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 EA29ECCA471 for ; Mon, 6 Oct 2025 08:46:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type: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=YJI7q6B3emI0H+Y1EkhR3JyGr0ihI4f6526cvbP0lWQ=; b=TE/BHgU7x4apzM/mJUpB1fiQTS NwwG+vq5Gp7k9R1U0myX3aBHgVBZoEdi9SnGckGF9H/5ov7Wo3thPCDDA3mKNc4XxLc6Bmqu+sQWu nZUQfg7jMLgqbHabyQd07fWBbmGElq60DYBd5YB2gKghyBTRXens0mtvkbNYYLkHbnLNK4FRaJ+CE 1TG2byo2EFJYT257s1TI9+uFQ29DpuUk9eakAIHgK+fZJm9H/oBCrj1YUqlrZ+ZDGx19ds+3/37Vs Rq+evBCk8TcYg6gb4BD4VYeUNkaeX7o686f9yn1lg9yaDRCm5IyOc+9FvCnxHqjG871TW6ykLCjhu smB2nTig==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v5grb-0000000HCcY-0DiS; Mon, 06 Oct 2025 08:46:35 +0000 Received: from perceval.ideasonboard.com ([213.167.242.64]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v5grY-0000000HCc9-11aP; Mon, 06 Oct 2025 08:46:33 +0000 Received: from [192.168.0.43] (cpc141996-chfd3-2-0-cust928.12-3.cable.virginm.net [86.13.91.161]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 64D1DBD2; Mon, 6 Oct 2025 10:44:57 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1759740297; bh=lg/0CoDJFVsjnpabZKc/yrmMxMAlxruKk619GK2DT2U=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=FnXoz5QWH/2mMWru77xfToPvAHl8UUykfDJG/wyRvbdHQRR9FDV2xowV8SYNM10GS xFbcWIuM+vmj1PA287rEXnsXkeuSA7aRGVQBAOEDG/FBok3GhLDxtL3N8OcYbv9Gpl A1o3MkLwJSKAmMMJOIAthOJMCgkZwv3ajRNYSpms= Message-ID: <246ae834-3077-4e38-b419-5c8773139e65@ideasonboard.com> Date: Mon, 6 Oct 2025 09:46:26 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 1/8] media: uapi: Introduce V4L2 generic ISP types To: Laurent Pinchart Cc: Jacopo Mondi , Dafna Hirschfeld , Keke Li , Mauro Carvalho Chehab , Heiko Stuebner , Sakari Ailus , Antoine Bouyer , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-arm-kernel@lists.infradead.org References: <20250915-extensible-parameters-validation-v5-0-e6db94468af3@ideasonboard.com> <20250915-extensible-parameters-validation-v5-1-e6db94468af3@ideasonboard.com> <20251005000602.GA13055@pendragon.ideasonboard.com> <20251006082751.GA16422@pendragon.ideasonboard.com> Content-Language: en-US From: Dan Scally In-Reply-To: <20251006082751.GA16422@pendragon.ideasonboard.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251006_014632_572192_43A40F70 X-CRM114-Status: GOOD ( 33.85 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 06/10/2025 09:27, Laurent Pinchart wrote: > On Mon, Oct 06, 2025 at 09:15:47AM +0100, Daniel Scally wrote: >> On 05/10/2025 01:06, Laurent Pinchart wrote: >>> On Mon, Sep 15, 2025 at 07:18:10PM +0200, Jacopo Mondi wrote: >>>> Introduce v4l2-isp.h in the Linux kernel uAPI. >>>> >>>> The header includes types for generic ISP configuration parameters >>>> and will be extended in future with support for generic ISP statistics >>> >>> s/in future/in the future/ >>> >>> (and you can reflow the commit message) >>> >>>> formats. >>>> >>>> Generic ISP parameters support is provided by introducing two new >>>> types that represent an extensible and versioned buffer of ISP >>>> configuration parameters. >>>> >>>> The v4l2_params_block_header structure represents the header to be >>>> prepend to each ISP configuration block and the v4l2_params_buffer type >>>> represents the base type for the configuration parameters buffer. >>> >>> The second part of the sentence describes the same structure as the next >>> paragraph. >>> >>>> The v4l2_params_buffer represents the container for the ISP >>>> configuration data block. The generic type is defined with a 0-sized >>>> data member that the ISP driver implementations shall properly size >>>> according to their capabilities. >>> >>> This will be easier to understand if you describe v4l2_params_buffer >>> first. >>> >>> The commit message would benefit from being rewritten. >>> >>>> [Add v4l2_params_buffer_size()] >>>> Signed-off-by: Daniel Scally >>>> Reviewed-by: Daniel Scally >>>> Signed-off-by: Jacopo Mondi >>>> --- >>>> MAINTAINERS | 6 +++ >>>> include/uapi/linux/media/v4l2-isp.h | 100 ++++++++++++++++++++++++++++++++++++ >>>> 2 files changed, 106 insertions(+) >>>> >>>> diff --git a/MAINTAINERS b/MAINTAINERS >>>> index ee8cb2db483f6a5e96b62b6f2edd05b1427b69f5..e82c3d0758d6033fe8fcd56ffde2c03c4319fd11 100644 >>>> --- a/MAINTAINERS >>>> +++ b/MAINTAINERS >>>> @@ -26410,6 +26410,12 @@ F: drivers/media/i2c/vd55g1.c >>>> F: drivers/media/i2c/vd56g3.c >>>> F: drivers/media/i2c/vgxy61.c >>>> >>>> +V4L2 GENERIC ISP PARAMETERS AND STATISTIC FORMATS >>>> +M: Jacopo Mondi >>>> +L: linux-media@vger.kernel.org >>>> +S: Maintained >>>> +F: include/uapi/linux/media/v4l2-isp.h >>>> + >>>> VF610 NAND DRIVER >>>> M: Stefan Agner >>>> L: linux-mtd@lists.infradead.org >>>> diff --git a/include/uapi/linux/media/v4l2-isp.h b/include/uapi/linux/media/v4l2-isp.h >>>> new file mode 100644 >>>> index 0000000000000000000000000000000000000000..b838555dce2b290a14136ab09ea4d2dfdc95b26b >>>> --- /dev/null >>>> +++ b/include/uapi/linux/media/v4l2-isp.h >>>> @@ -0,0 +1,100 @@ >>>> +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ >>>> +/* >>>> + * Video4Linux2 generic ISP parameters and statistics support >>>> + * >>>> + * Copyright (C) 2025 Ideas On Board Oy >>>> + * Author: Jacopo Mondi >>>> + */ >>>> + >>>> +#ifndef _UAPI_V4L2_ISP_H_ >>>> +#define _UAPI_V4L2_ISP_H_ >>>> + >>>> +#include >>>> +#include >>>> + >>>> +#define V4L2_PARAMS_FL_BLOCK_DISABLE (1U << 0) >>>> +#define V4L2_PARAMS_FL_BLOCK_ENABLE (1U << 1) >>>> + >>>> +/* >>>> + * Reserve the first 8 bits for V4L2_PARAMS_FL_* flag. >>>> + * >>>> + * Driver-specific flags should be defined as: >>>> + * #define PLATFORM_SPECIFIC_FLAG0 ((1U << V4L2_PARAMS_FL_DRIVER_FLAGS(0)) >>> >>> s/PLATFORM/DRIVER/ >>> >>>> + * #define PLATFORM_SPECIFIC_FLAG1 ((1U << V4L2_PARAMS_FL_DRIVER_FLAGS(1)) >>>> + */ >>>> +#define V4L2_PARAMS_FL_DRIVER_FLAGS(n) ((n) + 8) >>>> + >>>> +/** >>>> + * struct v4l2_params_block_header - V4L2 extensible parameters block header >>>> + * >>>> + * This structure represents the common part of all the ISP configuration >>>> + * blocks. Each parameters block shall embed an instance of this structure type >>>> + * as its first member, followed by the block-specific configuration data. The >>>> + * driver inspects this common header to discern the block type and its size and >>>> + * properly handle the block content. >>> >>> The last sentence is not relevant for the UAPI. >>> >>>> + * >>>> + * The @type field is an ISP driver-specific value that identifies the block >>>> + * type. The @size field specifies the size of the parameters block. >>>> + * >>>> + * The @flags field is a bitmask of per-block flags V4L2_PARAMS_FL_* and >>>> + * driver-specific flags specified by the driver header. >>>> + * >>>> + * @type: The parameters block type (driver-specific) >>>> + * @flags: A bitmask of block flags (driver-specific) >>>> + * @size: Size (in bytes) of the parameters block, including this header >>> >>> I think the fields usually go right after the structure name, followed >>> by the rest of the documentation. >>> >>>> + */ >>>> +struct v4l2_params_block_header { >>>> + __u16 type; >>>> + __u16 flags; >>>> + __u32 size; >>>> +} __attribute__((aligned(8))); >>>> + >>>> +/** >>>> + * v4l2_params_buffer_size - Calculate size of v4l2_params_buffer for a platform >>>> + * >>>> + * Users of the v4l2 extensible parameters will have differing sized data arrays >>>> + * depending on their specific parameter buffers. Drivers and userspace will >>>> + * need to be able to calculate the appropriate size of the struct to >>>> + * accommodate all ISP configuration blocks provided by the platform. >>>> + * This macro provides a convenient tool for the calculation. >>>> + * >>>> + * @max_params_size: The total size of the ISP configuration blocks >>>> + */ >>>> +#define v4l2_params_buffer_size(max_params_size) \ >>>> + (offsetof(struct v4l2_params_buffer, data) + (max_params_size)) >>> >>> This isn't used in this series as far as I can tell, and neither is it >>> used in your libcamera implementation. I'd drop the macro (as well as >>> the mention in the commit message). >> >> This is because the rkisp1 and c3 ISP implementations are already merged with a custom parameters >> buffer struct defined at [1] and [2]. There the array size is set to the max size macro. This series >> just asserts that the header part is a size match for struct v4l2_params_buffer to guarantee >> compatibility, so throughout those drivers they can use sizeof(struct c3_isp_params_cfg) or the >> rkisp equivalent and it's fine. >> >> For new users that don't have a custom struct in their uAPI and are relying on struct >> v4l2_params_buffer we can't just do sizeof(), so the idea was for this to provide a canonical way >> for the size calculation to be done across both the kernel and userspace. >> >> If we decide that it's worth keeping but want a user in this series to justify its inclusion, it >> could be used in patches 2 and 3 - I'll reply to patch 2 in a second to indicate where. > > Will it be used by userspace too for the Mali C55, or only by the kernel I have used it in userspace too. Thanks Dan > driver ? > >> [1] https://elixir.bootlin.com/linux/v6.17/source/include/uapi/linux/rkisp1-config.h#L1675 >> [2] https://elixir.bootlin.com/linux/v6.17/source/include/uapi/linux/media/amlogic/c3-isp-config.h#L558> >> >>>> + >>>> +/** >>>> + * struct v4l2_params_buffer - V4L2 extensible parameters configuration >>>> + * >>>> + * This struct contains the configuration parameters of the ISP algorithms, >>> >>> s/struct/structure/ >>> >>>> + * serialized by userspace into a data buffer. Each configuration parameter >>>> + * block is represented by a block-specific structure which contains a >>>> + * :c:type:`v4l2_params_block_header` entry as first member. Userspace populates >>>> + * the @data buffer with configuration parameters for the blocks that it intends >>>> + * to configure. As a consequence, the data buffer effective size changes >>>> + * according to the number of ISP blocks that userspace intends to configure and >>>> + * is set by userspace in the @data_size field. >>>> + * >>>> + * The parameters buffer is versioned by the @version field to allow modifying >>>> + * and extending its definition. Userspace shall populate the @version field to >>>> + * inform the driver about the version it intends to use. The driver will parse >>>> + * and handle the @data buffer according to the data layout specific to the >>>> + * indicated version and return an error if the desired version is not >>>> + * supported. >>>> + * >>>> + * For each ISP block that userspace wants to configure, a block-specific >>>> + * structure is appended to the @data buffer, one after the other without gaps >>>> + * in between nor overlaps. Userspace shall populate the @data_size field with >>> >>> I think you can drop "nor overlaps", nobody in their right mind should >>> think the blocks could be overlayed :-) >>> >>>> + * the effective size, in bytes, of the @data buffer. >>>> + * >>>> + * @version: The parameters buffer version (driver-specific) >>>> + * @data_size: The configuration data effective size, excluding this header >>>> + * @data: The configuration data >>> >>> Move the fields up just after the structure name. >>> >>> Reviewed-by: Laurent Pinchart >>> >>>> + */ >>>> +struct v4l2_params_buffer { >>>> + __u32 version; >>>> + __u32 data_size; >>>> + __u8 data[] __counted_by(data_size); >>>> +}; >>>> + >>>> +#endif /* _UAPI_V4L2_ISP_H_ */ >