From patchwork Thu Apr 28 12:12:20 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Szyprowski X-Patchwork-Id: 8969161 Return-Path: X-Original-To: patchwork-linux-samsung-soc@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 3FDA1BF29F for ; Thu, 28 Apr 2016 12:12:36 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 42D55202BE for ; Thu, 28 Apr 2016 12:12:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 328AC202AE for ; Thu, 28 Apr 2016 12:12:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753178AbcD1MMb (ORCPT ); Thu, 28 Apr 2016 08:12:31 -0400 Received: from mailout1.w1.samsung.com ([210.118.77.11]:45849 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753005AbcD1MMa (ORCPT ); Thu, 28 Apr 2016 08:12:30 -0400 Received: from eucpsbgm2.samsung.com (unknown [203.254.199.245]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0O6C00LPIF8REUB0@mailout1.w1.samsung.com>; Thu, 28 Apr 2016 13:12:27 +0100 (BST) X-AuditID: cbfec7f5-f792a6d000001302-a1-5721fe2b8571 Received: from eusync2.samsung.com ( [203.254.199.212]) by eucpsbgm2.samsung.com (EUCPMTA) with SMTP id EF.32.04866.B2EF1275; Thu, 28 Apr 2016 13:12:27 +0100 (BST) Received: from amdc1339.digital.local ([106.116.147.30]) by eusync2.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTPA id <0O6C005M4F8NFU70@eusync2.samsung.com>; Thu, 28 Apr 2016 13:12:27 +0100 (BST) From: Marek Szyprowski To: linux-media@vger.kernel.org, linux-samsung-soc@vger.kernel.org Cc: Marek Szyprowski , Sylwester Nawrocki , Laurent Pinchart , Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , Hans Verkuil Subject: [PATCH] media: vb2-dma-contig: configure DMA max segment size properly Date: Thu, 28 Apr 2016 14:12:20 +0200 Message-id: <1461845540-26454-1-git-send-email-m.szyprowski@samsung.com> X-Mailer: git-send-email 1.9.2 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrDJMWRmVeSWpSXmKPExsVy+t/xK7ra/xTDDfo/cFpsnLGe1WLJz11M Fq9fGFp0TlzCbtGzYSurxYzz+5gs1h65y25x+E07qwOHx5TfG1k9ZnfMZPXo27KK0ePzJrkA ligum5TUnMyy1CJ9uwSujPWne9gLLipUXPr4hKmB8Z9UFyMnh4SAicSK7tssELaYxIV769m6 GLk4hASWMkrM6J3NDOE0MUm8bTrMBlLFJmAo0fW2C8wWEXCSWDjrLztIEbPACqCiuZfAEsIC /hL/u58ygtgsAqoS53v3M4PYvAIeEkcvPmGCWCcn8f/lCqYJjNwLGBlWMYqmliYXFCel5xrp FSfmFpfmpesl5+duYoSEydcdjEuPWR1iFOBgVOLhnZCgGC7EmlhWXJl7iFGCg1lJhPfNH6AQ b0piZVVqUX58UWlOavEhRmkOFiVx3pm73ocICaQnlqRmp6YWpBbBZJk4OKUaGFt+Ns99KJyX M2tO6c6VuyY1hc9erNa+mrvAK3/3mhOl1k1hnTESRZcXJZ7pczOUcNV6Z9UvLXB6b+DkxSvY BZ508IT87uaZeFLvbnDp1DlNZQw9NsIbBISP7ZssO/uf/bWLJolz8ouCmT8XGVsomv+NkVz6 aGLOiaSy6X7BnHP1firMmRF4QImlOCPRUIu5qDgRAN4AifAPAgAA Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org X-Spam-Status: No, score=-7.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch lets vb2-dma-contig memory allocator to configure DMA max segment size properly for the client device. Setting it is needed to let DMA-mapping subsystem to create a single, contiguous mapping in DMA address space. This is essential for all devices, which use dma-contig videobuf2 memory allocator and shared buffers (in USERPTR or DMAbuf modes of operations). Signed-off-by: Marek Szyprowski --- Hello, This patch is a follow-up of my previous attempts to let Exynos multimedia devices to work properly with shared buffers when IOMMU is enabled: 1. https://www.mail-archive.com/linux-media@vger.kernel.org/msg96946.html 2. http://thread.gmane.org/gmane.linux.drivers.video-input-infrastructure/97316 3. https://patchwork.linuxtv.org/patch/30870/ As sugested by Hans, configuring DMA max segment size should be done by videobuf2-dma-contig module instead of requiring all device drivers to do it on their own. Here is some backgroud why this is done in videobuf2-dc not in the respective generic bus code: http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/305913.html Best regards, Marek Szyprowski --- drivers/media/v4l2-core/videobuf2-dma-contig.c | 39 ++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 461ae55eaa98..871e370f8e88 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -443,6 +443,35 @@ static void vb2_dc_put_userptr(void *buf_priv) } /* + * To allow mapping scatter-list into signle chunk in DMA address space, + * device is required to have DMA max segment size parameter set to value + * larger than the buffer size. Otherwise, DMA-mapping subsystem will + * split the mapping into max segment size chunks. + * This function increases DMA max segment size parameter to let + * DMA-mapping to map a buffer as a single chunk in DMA address space. + * This code assumes that the DMA-mapping subsystem will merge all + * scatter-list segments if this is really possible (for example when + * IOMMU is available and enabled). + * Ideally, this parameter should be set by generic bus code, but it is + * left with the default 64KiB value due to some historical limitations + * in other subsystems (like limited USB host drivers) and there is no + * good place to set it to the proper value. It is done here to avoid + * fixing all vb2-dc client drivers. + */ +static int vb2_dc_set_max_seg_size(struct device *dev, unsigned int size) +{ + if (!dev->dma_parms) { + dev->dma_parms = kzalloc(sizeof(dev->dma_parms), GFP_KERNEL); + if (!dev->dma_parms) + return -ENOMEM; + } + if (dma_get_max_seg_size(dev) < size) + return dma_set_max_seg_size(dev, size); + + return 0; +} + +/* * For some kind of reserved memory there might be no struct page available, * so all that can be done to support such 'pages' is to try to convert * pfn to dma address or at the last resort just assume that @@ -499,6 +528,10 @@ static void *vb2_dc_get_userptr(struct device *dev, unsigned long vaddr, return ERR_PTR(-EINVAL); } + ret = vb2_dc_set_max_seg_size(dev, PAGE_ALIGN(size + PAGE_SIZE)); + if (!ret) + return ERR_PTR(ret); + buf = kzalloc(sizeof *buf, GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); @@ -675,10 +708,15 @@ static void *vb2_dc_attach_dmabuf(struct device *dev, struct dma_buf *dbuf, { struct vb2_dc_buf *buf; struct dma_buf_attachment *dba; + int ret; if (dbuf->size < size) return ERR_PTR(-EFAULT); + ret = vb2_dc_set_max_seg_size(dev, PAGE_ALIGN(size)); + if (!ret) + return ERR_PTR(ret); + buf = kzalloc(sizeof(*buf), GFP_KERNEL); if (!buf) return ERR_PTR(-ENOMEM); @@ -722,6 +760,7 @@ const struct vb2_mem_ops vb2_dma_contig_memops = { }; EXPORT_SYMBOL_GPL(vb2_dma_contig_memops); + MODULE_DESCRIPTION("DMA-contig memory handling routines for videobuf2"); MODULE_AUTHOR("Pawel Osciak "); MODULE_LICENSE("GPL");