From patchwork Fri Jan 19 14:13:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13523830 Received: from aposti.net (aposti.net [89.234.176.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A0A6553E1E; Fri, 19 Jan 2024 14:14:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=89.234.176.197 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705673663; cv=none; b=TFDcpWM0uAOkuXI3OYcCuNAS5kcpRsGY0ehvwEqu0tqB/VjY05xz25hOunhkFbs9EFxVGKKMHIhS5r6AEcr9uMhTUvlQkmrSillre9uik9LO0ki0Fn0NH7DInM5deVnFnK2LSq/RqQgjXjIfNJ/loLq9ZBJ9QlEtV+yihRCwTDQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705673663; c=relaxed/simple; bh=P3boRy4GijUdd5qAAmLJvetYFLnC/Yi9tbpDH7/AzQY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=D6WvFQlafE6+qa1wVE9ac/3CQB7yjQJtWOvMHc05Kqs1AiQaZQ/XGZWdx9FqxJzZ8pLDqypf15jvaiNv7vqRJf7RdgKPtGaQ1fkRlxmVSWaYxrQuw27ZzEWvQKGXv81tlnsDgGyAE4+woQT0tYrgPIrGom+pVv2Z4kt2Ll4uqCI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=crapouillou.net; spf=pass smtp.mailfrom=crapouillou.net; dkim=pass (1024-bit key) header.d=crapouillou.net header.i=@crapouillou.net header.b=nihKf29Q; arc=none smtp.client-ip=89.234.176.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=crapouillou.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=crapouillou.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=crapouillou.net header.i=@crapouillou.net header.b="nihKf29Q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1705673651; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VqYgKFlSXeXJ+ek05cChLqHNIcn71hJPj0SKGxZRr1E=; b=nihKf29QM3PAzCv1lf02nN0Lm7J1hFfqxSiJIykkJWXBNUWAts3p9naI7FhbAo3qS1vUZ+ AQnGMwjj3hS2I+vprXp5cMewxBvtbj1QizrYkrsEZ5nETFXsE//UAy/FMDfPFQvI/KRz1x ZpJEeAwef/CDAgBRqgMIUAVTEo2wVuY= From: Paul Cercueil To: Greg Kroah-Hartman , Jonathan Corbet , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Cc: Jonathan Cameron , =?utf-8?q?Nuno_S=C3=A1?= , Michael Hennerich , linux-usb@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, Paul Cercueil Subject: [PATCH v5 1/6] dma-buf: Add dma_buf_{begin,end}_access() Date: Fri, 19 Jan 2024 15:13:57 +0100 Message-ID: <20240119141402.44262-2-paul@crapouillou.net> In-Reply-To: <20240119141402.44262-1-paul@crapouillou.net> References: <20240119141402.44262-1-paul@crapouillou.net> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam: Yes These functions should be used by device drivers when they start and stop accessing the data of DMABUF. It allows DMABUF importers to cache the dma_buf_attachment while ensuring that the data they want to access is available for their device when the DMA transfers take place. Signed-off-by: Paul Cercueil --- v5: New patch --- drivers/dma-buf/dma-buf.c | 66 +++++++++++++++++++++++++++++++++++++++ include/linux/dma-buf.h | 37 ++++++++++++++++++++++ 2 files changed, 103 insertions(+) diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 8fe5aa67b167..a8bab6c18fcd 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -830,6 +830,8 @@ static struct sg_table * __map_dma_buf(struct dma_buf_attachment *attach, * - dma_buf_mmap() * - dma_buf_begin_cpu_access() * - dma_buf_end_cpu_access() + * - dma_buf_begin_access() + * - dma_buf_end_access() * - dma_buf_map_attachment_unlocked() * - dma_buf_unmap_attachment_unlocked() * - dma_buf_vmap_unlocked() @@ -1602,6 +1604,70 @@ void dma_buf_vunmap_unlocked(struct dma_buf *dmabuf, struct iosys_map *map) } EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap_unlocked, DMA_BUF); +/** + * @dma_buf_begin_access - Call before any hardware access from/to the DMABUF + * @attach: [in] attachment used for hardware access + * @sg_table: [in] scatterlist used for the DMA transfer + * @direction: [in] direction of DMA transfer + */ +int dma_buf_begin_access(struct dma_buf_attachment *attach, + struct sg_table *sgt, enum dma_data_direction dir) +{ + struct dma_buf *dmabuf; + bool cookie; + int ret; + + if (WARN_ON(!attach)) + return -EINVAL; + + dmabuf = attach->dmabuf; + + if (!dmabuf->ops->begin_access) + return 0; + + cookie = dma_fence_begin_signalling(); + ret = dmabuf->ops->begin_access(attach, sgt, dir); + dma_fence_end_signalling(cookie); + + if (WARN_ON_ONCE(ret)) + return ret; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(dma_buf_begin_access, DMA_BUF); + +/** + * @dma_buf_end_access - Call after any hardware access from/to the DMABUF + * @attach: [in] attachment used for hardware access + * @sg_table: [in] scatterlist used for the DMA transfer + * @direction: [in] direction of DMA transfer + */ +int dma_buf_end_access(struct dma_buf_attachment *attach, + struct sg_table *sgt, enum dma_data_direction dir) +{ + struct dma_buf *dmabuf; + bool cookie; + int ret; + + if (WARN_ON(!attach)) + return -EINVAL; + + dmabuf = attach->dmabuf; + + if (!dmabuf->ops->end_access) + return 0; + + cookie = dma_fence_begin_signalling(); + ret = dmabuf->ops->end_access(attach, sgt, dir); + dma_fence_end_signalling(cookie); + + if (WARN_ON_ONCE(ret)) + return ret; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(dma_buf_end_access, DMA_BUF); + #ifdef CONFIG_DEBUG_FS static int dma_buf_debug_show(struct seq_file *s, void *unused) { diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 8ff4add71f88..8ba612c7cc16 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -246,6 +246,38 @@ struct dma_buf_ops { */ int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction); + /** + * @begin_access: + * + * This is called from dma_buf_begin_access() when a device driver + * wants to access the data of the DMABUF. The exporter can use this + * to flush/sync the caches if needed. + * + * This callback is optional. + * + * Returns: + * + * 0 on success or a negative error code on failure. + */ + int (*begin_access)(struct dma_buf_attachment *, struct sg_table *, + enum dma_data_direction); + + /** + * @end_access: + * + * This is called from dma_buf_end_access() when a device driver is + * done accessing the data of the DMABUF. The exporter can use this + * to flush/sync the caches if needed. + * + * This callback is optional. + * + * Returns: + * + * 0 on success or a negative error code on failure. + */ + int (*end_access)(struct dma_buf_attachment *, struct sg_table *, + enum dma_data_direction); + /** * @mmap: * @@ -606,6 +638,11 @@ void dma_buf_detach(struct dma_buf *dmabuf, int dma_buf_pin(struct dma_buf_attachment *attach); void dma_buf_unpin(struct dma_buf_attachment *attach); +int dma_buf_begin_access(struct dma_buf_attachment *attach, + struct sg_table *sgt, enum dma_data_direction dir); +int dma_buf_end_access(struct dma_buf_attachment *attach, + struct sg_table *sgt, enum dma_data_direction dir); + struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info); int dma_buf_fd(struct dma_buf *dmabuf, int flags);