DMA pool similar to default CMA
area concept. To keep other users safe code kept under CONFIG_ARM.

Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-by: default avatarRobin Murphy <robin.murphy@arm.com>
Tested-by: default avatarBenjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: default avatarAndras Szemzo <sza@esh.hu>
Tested-by: default avatarAlexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: default avatarVladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent c41f9ea9

Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt

+3 −0
Original line number Diff line number Diff line
@@ -68,6 +68,9 @@ Linux implementation note: 
- If a "linux,cma-default" property is present, then Linux will use the

  region for the default pool of the contiguous memory allocator.



- If a "linux,dma-default" property is present, then Linux will use the

  region for the default pool of the consistent DMA allocator.



Device node references to reserved memory

-----------------------------------------

Regions in the /reserved-memory node may be referenced by other device

drivers/base/dma-coherent.c

+52 −7
Original line number Diff line number Diff line
@@ -19,6 +19,15 @@ struct dma_coherent_mem { 
	bool		use_dev_dma_pfn_offset;

};



static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;



static inline struct dma_coherent_mem *dev_get_coherent_memory(struct device *dev)

{

	if (dev && dev->dma_mem)

		return dev->dma_mem;

	return dma_coherent_default_memory;

}



static inline dma_addr_t dma_get_device_base(struct device *dev,

					     struct dma_coherent_mem * mem)

{
@@ -93,6 +102,9 @@ static void dma_release_coherent_memory(struct dma_coherent_mem *mem) 
static int dma_assign_coherent_memory(struct device *dev,

				      struct dma_coherent_mem *mem)

{

	if (!dev)

		return -ENODEV;



	if (dev->dma_mem)

		return -EBUSY;
@@ -171,15 +183,12 @@ EXPORT_SYMBOL(dma_mark_declared_memory_occupied); 
int dma_alloc_from_coherent(struct device *dev, ssize_t size,

				       dma_addr_t *dma_handle, void **ret)

{

	struct dma_coherent_mem *mem;

	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);

	int order = get_order(size);

	unsigned long flags;

	int pageno;

	int dma_memory_map;



	if (!dev)

		return 0;

	mem = dev->dma_mem;

	if (!mem)

		return 0;
@@ -233,7 +242,7 @@ EXPORT_SYMBOL(dma_alloc_from_coherent); 
 */

int dma_release_from_coherent(struct device *dev, int order, void *vaddr)

{

	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;

	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);



	if (mem && vaddr >= mem->virt_base && vaddr <

		   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
@@ -267,7 +276,7 @@ EXPORT_SYMBOL(dma_release_from_coherent); 
int dma_mmap_from_coherent(struct device *dev, struct vm_area_struct *vma,

			   void *vaddr, size_t size, int *ret)

{

	struct dma_coherent_mem *mem = dev ? dev->dma_mem : NULL;

	struct dma_coherent_mem *mem = dev_get_coherent_memory(dev);



	if (mem && vaddr >= mem->virt_base && vaddr + size <=

		   (mem->virt_base + (mem->size << PAGE_SHIFT))) {
@@ -297,6 +306,8 @@ EXPORT_SYMBOL(dma_mmap_from_coherent); 
#include <linux/of_fdt.h>

#include <linux/of_reserved_mem.h>



static struct reserved_mem *dma_reserved_default_memory __initdata;



static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev)

{

	struct dma_coherent_mem *mem = rmem->priv;
@@ -318,6 +329,7 @@ static int rmem_dma_device_init(struct reserved_mem *rmem, struct device *dev) 
static void rmem_dma_device_release(struct reserved_mem *rmem,

				    struct device *dev)

{

	if (dev)

		dev->dma_mem = NULL;

}
@@ -338,6 +350,12 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem) 
		pr_err("Reserved memory: regions without no-map are not yet supported\n");

		return -EINVAL;

	}



	if (of_get_flat_dt_prop(node, "linux,dma-default", NULL)) {

		WARN(dma_reserved_default_memory,

		     "Reserved memory: region for default DMA coherent area is redefined\n");

		dma_reserved_default_memory = rmem;

	}

#endif



	rmem->ops = &rmem_dma_ops;
@@ -345,5 +363,32 @@ static int __init rmem_dma_setup(struct reserved_mem *rmem) 
		&rmem->base, (unsigned long)rmem->size / SZ_1M);

	return 0;

}



static int __init dma_init_reserved_memory(void)

{

	const struct reserved_mem_ops *ops;

	int ret;



	if (!dma_reserved_default_memory)

		return -ENOMEM;



	ops = dma_reserved_default_memory->ops;



	/*

	 * We rely on rmem_dma_device_init() does not propagate error of

	 * dma_assign_coherent_memory() for "NULL" device.

	 */

	ret = ops->device_init(dma_reserved_default_memory, NULL);



	if (!ret) {

		dma_coherent_default_memory = dma_reserved_default_memory->priv;

		pr_info("DMA: default coherent area is set\n");

	}



	return ret;

}



core_initcall(dma_init_reserved_memory);



RESERVEDMEM_OF_DECLARE(dma, "shared-dma-pool", rmem_dma_setup);

#endif