Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755930AbcJZIwp (ORCPT ); Wed, 26 Oct 2016 04:52:45 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:40525 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752269AbcJZIwZ (ORCPT ); Wed, 26 Oct 2016 04:52:25 -0400 From: Thierry Escande To: Mauro Carvalho Chehab , Sakari Ailus Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Pawel Osciak , Marek Szyprowski , Kyungmin Park Subject: [PATCH v3 2/2] [media] videobuf2-dc: Support cacheable MMAP Date: Wed, 26 Oct 2016 10:52:06 +0200 Message-Id: <1477471926-15796-3-git-send-email-thierry.escande@collabora.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1477471926-15796-1-git-send-email-thierry.escande@collabora.com> References: <1477471926-15796-1-git-send-email-thierry.escande@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset = "utf-8" Content-Transfert-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2428 Lines: 64 From: Heng-Ruey Hsu DMA allocations for MMAP type are uncached by default. But for some cases, CPU has to access the buffers. ie: memcpy for format converter. Supporting cacheable MMAP improves huge performance. This patch enables cacheable memory for DMA coherent allocator in mmap buffer allocation if non-consistent DMA attribute is set and kernel mapping is present. Even if userspace doesn't mmap the buffer, sync still should be happening if kernel mapping is present. If not done in allocation, it is enabled when memory is mapped from userspace (if non-consistent DMA attribute is set). Signed-off-by: Heng-Ruey Hsu Tested-by: Heng-ruey Hsu Reviewed-by: Tomasz Figa Signed-off-by: Thierry Escande --- drivers/media/v4l2-core/videobuf2-dma-contig.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c index 0d9665d..89b534a 100644 --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c @@ -151,6 +151,10 @@ static void vb2_dc_put(void *buf_priv) sg_free_table(buf->sgt_base); kfree(buf->sgt_base); } + if (buf->dma_sgt) { + sg_free_table(buf->dma_sgt); + kfree(buf->dma_sgt); + } dma_free_attrs(buf->dev, buf->size, buf->cookie, buf->dma_addr, buf->attrs); put_device(buf->dev); @@ -192,6 +196,14 @@ static void *vb2_dc_alloc(struct device *dev, unsigned long attrs, buf->handler.put = vb2_dc_put; buf->handler.arg = buf; + /* + * Enable cache maintenance. Even if userspace doesn't mmap the buffer, + * sync still should be happening if kernel mapping is present. + */ + if (!(buf->attrs & DMA_ATTR_NO_KERNEL_MAPPING) && + buf->attrs & DMA_ATTR_NON_CONSISTENT) + buf->dma_sgt = vb2_dc_get_base_sgt(buf); + atomic_inc(&buf->refcount); return buf; @@ -227,6 +239,10 @@ static int vb2_dc_mmap(void *buf_priv, struct vm_area_struct *vma) vma->vm_ops->open(vma); + /* Enable cache maintenance if not enabled in allocation. */ + if (!buf->dma_sgt && buf->attrs & DMA_ATTR_NON_CONSISTENT) + buf->dma_sgt = vb2_dc_get_base_sgt(buf); + pr_debug("%s: mapped dma addr 0x%08lx at 0x%08lx, size %ld\n", __func__, (unsigned long)buf->dma_addr, vma->vm_start, buf->size); -- 2.7.4