[v2,1/4] include: linux: Add v4l2-isp.h
diff mbox series

Message ID 20250916-v4l2-params-v2-1-764471ed6435@ideasonboard.com
State New
Headers show
Series
  • ipa: libipa: Introduce V4L2Params
Related show

Commit Message

Jacopo Mondi Sept. 16, 2025, 12:28 p.m. UTC
Import the v4l2-isp.h header from the Linux kernel sources.

The file has not been merged in mainline Linux yet but is available
at:
https://lore.kernel.org/all/20250915-extensible-parameters-validation-v5-0-e6db94468af3@ideasonboard.com/

Create the include/linux/media/ directory so that header files
exported from the kernel which include this file do not need
to be adjusted when imported in libcamera.

Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Tested-By: Antoine Bouyer <antoine.bouyer@nxp.com>
---
 include/linux/media/v4l2-isp.h | 100 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 100 insertions(+)

Patch
diff mbox series

diff --git a/include/linux/media/v4l2-isp.h b/include/linux/media/v4l2-isp.h
new file mode 100644
index 0000000000000000000000000000000000000000..fed89b5678585a3565d33cf873d0313dc089524f
--- /dev/null
+++ b/include/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 <jacopo.mondi@ideasonboard.com>
+ */
+
+#ifndef _V4L2_ISP_H_
+#define _V4L2_ISP_H_
+
+#include <linux/stddef.h>
+#include <linux/types.h>
+
+#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))
+ * #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 @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
+ */
+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))
+
+/**
+ * struct v4l2_params_buffer - V4L2 extensible parameters configuration
+ *
+ * This struct contains the configuration parameters of the ISP algorithms,
+ * 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
+ * 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
+ */
+struct v4l2_params_buffer {
+	__u32 version;
+	__u32 data_size;
+	__u8 data[] __counted_by(data_size);
+};
+
+#endif /* _V4L2_ISP_H_ */