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author | Bart Van Assche <bart.vanassche@sandisk.com> | 2017-01-20 13:04:07 -0800 |
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committer | Doug Ledford <dledford@redhat.com> | 2017-01-24 12:23:35 -0500 |
commit | 551199aca1c3102ebed390566d681cc1290284ca (patch) | |
tree | a093ec747368b2b0fa7d9e7e1e95032502f89541 /lib/dma-virt.c | |
parent | 7844572c633964c864d9f32dc3f2a8ffe5d70371 (diff) | |
download | op-kernel-dev-551199aca1c3102ebed390566d681cc1290284ca.zip op-kernel-dev-551199aca1c3102ebed390566d681cc1290284ca.tar.gz |
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: Bart 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: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'lib/dma-virt.c')
-rw-r--r-- | lib/dma-virt.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/lib/dma-virt.c b/lib/dma-virt.c new file mode 100644 index 0000000..dcd4df1 --- /dev/null +++ b/lib/dma-virt.c @@ -0,0 +1,72 @@ +/* + * 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); |