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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_032627_683771_C3C927F0 X-CRM114-Status: GOOD ( 35.70 ) 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 Hi Laurent On 06/10/2025 10:58, Laurent Pinchart wrote: > On Mon, Oct 06, 2025 at 10:51:33AM +0100, Daniel Scally wrote: >> On 06/10/2025 10:06, Laurent Pinchart wrote: >>> On Mon, Oct 06, 2025 at 09:46:26AM +0100, Daniel Scally wrote: >>>> 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. >>> >>> Any pointer to the code ? >> >> I didn't post my commits to adapt the mali-c55 IPA to the extensible parameters, but it's basically >> the same as Jacopo's patch here: >> https://lists.libcamera.org/pipermail/libcamera-devel/2025-October/053567.html >> >> And the change I made using the macro was in IPAMaliC55::fillParams(): Just for context, that function currently is: void IPAMaliC55::fillParams(unsigned int request, [[maybe_unused]] uint32_t bufferId) { struct mali_c55_params_buffer *params; IPAFrameContext &frameContext = context_.frameContexts.get(request); params = reinterpret_cast( buffers_.at(bufferId).planes()[0].data()); memset(params, 0, sizeof(mali_c55_params_buffer)); params->version = MALI_C55_PARAM_BUFFER_V1; for (auto const &algo : algorithms()) { algo->prepare(context_, request, frameContext, params); ASSERT(params->total_size <= MALI_C55_PARAMS_MAX_SIZE); } size_t bytesused = offsetof(struct mali_c55_params_buffer, data) + params->total_size; paramsComputed.emit(request, bytesused); } >> >> - memset(params, 0, sizeof(mali_c55_params_buffer)); >> + memset(params, 0, v4l2_params_buffer_size(MALI_C55_PARAMS_MAX_SIZE)); > > Given that the buffer should be sized for the worst case, wouldn't it be > better to memset .planes()[0].data().size() ? Won't buffers_.at(bufferId).planes()[0].size() be the same as v4l2_params_buffer_size(MALI_C55_PARAMS_MAX_SIZE)? I am under the impression that that size will come ultimately from .queue_setup() which will be setting the sizes with: sizes[0] = v4l2_params_buffer_size(MALI_C55_PARAMS_MAX_SIZE); In that sense I suppose that that would remove the need for v4l2_params_buffer_size() to be used in userspace and we could just fallback to struct_size_t() within the kernel though. > >>>>> 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_ */ >