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[91.14.172.254]) by smtp.gmail.com with ESMTPSA id s15-20020a05640217cf00b0045467008dd0sm12091979edy.35.2022.10.20.05.13.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Oct 2022 05:13:20 -0700 (PDT) From: " =?utf-8?q?Christian_K=C3=B6nig?= " X-Google-Original-From: =?utf-8?q?Christian_K=C3=B6nig?= To: l.stach@pengutronix.de, nicolas@ndufresne.ca, ppaalanen@gmail.com, sumit.semwal@linaro.org, daniel@ffwll.ch, robdclark@gmail.com, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-media@vger.kernel.org Cc: =?utf-8?q?Christian_K=C3=B6nig?= Subject: [PATCH 1/3] dma-buf: add dma_coherent flag Date: Thu, 20 Oct 2022 14:13:14 +0200 Message-Id: <20221020121316.3946-2-christian.koenig@amd.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20221020121316.3946-1-christian.koenig@amd.com> References: <20221020121316.3946-1-christian.koenig@amd.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Start to fix the coherency issues for non PCI devices by adding a dma_coherent flag to the DMA-buf. The flag should be set by the exporter if only devices which can do coherent DMA-access with respect to the CPU cache are allowed to access the buffer. Signed-off-by: Christian König --- drivers/dma-buf/dma-buf.c | 5 +++++ include/linux/dma-buf.h | 16 ++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index c40d72d318fd..7509807bf485 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -635,6 +636,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) dmabuf->priv = exp_info->priv; dmabuf->ops = exp_info->ops; + dmabuf->dma_coherent = exp_info->coherent; dmabuf->size = exp_info->size; dmabuf->exp_name = exp_info->exp_name; dmabuf->owner = exp_info->owner; @@ -894,6 +896,9 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, struct device *dev, if (WARN_ON(importer_ops && !importer_ops->move_notify)) return ERR_PTR(-EINVAL); + if (dmabuf->dma_coherent && !dev_is_dma_coherent(dev)) + return ERR_PTR(-EINVAL); + attach = kzalloc(sizeof(*attach), GFP_KERNEL); if (!attach) return ERR_PTR(-ENOMEM); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 6fa8d4e29719..f2083b94b116 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -326,6 +326,20 @@ struct dma_buf { /** @ops: dma_buf_ops associated with this buffer object. */ const struct dma_buf_ops *ops; + /** + * @dma_coherent: + * + * True if the buffer is backed by DMA coherent memory with respect to + * the CPU cache even if the architecture can support incoherent + * devices. + * + * Usually mirrors the result of dev_is_dma_coherent() of the exporter, + * but can be cleared by the exporter to allow incoherent devices + * access to the buffer if the exporter takes care of coherency for CPU + * accesses. + */ + bool dma_coherent; + /** * @vmapping_counter: * @@ -524,6 +538,7 @@ struct dma_buf_attachment { * @ops: Attach allocator-defined dma buf ops to the new buffer * @size: Size of the buffer - invariant over the lifetime of the buffer * @flags: mode flags for the file + * @coherent: If DMA accesses must be coherent to the CPU cache. * @resv: reservation-object, NULL to allocate default one * @priv: Attach private data of allocator to this buffer * @@ -536,6 +551,7 @@ struct dma_buf_export_info { const struct dma_buf_ops *ops; size_t size; int flags; + bool coherent; struct dma_resv *resv; void *priv; };