From 551199aca1c3102ebed390566d681cc1290284ca Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Fri, 20 Jan 2017 13:04:07 -0800 Subject: 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 Cc: Christian Borntraeger Cc: Joerg Roedel Cc: Andy Lutomirski Cc: Michael S. Tsirkin Signed-off-by: Doug Ledford --- lib/Kconfig | 5 ++++ lib/Makefile | 1 + lib/dma-virt.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 78 insertions(+) create mode 100644 lib/dma-virt.c (limited to 'lib') diff --git a/lib/Kconfig b/lib/Kconfig index b6baf0609e8b..97af23b26f33 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -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 diff --git a/lib/Makefile b/lib/Makefile index ada06d5652e8..b97e9a814854 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -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 diff --git a/lib/dma-virt.c b/lib/dma-virt.c new file mode 100644 index 000000000000..dcd4df1f7174 --- /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 +#include +#include +#include + +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); -- cgit v1.2.3