From patchwork Thu Oct 15 12:38:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Zimmermann X-Patchwork-Id: 11839201 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A1FB91744 for ; Thu, 15 Oct 2020 12:38:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A3DC22267 for ; Thu, 15 Oct 2020 12:38:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728780AbgJOMiU (ORCPT ); Thu, 15 Oct 2020 08:38:20 -0400 Received: from mx2.suse.de ([195.135.220.15]:44398 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727348AbgJOMiT (ORCPT ); Thu, 15 Oct 2020 08:38:19 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id C09D8B1A7; Thu, 15 Oct 2020 12:38:16 +0000 (UTC) From: Thomas Zimmermann To: maarten.lankhorst@linux.intel.com, mripard@kernel.org, airlied@linux.ie, daniel@ffwll.ch, sam@ravnborg.org, alexander.deucher@amd.com, christian.koenig@amd.com, kraxel@redhat.com, l.stach@pengutronix.de, linux+etnaviv@armlinux.org.uk, christian.gmeiner@gmail.com, inki.dae@samsung.com, jy0922.shim@samsung.com, sw0312.kim@samsung.com, kyungmin.park@samsung.com, kgene@kernel.org, krzk@kernel.org, yuq825@gmail.com, bskeggs@redhat.com, robh@kernel.org, tomeu.vizoso@collabora.com, steven.price@arm.com, alyssa.rosenzweig@collabora.com, hjc@rock-chips.com, heiko@sntech.de, hdegoede@redhat.com, sean@poorly.run, eric@anholt.net, oleksandr_andrushchenko@epam.com, ray.huang@amd.com, sumit.semwal@linaro.org, emil.velikov@collabora.com, luben.tuikov@amd.com, apaneers@amd.com, linus.walleij@linaro.org, melissa.srw@gmail.com, chris@chris-wilson.co.uk, miaoqinglang@huawei.com Cc: dri-devel@lists.freedesktop.org, amd-gfx@lists.freedesktop.org, virtualization@lists.linux-foundation.org, etnaviv@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, lima@lists.freedesktop.org, nouveau@lists.freedesktop.org, spice-devel@lists.freedesktop.org, linux-rockchip@lists.infradead.org, xen-devel@lists.xenproject.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, Thomas Zimmermann Subject: [PATCH v4 09/10] dma-buf-map: Add memcpy and pointer-increment interfaces Date: Thu, 15 Oct 2020 14:38:05 +0200 Message-Id: <20201015123806.32416-10-tzimmermann@suse.de> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20201015123806.32416-1-tzimmermann@suse.de> References: <20201015123806.32416-1-tzimmermann@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org To do framebuffer updates, one needs memcpy from system memory and a pointer-increment function. Add both interfaces with documentation. Signed-off-by: Thomas Zimmermann Reviewed-by: Sam Ravnborg --- include/linux/dma-buf-map.h | 72 +++++++++++++++++++++++++++++++------ 1 file changed, 62 insertions(+), 10 deletions(-) diff --git a/include/linux/dma-buf-map.h b/include/linux/dma-buf-map.h index 2e8bbecb5091..6ca0f304dda2 100644 --- a/include/linux/dma-buf-map.h +++ b/include/linux/dma-buf-map.h @@ -32,6 +32,14 @@ * accessing the buffer. Use the returned instance and the helper functions * to access the buffer's memory in the correct way. * + * The type :c:type:`struct dma_buf_map ` and its helpers are + * actually independent from the dma-buf infrastructure. When sharing buffers + * among devices, drivers have to know the location of the memory to access + * the buffers in a safe way. :c:type:`struct dma_buf_map ` + * solves this problem for dma-buf and its users. If other drivers or + * sub-systems require similar functionality, the type could be generalized + * and moved to a more prominent header file. + * * Open-coding access to :c:type:`struct dma_buf_map ` is * considered bad style. Rather then accessing its fields directly, use one * of the provided helper functions, or implement your own. For example, @@ -51,6 +59,14 @@ * * dma_buf_map_set_vaddr_iomem(&map. 0xdeadbeaf); * + * Instances of struct dma_buf_map do not have to be cleaned up, but + * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings + * always refer to system memory. + * + * .. code-block:: c + * + * dma_buf_map_clear(&map); + * * Test if a mapping is valid with either dma_buf_map_is_set() or * dma_buf_map_is_null(). * @@ -73,17 +89,19 @@ * if (dma_buf_map_is_equal(&sys_map, &io_map)) * // always false * - * Instances of struct dma_buf_map do not have to be cleaned up, but - * can be cleared to NULL with dma_buf_map_clear(). Cleared mappings - * always refer to system memory. + * A set up instance of struct dma_buf_map can be used to access or manipulate + * the buffer memory. Depending on the location of the memory, the provided + * helpers will pick the correct operations. Data can be copied into the memory + * with dma_buf_map_memcpy_to(). The address can be manipulated with + * dma_buf_map_incr(). * - * The type :c:type:`struct dma_buf_map ` and its helpers are - * actually independent from the dma-buf infrastructure. When sharing buffers - * among devices, drivers have to know the location of the memory to access - * the buffers in a safe way. :c:type:`struct dma_buf_map ` - * solves this problem for dma-buf and its users. If other drivers or - * sub-systems require similar functionality, the type could be generalized - * and moved to a more prominent header file. + * .. code-block:: c + * + * const void *src = ...; // source buffer + * size_t len = ...; // length of src + * + * dma_buf_map_memcpy_to(&map, src, len); + * dma_buf_map_incr(&map, len); // go to first byte after the memcpy */ /** @@ -210,4 +228,38 @@ static inline void dma_buf_map_clear(struct dma_buf_map *map) } } +/** + * dma_buf_map_memcpy_to - Memcpy into dma-buf mapping + * @dst: The dma-buf mapping structure + * @src: The source buffer + * @len: The number of byte in src + * + * Copies data into a dma-buf mapping. The source buffer is in system + * memory. Depending on the buffer's location, the helper picks the correct + * method of accessing the memory. + */ +static inline void dma_buf_map_memcpy_to(struct dma_buf_map *dst, const void *src, size_t len) +{ + if (dst->is_iomem) + memcpy_toio(dst->vaddr_iomem, src, len); + else + memcpy(dst->vaddr, src, len); +} + +/** + * dma_buf_map_incr - Increments the address stored in a dma-buf mapping + * @map: The dma-buf mapping structure + * @incr: The number of bytes to increment + * + * Increments the address stored in a dma-buf mapping. Depending on the + * buffer's location, the correct value will be updated. + */ +static inline void dma_buf_map_incr(struct dma_buf_map *map, size_t incr) +{ + if (map->is_iomem) + map->vaddr_iomem += incr; + else + map->vaddr += incr; +} + #endif /* __DMA_BUF_MAP_H__ */