From patchwork Fri Dec 17 11:18:31 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 525646 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DBAF9C433EF for ; Fri, 17 Dec 2021 11:19:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233443AbhLQLTC (ORCPT ); Fri, 17 Dec 2021 06:19:02 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:53606 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233382AbhLQLTB (ORCPT ); Fri, 17 Dec 2021 06:19:01 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 815D7AF2; Fri, 17 Dec 2021 12:18:59 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639739940; bh=Zt+cQF0szSUOMc6Kwq5Xr2e/NDJ/FecwgvFFoBrrN5U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tKUBlc02bNIrqLsSHHPjY2B3S+Pe0XZuj/uKvsMFz/zuHYjgElLhBDPuAVOY/Dhag 7uFHI+ZCWvUQ+ahIwWOf2MqtBWnEMa8k4YwMHG+UfkZAK8G2Z4FmeyK8iDhzC3pOuo C4pFehPMaRTAO+ahxYSMHnZlNGHcAsgsHS6JKSSY= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen , Jacopo Mondi Subject: [PATCH 1/6] media: subdev: rename subdev-state alloc & free Date: Fri, 17 Dec 2021 13:18:31 +0200 Message-Id: <20211217111836.225013-2-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> References: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org v4l2_subdev_alloc_state() and v4l2_subdev_free_state() are not supposed to be used by the drivers. However, we do have a few drivers that use those at the moment, so we need to expose these functions for the time being. Prefix the functions with __ to mark the functions as internal. At the same time, rename them to v4l2_subdev_state_alloc and v4l2_subdev_state_free to match the style used for other functions like video_device_alloc() and media_request_alloc(). Signed-off-by: Tomi Valkeinen Reviewed-by: Laurent Pinchart Reviewed-by: Hans Verkuil Reviewed-by: Jacopo Mondi --- drivers/media/platform/rcar-vin/rcar-v4l2.c | 4 ++-- drivers/media/platform/vsp1/vsp1_entity.c | 4 ++-- drivers/media/v4l2-core/v4l2-subdev.c | 12 ++++++------ drivers/staging/media/tegra-video/vi.c | 4 ++-- include/media/v4l2-subdev.h | 10 +++++----- 5 files changed, 17 insertions(+), 17 deletions(-) diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c index 2e60b9fce03b..5aae01456c04 100644 --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c @@ -263,7 +263,7 @@ static int rvin_try_format(struct rvin_dev *vin, u32 which, u32 width, height; int ret; - sd_state = v4l2_subdev_alloc_state(sd); + sd_state = __v4l2_subdev_state_alloc(sd); if (IS_ERR(sd_state)) return PTR_ERR(sd_state); @@ -299,7 +299,7 @@ static int rvin_try_format(struct rvin_dev *vin, u32 which, rvin_format_align(vin, pix); done: - v4l2_subdev_free_state(sd_state); + __v4l2_subdev_state_free(sd_state); return ret; } diff --git a/drivers/media/platform/vsp1/vsp1_entity.c b/drivers/media/platform/vsp1/vsp1_entity.c index 823c15facd1b..869cadc1468d 100644 --- a/drivers/media/platform/vsp1/vsp1_entity.c +++ b/drivers/media/platform/vsp1/vsp1_entity.c @@ -675,7 +675,7 @@ int vsp1_entity_init(struct vsp1_device *vsp1, struct vsp1_entity *entity, * Allocate the pad configuration to store formats and selection * rectangles. */ - entity->config = v4l2_subdev_alloc_state(&entity->subdev); + entity->config = __v4l2_subdev_state_alloc(&entity->subdev); if (IS_ERR(entity->config)) { media_entity_cleanup(&entity->subdev.entity); return PTR_ERR(entity->config); @@ -690,6 +690,6 @@ void vsp1_entity_destroy(struct vsp1_entity *entity) entity->ops->destroy(entity); if (entity->subdev.ctrl_handler) v4l2_ctrl_handler_free(entity->subdev.ctrl_handler); - v4l2_subdev_free_state(entity->config); + __v4l2_subdev_state_free(entity->config); media_entity_cleanup(&entity->subdev.entity); } diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 5d27a27cc2f2..fe49c86a9b02 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -28,7 +28,7 @@ static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd) { struct v4l2_subdev_state *state; - state = v4l2_subdev_alloc_state(sd); + state = __v4l2_subdev_state_alloc(sd); if (IS_ERR(state)) return PTR_ERR(state); @@ -39,7 +39,7 @@ static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd) static void subdev_fh_free(struct v4l2_subdev_fh *fh) { - v4l2_subdev_free_state(fh->state); + __v4l2_subdev_state_free(fh->state); fh->state = NULL; } @@ -870,7 +870,7 @@ int v4l2_subdev_link_validate(struct media_link *link) } EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate); -struct v4l2_subdev_state *v4l2_subdev_alloc_state(struct v4l2_subdev *sd) +struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd) { struct v4l2_subdev_state *state; int ret; @@ -903,9 +903,9 @@ struct v4l2_subdev_state *v4l2_subdev_alloc_state(struct v4l2_subdev *sd) return ERR_PTR(ret); } -EXPORT_SYMBOL_GPL(v4l2_subdev_alloc_state); +EXPORT_SYMBOL_GPL(__v4l2_subdev_state_alloc); -void v4l2_subdev_free_state(struct v4l2_subdev_state *state) +void __v4l2_subdev_state_free(struct v4l2_subdev_state *state) { if (!state) return; @@ -913,7 +913,7 @@ void v4l2_subdev_free_state(struct v4l2_subdev_state *state) kvfree(state->pads); kfree(state); } -EXPORT_SYMBOL_GPL(v4l2_subdev_free_state); +EXPORT_SYMBOL_GPL(__v4l2_subdev_state_free); #endif /* CONFIG_MEDIA_CONTROLLER */ diff --git a/drivers/staging/media/tegra-video/vi.c b/drivers/staging/media/tegra-video/vi.c index 69d9787d5338..b01f19e0f332 100644 --- a/drivers/staging/media/tegra-video/vi.c +++ b/drivers/staging/media/tegra-video/vi.c @@ -507,7 +507,7 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan, if (!subdev) return -ENODEV; - sd_state = v4l2_subdev_alloc_state(subdev); + sd_state = __v4l2_subdev_state_alloc(subdev); if (IS_ERR(sd_state)) return PTR_ERR(sd_state); /* @@ -558,7 +558,7 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan, v4l2_fill_pix_format(pix, &fmt.format); tegra_channel_fmt_align(chan, pix, fmtinfo->bpp); - v4l2_subdev_free_state(sd_state); + __v4l2_subdev_state_free(sd_state); return 0; } diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index 95ec18c2f49c..e52bf508c75b 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -1135,20 +1135,20 @@ int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd, int v4l2_subdev_link_validate(struct media_link *link); /** - * v4l2_subdev_alloc_state - allocate v4l2_subdev_state + * __v4l2_subdev_state_alloc - allocate v4l2_subdev_state * * @sd: pointer to &struct v4l2_subdev for which the state is being allocated. * - * Must call v4l2_subdev_free_state() when state is no longer needed. + * Must call __v4l2_subdev_state_free() when state is no longer needed. */ -struct v4l2_subdev_state *v4l2_subdev_alloc_state(struct v4l2_subdev *sd); +struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd); /** - * v4l2_subdev_free_state - free a v4l2_subdev_state + * __v4l2_subdev_state_free - free a v4l2_subdev_state * * @state: v4l2_subdev_state to be freed. */ -void v4l2_subdev_free_state(struct v4l2_subdev_state *state); +void __v4l2_subdev_state_free(struct v4l2_subdev_state *state); #endif /* CONFIG_MEDIA_CONTROLLER */ From patchwork Fri Dec 17 11:18:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 525645 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60545C433FE for ; Fri, 17 Dec 2021 11:19:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235306AbhLQLTD (ORCPT ); Fri, 17 Dec 2021 06:19:03 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:53618 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233419AbhLQLTC (ORCPT ); Fri, 17 Dec 2021 06:19:02 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 51B5B12BF; Fri, 17 Dec 2021 12:19:00 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639739940; bh=G6Ge8dOd9Nh/wNL7r/lvKzWx8tLDCrIF7q6KmZt+4uw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DCE7fx0cRW36Pqn3nWc9LMAwnlus7eBN6O/m8rcuA4OQafk5F6aIHNLjYeXMLG4Yl DWIqeo6UHB6aGRtZF30Brvo5Y9U85ahbNzWzGCIVbiiyajvnnnhwOZ5sD4cGTPWtLE yY4Jxs9XkIlPvAbnjqcPfsKC3VH42WJAOa/2tO58= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen Subject: [PATCH 2/6] media: subdev: add active state to struct v4l2_subdev Date: Fri, 17 Dec 2021 13:18:32 +0200 Message-Id: <20211217111836.225013-3-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> References: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add a new 'active_state' field to struct v4l2_subdev to which we can store the active state of a subdev. This will place the subdev configuration into a known place, allowing us to use the state directly from the v4l2 framework, thus simplifying the drivers. Also add functions v4l2_subdev_init_finalize() and v4l2_subdev_cleanup(), which will allocate and free the active state. The functions are named in a generic way so that they can be also used for other subdev initialization work. Signed-off-by: Tomi Valkeinen Reviewed-by: Hans Verkuil --- drivers/media/v4l2-core/v4l2-subdev.c | 21 ++++++++++ include/media/v4l2-subdev.h | 58 +++++++++++++++++++++++++++ 2 files changed, 79 insertions(+) diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index fe49c86a9b02..de160140d63b 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -943,3 +943,24 @@ void v4l2_subdev_notify_event(struct v4l2_subdev *sd, v4l2_subdev_notify(sd, V4L2_DEVICE_NOTIFY_EVENT, (void *)ev); } EXPORT_SYMBOL_GPL(v4l2_subdev_notify_event); + +int v4l2_subdev_init_finalize(struct v4l2_subdev *sd) +{ + struct v4l2_subdev_state *state; + + state = __v4l2_subdev_state_alloc(sd); + if (IS_ERR(state)) + return PTR_ERR(state); + + sd->active_state = state; + + return 0; +} +EXPORT_SYMBOL_GPL(v4l2_subdev_init_finalize); + +void v4l2_subdev_cleanup(struct v4l2_subdev *sd) +{ + __v4l2_subdev_state_free(sd->active_state); + sd->active_state = NULL; +} +EXPORT_SYMBOL_GPL(v4l2_subdev_cleanup); diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index e52bf508c75b..eddf72768e10 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -645,6 +645,9 @@ struct v4l2_subdev_ir_ops { * This structure only needs to be passed to the pad op if the 'which' field * of the main argument is set to %V4L2_SUBDEV_FORMAT_TRY. For * %V4L2_SUBDEV_FORMAT_ACTIVE it is safe to pass %NULL. + * + * Note: This struct is also used in active state, and the try_ prefix is + * historical and to be removed. */ struct v4l2_subdev_pad_config { struct v4l2_mbus_framefmt try_fmt; @@ -898,6 +901,9 @@ struct v4l2_subdev_platform_data { * @subdev_notifier: A sub-device notifier implicitly registered for the sub- * device using v4l2_async_register_subdev_sensor(). * @pdata: common part of subdevice platform data + * @active_state: Active state for the subdev (NULL for subdevs tracking the + * state internally). Initialized by calling + * v4l2_subdev_init_finalize(). * * Each instance of a subdev driver should create this struct, either * stand-alone or embedded in a larger struct. @@ -929,6 +935,19 @@ struct v4l2_subdev { struct v4l2_async_notifier *notifier; struct v4l2_async_notifier *subdev_notifier; struct v4l2_subdev_platform_data *pdata; + + /* + * The fields below are private, and should only be accessed via + * appropriate functions. + */ + + /* + * TODO: active_state should most likely be changed from a pointer to an + * embedded field. For the time being it's kept as a pointer to more + * easily catch uses of active_state in the cases where the driver + * doesn't support it. + */ + struct v4l2_subdev_state *active_state; }; @@ -1217,4 +1236,43 @@ extern const struct v4l2_subdev_ops v4l2_subdev_call_wrappers; void v4l2_subdev_notify_event(struct v4l2_subdev *sd, const struct v4l2_event *ev); +/** + * v4l2_subdev_init_finalize() - Finalizes the initialization of the subdevice + * @sd: The subdev + * + * This function finalizes the initialization of the subdev, including + * allocation of the active state for the subdev. + * + * This function must be called by the subdev drivers that use the centralized + * active state, after the subdev struct has been initialized and + * media_entity_pads_init() has been called, but before registering the + * subdev. + * + * The user must call v4l2_subdev_cleanup() when the subdev is being removed. + */ +int v4l2_subdev_init_finalize(struct v4l2_subdev *sd); + +/** + * v4l2_subdev_cleanup() - Releases the resources needed by the subdevice + * @sd: The subdevice + * + * This function will release the resources allocated in + * v4l2_subdev_init_finalize. + */ +void v4l2_subdev_cleanup(struct v4l2_subdev *sd); + +/** + * v4l2_subdev_get_active_state() - Returns the active subdev state for + * subdevice + * @sd: The subdevice + * + * Returns the active state for the subdevice, or NULL if the subdev does not + * support active state. + */ +static inline struct v4l2_subdev_state * +v4l2_subdev_get_active_state(struct v4l2_subdev *sd) +{ + return sd->active_state; +} + #endif From patchwork Fri Dec 17 11:18:33 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 525371 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA086C4332F for ; Fri, 17 Dec 2021 11:19:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235309AbhLQLTE (ORCPT ); Fri, 17 Dec 2021 06:19:04 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:53628 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233461AbhLQLTD (ORCPT ); Fri, 17 Dec 2021 06:19:03 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 1607E1540; Fri, 17 Dec 2021 12:19:01 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639739941; bh=gocSOr+LT36zlY19kSeuA3cxSa4tHBMsvbUQAw51Zww=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OPeiQvg6npKrXoLVEEtY37B6uDf9CJkqQXJNcI7M+VALUOoibR/YZAn1dJcduBYVZ WL5aAtI0pv0A5riGBB7xwKutxqz4n8ASZxPqsx5hol9u8iCmfbHjxjvId2m6EIjssp ldoLNghXKjoI7pcq+VXQlybYuL64Bs6ijpe5Ay10= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen Subject: [PATCH 3/6] media: subdev: pass also the active state to subdevs from ioctls Date: Fri, 17 Dec 2021 13:18:33 +0200 Message-Id: <20211217111836.225013-4-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> References: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org At the moment when a subdev op is called, the TRY subdev state (subdev_fh->state) is passed as a parameter even for the ACTIVE case, or alternatively a NULL can be passed for ACTIVE case. This used to make sense, as the ACTIVE state was handled internally by the subdev drivers. We now have a state for the ACTIVE case in a standard place, and can pass that also to the drivers. This patch changes the subdev ioctls to either pass the TRY or ACTIVE state to the subdev. Unfortunately many drivers call ops from other subdevs, and implicitly pass NULL as the state, so this is just a partial solution. A coccinelle spatch could perhaps be created which fixes the drivers' subdev calls. For all current upstream drivers this doesn't matter, as they do not expect to get a valid state for ACTIVE case. But future drivers which support multiplexed streaming and routing will depend on getting a state for both active and try cases. For new drivers we can mandate that the pipelines where the drivers are used need to pass the state properly, or preferably, not call such subdev ops at all. However, if an existing subdev driver is changed to support multiplexed streams, the driver has to consider cases where its ops will be called with NULL state. The problem can easily be solved by using the v4l2_subdev_lock_and_return_state() helper, introduced in a follow up patch. Signed-off-by: Tomi Valkeinen Reviewed-by: Hans Verkuil Reviewed-by: Jacopo Mondi Reviewed-by: Laurent Pinchart --- drivers/media/v4l2-core/v4l2-subdev.c | 64 ++++++++++++++++++++++----- 1 file changed, 54 insertions(+), 10 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index de160140d63b..779d7ae2262d 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -353,6 +353,44 @@ const struct v4l2_subdev_ops v4l2_subdev_call_wrappers = { EXPORT_SYMBOL(v4l2_subdev_call_wrappers); #if defined(CONFIG_VIDEO_V4L2_SUBDEV_API) + +static struct v4l2_subdev_state * +subdev_ioctl_get_state(struct v4l2_subdev *sd, struct v4l2_subdev_fh *subdev_fh, + unsigned int cmd, void *arg) +{ + u32 which; + + switch (cmd) { + default: + return NULL; + case VIDIOC_SUBDEV_G_FMT: + case VIDIOC_SUBDEV_S_FMT: + which = ((struct v4l2_subdev_format *)arg)->which; + break; + case VIDIOC_SUBDEV_G_CROP: + case VIDIOC_SUBDEV_S_CROP: + which = ((struct v4l2_subdev_crop *)arg)->which; + break; + case VIDIOC_SUBDEV_ENUM_MBUS_CODE: + which = ((struct v4l2_subdev_mbus_code_enum *)arg)->which; + break; + case VIDIOC_SUBDEV_ENUM_FRAME_SIZE: + which = ((struct v4l2_subdev_frame_size_enum *)arg)->which; + break; + case VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL: + which = ((struct v4l2_subdev_frame_interval_enum *)arg)->which; + break; + case VIDIOC_SUBDEV_G_SELECTION: + case VIDIOC_SUBDEV_S_SELECTION: + which = ((struct v4l2_subdev_selection *)arg)->which; + break; + } + + return which == V4L2_SUBDEV_FORMAT_TRY ? + subdev_fh->state : + v4l2_subdev_get_active_state(sd); +} + static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) { struct video_device *vdev = video_devdata(file); @@ -360,8 +398,11 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) struct v4l2_fh *vfh = file->private_data; struct v4l2_subdev_fh *subdev_fh = to_v4l2_subdev_fh(vfh); bool ro_subdev = test_bit(V4L2_FL_SUBDEV_RO_DEVNODE, &vdev->flags); + struct v4l2_subdev_state *state; int rval; + state = subdev_ioctl_get_state(sd, subdev_fh, cmd, arg); + switch (cmd) { case VIDIOC_SUBDEV_QUERYCAP: { struct v4l2_subdev_capability *cap = arg; @@ -484,7 +525,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) memset(format->reserved, 0, sizeof(format->reserved)); memset(format->format.reserved, 0, sizeof(format->format.reserved)); - return v4l2_subdev_call(sd, pad, get_fmt, subdev_fh->state, format); + return v4l2_subdev_call(sd, pad, get_fmt, state, format); } case VIDIOC_SUBDEV_S_FMT: { @@ -495,7 +536,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) memset(format->reserved, 0, sizeof(format->reserved)); memset(format->format.reserved, 0, sizeof(format->format.reserved)); - return v4l2_subdev_call(sd, pad, set_fmt, subdev_fh->state, format); + return v4l2_subdev_call(sd, pad, set_fmt, state, format); } case VIDIOC_SUBDEV_G_CROP: { @@ -509,7 +550,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) sel.target = V4L2_SEL_TGT_CROP; rval = v4l2_subdev_call( - sd, pad, get_selection, subdev_fh->state, &sel); + sd, pad, get_selection, state, &sel); crop->rect = sel.r; @@ -531,7 +572,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) sel.r = crop->rect; rval = v4l2_subdev_call( - sd, pad, set_selection, subdev_fh->state, &sel); + sd, pad, set_selection, state, &sel); crop->rect = sel.r; @@ -542,7 +583,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) struct v4l2_subdev_mbus_code_enum *code = arg; memset(code->reserved, 0, sizeof(code->reserved)); - return v4l2_subdev_call(sd, pad, enum_mbus_code, subdev_fh->state, + return v4l2_subdev_call(sd, pad, enum_mbus_code, state, code); } @@ -550,7 +591,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) struct v4l2_subdev_frame_size_enum *fse = arg; memset(fse->reserved, 0, sizeof(fse->reserved)); - return v4l2_subdev_call(sd, pad, enum_frame_size, subdev_fh->state, + return v4l2_subdev_call(sd, pad, enum_frame_size, state, fse); } @@ -575,7 +616,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) struct v4l2_subdev_frame_interval_enum *fie = arg; memset(fie->reserved, 0, sizeof(fie->reserved)); - return v4l2_subdev_call(sd, pad, enum_frame_interval, subdev_fh->state, + return v4l2_subdev_call(sd, pad, enum_frame_interval, state, fie); } @@ -584,7 +625,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) memset(sel->reserved, 0, sizeof(sel->reserved)); return v4l2_subdev_call( - sd, pad, get_selection, subdev_fh->state, sel); + sd, pad, get_selection, state, sel); } case VIDIOC_SUBDEV_S_SELECTION: { @@ -595,7 +636,7 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg) memset(sel->reserved, 0, sizeof(sel->reserved)); return v4l2_subdev_call( - sd, pad, set_selection, subdev_fh->state, sel); + sd, pad, set_selection, state, sel); } case VIDIOC_G_EDID: { @@ -829,10 +870,13 @@ v4l2_subdev_link_validate_get_format(struct media_pad *pad, if (is_media_entity_v4l2_subdev(pad->entity)) { struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(pad->entity); + struct v4l2_subdev_state *state; + + state = v4l2_subdev_get_active_state(sd); fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE; fmt->pad = pad->index; - return v4l2_subdev_call(sd, pad, get_fmt, NULL, fmt); + return v4l2_subdev_call(sd, pad, get_fmt, state, fmt); } WARN(pad->entity->function != MEDIA_ENT_F_IO_V4L, From patchwork Fri Dec 17 11:18:34 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 525370 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5A56DC43219 for ; Fri, 17 Dec 2021 11:19:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235310AbhLQLTE (ORCPT ); Fri, 17 Dec 2021 06:19:04 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:53618 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233444AbhLQLTD (ORCPT ); Fri, 17 Dec 2021 06:19:03 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id CC8DF18EE; Fri, 17 Dec 2021 12:19:01 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639739942; bh=CnpBsdIG89VM8SYqEgonPWhoSQJ0yMQy/rfEHKQbyLs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=woMcYot3eeD/Tb8WwLblCCvSV2aK0Jxv5vlhaFLuM7spow4t6c3agqt2WIEE+wbiT J6ZWMHA3IlYVBHV8nRaRluHAK/vqYDm1rKzi0ftOTo7YrYzIZLC3CN05uhliPQbPzm 9zBQMAz1AxurlFLmaQPB3WdwacrgqB+egKpDJwq8= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen Subject: [PATCH 4/6] media: subdev: add subdev state locking Date: Fri, 17 Dec 2021 13:18:34 +0200 Message-Id: <20211217111836.225013-5-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> References: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org The V4L2 subdevs have managed without centralized locking for the state (previously pad_config), as the try-state is supposedly safe (although I believe two TRY ioctls for the same fd would race), and the active-state, and its locking, is managed by the drivers internally. We now have active-state in a centralized position, and need locking. Strictly speaking the locking is only needed for new drivers that use the new state, as the current drivers continue behaving as they used to. Add a mutex to the struct v4l2_subdev_state, along with a few helper functions for locking/unlocking. Signed-off-by: Tomi Valkeinen Reviewed-by: Jacopo Mondi Reviewed-by: Laurent Pinchart --- drivers/media/platform/rcar-vin/rcar-v4l2.c | 7 ++- drivers/media/platform/vsp1/vsp1_entity.c | 8 +++- drivers/media/v4l2-core/v4l2-subdev.c | 38 +++++++++++++--- drivers/staging/media/tegra-video/vi.c | 8 +++- include/media/v4l2-subdev.h | 50 ++++++++++++++++++++- 5 files changed, 101 insertions(+), 10 deletions(-) diff --git a/drivers/media/platform/rcar-vin/rcar-v4l2.c b/drivers/media/platform/rcar-vin/rcar-v4l2.c index 5aae01456c04..3759f4619a77 100644 --- a/drivers/media/platform/rcar-vin/rcar-v4l2.c +++ b/drivers/media/platform/rcar-vin/rcar-v4l2.c @@ -255,6 +255,7 @@ static int rvin_try_format(struct rvin_dev *vin, u32 which, { struct v4l2_subdev *sd = vin_to_source(vin); struct v4l2_subdev_state *sd_state; + static struct lock_class_key key; struct v4l2_subdev_format format = { .which = which, .pad = vin->parallel.source_pad, @@ -263,7 +264,11 @@ static int rvin_try_format(struct rvin_dev *vin, u32 which, u32 width, height; int ret; - sd_state = __v4l2_subdev_state_alloc(sd); + /* + * FIXME: Drop this call, drivers are not supposed to use + * __v4l2_subdev_state_alloc(). + */ + sd_state = __v4l2_subdev_state_alloc(sd, "rvin:state->lock", &key); if (IS_ERR(sd_state)) return PTR_ERR(sd_state); diff --git a/drivers/media/platform/vsp1/vsp1_entity.c b/drivers/media/platform/vsp1/vsp1_entity.c index 869cadc1468d..a116a3362f9e 100644 --- a/drivers/media/platform/vsp1/vsp1_entity.c +++ b/drivers/media/platform/vsp1/vsp1_entity.c @@ -613,6 +613,7 @@ int vsp1_entity_init(struct vsp1_device *vsp1, struct vsp1_entity *entity, const char *name, unsigned int num_pads, const struct v4l2_subdev_ops *ops, u32 function) { + static struct lock_class_key key; struct v4l2_subdev *subdev; unsigned int i; int ret; @@ -675,7 +676,12 @@ int vsp1_entity_init(struct vsp1_device *vsp1, struct vsp1_entity *entity, * Allocate the pad configuration to store formats and selection * rectangles. */ - entity->config = __v4l2_subdev_state_alloc(&entity->subdev); + /* + * FIXME: Drop this call, drivers are not supposed to use + * __v4l2_subdev_state_alloc(). + */ + entity->config = __v4l2_subdev_state_alloc(&entity->subdev, + "vsp1:config->lock", &key); if (IS_ERR(entity->config)) { media_entity_cleanup(&entity->subdev.entity); return PTR_ERR(entity->config); diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c index 779d7ae2262d..5322329d396f 100644 --- a/drivers/media/v4l2-core/v4l2-subdev.c +++ b/drivers/media/v4l2-core/v4l2-subdev.c @@ -27,8 +27,9 @@ static int subdev_fh_init(struct v4l2_subdev_fh *fh, struct v4l2_subdev *sd) { struct v4l2_subdev_state *state; + static struct lock_class_key key; - state = __v4l2_subdev_state_alloc(sd); + state = __v4l2_subdev_state_alloc(sd, "fh->state->lock", &key); if (IS_ERR(state)) return PTR_ERR(state); @@ -914,7 +915,9 @@ int v4l2_subdev_link_validate(struct media_link *link) } EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate); -struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd) +struct v4l2_subdev_state * +__v4l2_subdev_state_alloc(struct v4l2_subdev *sd, const char *lock_name, + struct lock_class_key *lock_key) { struct v4l2_subdev_state *state; int ret; @@ -923,6 +926,8 @@ struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd) if (!state) return ERR_PTR(-ENOMEM); + __mutex_init(&state->lock, lock_name, lock_key); + if (sd->entity.num_pads) { state->pads = kvmalloc_array(sd->entity.num_pads, sizeof(*state->pads), @@ -954,6 +959,8 @@ void __v4l2_subdev_state_free(struct v4l2_subdev_state *state) if (!state) return; + mutex_destroy(&state->lock); + kvfree(state->pads); kfree(state); } @@ -988,11 +995,12 @@ void v4l2_subdev_notify_event(struct v4l2_subdev *sd, } EXPORT_SYMBOL_GPL(v4l2_subdev_notify_event); -int v4l2_subdev_init_finalize(struct v4l2_subdev *sd) +int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name, + struct lock_class_key *key) { struct v4l2_subdev_state *state; - state = __v4l2_subdev_state_alloc(sd); + state = __v4l2_subdev_state_alloc(sd, name, key); if (IS_ERR(state)) return PTR_ERR(state); @@ -1000,7 +1008,7 @@ int v4l2_subdev_init_finalize(struct v4l2_subdev *sd) return 0; } -EXPORT_SYMBOL_GPL(v4l2_subdev_init_finalize); +EXPORT_SYMBOL_GPL(__v4l2_subdev_init_finalize); void v4l2_subdev_cleanup(struct v4l2_subdev *sd) { @@ -1008,3 +1016,23 @@ void v4l2_subdev_cleanup(struct v4l2_subdev *sd) sd->active_state = NULL; } EXPORT_SYMBOL_GPL(v4l2_subdev_cleanup); + +struct v4l2_subdev_state *v4l2_subdev_lock_active_state(struct v4l2_subdev *sd) +{ + mutex_lock(&sd->active_state->lock); + + return sd->active_state; +} +EXPORT_SYMBOL_GPL(v4l2_subdev_lock_active_state); + +void v4l2_subdev_lock_state(struct v4l2_subdev_state *state) +{ + mutex_lock(&state->lock); +} +EXPORT_SYMBOL_GPL(v4l2_subdev_lock_state); + +void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state) +{ + mutex_unlock(&state->lock); +} +EXPORT_SYMBOL_GPL(v4l2_subdev_unlock_state); diff --git a/drivers/staging/media/tegra-video/vi.c b/drivers/staging/media/tegra-video/vi.c index b01f19e0f332..b366b56df15c 100644 --- a/drivers/staging/media/tegra-video/vi.c +++ b/drivers/staging/media/tegra-video/vi.c @@ -491,6 +491,7 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan, struct v4l2_pix_format *pix) { const struct tegra_video_format *fmtinfo; + static struct lock_class_key key; struct v4l2_subdev *subdev; struct v4l2_subdev_format fmt; struct v4l2_subdev_state *sd_state; @@ -507,7 +508,12 @@ static int __tegra_channel_try_format(struct tegra_vi_channel *chan, if (!subdev) return -ENODEV; - sd_state = __v4l2_subdev_state_alloc(subdev); + /* + * FIXME: Drop this call, drivers are not supposed to use + * __v4l2_subdev_state_alloc(). + */ + sd_state = __v4l2_subdev_state_alloc(subdev, "tegra:state->lock", + &key); if (IS_ERR(sd_state)) return PTR_ERR(sd_state); /* diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index eddf72768e10..80cd0ffb60d1 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -658,6 +658,7 @@ struct v4l2_subdev_pad_config { /** * struct v4l2_subdev_state - Used for storing subdev state information. * + * @lock: mutex for the state * @pads: &struct v4l2_subdev_pad_config array * * This structure only needs to be passed to the pad op if the 'which' field @@ -665,6 +666,8 @@ struct v4l2_subdev_pad_config { * %V4L2_SUBDEV_FORMAT_ACTIVE it is safe to pass %NULL. */ struct v4l2_subdev_state { + /* lock for the struct v4l2_subdev_state fields */ + struct mutex lock; struct v4l2_subdev_pad_config *pads; }; @@ -1157,10 +1160,14 @@ int v4l2_subdev_link_validate(struct media_link *link); * __v4l2_subdev_state_alloc - allocate v4l2_subdev_state * * @sd: pointer to &struct v4l2_subdev for which the state is being allocated. + * @lock_name: name of the state lock + * @key: lock_class_key for the lock * * Must call __v4l2_subdev_state_free() when state is no longer needed. */ -struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd); +struct v4l2_subdev_state *__v4l2_subdev_state_alloc(struct v4l2_subdev *sd, + const char *lock_name, + struct lock_class_key *key); /** * __v4l2_subdev_state_free - free a v4l2_subdev_state @@ -1250,7 +1257,16 @@ void v4l2_subdev_notify_event(struct v4l2_subdev *sd, * * The user must call v4l2_subdev_cleanup() when the subdev is being removed. */ -int v4l2_subdev_init_finalize(struct v4l2_subdev *sd); +#define v4l2_subdev_init_finalize(sd) \ + ({ \ + static struct lock_class_key __key; \ + const char *name = KBUILD_BASENAME \ + ":" __stringify(__LINE__) ":subdev->state->lock"; \ + __v4l2_subdev_init_finalize(sd, name, &__key); \ + }) + +int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name, + struct lock_class_key *key); /** * v4l2_subdev_cleanup() - Releases the resources needed by the subdevice @@ -1275,4 +1291,34 @@ v4l2_subdev_get_active_state(struct v4l2_subdev *sd) return sd->active_state; } +/** + * v4l2_subdev_lock_active_state() - Locks and returns the active subdev state + * for the subdevice + * @sd: The subdevice + * + * Returns the locked active state for the subdevice, or NULL if the subdev + * does not support active state. + * + * The state must be unlocked with v4l2_subdev_unlock_state() after use. + */ +struct v4l2_subdev_state *v4l2_subdev_lock_active_state(struct v4l2_subdev *sd); + +/** + * v4l2_subdev_lock_state() - Locks the subdev state + * @state: The subdevice state + * + * Locks the given subdev state. + * + * The state must be unlocked with v4l2_subdev_unlock_state() after use. + */ +void v4l2_subdev_lock_state(struct v4l2_subdev_state *state); + +/** + * v4l2_subdev_unlock_state() - Unlocks the subdev state + * @state: The subdevice state + * + * Unlocks the given subdev state. + */ +void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state); + #endif From patchwork Fri Dec 17 11:18:35 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 525644 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 075D1C433F5 for ; Fri, 17 Dec 2021 11:19:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235263AbhLQLTF (ORCPT ); Fri, 17 Dec 2021 06:19:05 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:53628 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233419AbhLQLTE (ORCPT ); Fri, 17 Dec 2021 06:19:04 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 916DE1906; Fri, 17 Dec 2021 12:19:02 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639739943; bh=JHB41rTGnAtiTXBpJ+j9CSH30KwaNVTpLpY4xjQq0eI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VpKCXycKTZgo6N+Et+8QOlZt9HBTO2L/PM1eH29h3hUcaOUTO/4YpChU6rcJ7hILK mmXaq2DzRsrYof8yT785CkeeGSEiEzrM6aIfyLBz02wFz2jm/iznlqDSI1exDGfv8y VpPBXCZiVnaf+vFIY4rtDMFIj9q3YpaxE2pVnSLg= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen Subject: [PATCH 5/6] media: subdev: Add v4l2_subdev_lock_and_return_state() Date: Fri, 17 Dec 2021 13:18:35 +0200 Message-Id: <20211217111836.225013-6-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> References: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org All suitable subdev ops are now passed either the TRY or the ACTIVE state by the v4l2 core. However, other subdev drivers can still call the ops passing NULL as the state, implying the active case. For all current upstream drivers this doesn't matter, as they do not expect to get a valid state for ACTIVE case. But future drivers which support multiplexed streaming and routing will depend on getting a state for both active and try cases. For new drivers we can mandate that the pipelines where the drivers are used need to pass the state properly, or preferably, not call such subdev ops at all. However, if an existing subdev driver is changed to support multiplexed streams, the driver has to consider cases where its ops will be called with NULL state. The problem can easily be solved by using the v4l2_subdev_lock_and_return_state() helper, introduced here. Signed-off-by: Tomi Valkeinen Reviewed-by: Laurent Pinchart --- include/media/v4l2-subdev.h | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h index 80cd0ffb60d1..4bc3cc04cc6e 100644 --- a/include/media/v4l2-subdev.h +++ b/include/media/v4l2-subdev.h @@ -8,6 +8,7 @@ #ifndef _V4L2_SUBDEV_H #define _V4L2_SUBDEV_H +#include "linux/dev_printk.h" #include #include #include @@ -1321,4 +1322,38 @@ void v4l2_subdev_lock_state(struct v4l2_subdev_state *state); */ void v4l2_subdev_unlock_state(struct v4l2_subdev_state *state); +/** + * v4l2_subdev_lock_and_return_state() - Gets locked try or active subdev state + * @sd: subdevice + * @state: subdevice state as passed to the subdev op + * + * Due to legacy reasons, when subdev drivers call ops in other subdevs they use + * NULL as the state parameter, as subdevs always used to have their active + * state stored privately. + * + * However, newer state-aware subdev drivers, which store their active state in + * a common place, subdev->active_state, expect to always get a proper state as + * a parameter. + * + * These state-aware drivers can use v4l2_subdev_lock_and_return_state() instead + * of v4l2_subdev_lock_state(). v4l2_subdev_lock_and_return_state() solves the + * issue by using subdev->state in case the passed state is NULL. + * + * This is a temporary helper function, and should be removed when we can ensure + * that all drivers pass proper state when calling other subdevs. + */ +static inline struct v4l2_subdev_state * +v4l2_subdev_lock_and_return_state(struct v4l2_subdev *sd, + struct v4l2_subdev_state *state) +{ + if (!state) + dev_notice_once(sd->dev, "source subdev should be ported to new state management\n"); + + state = state ? state : sd->active_state; + + v4l2_subdev_lock_state(state); + + return state; +} + #endif From patchwork Fri Dec 17 11:18:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tomi Valkeinen X-Patchwork-Id: 525643 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6AFE6C433EF for ; Fri, 17 Dec 2021 11:19:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235311AbhLQLTG (ORCPT ); Fri, 17 Dec 2021 06:19:06 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:53618 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235308AbhLQLTE (ORCPT ); Fri, 17 Dec 2021 06:19:04 -0500 Received: from deskari.lan (91-156-85-209.elisa-laajakaista.fi [91.156.85.209]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 538311924; Fri, 17 Dec 2021 12:19:03 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639739943; bh=732HiiWUdZIdEep7+7DfYkqnoMnx9CnXwEhjM3+SYX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ADIOQNI5vDb0PJtKHEJ0JkUp+fKUcQczdJDDIfvkuJ/onIvpayUHs12Em9nFtN8BN GAr8NrCBWcK7cSIgpGhMRyDMPYBgKPkQGL/BHCnAyNDPjXQWJ3cbJNt3S5lm7JVTEr k2YUntq6iyrk3gEYsPmi2+BRmINsjvwZVQw2qRg0= From: Tomi Valkeinen To: linux-media@vger.kernel.org, sakari.ailus@linux.intel.com, Jacopo Mondi , Laurent Pinchart , niklas.soderlund+renesas@ragnatech.se, Mauro Carvalho Chehab , Hans Verkuil , Pratyush Yadav Cc: Tomi Valkeinen Subject: [PATCH 6/6] media: Documentation: add documentation about subdev state Date: Fri, 17 Dec 2021 13:18:36 +0200 Message-Id: <20211217111836.225013-7-tomi.valkeinen@ideasonboard.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> References: <20211217111836.225013-1-tomi.valkeinen@ideasonboard.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Add documentation about centrally managed subdev state. Signed-off-by: Tomi Valkeinen --- .../driver-api/media/v4l2-subdev.rst | 58 +++++++++++++++++++ 1 file changed, 58 insertions(+) diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst index 08ea2673b19e..f0ba04c80563 100644 --- a/Documentation/driver-api/media/v4l2-subdev.rst +++ b/Documentation/driver-api/media/v4l2-subdev.rst @@ -518,6 +518,64 @@ The :c:func:`v4l2_i2c_new_subdev` function will call :c:type:`i2c_board_info` structure using the ``client_type`` and the ``addr`` to fill it. +Centrally managed subdev active state +------------------------------------- + +Traditionally V4L2 subdev drivers maintained internal state for the active +configuration for the subdev. This is often implemented e.g. as an array of +struct v4l2_mbus_framefmt, one entry for each pad, and similarly for cropping +and composition using struct v4l2_rect. + +In addition to the active configuration, each subdev filehandle has an array of +struct v4l2_subdev_pad_config, managed by V4L2 core, which contains the try +configuration. + +To simplify the subdev drivers the V4L2 subdev API now optionally supports a +centrally managed active configuration represented by +:c:type:`v4l2_subdev_state`. One instance of state, which contains the active +device configuration, is associated with the sub-device itself as part of +the :c:type:`v4l2_subdev` structure, while the core associates to each open +file handle a try state, which contains the configuration valid in the +file-handle context only. + +Sub-device drivers can opt-in and use state to manage their active configuration +by initializing the subdevice state with a call to v4l2_subdev_init_finalize() +before registering the sub-device. They must also call v4l2_subdev_cleanup() +to release all the acquired resources before unregistering the sub-device. +The core automatically initializes a state for each open file handle where to +store the try configurations and releases them at file handle closing time. + +V4L2 sub-device operations that operate on both the :ref:`ACTIVE and TRY formats +` receive the correct state to operate on an +operation parameter. The sub-device driver can access and modify the +configuration stored in the provided state after having locked it by calling +:c:func:`v4l2_subdev_lock_state()`. The driver must then call +:c:func:`v4l2_subdev_unlock_state()` to unlock the state when done. + +Operations that do not receive a state parameter implicitly operate on the +subdevice active state, which drivers can exclusively access by +calling :c:func:`v4l2_subdev_lock_active_state()`. The sub-device active state +should equally be released by calling +:c:func:`v4l2_subdev_unlock_state()`. + +In no occasions driver should try to manually access the state stored +in the :c:type:`v4l2_subdev` or in the file handle without going +through the designated helpers. + +The V4L2 core will pass either the try- or active-state to various subdev ops. +Unfortunately not all the callers comply with this yet, and may pass NULL as +the active-state. This is only a problem for subdev drivers which use the +centrally managed active-state and are used in media pipelines with older +subdev drivers. In these cases the called subdev ops must also handle the NULL +case. This can be easily managed by the use of +v4l2_subdev_validate_and_lock_state() helper. + +v4l2_subdev_validate_and_lock_state() should only be used when porting an +existing driver to the new state management when it cannot be guaranteed that +the current callers will pass the state properly. The function prints a notice +when the passed state is NULL to encourage the porting of the callers to the +new state management. + V4L2 sub-device functions and data structures ---------------------------------------------