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Commit 551199ac authored by Bart Van Assche's avatar Bart Van Assche Committed by Doug Ledford
Browse files

lib/dma-virt: Add dma_virt_ops 



Several RDMA drivers (hfi1, qib and rxe) expect that ib_sge.addr
is a virtual address. Provide DMA mapping operations that are
suitable for these drivers.

Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent 7844572c

include/linux/dma-mapping.h

+1 −0
Original line number Diff line number Diff line
@@ -128,6 +128,7 @@ struct dma_map_ops { 
};



extern const struct dma_map_ops dma_noop_ops;

extern const struct dma_map_ops dma_virt_ops;



#define DMA_BIT_MASK(n)	(((n) == 64) ? ~0ULL : ((1ULL<<(n))-1))

lib/Kconfig

+5 −0
Original line number Diff line number Diff line
@@ -400,6 +400,11 @@ config DMA_NOOP_OPS 
	depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)

	default n



config DMA_VIRT_OPS

	bool

	depends on HAS_DMA && (!64BIT || ARCH_DMA_ADDR_T_64BIT)

	default n



config CHECK_SIGNATURE

	bool

lib/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ 
lib-$(CONFIG_MMU) += ioremap.o

lib-$(CONFIG_SMP) += cpumask.o

lib-$(CONFIG_DMA_NOOP_OPS) += dma-noop.o

lib-$(CONFIG_DMA_VIRT_OPS) += dma-virt.o



lib-y	+= kobject.o klist.o

obj-y	+= lockref.o

lib/dma-virt.c

0 → 100644
+72 −0
Original line number Diff line number Diff line 
/*

 *	lib/dma-virt.c

 *

 * DMA operations that map to virtual addresses without flushing memory.

 */

#include <linux/export.h>

#include <linux/mm.h>

#include <linux/dma-mapping.h>

#include <linux/scatterlist.h>



static void *dma_virt_alloc(struct device *dev, size_t size,

			    dma_addr_t *dma_handle, gfp_t gfp,

			    unsigned long attrs)

{

	void *ret;



	ret = (void *)__get_free_pages(gfp, get_order(size));

	if (ret)

		*dma_handle = (uintptr_t)ret;

	return ret;

}



static void dma_virt_free(struct device *dev, size_t size,

			  void *cpu_addr, dma_addr_t dma_addr,

			  unsigned long attrs)

{

	free_pages((unsigned long)cpu_addr, get_order(size));

}



static dma_addr_t dma_virt_map_page(struct device *dev, struct page *page,

				    unsigned long offset, size_t size,

				    enum dma_data_direction dir,

				    unsigned long attrs)

{

	return (uintptr_t)(page_address(page) + offset);

}



static int dma_virt_map_sg(struct device *dev, struct scatterlist *sgl,

			   int nents, enum dma_data_direction dir,

			   unsigned long attrs)

{

	int i;

	struct scatterlist *sg;



	for_each_sg(sgl, sg, nents, i) {

		BUG_ON(!sg_page(sg));

		sg_dma_address(sg) = (uintptr_t)sg_virt(sg);

		sg_dma_len(sg) = sg->length;

	}



	return nents;

}



static int dma_virt_mapping_error(struct device *dev, dma_addr_t dma_addr)

{

	return false;

}



static int dma_virt_supported(struct device *dev, u64 mask)

{

	return true;

}



const struct dma_map_ops dma_virt_ops = {

	.alloc			= dma_virt_alloc,

	.free			= dma_virt_free,

	.map_page		= dma_virt_map_page,

	.map_sg			= dma_virt_map_sg,

	.mapping_error		= dma_virt_mapping_error,

	.dma_supported		= dma_virt_supported,

};

EXPORT_SYMBOL(dma_virt_ops);