From mboxrd@z Thu Jan 1 00:00:00 1970 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 EACC4C43334 for ; Fri, 17 Jun 2022 11:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=aVhB5UqlZRoPEoblwGMcl2ogHvBUu2sX3RDsZslnq9E=; b=D3ZW1UHglEttvi 949T2eoIC2BnhQfdHmhvJEAcwqxSe1CZ9zer5A9X8ymGthcvqF3j5K9nSMs2ZdoI0Pk2KVXCGD6D7 A1xvICZ93Zxu/MKSp0RAxYkLFU1jk492wUE3xsAKWIex3ERbXq++QIKoccWchp/W8Knpq3gzeZJZL 6yD+awnVOkF7AK8/80v+dpIi0vIdLTDBt0ekabtXRWuWn9aAoV+PEIIFoDeUmufqIm3QjmjFmAPXF gGQ66uYuV2Amk8xXZXtzOuG97nG56YWP4iVBNsj9CVW1i6dc/KpWfXDQ/O4eIx7uyL66UwoF2Qdyn SZXKYRSH3bpwBFVo9kTg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o2ASS-007QU7-JF; Fri, 17 Jun 2022 11:48:12 +0000 Received: from dfw.source.kernel.org ([139.178.84.217]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o2ASP-007QSi-GI for linux-rockchip@lists.infradead.org; Fri, 17 Jun 2022 11:48:11 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 0959961F45; Fri, 17 Jun 2022 11:48:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA0E9C3411B; Fri, 17 Jun 2022 11:48:06 +0000 (UTC) Message-ID: <6a718a13-e441-f093-d86e-5480d0a46103@xs4all.nl> Date: Fri, 17 Jun 2022 13:48:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH 37/55] media: mc-entity: Add a new helper function to get a remote pad Content-Language: en-US To: Paul Elder , linux-media@vger.kernel.org Cc: Laurent Pinchart , dafna@fastmail.com, heiko@sntech.de, jeanmichel.hautbois@ideasonboard.com, jacopo@jmondi.org, djrscally@gmail.com, helen.koike@collabora.com, linux-rockchip@lists.infradead.org References: <20220614191127.3420492-1-paul.elder@ideasonboard.com> <20220614191127.3420492-38-paul.elder@ideasonboard.com> From: Hans Verkuil In-Reply-To: <20220614191127.3420492-38-paul.elder@ideasonboard.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220617_044809_656356_932BC846 X-CRM114-Status: GOOD ( 38.59 ) X-BeenThere: linux-rockchip@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Upstream kernel work for Rockchip platforms List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+linux-rockchip=archiver.kernel.org@lists.infradead.org On 6/14/22 21:11, Paul Elder wrote: > From: Laurent Pinchart > > The media_entity_remote_pad() helper function returns the first remote > pad it find connected to a given pad. Beside being possibly ill-named > (as it operates on a pad, not an entity) and non-deterministic (as it > stops at the first enabled link), the fact that it returns the first > match makes it unsuitable for drivers that need to guarantee that a > single link is enabled, for instance when an entity can process data > from one of multiple sources at a time. Question: of all the callers of this function, are there any that really need media_entity_remote_pad() instead of media_pad_remote_pad_unique()? Would it be possible to replace all callers of the old function with the new function? If that's the case, then the _unique suffix can be dropped, since that would effectively be the default. And if a function is needed to handle the case where there are multiple enabled links, then a new function should be created. Also, media_entity_remote_pad() should really be renamed to media_pad_remote_pad_first() or something like that, right? I'm not saying you should, but that's really what it does, as I understand it. Regards, Hans > > For those use cases, add a new helper function, > media_entity_remote_pad_unique(), that operates on an entity and returns > a remote pad, with a guarantee that only one link is enabled. To ease > its use in drivers, also add an inline wrapper that locates source pads > specifically. A wrapper that locates sink pads can easily be added when > needed. > > Signed-off-by: Laurent Pinchart > --- > Documentation/driver-api/media/mc-core.rst | 4 +- > drivers/media/mc/mc-entity.c | 38 ++++++++++++++++++ > include/media/media-entity.h | 45 ++++++++++++++++++++++ > 3 files changed, 85 insertions(+), 2 deletions(-) > > diff --git a/Documentation/driver-api/media/mc-core.rst b/Documentation/driver-api/media/mc-core.rst > index 02481a2513b9..a2d1e32e3abb 100644 > --- a/Documentation/driver-api/media/mc-core.rst > +++ b/Documentation/driver-api/media/mc-core.rst > @@ -186,8 +186,8 @@ is required and the graph structure can be freed normally. > > Helper functions can be used to find a link between two given pads, or a pad > connected to another pad through an enabled link > -:c:func:`media_entity_find_link()` and > -:c:func:`media_entity_remote_pad()`. > +(:c:func:`media_entity_find_link()`, :c:func:`media_entity_remote_pad()` and > +:c:func:`media_entity_remote_source_pad()`). > > Use count and power handling > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c > index 11f5207f73aa..1febf5a86be6 100644 > --- a/drivers/media/mc/mc-entity.c > +++ b/drivers/media/mc/mc-entity.c > @@ -9,6 +9,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -920,6 +921,43 @@ struct media_pad *media_entity_remote_pad(const struct media_pad *pad) > } > EXPORT_SYMBOL_GPL(media_entity_remote_pad); > > +struct media_pad * > +media_entity_remote_pad_unique(const struct media_entity *entity, > + unsigned int type) > +{ > + struct media_pad *pad = NULL; > + struct media_link *link; > + > + list_for_each_entry(link, &entity->links, list) { > + struct media_pad *local_pad; > + struct media_pad *remote_pad; > + > + if (!(link->flags & MEDIA_LNK_FL_ENABLED)) > + continue; > + > + if (type == MEDIA_PAD_FL_SOURCE) { > + local_pad = link->sink; > + remote_pad = link->source; > + } else { > + local_pad = link->source; > + remote_pad = link->sink; > + } > + > + if (local_pad->entity == entity) { > + if (pad) > + return ERR_PTR(-ENOTUNIQ); > + > + pad = remote_pad; > + } > + } > + > + if (!pad) > + return ERR_PTR(-ENOLINK); > + > + return pad; > +} > +EXPORT_SYMBOL_GPL(media_entity_remote_pad_unique); > + > static void media_interface_init(struct media_device *mdev, > struct media_interface *intf, > u32 gobj_type, > diff --git a/include/media/media-entity.h b/include/media/media-entity.h > index a9a1c0ec5d1c..33d5f52719a0 100644 > --- a/include/media/media-entity.h > +++ b/include/media/media-entity.h > @@ -859,6 +859,51 @@ struct media_link *media_entity_find_link(struct media_pad *source, > */ > struct media_pad *media_entity_remote_pad(const struct media_pad *pad); > > +/** > + * media_entity_remote_pad_unique - Find a remote pad connected to an entity > + * @entity: The entity > + * @type: The type of pad to find (MEDIA_PAD_FL_SINK or MEDIA_PAD_FL_SOURCE) > + * > + * Search for and return a remote pad of @type connected to @entity through an > + * enabled link. If multiple (or no) remote pads match these criteria, an error > + * is returned. > + * > + * The uniqueness constraint makes this helper function suitable for entities > + * that support a single active source or sink at a time. > + * > + * Return: A pointer to the remote pad, or one of the following error pointers > + * if an error occurs: > + * > + * * -ENOTUNIQ - Multiple links are enabled > + * * -ENOLINK - No connected pad found > + */ > +struct media_pad * > +media_entity_remote_pad_unique(const struct media_entity *entity, > + unsigned int type); > + > +/** > + * media_entity_remote_source_pad - Find a remote source pad connected to an entity > + * @entity: The entity > + * > + * Search for and return a remote source pad connected to @entity through an > + * enabled link. If multiple (or no) remote pads match these criteria, an error > + * is returned. > + * > + * The uniqueness constraint makes this helper function suitable for entities > + * that support a single active source at a time. > + * > + * Return: A pointer to the remote pad, or one of the following error pointers > + * if an error occurs: > + * > + * * -ENOTUNIQ - Multiple links are enabled > + * * -ENOLINK - No connected pad found > + */ > +static inline struct media_pad * > +media_entity_remote_source_pad(const struct media_entity *entity) > +{ > + return media_entity_remote_pad_unique(entity, MEDIA_PAD_FL_SOURCE); > +} > + > /** > * media_entity_is_streaming - Test if an entity is part of a streaming pipeline > * @entity: The entity _______________________________________________ Linux-rockchip mailing list Linux-rockchip@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-rockchip From mboxrd@z Thu Jan 1 00:00:00 1970 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 11779C43334 for ; Fri, 17 Jun 2022 11:48:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381965AbiFQLsO (ORCPT ); Fri, 17 Jun 2022 07:48:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45328 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236286AbiFQLsK (ORCPT ); Fri, 17 Jun 2022 07:48:10 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 69ECA3137B for ; Fri, 17 Jun 2022 04:48:09 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 091F461F32 for ; Fri, 17 Jun 2022 11:48:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AA0E9C3411B; Fri, 17 Jun 2022 11:48:06 +0000 (UTC) Message-ID: <6a718a13-e441-f093-d86e-5480d0a46103@xs4all.nl> Date: Fri, 17 Jun 2022 13:48:05 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH 37/55] media: mc-entity: Add a new helper function to get a remote pad Content-Language: en-US To: Paul Elder , linux-media@vger.kernel.org Cc: Laurent Pinchart , dafna@fastmail.com, heiko@sntech.de, jeanmichel.hautbois@ideasonboard.com, jacopo@jmondi.org, djrscally@gmail.com, helen.koike@collabora.com, linux-rockchip@lists.infradead.org References: <20220614191127.3420492-1-paul.elder@ideasonboard.com> <20220614191127.3420492-38-paul.elder@ideasonboard.com> From: Hans Verkuil In-Reply-To: <20220614191127.3420492-38-paul.elder@ideasonboard.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On 6/14/22 21:11, Paul Elder wrote: > From: Laurent Pinchart > > The media_entity_remote_pad() helper function returns the first remote > pad it find connected to a given pad. Beside being possibly ill-named > (as it operates on a pad, not an entity) and non-deterministic (as it > stops at the first enabled link), the fact that it returns the first > match makes it unsuitable for drivers that need to guarantee that a > single link is enabled, for instance when an entity can process data > from one of multiple sources at a time. Question: of all the callers of this function, are there any that really need media_entity_remote_pad() instead of media_pad_remote_pad_unique()? Would it be possible to replace all callers of the old function with the new function? If that's the case, then the _unique suffix can be dropped, since that would effectively be the default. And if a function is needed to handle the case where there are multiple enabled links, then a new function should be created. Also, media_entity_remote_pad() should really be renamed to media_pad_remote_pad_first() or something like that, right? I'm not saying you should, but that's really what it does, as I understand it. Regards, Hans > > For those use cases, add a new helper function, > media_entity_remote_pad_unique(), that operates on an entity and returns > a remote pad, with a guarantee that only one link is enabled. To ease > its use in drivers, also add an inline wrapper that locates source pads > specifically. A wrapper that locates sink pads can easily be added when > needed. > > Signed-off-by: Laurent Pinchart > --- > Documentation/driver-api/media/mc-core.rst | 4 +- > drivers/media/mc/mc-entity.c | 38 ++++++++++++++++++ > include/media/media-entity.h | 45 ++++++++++++++++++++++ > 3 files changed, 85 insertions(+), 2 deletions(-) > > diff --git a/Documentation/driver-api/media/mc-core.rst b/Documentation/driver-api/media/mc-core.rst > index 02481a2513b9..a2d1e32e3abb 100644 > --- a/Documentation/driver-api/media/mc-core.rst > +++ b/Documentation/driver-api/media/mc-core.rst > @@ -186,8 +186,8 @@ is required and the graph structure can be freed normally. > > Helper functions can be used to find a link between two given pads, or a pad > connected to another pad through an enabled link > -:c:func:`media_entity_find_link()` and > -:c:func:`media_entity_remote_pad()`. > +(:c:func:`media_entity_find_link()`, :c:func:`media_entity_remote_pad()` and > +:c:func:`media_entity_remote_source_pad()`). > > Use count and power handling > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > diff --git a/drivers/media/mc/mc-entity.c b/drivers/media/mc/mc-entity.c > index 11f5207f73aa..1febf5a86be6 100644 > --- a/drivers/media/mc/mc-entity.c > +++ b/drivers/media/mc/mc-entity.c > @@ -9,6 +9,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -920,6 +921,43 @@ struct media_pad *media_entity_remote_pad(const struct media_pad *pad) > } > EXPORT_SYMBOL_GPL(media_entity_remote_pad); > > +struct media_pad * > +media_entity_remote_pad_unique(const struct media_entity *entity, > + unsigned int type) > +{ > + struct media_pad *pad = NULL; > + struct media_link *link; > + > + list_for_each_entry(link, &entity->links, list) { > + struct media_pad *local_pad; > + struct media_pad *remote_pad; > + > + if (!(link->flags & MEDIA_LNK_FL_ENABLED)) > + continue; > + > + if (type == MEDIA_PAD_FL_SOURCE) { > + local_pad = link->sink; > + remote_pad = link->source; > + } else { > + local_pad = link->source; > + remote_pad = link->sink; > + } > + > + if (local_pad->entity == entity) { > + if (pad) > + return ERR_PTR(-ENOTUNIQ); > + > + pad = remote_pad; > + } > + } > + > + if (!pad) > + return ERR_PTR(-ENOLINK); > + > + return pad; > +} > +EXPORT_SYMBOL_GPL(media_entity_remote_pad_unique); > + > static void media_interface_init(struct media_device *mdev, > struct media_interface *intf, > u32 gobj_type, > diff --git a/include/media/media-entity.h b/include/media/media-entity.h > index a9a1c0ec5d1c..33d5f52719a0 100644 > --- a/include/media/media-entity.h > +++ b/include/media/media-entity.h > @@ -859,6 +859,51 @@ struct media_link *media_entity_find_link(struct media_pad *source, > */ > struct media_pad *media_entity_remote_pad(const struct media_pad *pad); > > +/** > + * media_entity_remote_pad_unique - Find a remote pad connected to an entity > + * @entity: The entity > + * @type: The type of pad to find (MEDIA_PAD_FL_SINK or MEDIA_PAD_FL_SOURCE) > + * > + * Search for and return a remote pad of @type connected to @entity through an > + * enabled link. If multiple (or no) remote pads match these criteria, an error > + * is returned. > + * > + * The uniqueness constraint makes this helper function suitable for entities > + * that support a single active source or sink at a time. > + * > + * Return: A pointer to the remote pad, or one of the following error pointers > + * if an error occurs: > + * > + * * -ENOTUNIQ - Multiple links are enabled > + * * -ENOLINK - No connected pad found > + */ > +struct media_pad * > +media_entity_remote_pad_unique(const struct media_entity *entity, > + unsigned int type); > + > +/** > + * media_entity_remote_source_pad - Find a remote source pad connected to an entity > + * @entity: The entity > + * > + * Search for and return a remote source pad connected to @entity through an > + * enabled link. If multiple (or no) remote pads match these criteria, an error > + * is returned. > + * > + * The uniqueness constraint makes this helper function suitable for entities > + * that support a single active source at a time. > + * > + * Return: A pointer to the remote pad, or one of the following error pointers > + * if an error occurs: > + * > + * * -ENOTUNIQ - Multiple links are enabled > + * * -ENOLINK - No connected pad found > + */ > +static inline struct media_pad * > +media_entity_remote_source_pad(const struct media_entity *entity) > +{ > + return media_entity_remote_pad_unique(entity, MEDIA_PAD_FL_SOURCE); > +} > + > /** > * media_entity_is_streaming - Test if an entity is part of a streaming pipeline > * @entity: The entity