From patchwork Fri Mar 29 02:40:44 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Simon Horman X-Patchwork-Id: 2361441 Return-Path: X-Original-To: patchwork-ltsi-dev@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) by patchwork1.kernel.org (Postfix) with ESMTP id EE6D03FD40 for ; Fri, 29 Mar 2013 02:50:01 +0000 (UTC) Received: from mail.linux-foundation.org (localhost [IPv6:::1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 4EA2FC2A; Fri, 29 Mar 2013 02:46:11 +0000 (UTC) X-Original-To: ltsi-dev@lists.linuxfoundation.org Delivered-To: ltsi-dev@mail.linuxfoundation.org Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTP id DDE40C19 for ; Fri, 29 Mar 2013 02:46:03 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from kirsty.vergenet.net (kirsty.vergenet.net [202.4.237.240]) by smtp1.linuxfoundation.org (Postfix) with ESMTP id C0A8C20183 for ; Fri, 29 Mar 2013 02:45:54 +0000 (UTC) Received: from ayumi.akashicho.tokyo.vergenet.net (p8120-ipbfp1001kobeminato.hyogo.ocn.ne.jp [118.10.137.120]) by kirsty.vergenet.net (Postfix) with ESMTP id B97222C69FF; Fri, 29 Mar 2013 13:45:38 +1100 (EST) Received: by ayumi.akashicho.tokyo.vergenet.net (Postfix, from userid 7100) id 599DBEDEA20; Fri, 29 Mar 2013 11:45:37 +0900 (JST) From: Simon Horman To: ltsi-dev@lists.linuxfoundation.org Date: Fri, 29 Mar 2013 11:40:44 +0900 Message-Id: <1364525119-31791-116-git-send-email-horms+renesas@verge.net.au> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1364525119-31791-1-git-send-email-horms+renesas@verge.net.au> References: <1364525119-31791-1-git-send-email-horms+renesas@verge.net.au> X-Spam-Status: No, score=-3.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, RP_MATCHES_RCVD autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Cc: Magnus Damm Subject: [LTSI-dev] [PATCH/RFC 115/390] common: dma-mapping: introduce dma_get_sgtable() function X-BeenThere: ltsi-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: "A list to discuss patches, development, and other things related to the LTSI project" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: ltsi-dev-bounces@lists.linuxfoundation.org Errors-To: ltsi-dev-bounces@lists.linuxfoundation.org From: Marek Szyprowski 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 (cherry picked from commit d2b7428eb0caa7c66e34b6ac869a43915b294123) Signed-off-by: Simon Horman --- drivers/base/dma-mapping.c | 18 ++++++++++++++++++ include/asm-generic/dma-mapping-common.h | 18 ++++++++++++++++++ include/linux/dma-mapping.h | 3 +++ 3 files changed, 39 insertions(+) diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c index db5db02..3fbedc7 100644 --- a/drivers/base/dma-mapping.c +++ b/drivers/base/dma-mapping.c @@ -218,6 +218,24 @@ void dmam_release_declared_memory(struct device *dev) } EXPORT_SYMBOL(dmam_release_declared_memory); +/* + * 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(dma_common_get_sgtable); + #endif /* diff --git a/include/asm-generic/dma-mapping-common.h b/include/asm-generic/dma-mapping-common.h index 9073aeb..de8bf89 100644 --- a/include/asm-generic/dma-mapping-common.h +++ b/include/asm-generic/dma-mapping-common.h @@ -213,4 +213,22 @@ static inline int dma_mmap_writecombine(struct device *dev, struct vm_area_struc return dma_mmap_attrs(dev, vma, cpu_addr, dma_addr, size, &attrs); } +int +dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, + void *cpu_addr, dma_addr_t dma_addr, size_t size); + +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) +{ + struct dma_map_ops *ops = get_dma_ops(dev); + BUG_ON(!ops); + if (ops->get_sgtable) + return ops->get_sgtable(dev, sgt, cpu_addr, dma_addr, size, + 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) + #endif diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index dfc099e..94af418 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -18,6 +18,9 @@ struct dma_map_ops { int (*mmap)(struct device *, struct vm_area_struct *, void *, dma_addr_t, size_t, struct dma_attrs *attrs); + int (*get_sgtable)(struct device *dev, struct sg_table *sgt, void *, + dma_addr_t, size_t, struct dma_attrs *attrs); + dma_addr_t (*map_page)(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir,