From nobody Mon Oct 6 20:59:28 2025 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 69C5C29ACC8; Thu, 17 Jul 2025 10:45:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752749150; cv=none; b=ezvzy+jx/VLopkaeqdIkQ52ZQnCZeixiFpSpXS0rgNsm8KaK8yAFE85rJDTNpBK2pTZC/hmaw/1BUoCHYT4Pc6rrQf2zdpPyJIFAlwx88HAR/ZY6epzFnNwnh0asGF9CUHS8nCNf38AtXBSsetsVjTn065mnK68fYkdUI+hjwUU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752749150; c=relaxed/simple; bh=MQRwA7fqy++hrn9wDtM90iaXfefqzRiYRYRIsmH0eBo=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=aiK7AIRMfBeF8vx6181uc+9PTBfPTbWxCfgdlkUefYKXrllrJO80C08fLXjxAPGgeYhOL4Rlzt0JqbyuvCyWJxMf7dT623rcPNCmtfnu/zpKFVyBMzg0f2WBYcsXwqj5BPJzJ8vGQfp2Q1kcNJqYHt2FPXuz/C4QR8wpggngvsk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=UmMTSjqp; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="UmMTSjqp" Received: from [192.168.0.172] (mob-5-90-140-254.net.vodafone.it [5.90.140.254]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 2334920EE; Thu, 17 Jul 2025 12:45:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1752749110; bh=MQRwA7fqy++hrn9wDtM90iaXfefqzRiYRYRIsmH0eBo=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=UmMTSjqpvuVK3Q9KhJ/6vo6FB2X7TmnS9CtKSLhWRQWZkt9vsA1wVHbZOThrW7dhz IhhdheGJKW8JWVr1A2GaERsmxTUZv78WloBiw4NxFgKEclyMQYv5i+sdFiRtexJAZH lziStg4Yo7dms0xsYVljmvVKFq0eT2rBh4QE/c9U= From: Jacopo Mondi Date: Thu, 17 Jul 2025 12:45:29 +0200 Subject: [PATCH 03/26] media: media-entity: Introduce media_entity_context Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250717-multicontext-mainline-2025-v1-3-81ac18979c03@ideasonboard.com> References: <20250717-multicontext-mainline-2025-v1-0-81ac18979c03@ideasonboard.com> In-Reply-To: <20250717-multicontext-mainline-2025-v1-0-81ac18979c03@ideasonboard.com> To: Sakari Ailus , Laurent Pinchart , Tomi Valkeinen , Kieran Bingham , Nicolas Dufresne , Mauro Carvalho Chehab , Tomasz Figa , Marek Szyprowski , Raspberry Pi Kernel Maintenance , Florian Fainelli , Broadcom internal kernel review list , Hans Verkuil Cc: linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Jacopo Mondi X-Mailer: b4 0.14.2 X-Developer-Signature: v=1; a=openpgp-sha256; l=7515; i=jacopo.mondi@ideasonboard.com; h=from:subject:message-id; bh=MQRwA7fqy++hrn9wDtM90iaXfefqzRiYRYRIsmH0eBo=; b=owEBbQKS/ZANAwAKAXI0Bo8WoVY8AcsmYgBoeNRP61XYyB838338Dlg46RgQigjlhUEOJLdzh pII+hfKMCSJAjMEAAEKAB0WIQS1xD1IgJogio9YOMByNAaPFqFWPAUCaHjUTwAKCRByNAaPFqFW PI2dEACya3+bVHv1j5Q2ClKKwUIQDW7LYn3klEs1T+ShPGyyx4nq8E5dcUCsVwIxWxozjM7CUoD smQnWh4p2o9Spj5d0CBlpbwE3Lbwb3MgCdy714aRGAVEBiZ21gdBPX0oGsqZsj0ypzH3Zv/ShA0 aEhfY+C2MYh3DELVyD7jTOqXH5qxv+tJ1FgWzHeow2PfbBwgDKA7XmWptovTY7Z9snAg3bEIb8Z m76uybcPBLDfk/wT0oawiBV8sqP1Ime9lccZPSZ5tcZ+XXnlahPesOCAvTrd2ynoMcZd8wFSJwj SxBQGy0y1O90+ZlZF3KHS6q7ACip6TWG+9JWbAseveDK6ErmPrvLZtKZK9uBnsu5F+vMDMDZIq8 U8iuwMrfglLTNOl+3REOkp0VWAULKQB12uhf6LBjOs1ytGK/l0V7+7V2pvAauXsjB2BVEKsgYDm OtizhgDp40rxeDL1Kx2Q343YbH5JjvwakLgC3Z5BplfsBvQvlNc0ysRz42heI+5ZIhwEgP1CBJ1 GOr0O9+qEljK1wqSCi6uVGWD5P5vtlwPqxAoKPcRzzGIciWb9yXayQryVB4AM7UCtHh0Mly+oY0 SW1PMxXxt8rL4Kdf5wbgwRgpamluIh1JMZ6DfMMrR5nCHHNkiWJh/AuRRcjyRce5129+T81TZWS UHFcHlZr5cbHwWQ== X-Developer-Key: i=jacopo.mondi@ideasonboard.com; a=openpgp; fpr=72392EDC88144A65C701EA9BA5826A2587AD026B Introduce the 'struct media_entity_context' type, which serves for reference counting and introduce two new media entity operations to allow drivers to allocate and free a media entity context. The newly introduced type will be used as a base type for the device context types (video_device_context and v4l2_subdevice_context) that will be introduced in the next patches. Signed-off-by: Jacopo Mondi --- drivers/media/mc/mc-entity.c | 46 ++++++++++++++++++++ include/media/media-entity.h | 101 +++++++++++++++++++++++++++++++++++++++= ++++ 2 files changed, 147 insertions(+) diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c index 045590905582054c46656e20463271b1f93fa6b4..b4a9f0a0aa7353d7a3333f20903= 980956b3df4a7 100644 --- a/drivers/media/mc/mc-entity.c +++ b/drivers/media/mc/mc-entity.c @@ -1673,3 +1673,49 @@ struct media_link *__media_entity_next_link(struct m= edia_entity *entity, return NULL; } EXPORT_SYMBOL_GPL(__media_entity_next_link); + +static void media_entity_release_context(struct kref *refcount) +{ + struct media_entity_context *ctx =3D + container_of(refcount, struct media_entity_context, refcount); + + ctx->entity->ops->destroy_context(ctx); +} + +struct media_entity_context * +media_entity_context_get(struct media_entity_context *ctx) +{ + if (!ctx) + return ERR_PTR(-EINVAL); + + kref_get(&ctx->refcount); + + return ctx; +} +EXPORT_SYMBOL_GPL(media_entity_context_get); + +void media_entity_context_put(struct media_entity_context *ctx) +{ + if (!ctx) + return; + + kref_put(&ctx->refcount, media_entity_release_context); +} +EXPORT_SYMBOL_GPL(media_entity_context_put); + +void media_entity_init_context(struct media_entity *entity, + struct media_entity_context *ctx) +{ + if (!ctx) + return; + + ctx->entity =3D entity; + kref_init(&ctx->refcount); + INIT_LIST_HEAD(&ctx->list); +} +EXPORT_SYMBOL_GPL(media_entity_init_context); + +void media_entity_cleanup_context(struct media_entity_context *ctx) +{ +} +EXPORT_SYMBOL_GPL(media_entity_cleanup_context); diff --git a/include/media/media-entity.h b/include/media/media-entity.h index 64cf590b11343f68a456c5870ca2f32917c122f9..32298fe8a18c6ee3c1dbcff9ef8= 69548904417a7 100644 --- a/include/media/media-entity.h +++ b/include/media/media-entity.h @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -248,6 +249,37 @@ struct media_pad { struct media_pipeline *pipe; }; =20 +/** + * struct media_entity_context - A media entity execution context + * @mdev_context: The media device context this media entity is bound to. + * The field is initialized when the entity is bound to a media + * device context. + * @entity: The media entity this context belongs to + * @refcount: The kref reference counter + * list: The list entry to link the entity context in the media device con= text + * + * This type represent the 'base class' used to implement execution contex= t for + * video device contexts and subdevice contexts. Those types embedds an in= stance + * of 'struct media_entity_context' as their first member, allowing the MC= core + * to implement type polymorphism and handle video device and subdevice co= ntexts + * transparently. + * + * The main function of this type is to provide reference counting for the + * 'dervived' device context types. The video device and subdevice core + * populates the 'context_release' function pointer that implement specific + * clean-up operations, similar to what a 'virtual destructor' would do in= C++. + * + * Drivers are not expected to use this type directly, but only the MC core + * will. + */ +struct media_device_context; +struct media_entity_context { + struct media_device_context *mdev_context; + struct media_entity *entity; + struct kref refcount; + struct list_head list; +}; + /** * struct media_entity_operations - Media entity operations * @get_fwnode_pad: Return the pad number based on a fwnode endpoint or @@ -269,6 +301,15 @@ struct media_pad { * media_entity_has_pad_interdep(). * Optional: If the operation isn't implemented all pads * will be considered as interdependent. + * @alloc_context: Allocate a media entity context. Drivers are allowed to + * sub-class the entity context type by defining a driver + * specific type that embeds an instance of either a + * video_device_context or subdevice_context as first + * member, and allocate the size of a driver-specific type + * in the implementation of this operation. Returns 0 for + * success, or an error code < 0 otherwise. + * @destroy_context: Release a media entity context previously allocated by + * the driver. * * .. note:: * @@ -284,6 +325,9 @@ struct media_entity_operations { int (*link_validate)(struct media_link *link); bool (*has_pad_interdep)(struct media_entity *entity, unsigned int pad0, unsigned int pad1); + int (*alloc_context)(struct media_entity *entity, + struct media_entity_context **context); + void (*destroy_context)(struct media_entity_context *context); }; =20 /** @@ -1448,3 +1492,60 @@ struct media_link *__media_entity_next_link(struct m= edia_entity *entity, MEDIA_LNK_FL_DATA_LINK)) =20 #endif + +/** + * media_entity_context_get - Increase the media entity context reference = count + * and return a reference to it + * + * @ctx: the media entity context + * + * Increase the media entity context reference count. The reference count + * is increased by the V4L2 core when: + * + * * a new context is allocated when bounding a media entity to a media de= vice + * context (by kref_init()) + * * the media pipeline the context is part of starts streaming + * + * The entity context gets automatically decreased by the V4L2 core when: + * + * * a context is unbound + * * the pipeline stops streaming + */ +struct media_entity_context * +media_entity_context_get(struct media_entity_context *ctx); + +/** + * media_entity_context_put - Decrease the media entity context reference = count + * + * @ctx: the media entity context + * + * Decrease the media entity context reference count. The reference count + * is decreased by the V4L2 core when: + * + * * the file handle the context is associated with is closed + * * the media pipeline the context is part of is stopped + */ +void media_entity_context_put(struct media_entity_context *ctx); + +/** + * media_entity_init_context - Initialize the media entity context + * + * @entity: the media entity this context belongs to + * @ctx: the media entity context + * + * Initialize the media entity context by initializing the kref reference + * counter. The intended caller of this function are the video device cont= ext + * and subdevic context initialize functions. + */ +void media_entity_init_context(struct media_entity *entity, + struct media_entity_context *ctx); + +/** + * media_entity_cleanup_context - Cleanup the media entity context + * + * @ctx: the media entity context + * + * Cleanup the media entity context. The intended caller of this function = are + * the video device and subdevice context cleanup functions. + */ +void media_entity_cleanup_context(struct media_entity_context *ctx); --=20 2.49.0