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Commit ee7e5516 authored by Dmitry Eremin-Solenikov's avatar Dmitry Eremin-Solenikov Committed by Ingo Molnar
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generic: per-device coherent dma allocator 



Currently x86_32, sh and cris-v32 provide per-device coherent dma
memory allocator.

However their implementation is nearly identical. Refactor out
common code to be reused by them.

Signed-off-by: default avatarDmitry Baryshkov <dbaryshkov@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 543cf4cb

include/asm-generic/dma-coherent.h

0 → 100644
+32 −0
Original line number Diff line number Diff line 
#ifndef DMA_COHERENT_H

#define DMA_COHERENT_H



#ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT

/*

 * These two functions are only for dma allocator.

 * Don't use them in device drivers.

 */

int dma_alloc_from_coherent(struct device *dev, ssize_t size,

				       dma_addr_t *dma_handle, void **ret);

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



/*

 * Standard interface

 */

#define ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY

extern int

dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,

			    dma_addr_t device_addr, size_t size, int flags);



extern void

dma_release_declared_memory(struct device *dev);



extern void *

dma_mark_declared_memory_occupied(struct device *dev,

				  dma_addr_t device_addr, size_t size);

#else

#define dma_alloc_from_coherent(dev, size, handle, ret) (0)

#define dma_release_from_coherent(dev, order, vaddr) (0)

#endif



#endif

init/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -802,6 +802,10 @@ config PROC_PAGE_MONITOR 


endmenu		# General setup



config HAVE_GENERIC_DMA_COHERENT

	bool

	default n



config SLABINFO

	bool

	depends on PROC_FS

kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ obj-$(CONFIG_TASK_DELAY_ACCT) += delayacct.o 
obj-$(CONFIG_TASKSTATS) += taskstats.o tsacct.o

obj-$(CONFIG_MARKERS) += marker.o

obj-$(CONFIG_LATENCYTOP) += latencytop.o

obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o



ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)

# According to Alan Modra <alan@linuxcare.com.au>, the -fno-omit-frame-pointer is

kernel/dma-coherent.c

0 → 100644
+127 −0
Original line number Diff line number Diff line 
/*

 * Coherent per-device memory handling.

 * Borrowed from i386

 */

#include <linux/kernel.h>

#include <linux/dma-mapping.h>



struct dma_coherent_mem {

	void		*virt_base;

	u32		device_base;

	int		size;

	int		flags;

	unsigned long	*bitmap;

};



int dma_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,

				dma_addr_t device_addr, size_t size, int flags)

{

	void __iomem *mem_base = NULL;

	int pages = size >> PAGE_SHIFT;

	int bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);



	if ((flags & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) == 0)

		goto out;

	if (!size)

		goto out;

	if (dev->dma_mem)

		goto out;



	/* FIXME: this routine just ignores DMA_MEMORY_INCLUDES_CHILDREN */



	mem_base = ioremap(bus_addr, size);

	if (!mem_base)

		goto out;



	dev->dma_mem = kzalloc(sizeof(struct dma_coherent_mem), GFP_KERNEL);

	if (!dev->dma_mem)

		goto out;

	dev->dma_mem->bitmap = kzalloc(bitmap_size, GFP_KERNEL);

	if (!dev->dma_mem->bitmap)

		goto free1_out;



	dev->dma_mem->virt_base = mem_base;

	dev->dma_mem->device_base = device_addr;

	dev->dma_mem->size = pages;

	dev->dma_mem->flags = flags;



	if (flags & DMA_MEMORY_MAP)

		return DMA_MEMORY_MAP;



	return DMA_MEMORY_IO;



 free1_out:

	kfree(dev->dma_mem);

 out:

	if (mem_base)

		iounmap(mem_base);

	return 0;

}

EXPORT_SYMBOL(dma_declare_coherent_memory);



void dma_release_declared_memory(struct device *dev)

{

	struct dma_coherent_mem *mem = dev->dma_mem;



	if (!mem)

		return;

	dev->dma_mem = NULL;

	iounmap(mem->virt_base);

	kfree(mem->bitmap);

	kfree(mem);

}

EXPORT_SYMBOL(dma_release_declared_memory);



void *dma_mark_declared_memory_occupied(struct device *dev,

					dma_addr_t device_addr, size_t size)

{

	struct dma_coherent_mem *mem = dev->dma_mem;

	int pos, err;

	int pages = (size + (device_addr & ~PAGE_MASK) + PAGE_SIZE - 1);



	pages >>= PAGE_SHIFT;



	if (!mem)

		return ERR_PTR(-EINVAL);



	pos = (device_addr - mem->device_base) >> PAGE_SHIFT;

	err = bitmap_allocate_region(mem->bitmap, pos, get_order(pages));

	if (err != 0)

		return ERR_PTR(err);

	return mem->virt_base + (pos << PAGE_SHIFT);

}

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 = dev ? dev->dma_mem : NULL;

	int order = get_order(size);



	if (mem) {

		int page = bitmap_find_free_region(mem->bitmap, mem->size,

						     order);

		if (page >= 0) {

			*dma_handle = mem->device_base + (page << PAGE_SHIFT);

			*ret = mem->virt_base + (page << PAGE_SHIFT);

			memset(*ret, 0, size);

		}

		if (mem->flags & DMA_MEMORY_EXCLUSIVE)

			*ret = NULL;

	}

	return (mem != NULL);

}



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

{

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



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

		   (mem->virt_base + (mem->size << PAGE_SHIFT))) {

		int page = (vaddr - mem->virt_base) >> PAGE_SHIFT;



		bitmap_release_region(mem->bitmap, page, order);

		return 1;

	}

	return 0;

}