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 1B184C43334 for ; Fri, 17 Jun 2022 21:34:39 +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=7n+c219kaxOkh9kitJ7iamMVeOzF7grgVzsRzWJe+ik=; b=cbH+1qkityNmAA 9pA03WRQuJDWbOp/+JZ1JX6U8FzlwhUhyN9EPiJCs0rvQojdoFXhDvBjJLB5fikJl+ILT2Pd3OrD+ 0MU6QJw7Z1p6sZa85ST26HO7sB1VlNazaDvqN+ZJSb1K+5zM2sOkaGFqolpZeBrGHT0bPKE4y7eTt JsfjBTypMssXrPFlqk80oste4euLS8qmBDYve5bGGTRnftY/RK+mkChli/b+iG93MRW2qCCV4LEm2 DmvbwPJYHKV7xJWweXvAqZof+SZla7V0sha0X2DxanPux6RhXoOLott4F+w8aYruF9CiIq5kBLJDG ZVRqCZJcC4yBDWHucvVA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o2Jbn-009H5p-78; Fri, 17 Jun 2022 21:34:27 +0000 Received: from mail-wr1-x435.google.com ([2a00:1450:4864:20::435]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o2Jbk-009H3o-EI for linux-rockchip@lists.infradead.org; Fri, 17 Jun 2022 21:34:26 +0000 Received: by mail-wr1-x435.google.com with SMTP id a15so7217616wrh.2 for ; Fri, 17 Jun 2022 14:34:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=E6J2GDFXNA9d2Ur0cBOwlB2pD33WtCla1AS4T/F8zFc=; b=McfFr2H4uUyZBLWPhYsclLMDsaAEJs/nwet2oYKtO3ZovJP4GOwXQLvfdYsScpq7xD 4DaC1AaMfV1ERdwVCiOAGgZG0aH/ZU9qm9jUeGsSda7wTpFCCk3xr28DOSCmKDYRJ41C wIWiBY+RFTq2HBdlLJ85v/WUSY6Zx2upu5aTBIW7DgDtnMyFLUe8MXqUOW1PwUN2HQCk ks9TQzB5qpfrNby4EeTZCbNEhaslwQHRM7o6tsCxaF7f0HeqPUN98AIY0LGKh6s4NWuC rXln+QFcs3i0OKMbzkV1J3HjxyEyEtfF0cjNRh7rS13Jzlc5789crPJsulBnsXBWngTl IMGw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=E6J2GDFXNA9d2Ur0cBOwlB2pD33WtCla1AS4T/F8zFc=; b=a3tMzeJu1bbG2QoDksIQBwZ3KPwoOAz8xUwQV+Sx3/n6X6GQRaFlh5070S8ePKT5Qa AtajpmrN6yUkN35Fi4FfHH4rexAIsHNrBZZ+CuM/uA9TrRqlh5MuAY/zc5HH46/jUKD+ mDhjyn+7Fgg9F0ddkmrL0aQHCnIFpvv3AdAZzg3ZRI9qhXBqWwq95mjhNDZivOLyfMz2 nwep1D4p1ZwZ5NRgL7AcGe9BT8qEeXbqd5Jcub/NhleOP5eDJtS2NbuU5xtAbAlR+mnp PAjxQymkIgwNtbphrdk+d7xIDkrOPABVUt/r06eak9fZ6jAESKfz+Pjx5y9GTiRsnBzQ z5cA== X-Gm-Message-State: AJIora8Um8qzHgEP8E8aYQDXmBdxjOzc/QAT3n9g15Tdy4aPXSb807c2 q9f/6d9oOZxGtf34xb9WkyraBM6ya94= X-Google-Smtp-Source: AGRyM1sdfmWAB71n854msPnVjKa+QfE2XohTi2r41xyncb8L436Q4uzI/6R0Hi6OZnryZgZ5y0SzYQ== X-Received: by 2002:a5d:598e:0:b0:218:531a:eb5 with SMTP id n14-20020a5d598e000000b00218531a0eb5mr10917451wri.334.1655501661377; Fri, 17 Jun 2022 14:34:21 -0700 (PDT) Received: from [192.168.0.14] (cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net. [86.13.91.161]) by smtp.gmail.com with ESMTPSA id l14-20020adfe58e000000b0021a56cda047sm3312866wrm.60.2022.06.17.14.34.20 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Jun 2022 14:34:20 -0700 (PDT) Message-ID: Date: Fri, 17 Jun 2022 22:34:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 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, 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: Daniel Scally 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_143424_554674_380D3280 X-CRM114-Status: GOOD ( 37.75 ) 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 Hello all On 14/06/2022 20:11, 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. > > 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; Does this need another guard here to make sure the link isn't an ancillary link? Only likely to happen at least in the immediate future where the entity represents a camera sensor, so possibly not applicable here - I couldn't find where the new function is used in the series to check. I _think_ it would actually work ok regardless...media_gobj type-punning makes my brain ache, but I think the local_pad->entity == entity comparison would actually compare the entity->name member of the entity at the end of an ancillary link to the entity parameter, not find a match and so continue the loop without failing, but that feels a bit sub-optimal. > + > + 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