Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
media: uapi: Add 3a stats buffer for mali-c55
Describe the format of the 3A statistics buffers in the userspace API
header for the mali-c55 ISP.
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Nayden Kanchev <nayden.kanchev@arm.com>
Co-developed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
authored by
Daniel Scally
and committed by
Hans Verkuil
c7f832f6
4d36f732
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MAINTAINERS
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MAINTAINERS
···
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F: Documentation/devicetree/bindings/media/arm,mali-c55.yaml
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F: Documentation/userspace-api/media/drivers/mali-c55.rst
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F: drivers/media/platform/arm/mali-c55/
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F: include/uapi/linux/media/arm/mali-c55-config.h
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ARM MALI PANTHOR DRM DRIVER
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M: Boris Brezillon <boris.brezillon@collabora.com>
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include/uapi/linux/media/arm/mali-c55-config.h
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include/uapi/linux/media/arm/mali-c55-config.h
···
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#ifndef __UAPI_MALI_C55_CONFIG_H
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#define __UAPI_MALI_C55_CONFIG_H
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#include <linux/types.h>
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#include <linux/v4l2-controls.h>
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#define V4L2_CID_MALI_C55_CAPABILITIES (V4L2_CID_USER_MALI_C55_BASE + 0x0)
···
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#define MALI_C55_GPS_CNR (1U << 8)
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#define MALI_C55_GPS_FRSCALER (1U << 9)
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#define MALI_C55_GPS_DS_PIPE (1U << 10)
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/*
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* Frames are split into zones of almost equal width and height - a zone is a
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* rectangular tile of a frame. The metering blocks within the ISP collect
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* aggregated statistics per zone. A maximum of 15x15 zones can be configured,
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* and so the statistics buffer within the hardware is sized to accommodate
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* that.
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*
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* The utilised number of zones is runtime configurable.
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*/
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#define MALI_C55_MAX_ZONES (15 * 15)
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/**
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* struct mali_c55_ae_1024bin_hist - Auto Exposure 1024-bin histogram statistics
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*
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* @bins: 1024 element array of 16-bit pixel counts.
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*
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* The 1024-bin histogram module collects image-global but zone-weighted
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* intensity distributions of pixels in fixed-width bins. The modules can be
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* configured into different "plane modes" which affect the contents of the
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* collected statistics. In plane mode 0, pixel intensities are taken regardless
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* of colour plane into a single 1024-bin histogram with a bin width of 4. In
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* plane mode 1, four 256-bin histograms with a bin width of 16 are collected -
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* one for each CFA colour plane. In plane modes 4, 5, 6 and 7 two 512-bin
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* histograms with a bin width of 8 are collected - in each mode one of the
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* colour planes is collected into the first histogram and all the others are
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* combined into the second. The histograms are stored consecutively in the bins
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* array.
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*
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* The 16-bit pixel counts are stored as a 4-bit exponent in the most
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* significant bits followed by a 12-bit mantissa. Conversion to a usable
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* format can be done according to the following pseudo-code::
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*
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* if (e == 0) {
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* bin = m * 2;
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* } else {
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* bin = (m + 4096) * 2^e
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* }
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*
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* where
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* e is the exponent value in range 0..15
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* m is the mantissa value in range 0..4095
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*
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* The pixels used in calculating the statistics can be masked using three
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* methods:
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*
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* 1. Pixels can be skipped in X and Y directions independently.
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* 2. Minimum/Maximum intensities can be configured
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* 3. Zones can be differentially weighted, including 0 weighted to mask them
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*
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* The data for this histogram can be collected from different tap points in the
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* ISP depending on configuration - after the white balance or digital gain
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* blocks, or immediately after the input crossbar.
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*/
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struct mali_c55_ae_1024bin_hist {
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__u16 bins[1024];
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} __attribute__((packed));
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/**
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* struct mali_c55_ae_5bin_hist - Auto Exposure 5-bin histogram statistics
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*
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* @hist0: 16-bit normalised pixel count for the 0th intensity bin
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* @hist1: 16-bit normalised pixel count for the 1st intensity bin
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* @hist3: 16-bit normalised pixel count for the 3rd intensity bin
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* @hist4: 16-bit normalised pixel count for the 4th intensity bin
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*
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* The ISP generates a 5-bin histogram of normalised pixel counts within bins of
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* pixel intensity for each of 225 possible zones within a frame. The centre bin
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* of the histogram for each zone is not available from the hardware and must be
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* calculated by subtracting the values of hist0, hist1, hist3 and hist4 from
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* 0xffff as in the following equation:
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*
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* hist2 = 0xffff - (hist0 + hist1 + hist3 + hist4)
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*/
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struct mali_c55_ae_5bin_hist {
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__u16 hist0;
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__u16 hist1;
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__u16 hist3;
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__u16 hist4;
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} __attribute__((packed));
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/**
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* struct mali_c55_awb_average_ratios - Auto White Balance colour ratios
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*
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* @avg_rg_gr: Average R/G or G/R ratio in Q4.8 format.
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* @avg_bg_br: Average B/G or B/R ratio in Q4.8 format.
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* @num_pixels: The number of pixels used in the AWB calculation
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*
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* The ISP calculates and collects average colour ratios for each zone in an
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* image and stores them in Q4.8 format (the lowest 8 bits are fractional, with
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* bits [11:8] representing the integer). The exact ratios collected (either
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* R/G, B/G or G/R, B/R) are configurable through the parameters buffer. The
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* value of the 4 high bits is undefined.
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*/
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struct mali_c55_awb_average_ratios {
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__u16 avg_rg_gr;
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__u16 avg_bg_br;
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__u32 num_pixels;
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} __attribute__((packed));
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/**
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* struct mali_c55_af_statistics - Auto Focus edge and intensity statistics
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*
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* @intensity_stats: Packed mantissa and exponent value for pixel intensity
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* @edge_stats: Packed mantissa and exponent values for edge intensity
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*
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* The ISP collects the squared sum of pixel intensities for each zone within a
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* configurable Region of Interest on the frame. Additionally, the same data are
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* collected after being passed through a bandpass filter which removes high and
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* low frequency components - these are referred to as the edge statistics.
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*
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* The intensity and edge statistics for a zone can be used to calculate the
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* contrast information for a zone
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*
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* C = E2 / I2
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*
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* Where I2 is the intensity statistic for a zone and E2 is the edge statistic
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* for that zone. Optimum focus is reached when C is at its maximum.
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*
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* The intensity and edge statistics are stored packed into a non-standard 16
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* bit floating point format, where the 7 most significant bits represent the
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* exponent and the 9 least significant bits the mantissa. This format can be
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* unpacked with the following pseudocode::
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*
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* if (e == 0) {
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* x = m;
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* } else {
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* x = 2^e-1 * (m + 2^9)
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* }
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*
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* where
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* e is the exponent value in range 0..127
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* m is the mantissa value in range 0..511
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*/
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struct mali_c55_af_statistics {
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__u16 intensity_stats;
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__u16 edge_stats;
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} __attribute__((packed));
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/**
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* struct mali_c55_stats_buffer - 3A statistics for the mali-c55 ISP
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*
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* @ae_1024bin_hist: 1024-bin frame-global pixel intensity histogram
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* @iridix_1024bin_hist: Post-Iridix block 1024-bin histogram
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* @ae_5bin_hists: 5-bin pixel intensity histograms for AEC
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* @reserved1: Undefined buffer space
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* @awb_ratios: Color balance ratios for Auto White Balance
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* @reserved2: Undefined buffer space
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* @af_statistics: Pixel intensity statistics for Auto Focus
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* @reserved3: Undefined buffer space
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*
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* This struct describes the metering statistics space in the Mali-C55 ISP's
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* hardware in its entirety. The space between each defined area is marked as
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* "unknown" and may not be 0, but should not be used. The @ae_5bin_hists,
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* @awb_ratios and @af_statistics members are arrays of statistics per-zone.
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* The zones are arranged in the array in raster order starting from the top
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* left corner of the image.
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*/
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struct mali_c55_stats_buffer {
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struct mali_c55_ae_1024bin_hist ae_1024bin_hist;
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struct mali_c55_ae_1024bin_hist iridix_1024bin_hist;
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struct mali_c55_ae_5bin_hist ae_5bin_hists[MALI_C55_MAX_ZONES];
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__u32 reserved1[14];
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struct mali_c55_awb_average_ratios awb_ratios[MALI_C55_MAX_ZONES];
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__u32 reserved2[14];
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struct mali_c55_af_statistics af_statistics[MALI_C55_MAX_ZONES];
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__u32 reserved3[15];
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} __attribute__((packed));
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#endif /* __UAPI_MALI_C55_CONFIG_H */