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: 13523823 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9DCB2C47DAF for ; Fri, 19 Jan 2024 14:14:25 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id CC50010EA50; Fri, 19 Jan 2024 14:14:24 +0000 (UTC) Received: from aposti.net (aposti.net [89.234.176.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id B3D7F10EA4E for ; Fri, 19 Jan 2024 14:14:23 +0000 (UTC) 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?= 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> MIME-Version: 1.0 X-Spam: Yes X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Cercueil , Michael Hennerich , linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, =?utf-8?q?Nuno_S=C3=A1?= , Jonathan Cameron , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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); From patchwork Fri Jan 19 14:13:58 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13523824 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AF079C47DAF for ; Fri, 19 Jan 2024 14:14:31 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 2FC1710EA58; Fri, 19 Jan 2024 14:14:31 +0000 (UTC) Received: from aposti.net (aposti.net [89.234.176.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id CA36F10EA4E for ; Fri, 19 Jan 2024 14:14:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1705673652; 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=9iIxPbs0dWlzjgcaYm0qZReABojDho1rbr0/l/s8ieo=; b=VDmw/5dmFB8a7DjV5sQY6708zGHT8cN9da4xSjKPmDqd5JoGUoAWZFLA4iBJzYVtLoeMc0 534O4/q85cvb0JyL4RkqR4fcFW36IeUqTLCBrV3EPttmKkeaTxQBZIvVT+hfm/hQr1U2rC b1Gx/QWvHOF3f7bFVi1IGm2UPpG4KrU= From: Paul Cercueil To: Greg Kroah-Hartman , Jonathan Corbet , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Subject: [PATCH v5 2/6] dma-buf: udmabuf: Implement .{begin,end}_access Date: Fri, 19 Jan 2024 15:13:58 +0100 Message-ID: <20240119141402.44262-3-paul@crapouillou.net> In-Reply-To: <20240119141402.44262-1-paul@crapouillou.net> References: <20240119141402.44262-1-paul@crapouillou.net> MIME-Version: 1.0 X-Spam: Yes X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Cercueil , Michael Hennerich , linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, =?utf-8?q?Nuno_S=C3=A1?= , Jonathan Cameron , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Implement .begin_access() and .end_access() callbacks. For now these functions will simply sync/flush the CPU cache when needed. Signed-off-by: Paul Cercueil --- v5: New patch --- drivers/dma-buf/udmabuf.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index c40645999648..a87d89b58816 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -179,6 +179,31 @@ static int end_cpu_udmabuf(struct dma_buf *buf, return 0; } +static int begin_udmabuf(struct dma_buf_attachment *attach, + struct sg_table *sgt, + enum dma_data_direction dir) +{ + struct dma_buf *buf = attach->dmabuf; + struct udmabuf *ubuf = buf->priv; + struct device *dev = ubuf->device->this_device; + + dma_sync_sg_for_device(dev, sgt->sgl, sg_nents(sgt->sgl), dir); + return 0; +} + +static int end_udmabuf(struct dma_buf_attachment *attach, + struct sg_table *sgt, + enum dma_data_direction dir) +{ + struct dma_buf *buf = attach->dmabuf; + struct udmabuf *ubuf = buf->priv; + struct device *dev = ubuf->device->this_device; + + if (dir != DMA_TO_DEVICE) + dma_sync_sg_for_cpu(dev, sgt->sgl, sg_nents(sgt->sgl), dir); + return 0; +} + static const struct dma_buf_ops udmabuf_ops = { .cache_sgt_mapping = true, .map_dma_buf = map_udmabuf, @@ -189,6 +214,8 @@ static const struct dma_buf_ops udmabuf_ops = { .vunmap = vunmap_udmabuf, .begin_cpu_access = begin_cpu_udmabuf, .end_cpu_access = end_cpu_udmabuf, + .begin_access = begin_udmabuf, + .end_access = end_udmabuf, }; #define SEALS_WANTED (F_SEAL_SHRINK) From patchwork Fri Jan 19 14:13:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13523825 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D9463C4725D for ; Fri, 19 Jan 2024 14:14:39 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0551910EA60; Fri, 19 Jan 2024 14:14:39 +0000 (UTC) Received: from aposti.net (aposti.net [89.234.176.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3A66910E9B7 for ; Fri, 19 Jan 2024 14:14:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1705673653; 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=SqXbfp61fzBHWNEqVrElLd46cr7HG/1wYVIvKKSn5jY=; b=NaAbiMYNA0AFJ1EOYLqs/WsQDOJFW4kjOTy5BHngcJ3g7fQNN1JRmaxyrKqwxaeT10DLx6 T/t9sAqiAQOdlMHR4xSm/2PaVYL5NNRDZmkExUzP1K+6bXsSsg+vJUIOe7o66dFXNKxz1T BAnGgTqNlP4vbEWAzuO4NKw3WXxW5dY= From: Paul Cercueil To: Greg Kroah-Hartman , Jonathan Corbet , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Subject: [PATCH v5 3/6] usb: gadget: Support already-mapped DMA SGs Date: Fri, 19 Jan 2024 15:13:59 +0100 Message-ID: <20240119141402.44262-4-paul@crapouillou.net> In-Reply-To: <20240119141402.44262-1-paul@crapouillou.net> References: <20240119141402.44262-1-paul@crapouillou.net> MIME-Version: 1.0 X-Spam: Yes X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Cercueil , Michael Hennerich , linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, =?utf-8?q?Nuno_S=C3=A1?= , Jonathan Cameron , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add a new 'sg_was_mapped' field to the struct usb_request. This field can be used to indicate that the scatterlist associated to the USB transfer has already been mapped into the DMA space, and it does not have to be done internally. Signed-off-by: Paul Cercueil --- drivers/usb/gadget/udc/core.c | 7 ++++++- include/linux/usb/gadget.h | 2 ++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c index d59f94464b87..9d4150124fdb 100644 --- a/drivers/usb/gadget/udc/core.c +++ b/drivers/usb/gadget/udc/core.c @@ -903,6 +903,11 @@ int usb_gadget_map_request_by_dev(struct device *dev, if (req->length == 0) return 0; + if (req->sg_was_mapped) { + req->num_mapped_sgs = req->num_sgs; + return 0; + } + if (req->num_sgs) { int mapped; @@ -948,7 +953,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_map_request); void usb_gadget_unmap_request_by_dev(struct device *dev, struct usb_request *req, int is_in) { - if (req->length == 0) + if (req->length == 0 || req->sg_was_mapped) return; if (req->num_mapped_sgs) { diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h index a771ccc038ac..c529e4e06997 100644 --- a/include/linux/usb/gadget.h +++ b/include/linux/usb/gadget.h @@ -52,6 +52,7 @@ struct usb_ep; * @short_not_ok: When reading data, makes short packets be * treated as errors (queue stops advancing till cleanup). * @dma_mapped: Indicates if request has been mapped to DMA (internal) + * @sg_was_mapped: Set if the scatterlist has been mapped before the request * @complete: Function called when request completes, so this request and * its buffer may be re-used. The function will always be called with * interrupts disabled, and it must not sleep. @@ -111,6 +112,7 @@ struct usb_request { unsigned zero:1; unsigned short_not_ok:1; unsigned dma_mapped:1; + unsigned sg_was_mapped:1; void (*complete)(struct usb_ep *ep, struct usb_request *req); From patchwork Fri Jan 19 14:14:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13523826 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 74051C47DAF for ; Fri, 19 Jan 2024 14:14:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id AB0C410EA64; Fri, 19 Jan 2024 14:14:45 +0000 (UTC) Received: from aposti.net (aposti.net [89.234.176.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2298110EA64 for ; Fri, 19 Jan 2024 14:14:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1705673653; 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=PFENih9XWAd70944xbCOau+9oHw/D103WR9u3LQvnx8=; b=Gt2xMOokNy++NJFR1tq2AUBcDdKRgJGiiz5FSZvayuQanfDZYEBEehUt+TLwRdtKYYMQX0 N+tcnAwYsDx961blLSEEEMkDtaedDVVXIhQ3h6d+0+HHoJaBgCZxoP1TkzfBHso6z1qKo7 EDDtwRL25WF5+PCGPOhNibxKGarkIyE= From: Paul Cercueil To: Greg Kroah-Hartman , Jonathan Corbet , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Subject: [PATCH v5 4/6] usb: gadget: functionfs: Factorize wait-for-endpoint code Date: Fri, 19 Jan 2024 15:14:00 +0100 Message-ID: <20240119141402.44262-5-paul@crapouillou.net> In-Reply-To: <20240119141402.44262-1-paul@crapouillou.net> References: <20240119141402.44262-1-paul@crapouillou.net> MIME-Version: 1.0 X-Spam: Yes X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Cercueil , Michael Hennerich , linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, =?utf-8?q?Nuno_S=C3=A1?= , Jonathan Cameron , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This exact same code was duplicated in two different places. Signed-off-by: Paul Cercueil --- drivers/usb/gadget/function/f_fs.c | 48 +++++++++++++++++------------- 1 file changed, 27 insertions(+), 21 deletions(-) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 6bff6cb93789..ed2a6d5fcef7 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -934,31 +934,44 @@ static ssize_t __ffs_epfile_read_data(struct ffs_epfile *epfile, return ret; } -static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) +static struct ffs_ep *ffs_epfile_wait_ep(struct file *file) { struct ffs_epfile *epfile = file->private_data; - struct usb_request *req; struct ffs_ep *ep; - char *data = NULL; - ssize_t ret, data_len = -EINVAL; - int halt; - - /* Are we still active? */ - if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) - return -ENODEV; + int ret; /* Wait for endpoint to be enabled */ ep = epfile->ep; if (!ep) { if (file->f_flags & O_NONBLOCK) - return -EAGAIN; + return ERR_PTR(-EAGAIN); ret = wait_event_interruptible( epfile->ffs->wait, (ep = epfile->ep)); if (ret) - return -EINTR; + return ERR_PTR(-EINTR); } + return ep; +} + +static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) +{ + struct ffs_epfile *epfile = file->private_data; + struct usb_request *req; + struct ffs_ep *ep; + char *data = NULL; + ssize_t ret, data_len = -EINVAL; + int halt; + + /* Are we still active? */ + if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) + return -ENODEV; + + ep = ffs_epfile_wait_ep(file); + if (IS_ERR(ep)) + return PTR_ERR(ep); + /* Do we halt? */ halt = (!io_data->read == !epfile->in); if (halt && epfile->isoc) @@ -1280,16 +1293,9 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, return -ENODEV; /* Wait for endpoint to be enabled */ - ep = epfile->ep; - if (!ep) { - if (file->f_flags & O_NONBLOCK) - return -EAGAIN; - - ret = wait_event_interruptible( - epfile->ffs->wait, (ep = epfile->ep)); - if (ret) - return -EINTR; - } + ep = ffs_epfile_wait_ep(file); + if (IS_ERR(ep)) + return PTR_ERR(ep); spin_lock_irq(&epfile->ffs->eps_lock); From patchwork Fri Jan 19 14:14:01 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13523827 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ED3A9C47DAF for ; Fri, 19 Jan 2024 14:14:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 332C510EA34; Fri, 19 Jan 2024 14:14:52 +0000 (UTC) Received: from aposti.net (aposti.net [89.234.176.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4275610E0EA for ; Fri, 19 Jan 2024 14:14:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1705673654; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HEEYiuLeIQ4/+QA+DhT4nVTv5/edVx50oVzMxKrH1w4=; b=QLAS56wgZGcnmqpfLGkhpK2KY6pPcsu9xTYj6Ew50+hPNTxlR3ICIKcjyYllFnQrPQHFHj Rck42IjixnGA44D199A8PCaacR7czLUsqGSRtUIwThMaBwfToU4WaT1N7G6WfDPlNSt9gs DafXR9L6AJP3uMdMCBmlY18Ml7FqGzg= From: Paul Cercueil To: Greg Kroah-Hartman , Jonathan Corbet , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Subject: [PATCH v5 5/6] usb: gadget: functionfs: Add DMABUF import interface Date: Fri, 19 Jan 2024 15:14:01 +0100 Message-ID: <20240119141402.44262-6-paul@crapouillou.net> In-Reply-To: <20240119141402.44262-1-paul@crapouillou.net> References: <20240119141402.44262-1-paul@crapouillou.net> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Cercueil , Michael Hennerich , linux-doc@vger.kernel.org, Daniel Vetter , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, =?utf-8?q?Nuno_S=C3=A1?= , Jonathan Cameron , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This patch introduces three new ioctls. They all should be called on a data endpoint (ie. not ep0). They are: - FUNCTIONFS_DMABUF_ATTACH, which takes the file descriptor of a DMABUF object to attach to the endpoint. - FUNCTIONFS_DMABUF_DETACH, which takes the file descriptor of the DMABUF to detach from the endpoint. Note that closing the endpoint's file descriptor will automatically detach all attached DMABUFs. - FUNCTIONFS_DMABUF_TRANSFER, which requests a data transfer from / to the given DMABUF. Its argument is a structure that packs the DMABUF's file descriptor, the size in bytes to transfer (which should generally be set to the size of the DMABUF), and a 'flags' field which is unused for now. Before this ioctl can be used, the related DMABUF must be attached with FUNCTIONFS_DMABUF_ATTACH. These three ioctls enable the FunctionFS code to transfer data between the USB stack and a DMABUF object, which can be provided by a driver from a completely different subsystem, in a zero-copy fashion. Signed-off-by: Paul Cercueil Acked-by: Daniel Vetter Acked-by: Christian König --- v2: - Make ffs_dma_resv_lock() static - Add MODULE_IMPORT_NS(DMA_BUF); - The attach/detach functions are now performed without locking the eps_lock spinlock. The transfer function starts with the spinlock unlocked, then locks it before allocating and queueing the USB transfer. v3: - Inline to_ffs_dma_fence() which was called only once. - Simplify ffs_dma_resv_lock() - Add comment explaining why we unref twice in ffs_dmabuf_detach() - Document uapi struct usb_ffs_dmabuf_transfer_req and IOCTLs v4: - Protect the DMABUF list with a mutex - Use incremental sequence number for the dma_fences - Unref attachments and DMABUFs in workers - Remove dead code in ffs_dma_resv_lock() - Fix non-block actually blocking - Use dma_fence_begin/end_signalling() - Add comment about cache-management and dma_buf_unmap_attachment() - Make sure dma_buf_map_attachment() is called with the dma-resv locked v5: - Cache the dma_buf_attachment while the DMABUF is attached. - Use dma_buf_begin/end_access() to ensure that the DMABUF data will be coherent to the hardware. - Remove comment about cache-management and dma_buf_unmap_attachment(), since we now use dma_buf_begin/end_access(). - Added Christian's ACK - Select DMA_SHARED_BUFFER in Kconfig entry --- drivers/usb/gadget/Kconfig | 1 + drivers/usb/gadget/function/f_fs.c | 456 ++++++++++++++++++++++++++++ include/uapi/linux/usb/functionfs.h | 41 +++ 3 files changed, 498 insertions(+) diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig index b3592bcb0f96..566ff0b1282a 100644 --- a/drivers/usb/gadget/Kconfig +++ b/drivers/usb/gadget/Kconfig @@ -190,6 +190,7 @@ config USB_F_MASS_STORAGE tristate config USB_F_FS + select DMA_SHARED_BUFFER tristate config USB_F_UAC1 diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index ed2a6d5fcef7..82cc449a4d7e 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -15,6 +15,9 @@ /* #define VERBOSE_DEBUG */ #include +#include +#include +#include #include #include #include @@ -43,6 +46,8 @@ #define FUNCTIONFS_MAGIC 0xa647361 /* Chosen by a honest dice roll ;) */ +MODULE_IMPORT_NS(DMA_BUF); + /* Reference counter handling */ static void ffs_data_get(struct ffs_data *ffs); static void ffs_data_put(struct ffs_data *ffs); @@ -124,6 +129,23 @@ struct ffs_ep { u8 num; }; +struct ffs_dmabuf_priv { + struct list_head entry; + struct kref ref; + struct ffs_data *ffs; + struct dma_buf_attachment *attach; + struct sg_table *sgt; + enum dma_data_direction dir; + spinlock_t lock; + u64 context; +}; + +struct ffs_dma_fence { + struct dma_fence base; + struct ffs_dmabuf_priv *priv; + struct work_struct work; +}; + struct ffs_epfile { /* Protects ep->ep and ep->req. */ struct mutex mutex; @@ -197,6 +219,11 @@ struct ffs_epfile { unsigned char isoc; /* P: ffs->eps_lock */ unsigned char _pad; + + /* Protects dmabufs */ + struct mutex dmabufs_mutex; + struct list_head dmabufs; /* P: dmabufs_mutex */ + atomic_t seqno; }; struct ffs_buffer { @@ -1271,10 +1298,51 @@ static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to) return res; } +static void ffs_dmabuf_release(struct kref *ref) +{ + struct ffs_dmabuf_priv *priv = container_of(ref, struct ffs_dmabuf_priv, ref); + struct dma_buf_attachment *attach = priv->attach; + struct dma_buf *dmabuf = attach->dmabuf; + + pr_debug("FFS DMABUF release\n"); + dma_resv_lock(dmabuf->resv, NULL); + dma_buf_unmap_attachment(attach, priv->sgt, priv->dir); + dma_resv_unlock(dmabuf->resv); + + dma_buf_detach(attach->dmabuf, attach); + dma_buf_put(dmabuf); + kfree(priv); +} + +static void ffs_dmabuf_get(struct dma_buf_attachment *attach) +{ + struct ffs_dmabuf_priv *priv = attach->importer_priv; + + kref_get(&priv->ref); +} + +static void ffs_dmabuf_put(struct dma_buf_attachment *attach) +{ + struct ffs_dmabuf_priv *priv = attach->importer_priv; + + kref_put(&priv->ref, ffs_dmabuf_release); +} + static int ffs_epfile_release(struct inode *inode, struct file *file) { struct ffs_epfile *epfile = inode->i_private; + struct ffs_dmabuf_priv *priv, *tmp; + + mutex_lock(&epfile->dmabufs_mutex); + + /* Close all attached DMABUFs */ + list_for_each_entry_safe(priv, tmp, &epfile->dmabufs, entry) { + list_del(&priv->entry); + ffs_dmabuf_put(priv->attach); + } + + mutex_unlock(&epfile->dmabufs_mutex); __ffs_epfile_read_buffer_free(epfile); ffs_data_closed(epfile->ffs); @@ -1282,6 +1350,354 @@ ffs_epfile_release(struct inode *inode, struct file *file) return 0; } +static void ffs_dmabuf_unmap_work(struct work_struct *work) +{ + struct ffs_dma_fence *dma_fence = + container_of(work, struct ffs_dma_fence, work); + struct ffs_dmabuf_priv *priv = dma_fence->priv; + struct dma_buf_attachment *attach = priv->attach; + struct dma_fence *fence = &dma_fence->base; + + ffs_dmabuf_put(attach); + dma_fence_put(fence); +} + +static void ffs_dmabuf_signal_done(struct ffs_dma_fence *dma_fence, int ret) +{ + struct ffs_dmabuf_priv *priv = dma_fence->priv; + struct dma_fence *fence = &dma_fence->base; + bool cookie = dma_fence_begin_signalling(); + + dma_fence_get(fence); + dma_buf_end_access(priv->attach, priv->sgt, priv->dir); + + fence->error = ret; + dma_fence_signal(fence); + dma_fence_end_signalling(cookie); + + /* + * The fence will be unref'd in ffs_dmabuf_unmap_work. + * It can't be done here, as the unref functions might try to lock + * the resv object, which would deadlock. + */ + INIT_WORK(&dma_fence->work, ffs_dmabuf_unmap_work); + queue_work(priv->ffs->io_completion_wq, &dma_fence->work); +} + +static void ffs_epfile_dmabuf_io_complete(struct usb_ep *ep, + struct usb_request *req) +{ + pr_debug("FFS: DMABUF transfer complete, status=%d\n", req->status); + ffs_dmabuf_signal_done(req->context, req->status); + usb_ep_free_request(ep, req); +} + +static const char *ffs_dmabuf_get_driver_name(struct dma_fence *fence) +{ + return "functionfs"; +} + +static const char *ffs_dmabuf_get_timeline_name(struct dma_fence *fence) +{ + return ""; +} + +static void ffs_dmabuf_fence_release(struct dma_fence *fence) +{ + struct ffs_dma_fence *dma_fence = + container_of(fence, struct ffs_dma_fence, base); + + kfree(dma_fence); +} + +static const struct dma_fence_ops ffs_dmabuf_fence_ops = { + .get_driver_name = ffs_dmabuf_get_driver_name, + .get_timeline_name = ffs_dmabuf_get_timeline_name, + .release = ffs_dmabuf_fence_release, +}; + +static int ffs_dma_resv_lock(struct dma_buf *dmabuf, bool nonblock) +{ + if (!nonblock) + return dma_resv_lock_interruptible(dmabuf->resv, NULL); + + if (!dma_resv_trylock(dmabuf->resv)) + return -EBUSY; + + return 0; +} + +static struct dma_buf_attachment * +ffs_dmabuf_find_attachment(struct ffs_epfile *epfile, struct dma_buf *dmabuf) +{ + struct device *dev = epfile->ffs->gadget->dev.parent; + struct dma_buf_attachment *attach = NULL; + struct ffs_dmabuf_priv *priv; + + mutex_lock(&epfile->dmabufs_mutex); + + list_for_each_entry(priv, &epfile->dmabufs, entry) { + if (priv->attach->dev == dev + && priv->attach->dmabuf == dmabuf) { + attach = priv->attach; + break; + } + } + + if (attach) + ffs_dmabuf_get(attach); + + mutex_unlock(&epfile->dmabufs_mutex); + + return attach ?: ERR_PTR(-EPERM); +} + +static int ffs_dmabuf_attach(struct file *file, int fd) +{ + bool nonblock = file->f_flags & O_NONBLOCK; + struct ffs_epfile *epfile = file->private_data; + struct usb_gadget *gadget = epfile->ffs->gadget; + struct dma_buf_attachment *attach; + struct ffs_dmabuf_priv *priv; + enum dma_data_direction dir; + struct sg_table *sg_table; + struct dma_buf *dmabuf; + int err; + + if (!gadget || !gadget->sg_supported) + return -EPERM; + + dmabuf = dma_buf_get(fd); + if (IS_ERR(dmabuf)) + return PTR_ERR(dmabuf); + + attach = dma_buf_attach(dmabuf, gadget->dev.parent); + if (IS_ERR(attach)) { + err = PTR_ERR(attach); + goto err_dmabuf_put; + } + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) { + err = -ENOMEM; + goto err_dmabuf_detach; + } + + dir = epfile->in ? DMA_FROM_DEVICE : DMA_TO_DEVICE; + + err = ffs_dma_resv_lock(dmabuf, nonblock); + if (err) + goto err_free_priv; + + sg_table = dma_buf_map_attachment(attach, dir); + dma_resv_unlock(dmabuf->resv); + + if (IS_ERR(sg_table)) { + err = PTR_ERR(sg_table); + goto err_free_priv; + } + + attach->importer_priv = priv; + + priv->sgt = sg_table; + priv->dir = dir; + priv->ffs = epfile->ffs; + priv->attach = attach; + spin_lock_init(&priv->lock); + kref_init(&priv->ref); + priv->context = dma_fence_context_alloc(1); + + mutex_lock(&epfile->dmabufs_mutex); + list_add(&priv->entry, &epfile->dmabufs); + mutex_unlock(&epfile->dmabufs_mutex); + + return 0; + +err_free_priv: + kfree(priv); +err_dmabuf_detach: + dma_buf_detach(dmabuf, attach); +err_dmabuf_put: + dma_buf_put(dmabuf); + + return err; +} + +static int ffs_dmabuf_detach(struct file *file, int fd) +{ + struct ffs_epfile *epfile = file->private_data; + struct device *dev = epfile->ffs->gadget->dev.parent; + struct ffs_dmabuf_priv *priv; + struct dma_buf *dmabuf; + int ret = -EPERM; + + dmabuf = dma_buf_get(fd); + if (IS_ERR(dmabuf)) + return PTR_ERR(dmabuf); + + mutex_lock(&epfile->dmabufs_mutex); + + list_for_each_entry(priv, &epfile->dmabufs, entry) { + if (priv->attach->dev == dev + && priv->attach->dmabuf == dmabuf) { + list_del(&priv->entry); + + /* Unref the reference from ffs_dmabuf_attach() */ + ffs_dmabuf_put(priv->attach); + ret = 0; + break; + } + } + + mutex_unlock(&epfile->dmabufs_mutex); + dma_buf_put(dmabuf); + + return ret; +} + +static int ffs_dmabuf_transfer(struct file *file, + const struct usb_ffs_dmabuf_transfer_req *req) +{ + bool nonblock = file->f_flags & O_NONBLOCK; + struct ffs_epfile *epfile = file->private_data; + struct dma_buf_attachment *attach; + struct ffs_dmabuf_priv *priv; + struct ffs_dma_fence *fence; + struct usb_request *usb_req; + struct dma_buf *dmabuf; + struct ffs_ep *ep; + bool cookie; + u32 seqno; + int ret; + + if (req->flags & ~USB_FFS_DMABUF_TRANSFER_MASK) + return -EINVAL; + + dmabuf = dma_buf_get(req->fd); + if (IS_ERR(dmabuf)) + return PTR_ERR(dmabuf); + + if (req->length > dmabuf->size || req->length == 0) { + ret = -EINVAL; + goto err_dmabuf_put; + } + + attach = ffs_dmabuf_find_attachment(epfile, dmabuf); + if (IS_ERR(attach)) { + ret = PTR_ERR(attach); + goto err_dmabuf_put; + } + + priv = attach->importer_priv; + + ep = ffs_epfile_wait_ep(file); + if (IS_ERR(ep)) { + ret = PTR_ERR(ep); + goto err_attachment_put; + } + + ret = dma_buf_begin_access(attach, priv->sgt, priv->dir); + if (ret) + goto err_attachment_put; + + ret = ffs_dma_resv_lock(dmabuf, nonblock); + if (ret) + goto err_end_access; + + /* Make sure we don't have writers */ + if (!dma_resv_test_signaled(dmabuf->resv, DMA_RESV_USAGE_WRITE)) { + pr_debug("FFS WRITE fence is not signaled\n"); + ret = -EBUSY; + goto err_resv_unlock; + } + + /* If we're writing to the DMABUF, make sure we don't have readers */ + if (epfile->in && + !dma_resv_test_signaled(dmabuf->resv, DMA_RESV_USAGE_READ)) { + pr_debug("FFS READ fence is not signaled\n"); + ret = -EBUSY; + goto err_resv_unlock; + } + + ret = dma_resv_reserve_fences(dmabuf->resv, 1); + if (ret) + goto err_resv_unlock; + + fence = kmalloc(sizeof(*fence), GFP_KERNEL); + if (!fence) { + ret = -ENOMEM; + goto err_resv_unlock; + } + + fence->priv = priv; + + spin_lock_irq(&epfile->ffs->eps_lock); + + /* In the meantime, endpoint got disabled or changed. */ + if (epfile->ep != ep) { + ret = -ESHUTDOWN; + goto err_fence_put; + } + + usb_req = usb_ep_alloc_request(ep->ep, GFP_ATOMIC); + if (!usb_req) { + ret = -ENOMEM; + goto err_fence_put; + } + + /* + * usb_ep_queue() guarantees that all transfers are processed in the + * order they are enqueued, so we can use a simple incrementing + * sequence number for the dma_fence. + */ + seqno = atomic_add_return(1, &epfile->seqno); + + dma_fence_init(&fence->base, &ffs_dmabuf_fence_ops, + &priv->lock, priv->context, seqno); + + dma_resv_add_fence(dmabuf->resv, &fence->base, + dma_resv_usage_rw(epfile->in)); + dma_resv_unlock(dmabuf->resv); + + /* Now that the dma_fence is in place, queue the transfer. */ + + usb_req->length = req->length; + usb_req->buf = NULL; + usb_req->sg = priv->sgt->sgl; + usb_req->num_sgs = sg_nents_for_len(priv->sgt->sgl, req->length); + usb_req->sg_was_mapped = true; + usb_req->context = fence; + usb_req->complete = ffs_epfile_dmabuf_io_complete; + + cookie = dma_fence_begin_signalling(); + ret = usb_ep_queue(ep->ep, usb_req, GFP_ATOMIC); + dma_fence_end_signalling(cookie); + if (ret) { + pr_warn("FFS: Failed to queue DMABUF: %d\n", ret); + ffs_dmabuf_signal_done(fence, ret); + usb_ep_free_request(ep->ep, usb_req); + } + + spin_unlock_irq(&epfile->ffs->eps_lock); + dma_buf_put(dmabuf); + + return ret; + +err_fence_put: + spin_unlock_irq(&epfile->ffs->eps_lock); + dma_fence_put(&fence->base); +err_resv_unlock: + dma_resv_unlock(dmabuf->resv); +err_end_access: + dma_buf_end_access(attach, priv->sgt, priv->dir); +err_attachment_put: + ffs_dmabuf_put(attach); +err_dmabuf_put: + dma_buf_put(dmabuf); + + return ret; +} + static long ffs_epfile_ioctl(struct file *file, unsigned code, unsigned long value) { @@ -1292,6 +1708,44 @@ static long ffs_epfile_ioctl(struct file *file, unsigned code, if (WARN_ON(epfile->ffs->state != FFS_ACTIVE)) return -ENODEV; + switch (code) { + case FUNCTIONFS_DMABUF_ATTACH: + { + int fd; + + if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) { + ret = -EFAULT; + break; + } + + return ffs_dmabuf_attach(file, fd); + } + case FUNCTIONFS_DMABUF_DETACH: + { + int fd; + + if (copy_from_user(&fd, (void __user *)value, sizeof(fd))) { + ret = -EFAULT; + break; + } + + return ffs_dmabuf_detach(file, fd); + } + case FUNCTIONFS_DMABUF_TRANSFER: + { + struct usb_ffs_dmabuf_transfer_req req; + + if (copy_from_user(&req, (void __user *)value, sizeof(req))) { + ret = -EFAULT; + break; + } + + return ffs_dmabuf_transfer(file, &req); + } + default: + break; + } + /* Wait for endpoint to be enabled */ ep = ffs_epfile_wait_ep(file); if (IS_ERR(ep)) @@ -1869,6 +2323,8 @@ static int ffs_epfiles_create(struct ffs_data *ffs) for (i = 1; i <= count; ++i, ++epfile) { epfile->ffs = ffs; mutex_init(&epfile->mutex); + mutex_init(&epfile->dmabufs_mutex); + INIT_LIST_HEAD(&epfile->dmabufs); if (ffs->user_flags & FUNCTIONFS_VIRTUAL_ADDR) sprintf(epfile->name, "ep%02x", ffs->eps_addrmap[i]); else diff --git a/include/uapi/linux/usb/functionfs.h b/include/uapi/linux/usb/functionfs.h index 078098e73fd3..9f88de9c3d66 100644 --- a/include/uapi/linux/usb/functionfs.h +++ b/include/uapi/linux/usb/functionfs.h @@ -86,6 +86,22 @@ struct usb_ext_prop_desc { __le16 wPropertyNameLength; } __attribute__((packed)); +/* Flags for usb_ffs_dmabuf_transfer_req->flags (none for now) */ +#define USB_FFS_DMABUF_TRANSFER_MASK 0x0 + +/** + * struct usb_ffs_dmabuf_transfer_req - Transfer request for a DMABUF object + * @fd: file descriptor of the DMABUF object + * @flags: one or more USB_FFS_DMABUF_TRANSFER_* flags + * @length: number of bytes used in this DMABUF for the data transfer. + * Should generally be set to the DMABUF's size. + */ +struct usb_ffs_dmabuf_transfer_req { + int fd; + __u32 flags; + __u64 length; +} __attribute__((packed)); + #ifndef __KERNEL__ /* @@ -290,6 +306,31 @@ struct usb_functionfs_event { #define FUNCTIONFS_ENDPOINT_DESC _IOR('g', 130, \ struct usb_endpoint_descriptor) +/* + * Attach the DMABUF object, identified by its file descriptor, to the + * data endpoint. Returns zero on success, and a negative errno value + * on error. + */ +#define FUNCTIONFS_DMABUF_ATTACH _IOW('g', 131, int) + +/* + * Detach the given DMABUF object, identified by its file descriptor, + * from the data endpoint. Returns zero on success, and a negative + * errno value on error. Note that closing the endpoint's file + * descriptor will automatically detach all attached DMABUFs. + */ +#define FUNCTIONFS_DMABUF_DETACH _IOW('g', 132, int) + +/* + * Enqueue the previously attached DMABUF to the transfer queue. + * The argument is a structure that packs the DMABUF's file descriptor, + * the size in bytes to transfer (which should generally correspond to + * the size of the DMABUF), and a 'flags' field which is unused + * for now. Returns zero on success, and a negative errno value on + * error. + */ +#define FUNCTIONFS_DMABUF_TRANSFER _IOW('g', 133, \ + struct usb_ffs_dmabuf_transfer_req) #endif /* _UAPI__LINUX_FUNCTIONFS_H__ */ From patchwork Fri Jan 19 14:14:02 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paul Cercueil X-Patchwork-Id: 13523828 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 21993C47DAF for ; Fri, 19 Jan 2024 14:14:59 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 70B0E10EA5C; Fri, 19 Jan 2024 14:14:58 +0000 (UTC) Received: from aposti.net (aposti.net [89.234.176.197]) by gabe.freedesktop.org (Postfix) with ESMTPS id A633B10E0EA for ; Fri, 19 Jan 2024 14:14:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=crapouillou.net; s=mail; t=1705673655; 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=zL3Tp6j0FI2WH0LNy5N+K5/yV+yjLiDhRH8Apc3kyR0=; b=3LszNdqwVjq2wB4XbfV0SlOIPJE88IrYP6Nh6Aey3ecpOMPogYori6J5mRQT8+eARmgXUn kYdPu5/dlYKwuEclfM9xyYKYSrti2QlD4kewAKbelYZrc2+SJ6bJoEYnXfFlTrQ+Xhqm0+ l2KMj978BvE776w0tCxib3B3dGAZeks= From: Paul Cercueil To: Greg Kroah-Hartman , Jonathan Corbet , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= Subject: [PATCH v5 6/6] Documentation: usb: Document FunctionFS DMABUF API Date: Fri, 19 Jan 2024 15:14:02 +0100 Message-ID: <20240119141402.44262-7-paul@crapouillou.net> In-Reply-To: <20240119141402.44262-1-paul@crapouillou.net> References: <20240119141402.44262-1-paul@crapouillou.net> MIME-Version: 1.0 X-Spam: Yes X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paul Cercueil , Michael Hennerich , linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, =?utf-8?q?Nuno_S=C3=A1?= , Jonathan Cameron , linux-media@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Add documentation for the three ioctls used to attach or detach externally-created DMABUFs, and to request transfers from/to previously attached DMABUFs. Signed-off-by: Paul Cercueil --- v3: New patch --- Documentation/usb/functionfs.rst | 36 ++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) diff --git a/Documentation/usb/functionfs.rst b/Documentation/usb/functionfs.rst index a3054bea38f3..d05a775bc45b 100644 --- a/Documentation/usb/functionfs.rst +++ b/Documentation/usb/functionfs.rst @@ -2,6 +2,9 @@ How FunctionFS works ==================== +Overview +======== + From kernel point of view it is just a composite function with some unique behaviour. It may be added to an USB configuration only after the user space driver has registered by writing descriptors and @@ -66,3 +69,36 @@ have been written to their ep0's. Conversely, the gadget is unregistered after the first USB function closes its endpoints. + +DMABUF interface +================ + +FunctionFS additionally supports a DMABUF based interface, where the +userspace can attach DMABUF objects (externally created) to an endpoint, +and subsequently use them for data transfers. + +A userspace application can then use this interface to share DMABUF +objects between several interfaces, allowing it to transfer data in a +zero-copy fashion, for instance between IIO and the USB stack. + +As part of this interface, three new IOCTLs have been added. These three +IOCTLs have to be performed on a data endpoint (ie. not ep0). They are: + + ``FUNCTIONFS_DMABUF_ATTACH(int)`` + Attach the DMABUF object, identified by its file descriptor, to the + data endpoint. Returns zero on success, and a negative errno value + on error. + + ``FUNCTIONFS_DMABUF_DETACH(int)`` + Detach the given DMABUF object, identified by its file descriptor, + from the data endpoint. Returns zero on success, and a negative + errno value on error. Note that closing the endpoint's file + descriptor will automatically detach all attached DMABUFs. + + ``FUNCTIONFS_DMABUF_TRANSFER(struct usb_ffs_dmabuf_transfer_req *)`` + Enqueue the previously attached DMABUF to the transfer queue. + The argument is a structure that packs the DMABUF's file descriptor, + the size in bytes to transfer (which should generally correspond to + the size of the DMABUF), and a 'flags' field which is unused + for now. Returns zero on success, and a negative errno value on + error.