From: Luis R. Rodriguez Date: Wed, 10 Apr 2013 11:35:22 +0000 (-0700) Subject: compat: backport dma_get_sgtable() X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=8750ec4baab3f4b798f79fd4564be35778af30d2;p=openwrt%2Fstaging%2Fblogic.git compat: backport dma_get_sgtable() No architectures yet have their own dma_map_sg ops so we just use the commonly developed one for all archs in this implementation. We enable this only for 3.2 given that this is only needed for dma-buf ops implementations and we only port that down to 3.2 so far as well. mcgrof@frijol ~/linux-stable (git::master)$ git describe --contains d2b7428e v3.6-rc1~57^2~3 commit d2b7428eb0caa7c66e34b6ac869a43915b294123 Author: Marek Szyprowski Date: Wed Jun 13 10:05:52 2012 +0200 common: dma-mapping: introduce dma_get_sgtable() function This patch adds dma_get_sgtable() function which is required to let drivers to share the buffers allocated by DMA-mapping subsystem. Right now the driver gets a dma address of the allocated buffer and the kernel virtual mapping for it. If it wants to share it with other device (= map into its dma address space) it usually hacks around kernel virtual addresses to get pointers to pages or assumes that both devices share the DMA address space. Both solutions are just hacks for the special cases, which should be avoided in the final version of buffer sharing. To solve this issue in a generic way, a new call to DMA mapping has been introduced - dma_get_sgtable(). It allocates a scatter-list which describes the allocated buffer and lets the driver(s) to use it with other device(s) by calling dma_map_sg() on it. This patch provides a generic implementation based on virt_to_page() call. Architectures which require more sophisticated translation might provide their own get_sgtable() methods. Signed-off-by: Marek Szyprowski Reviewed-by: Kyungmin Park Reviewed-by: Daniel Vetter ckmake (only for compat) 1 2.6.24 [ OK ] 2 2.6.25 [ OK ] 3 2.6.26 [ OK ] 4 2.6.27 [ OK ] 5 2.6.28 [ OK ] 6 2.6.29 [ OK ] 7 2.6.30 [ OK ] 8 2.6.31 [ OK ] 9 2.6.32 [ OK ] 10 2.6.33 [ OK ] 11 2.6.34 [ OK ] 12 2.6.35 [ OK ] 13 2.6.36 [ OK ] 14 2.6.37 [ OK ] 15 2.6.38 [ OK ] 16 2.6.39 [ OK ] 17 3.0.65 [ OK ] 18 3.1.10 [ OK ] 19 3.2.38 [ OK ] 20 3.3.8 [ OK ] 21 3.4.32 [ OK ] 22 3.5.7 [ OK ] 23 3.6.11 [ OK ] 24 3.7.9 [ OK ] 25 3.8.0 [ OK ] 26 3.9-rc1 [ OK ] real 2m39.638s user 24m55.205s sys 12m59.349s Signed-off-by: Luis R. Rodriguez Signed-off-by: Johannes Berg --- diff --git a/backport/compat/compat-3.6.c b/backport/compat/compat-3.6.c index 05954d451fa8..5355cd220da1 100644 --- a/backport/compat/compat-3.6.c +++ b/backport/compat/compat-3.6.c @@ -16,6 +16,24 @@ #include #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,2,0)) +/* + * Create scatter-list for the already allocated DMA buffer. + */ +int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, + void *cpu_addr, dma_addr_t handle, size_t size) +{ + struct page *page = virt_to_page(cpu_addr); + int ret; + + ret = sg_alloc_table(sgt, 1, GFP_KERNEL); + if (unlikely(ret)) + return ret; + + sg_set_page(sgt->sgl, page, PAGE_ALIGN(size), 0); + return 0; +} +EXPORT_SYMBOL_GPL(dma_common_get_sgtable); + /** * __i2c_transfer - unlocked flavor of i2c_transfer * @adap: Handle to I2C bus diff --git a/backport/include/linux/compat-3.6.h b/backport/include/linux/compat-3.6.h index 8fddd3108add..ccc43a2ea333 100644 --- a/backport/include/linux/compat-3.6.h +++ b/backport/include/linux/compat-3.6.h @@ -26,6 +26,22 @@ int sg_alloc_table_from_pages(struct sg_table *sgt, unsigned long offset, unsigned long size, gfp_t gfp_mask); +#define dma_common_get_sgtable LINUX_BACKPORT(dma_common_get_sgtable) +int +dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, + void *cpu_addr, dma_addr_t dma_addr, size_t size); + +#define dma_get_sgtable_attrs LINUX_BACKPORT(dma_get_sgtable_attrs) +static inline int +dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt, void *cpu_addr, + dma_addr_t dma_addr, size_t size, struct dma_attrs *attrs) +{ + return dma_common_get_sgtable(dev, sgt, cpu_addr, dma_addr, size); +} + +#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, NULL) + + /** * Backports *