diff mbox series

[PATCHv2,1/5] drm/i915/display: Add support for histogram

Message ID 20240821102349.3961986-2-arun.r.murthy@intel.com (mailing list archive)
State New, archived
Headers show
Series Display Global histogram | expand

Commit Message

Murthy, Arun R Aug. 21, 2024, 10:23 a.m. UTC 
Statistics is generated from the image frame that is coming to display
and an event is sent to user after reading this histogram data.
This statistics/histogram is then shared with the user upon getting a
request from user. User can then use this histogram and generate an
enhancement factor. This enhancement factor can be multiplied/added with
the incoming pixel data frame.

v2: forward declaration in header file along with error handling (Jani)

Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
---
 drivers/gpu/drm/i915/Makefile                 |   1 +
 .../drm/i915/display/intel_display_types.h    |   2 +
 .../gpu/drm/i915/display/intel_histogram.c    | 205 ++++++++++++++++++
 .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
 drivers/gpu/drm/xe/Makefile                   |   1 +
 5 files changed, 287 insertions(+)
 create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
 create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h

Comments

Kulkarni, Vandita Sept. 10, 2024, 12:11 p.m. UTC | #1 
> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Arun
> R Murthy
> Sent: Wednesday, August 21, 2024 3:54 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: Murthy, Arun R <arun.r.murthy@intel.com>
> Subject: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> 
> Statistics is generated from the image frame that is coming to display and an
> event is sent to user after reading this histogram data.
> This statistics/histogram is then shared with the user upon getting a request
> from user. User can then use this histogram and generate an enhancement
> factor. This enhancement factor can be multiplied/added with the incoming
> pixel data frame.
> 
> v2: forward declaration in header file along with error handling (Jani)
> 
> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile                 |   1 +
>  .../drm/i915/display/intel_display_types.h    |   2 +
>  .../gpu/drm/i915/display/intel_histogram.c    | 205 ++++++++++++++++++
>  .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
>  drivers/gpu/drm/xe/Makefile                   |   1 +
>  5 files changed, 287 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
>  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h
> 
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index c63fa2133ccb..03caf3a24966 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -264,6 +264,7 @@ i915-y += \
>  	display/intel_hdcp.o \
>  	display/intel_hdcp_gsc.o \
>  	display/intel_hdcp_gsc_message.o \
> +	display/intel_histogram.o \
>  	display/intel_hotplug.o \
>  	display/intel_hotplug_irq.o \
>  	display/intel_hti.o \
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index bd290536a1b7..79d34d6d537d 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1537,6 +1537,8 @@ struct intel_crtc {
>  	/* for loading single buffered registers during vblank */
>  	struct pm_qos_request vblank_pm_qos;
> 
> +	struct intel_histogram *histogram;
> +
>  #ifdef CONFIG_DEBUG_FS
>  	struct intel_pipe_crc pipe_crc;
>  #endif
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c
> b/drivers/gpu/drm/i915/display/intel_histogram.c
> new file mode 100644
> index 000000000000..45e968e00af6
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> @@ -0,0 +1,205 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#include <drm/drm_device.h>
> +#include <drm/drm_file.h>
> +
> +#include "i915_reg.h"
> +#include "i915_drv.h"
> +#include "intel_display.h"
> +#include "intel_histogram.h"
> +#include "intel_display_types.h"
> +#include "intel_de.h"
> +
> +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    // 3.0% of
> the pipe's current pixel count.
> +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   // Precision
> factor for threshold guardband.
> +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> +
> +struct intel_histogram {
> +	struct drm_i915_private *i915;
> +	bool enable;
> +	bool can_enable;
> +	enum pipe pipe;
> +	u32 bindata[HISTOGRAM_BIN_COUNT];
> +};
> +
> +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +
> +	/* TODO: Restrictions for enabling histogram */
> +	histogram->can_enable = true;
> +
> +	return 0;
> +}
> +
Looks like we are totally bypassing crtc_state->dither.
Also I see some comments on dither not being enabled on anything which is not 6bpc. Is that constraint resolved now?

> +static void intel_histogram_enable_dithering(struct drm_i915_private
> *dev_priv,
> +					     enum pipe pipe)
> +{
> +	intel_de_rmw(dev_priv, PIPE_MISC(pipe),
> PIPE_MISC_DITHER_ENABLE,
> +		     PIPE_MISC_DITHER_ENABLE);
> +}
> +
> +static int intel_histogram_enable(struct intel_crtc *intel_crtc) {
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	int pipe = intel_crtc->pipe;
> +	u64 res;
> +	u32 gbandthreshold;
> +
> +	if (!histogram)
> +		return -EINVAL;
> +
> +	if (!histogram->can_enable) {
> +		return -EINVAL;
> +	}
> +
> +	if (histogram->enable)
> +		return 0;
> +
I don't see in the spec that dither should be enabled, any quick bspec references?
> +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> +	intel_histogram_enable_dithering(i915, pipe);
> +
> +	/*
> +	 * enable DPST_CTL Histogram mode
> +	 * Clear DPST_CTL Bin Reg function select to TC
> +	 */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_IE_HIST_EN |
> +		     DPST_CTL_HIST_MODE |
> DPST_CTL_IE_TABLE_VALUE_FORMAT,
> +		     DPST_CTL_BIN_REG_FUNC_TC | DPST_CTL_IE_HIST_EN |
> +		     DPST_CTL_HIST_MODE_HSV |
> +		     DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC);
> +
> +	/* Re-Visit: check if wait for one vblank is required */
> +	drm_crtc_wait_one_vblank(&intel_crtc->base);
> +
> +	/* TODO: one time programming: Program GuardBand Threshold */
> +	res = (intel_crtc->config->hw.adjusted_mode.vtotal *
> +				intel_crtc->config-
> >hw.adjusted_mode.htotal);
> +	gbandthreshold = (res *
> 	HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT) /
> +
> 	HISTOGRAM_GUARDBAND_PRECISION_FACTOR;
> +
> +	/* Enable histogram interrupt mode */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_THRESHOLD_GB_MASK |
> +		     DPST_GUARD_INTERRUPT_DELAY_MASK |
> DPST_GUARD_HIST_INT_EN,
> +		     DPST_GUARD_THRESHOLD_GB(gbandthreshold) |
> +
> DPST_GUARD_INTERRUPT_DELAY(HISTOGRAM_DEFAULT_GUARDBAND_DEL
> AY) |
> +		     DPST_GUARD_HIST_INT_EN);
> +
> +	/* Clear pending interrupts has to be done on separate write */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_HIST_EVENT_STATUS, 1);
> +
> +	histogram->enable = true;
> +
> +	return 0;
> +}
> +
> +static void intel_histogram_disable(struct intel_crtc *intel_crtc) {
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	int pipe = intel_crtc->pipe;
> +
> +	if (!histogram)
> +		return;
> +
> +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> +	intel_histogram_enable_dithering(i915, pipe);
> +
> +	/* Clear pending interrupts and disable interrupts */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_HIST_INT_EN |
> DPST_GUARD_HIST_EVENT_STATUS, 0);
> +
> +	/* disable DPST_CTL Histogram mode */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_IE_HIST_EN, 0);
> +
> +	histogram->enable = false;
> +}
> +
> +int intel_histogram_update(struct intel_crtc *intel_crtc, bool enable)
> +{
> +	if (enable)
> +		return intel_histogram_enable(intel_crtc);
> +
> +	intel_histogram_disable(intel_crtc);
> +	return 0;
> +}
> +
> +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32
> +*data) {
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	int pipe = intel_crtc->pipe;
> +	int i = 0;
> +
> +	if (!histogram)
> +		return -EINVAL;
> +
> +	if (!histogram->enable) {
> +		drm_err(&i915->drm, "histogram not enabled");
> +		return -EINVAL;
> +	}
> +
> +	if (!data) {
> +		drm_err(&i915->drm, "enhancement LUT data is NULL");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Set DPST_CTL Bin Reg function select to IE
> +	 * Set DPST_CTL Bin Register Index to 0
> +	 */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL |
> DPST_CTL_BIN_REG_MASK,
> +		     DPST_CTL_BIN_REG_FUNC_IE |
> DPST_CTL_BIN_REG_CLEAR);
> +
> +	for (i = 0; i < HISTOGRAM_IET_LENGTH; i++) {
> +		intel_de_rmw(i915, DPST_BIN(pipe),
> +			     DPST_BIN_DATA_MASK, data[i]);
> +		drm_dbg_atomic(&i915->drm, "iet_lut[%d]=%x\n", i, data[i]);
> +	}
> +
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_ENHANCEMENT_MODE_MASK |
> DPST_CTL_IE_MODI_TABLE_EN,
> +		     DPST_CTL_EN_MULTIPLICATIVE |
> DPST_CTL_IE_MODI_TABLE_EN);
> +
> +	/* Once IE is applied, change DPST CTL to TC */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL,
> DPST_CTL_BIN_REG_FUNC_TC);
> +
> +	return 0;
> +}
> +
> +void intel_histogram_deinit(struct intel_crtc *intel_crtc) {
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +
> +	kfree(histogram);
> +}
> +
> +int intel_histogram_init(struct intel_crtc *intel_crtc) {
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram;
> +
> +	/* Allocate histogram internal struct */
> +	histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
> +	if (!histogram) {
> +		return -ENOMEM;
> +	}
> +
> +	intel_crtc->histogram = histogram;
> +	histogram->pipe = intel_crtc->pipe;
> +	histogram->can_enable = false;
> +
> +	histogram->i915 = i915;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h
> b/drivers/gpu/drm/i915/display/intel_histogram.h
> new file mode 100644
> index 000000000000..b25091732274
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.h
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#ifndef __INTEL_HISTOGRAM_H__
> +#define __INTEL_HISTOGRAM_H__
> +
> +#include <linux/types.h>
> +
> +struct intel_crtc;
> +
> +/* GLOBAL_HIST related registers */
> +#define _DPST_CTL_A					0x490C0
> +#define _DPST_CTL_B					0x491C0
> +#define DPST_CTL(pipe)
> 	_MMIO_PIPE(pipe, _DPST_CTL_A, _DPST_CTL_B)
> +#define DPST_CTL_IE_HIST_EN				REG_BIT(31)
> +#define DPST_CTL_RESTORE				REG_BIT(28)
> +#define DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
> +#define DPST_CTL_HIST_MODE				REG_BIT(24)
> +#define DPST_CTL_ENHANCEMENT_MODE_MASK
> 	REG_GENMASK(14, 13)
> +#define DPST_CTL_EN_MULTIPLICATIVE
> 	REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT
> 	REG_BIT(15)
> +#define DPST_CTL_BIN_REG_FUNC_SEL			REG_BIT(11)
> +#define DPST_CTL_BIN_REG_FUNC_TC
> 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 0)
> +#define DPST_CTL_BIN_REG_FUNC_IE
> 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 1)
> +#define DPST_CTL_BIN_REG_MASK
> 	REG_GENMASK(6, 0)
> +#define DPST_CTL_BIN_REG_CLEAR
> 	REG_FIELD_PREP(DPST_CTL_BIN_REG_MASK, 0)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_2INT_8FRAC
> 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 1)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC
> 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 0)
> +#define DPST_CTL_HIST_MODE_YUV
> 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 0)
> +#define DPST_CTL_HIST_MODE_HSV
> 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 1)
> +
> +#define _DPST_GUARD_A					0x490C8
> +#define _DPST_GUARD_B					0x491C8
> +#define DPST_GUARD(pipe)				_MMIO_PIPE(pipe,
> _DPST_GUARD_A, _DPST_GUARD_B)
> +#define DPST_GUARD_HIST_INT_EN				REG_BIT(31)
> +#define DPST_GUARD_HIST_EVENT_STATUS			REG_BIT(30)
> +#define DPST_GUARD_INTERRUPT_DELAY_MASK
> 	REG_GENMASK(29, 22)
> +#define DPST_GUARD_INTERRUPT_DELAY(val)
> 	REG_FIELD_PREP(DPST_GUARD_INTERRUPT_DELAY_MASK, val)
> +#define DPST_GUARD_THRESHOLD_GB_MASK
> 	REG_GENMASK(21, 0)
> +#define DPST_GUARD_THRESHOLD_GB(val)
> 	REG_FIELD_PREP(DPST_GUARD_THRESHOLD_GB_MASK, val)
> +
> +#define _DPST_BIN_A					0x490C4
> +#define _DPST_BIN_B					0x491C4
> +#define DPST_BIN(pipe)
> 	_MMIO_PIPE(pipe, _DPST_BIN_A, _DPST_BIN_B)
> +#define DPST_BIN_DATA_MASK
> 	REG_GENMASK(23, 0)
> +#define DPST_BIN_BUSY					REG_BIT(31)
> +
> +#define INTEL_HISTOGRAM_PIPEA			0x90000000
> +#define INTEL_HISTOGRAM_PIPEB			0x90000002
> +#define INTEL_HISTOGRAM_EVENT(pipe)		PIPE(pipe, \
> +						     INTEL_HISTOGRAM_PIPEA,
> \
> +						     INTEL_HISTOGRAM_PIPEB)
> +
> +#define HISTOGRAM_BIN_COUNT			32
> +#define HISTOGRAM_IET_LENGTH			33
> +
> +enum intel_global_hist_status {
> +	INTEL_HISTOGRAM_ENABLE,
> +	INTEL_HISTOGRAM_DISABLE,
> +};
> +
> +enum intel_global_histogram {
> +	INTEL_HISTOGRAM,
> +};
> +
> +enum intel_global_hist_lut {
> +	INTEL_HISTOGRAM_PIXEL_FACTOR,
> +};
> +
> +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc); int
> +intel_histogram_update(struct intel_crtc *intel_crtc, bool enable); int
> +intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32 *data);
> +int intel_histogram_init(struct intel_crtc *intel_crtc); void
> +intel_histogram_deinit(struct intel_crtc *intel_crtc);
> +
> +#endif /* __INTEL_HISTOGRAM_H__ */
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index b9670ae09a9e..424ea43016dd 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -238,6 +238,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
>  	i915-display/intel_hdcp.o \
>  	i915-display/intel_hdcp_gsc_message.o \
>  	i915-display/intel_hdmi.o \
> +	i915-display/intel_histogram.o \
>  	i915-display/intel_hotplug.o \
>  	i915-display/intel_hotplug_irq.o \
>  	i915-display/intel_hti.o \
> --
> 2.25.1
Suraj Kandpal Sept. 11, 2024, 5:37 a.m. UTC | #2 
> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Arun R
> Murthy
> Sent: Wednesday, August 21, 2024 3:54 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: Murthy, Arun R <arun.r.murthy@intel.com>
> Subject: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> 
> Statistics is generated from the image frame that is coming to display and an
> event is sent to user after reading this histogram data.
> This statistics/histogram is then shared with the user upon getting a request
> from user. User can then use this histogram and generate an enhancement factor.
> This enhancement factor can be multiplied/added with the incoming pixel data
> frame.
> 
> v2: forward declaration in header file along with error handling (Jani)
> 
> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile                 |   1 +
>  .../drm/i915/display/intel_display_types.h    |   2 +
>  .../gpu/drm/i915/display/intel_histogram.c    | 205 ++++++++++++++++++
>  .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
>  drivers/gpu/drm/xe/Makefile                   |   1 +
>  5 files changed, 287 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
>  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h
> 
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index c63fa2133ccb..03caf3a24966 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -264,6 +264,7 @@ i915-y += \
>  	display/intel_hdcp.o \
>  	display/intel_hdcp_gsc.o \
>  	display/intel_hdcp_gsc_message.o \
> +	display/intel_histogram.o \
>  	display/intel_hotplug.o \
>  	display/intel_hotplug_irq.o \
>  	display/intel_hti.o \
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> b/drivers/gpu/drm/i915/display/intel_display_types.h
> index bd290536a1b7..79d34d6d537d 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1537,6 +1537,8 @@ struct intel_crtc {
>  	/* for loading single buffered registers during vblank */
>  	struct pm_qos_request vblank_pm_qos;
> 
> +	struct intel_histogram *histogram;
> +
>  #ifdef CONFIG_DEBUG_FS
>  	struct intel_pipe_crc pipe_crc;
>  #endif
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c
> b/drivers/gpu/drm/i915/display/intel_histogram.c
> new file mode 100644
> index 000000000000..45e968e00af6
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> @@ -0,0 +1,205 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#include <drm/drm_device.h>
> +#include <drm/drm_file.h>
> +
> +#include "i915_reg.h"
> +#include "i915_drv.h"
> +#include "intel_display.h"
> +#include "intel_histogram.h"
> +#include "intel_display_types.h"
> +#include "intel_de.h"
> +
> +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    // 3.0% of the
> pipe's current pixel count.
> +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   // Precision
> factor for threshold guardband.
> +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> +
> +struct intel_histogram {
> +	struct drm_i915_private *i915;

Lets use intel_display here instead of i915 as I can see this is mostly being used for reg read/writes
Read/write/rmw also work with intel_display well.

> +	bool enable;
> +	bool can_enable;
> +	enum pipe pipe;
> +	u32 bindata[HISTOGRAM_BIN_COUNT];
> +};
> +
> +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +
> +	/* TODO: Restrictions for enabling histogram */
> +	histogram->can_enable = true;
> +
> +	return 0;
> +}
> +
> +static void intel_histogram_enable_dithering(struct drm_i915_private
> *dev_priv,

Use intel_display here
> +					     enum pipe pipe)
> +{
> +	intel_de_rmw(dev_priv, PIPE_MISC(pipe), PIPE_MISC_DITHER_ENABLE,
> +		     PIPE_MISC_DITHER_ENABLE);

So every where below drm_i915_private can be replaced with intel_display
Ditto.

> +}
> +
> +static int intel_histogram_enable(struct intel_crtc *intel_crtc) {
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	int pipe = intel_crtc->pipe;
> +	u64 res;
> +	u32 gbandthreshold;
> +
> +	if (!histogram)
> +		return -EINVAL;
> +
> +	if (!histogram->can_enable) {
> +		return -EINVAL;
> +	}

No need for brackets here now atleast

> +
> +	if (histogram->enable)
> +		return 0;
> +
> +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> +	intel_histogram_enable_dithering(i915, pipe);
> +
> +	/*
> +	 * enable DPST_CTL Histogram mode
> +	 * Clear DPST_CTL Bin Reg function select to TC
> +	 */

Nit: maybe make it Enable DPST... and If we are mentioning the steps lets add
some number or points(-)

> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_IE_HIST_EN |
> +		     DPST_CTL_HIST_MODE |
> DPST_CTL_IE_TABLE_VALUE_FORMAT,
> +		     DPST_CTL_BIN_REG_FUNC_TC | DPST_CTL_IE_HIST_EN |
> +		     DPST_CTL_HIST_MODE_HSV |
> +		     DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC);
> +
> +	/* Re-Visit: check if wait for one vblank is required */
> +	drm_crtc_wait_one_vblank(&intel_crtc->base);
> +
> +	/* TODO: one time programming: Program GuardBand Threshold */
> +	res = (intel_crtc->config->hw.adjusted_mode.vtotal *
> +				intel_crtc->config->hw.adjusted_mode.htotal);
> +	gbandthreshold = (res *
> 	HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT) /
> +
> 	HISTOGRAM_GUARDBAND_PRECISION_FACTOR;
> +
> +	/* Enable histogram interrupt mode */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_THRESHOLD_GB_MASK |
> +		     DPST_GUARD_INTERRUPT_DELAY_MASK |
> DPST_GUARD_HIST_INT_EN,
> +		     DPST_GUARD_THRESHOLD_GB(gbandthreshold) |
> +
> DPST_GUARD_INTERRUPT_DELAY(HISTOGRAM_DEFAULT_GUARDBAND_DELAY)
> |
> +		     DPST_GUARD_HIST_INT_EN);
> +
> +	/* Clear pending interrupts has to be done on separate write */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_HIST_EVENT_STATUS, 1);
> +
> +	histogram->enable = true;
> +
> +	return 0;
> +}
> +
> +static void intel_histogram_disable(struct intel_crtc *intel_crtc) {
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	int pipe = intel_crtc->pipe;
> +
> +	if (!histogram)
> +		return;
> +
> +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> +	intel_histogram_enable_dithering(i915, pipe);
> +
> +	/* Clear pending interrupts and disable interrupts */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_HIST_INT_EN |
> DPST_GUARD_HIST_EVENT_STATUS, 0);
> +
> +	/* disable DPST_CTL Histogram mode */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_IE_HIST_EN, 0);
> +
> +	histogram->enable = false;
> +}
> +
> +int intel_histogram_update(struct intel_crtc *intel_crtc, bool enable)
> +{
> +	if (enable)
> +		return intel_histogram_enable(intel_crtc);
> +
> +	intel_histogram_disable(intel_crtc);
> +	return 0;
> +}
> +
> +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32
> +*data) {
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	int pipe = intel_crtc->pipe;
> +	int i = 0;
> +
> +	if (!histogram)
> +		return -EINVAL;
> +
> +	if (!histogram->enable) {
> +		drm_err(&i915->drm, "histogram not enabled");
> +		return -EINVAL;
> +	}
> +
> +	if (!data) {
> +		drm_err(&i915->drm, "enhancement LUT data is NULL");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Set DPST_CTL Bin Reg function select to IE
> +	 * Set DPST_CTL Bin Register Index to 0
> +	 */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_BIN_REG_MASK,
> +		     DPST_CTL_BIN_REG_FUNC_IE | DPST_CTL_BIN_REG_CLEAR);
> +
> +	for (i = 0; i < HISTOGRAM_IET_LENGTH; i++) {
> +		intel_de_rmw(i915, DPST_BIN(pipe),
> +			     DPST_BIN_DATA_MASK, data[i]);
> +		drm_dbg_atomic(&i915->drm, "iet_lut[%d]=%x\n", i, data[i]);
> +	}
> +
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_ENHANCEMENT_MODE_MASK |
> DPST_CTL_IE_MODI_TABLE_EN,
> +		     DPST_CTL_EN_MULTIPLICATIVE |
> DPST_CTL_IE_MODI_TABLE_EN);
> +
> +	/* Once IE is applied, change DPST CTL to TC */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL,
> DPST_CTL_BIN_REG_FUNC_TC);
> +
> +	return 0;
> +}
> +
> +void intel_histogram_deinit(struct intel_crtc *intel_crtc) {
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +
> +	kfree(histogram);
> +}
> +
> +int intel_histogram_init(struct intel_crtc *intel_crtc) {
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram;
> +
> +	/* Allocate histogram internal struct */
> +	histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
> +	if (!histogram) {
> +		return -ENOMEM;
> +	}
> +
> +	intel_crtc->histogram = histogram;
> +	histogram->pipe = intel_crtc->pipe;
> +	histogram->can_enable = false;
> +
> +	histogram->i915 = i915;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h
> b/drivers/gpu/drm/i915/display/intel_histogram.h
> new file mode 100644
> index 000000000000..b25091732274
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.h
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#ifndef __INTEL_HISTOGRAM_H__
> +#define __INTEL_HISTOGRAM_H__
> +
> +#include <linux/types.h>
> +
> +struct intel_crtc;
> +
> +/* GLOBAL_HIST related registers */
> +#define _DPST_CTL_A					0x490C0
> +#define _DPST_CTL_B					0x491C0
> +#define DPST_CTL(pipe)
> 	_MMIO_PIPE(pipe, _DPST_CTL_A, _DPST_CTL_B)
> +#define DPST_CTL_IE_HIST_EN				REG_BIT(31)
> +#define DPST_CTL_RESTORE				REG_BIT(28)
> +#define DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
> +#define DPST_CTL_HIST_MODE				REG_BIT(24)
> +#define DPST_CTL_ENHANCEMENT_MODE_MASK
> 	REG_GENMASK(14, 13)
> +#define DPST_CTL_EN_MULTIPLICATIVE
> 	REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT			REG_BIT(15)
> +#define DPST_CTL_BIN_REG_FUNC_SEL			REG_BIT(11)
> +#define DPST_CTL_BIN_REG_FUNC_TC
> 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 0)
> +#define DPST_CTL_BIN_REG_FUNC_IE
> 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 1)
> +#define DPST_CTL_BIN_REG_MASK
> 	REG_GENMASK(6, 0)
> +#define DPST_CTL_BIN_REG_CLEAR
> 	REG_FIELD_PREP(DPST_CTL_BIN_REG_MASK, 0)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_2INT_8FRAC
> 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 1)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC
> 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 0)
> +#define DPST_CTL_HIST_MODE_YUV
> 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 0)
> +#define DPST_CTL_HIST_MODE_HSV
> 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 1)
> +
> +#define _DPST_GUARD_A					0x490C8
> +#define _DPST_GUARD_B					0x491C8
> +#define DPST_GUARD(pipe)				_MMIO_PIPE(pipe,
> _DPST_GUARD_A, _DPST_GUARD_B)
> +#define DPST_GUARD_HIST_INT_EN				REG_BIT(31)
> +#define DPST_GUARD_HIST_EVENT_STATUS			REG_BIT(30)
> +#define DPST_GUARD_INTERRUPT_DELAY_MASK
> 	REG_GENMASK(29, 22)
> +#define DPST_GUARD_INTERRUPT_DELAY(val)
> 	REG_FIELD_PREP(DPST_GUARD_INTERRUPT_DELAY_MASK, val)
> +#define DPST_GUARD_THRESHOLD_GB_MASK
> 	REG_GENMASK(21, 0)
> +#define DPST_GUARD_THRESHOLD_GB(val)
> 	REG_FIELD_PREP(DPST_GUARD_THRESHOLD_GB_MASK, val)
> +
> +#define _DPST_BIN_A					0x490C4
> +#define _DPST_BIN_B					0x491C4
> +#define DPST_BIN(pipe)
> 	_MMIO_PIPE(pipe, _DPST_BIN_A, _DPST_BIN_B)
> +#define DPST_BIN_DATA_MASK
> 	REG_GENMASK(23, 0)
> +#define DPST_BIN_BUSY					REG_BIT(31)
> +
> +#define INTEL_HISTOGRAM_PIPEA			0x90000000
> +#define INTEL_HISTOGRAM_PIPEB			0x90000002
> +#define INTEL_HISTOGRAM_EVENT(pipe)		PIPE(pipe, \
> +						     INTEL_HISTOGRAM_PIPEA, \
> +						     INTEL_HISTOGRAM_PIPEB)

I don't think this is the right way. Lets have a file for intel_histogram_regs.h and intel_histogram.h
That will look a lot cleaner.

> +
> +#define HISTOGRAM_BIN_COUNT			32
> +#define HISTOGRAM_IET_LENGTH			33
> +
> +enum intel_global_hist_status {
> +	INTEL_HISTOGRAM_ENABLE,
> +	INTEL_HISTOGRAM_DISABLE,
> +};
> +
> +enum intel_global_histogram {
> +	INTEL_HISTOGRAM,
> +};
> +
> +enum intel_global_hist_lut {
> +	INTEL_HISTOGRAM_PIXEL_FACTOR,
> +};
> +
> +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc); int
> +intel_histogram_update(struct intel_crtc *intel_crtc, bool enable); int
> +intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32 *data);
> +int intel_histogram_init(struct intel_crtc *intel_crtc); void
> +intel_histogram_deinit(struct intel_crtc *intel_crtc);
> +
> +#endif /* __INTEL_HISTOGRAM_H__ */
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile index
> b9670ae09a9e..424ea43016dd 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -238,6 +238,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
>  	i915-display/intel_hdcp.o \
>  	i915-display/intel_hdcp_gsc_message.o \
>  	i915-display/intel_hdmi.o \
> +	i915-display/intel_histogram.o \
>  	i915-display/intel_hotplug.o \
>  	i915-display/intel_hotplug_irq.o \
>  	i915-display/intel_hti.o \

Lets try to separate xe and i915 changes into different patches as well as we can I know its tough to decouple some
Changes but the ones that can be done should be.

Regards,
Suraj Kandpal

> --
> 2.25.1
Suraj Kandpal Sept. 11, 2024, 9:45 a.m. UTC | #3 
> -----Original Message-----
> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of
> Kandpal, Suraj
> Sent: Wednesday, September 11, 2024 11:07 AM
> To: Murthy, Arun R <arun.r.murthy@intel.com>; intel-
> gfx@lists.freedesktop.org
> Cc: Murthy, Arun R <arun.r.murthy@intel.com>
> Subject: RE: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> 
> 
> 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of
> > Arun R Murthy
> > Sent: Wednesday, August 21, 2024 3:54 PM
> > To: intel-gfx@lists.freedesktop.org
> > Cc: Murthy, Arun R <arun.r.murthy@intel.com>
> > Subject: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> >
> > Statistics is generated from the image frame that is coming to display
> > and an event is sent to user after reading this histogram data.
> > This statistics/histogram is then shared with the user upon getting a
> > request from user. User can then use this histogram and generate an
> enhancement factor.
> > This enhancement factor can be multiplied/added with the incoming
> > pixel data frame.
> >
> > v2: forward declaration in header file along with error handling
> > (Jani)
> >
> > Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> > ---
> >  drivers/gpu/drm/i915/Makefile                 |   1 +
> >  .../drm/i915/display/intel_display_types.h    |   2 +
> >  .../gpu/drm/i915/display/intel_histogram.c    | 205 ++++++++++++++++++
> >  .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
> >  drivers/gpu/drm/xe/Makefile                   |   1 +
> >  5 files changed, 287 insertions(+)
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h
> >
> > diff --git a/drivers/gpu/drm/i915/Makefile
> > b/drivers/gpu/drm/i915/Makefile index c63fa2133ccb..03caf3a24966
> > 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -264,6 +264,7 @@ i915-y += \
> >  	display/intel_hdcp.o \
> >  	display/intel_hdcp_gsc.o \
> >  	display/intel_hdcp_gsc_message.o \
> > +	display/intel_histogram.o \
> >  	display/intel_hotplug.o \
> >  	display/intel_hotplug_irq.o \
> >  	display/intel_hti.o \
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index bd290536a1b7..79d34d6d537d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1537,6 +1537,8 @@ struct intel_crtc {
> >  	/* for loading single buffered registers during vblank */
> >  	struct pm_qos_request vblank_pm_qos;
> >
> > +	struct intel_histogram *histogram;
> > +
> >  #ifdef CONFIG_DEBUG_FS
> >  	struct intel_pipe_crc pipe_crc;
> >  #endif
> > diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c
> > b/drivers/gpu/drm/i915/display/intel_histogram.c
> > new file mode 100644
> > index 000000000000..45e968e00af6
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> > @@ -0,0 +1,205 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2024 Intel Corporation  */
> > +
> > +#include <drm/drm_device.h>
> > +#include <drm/drm_file.h>
> > +
> > +#include "i915_reg.h"
> > +#include "i915_drv.h"
> > +#include "intel_display.h"
> > +#include "intel_histogram.h"
> > +#include "intel_display_types.h"
> > +#include "intel_de.h"
> > +
> > +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    // 3.0% of
> the
> > pipe's current pixel count.
> > +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   //
> Precision
> > factor for threshold guardband.
> > +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> > +
> > +struct intel_histogram {
> > +	struct drm_i915_private *i915;
> 
> Lets use intel_display here instead of i915 as I can see this is mostly being
> used for reg read/writes Read/write/rmw also work with intel_display well.
> 

On another look I believe intel_display also is not required here I see intel_crtc is available
Almost everywhere hence you can derive it with to_intel_display(crtc)
And derive drm_i915_private wherever we cant avoid it with to_i915(display->drm)

Regards,
Suraj Kandpal

> > +	bool enable;
> > +	bool can_enable;
> > +	enum pipe pipe;
> > +	u32 bindata[HISTOGRAM_BIN_COUNT];
> > +};
> > +
> > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +
> > +	/* TODO: Restrictions for enabling histogram */
> > +	histogram->can_enable = true;
> > +
> > +	return 0;
> > +}
> > +
> > +static void intel_histogram_enable_dithering(struct drm_i915_private
> > *dev_priv,
> 
> Use intel_display here
> > +					     enum pipe pipe)
> > +{
> > +	intel_de_rmw(dev_priv, PIPE_MISC(pipe),
> PIPE_MISC_DITHER_ENABLE,
> > +		     PIPE_MISC_DITHER_ENABLE);
> 
> So every where below drm_i915_private can be replaced with intel_display
> Ditto.
> 
> > +}
> > +
> > +static int intel_histogram_enable(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	int pipe = intel_crtc->pipe;
> > +	u64 res;
> > +	u32 gbandthreshold;
> > +
> > +	if (!histogram)
> > +		return -EINVAL;
> > +
> > +	if (!histogram->can_enable) {
> > +		return -EINVAL;
> > +	}
> 
> No need for brackets here now atleast
> 
> > +
> > +	if (histogram->enable)
> > +		return 0;
> > +
> > +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> > +	intel_histogram_enable_dithering(i915, pipe);
> > +
> > +	/*
> > +	 * enable DPST_CTL Histogram mode
> > +	 * Clear DPST_CTL Bin Reg function select to TC
> > +	 */
> 
> Nit: maybe make it Enable DPST... and If we are mentioning the steps lets
> add some number or points(-)
> 
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_IE_HIST_EN |
> > +		     DPST_CTL_HIST_MODE |
> > DPST_CTL_IE_TABLE_VALUE_FORMAT,
> > +		     DPST_CTL_BIN_REG_FUNC_TC | DPST_CTL_IE_HIST_EN |
> > +		     DPST_CTL_HIST_MODE_HSV |
> > +		     DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC);
> > +
> > +	/* Re-Visit: check if wait for one vblank is required */
> > +	drm_crtc_wait_one_vblank(&intel_crtc->base);
> > +
> > +	/* TODO: one time programming: Program GuardBand Threshold */
> > +	res = (intel_crtc->config->hw.adjusted_mode.vtotal *
> > +				intel_crtc->config-
> >hw.adjusted_mode.htotal);
> > +	gbandthreshold = (res *
> > 	HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT) /
> > +
> > 	HISTOGRAM_GUARDBAND_PRECISION_FACTOR;
> > +
> > +	/* Enable histogram interrupt mode */
> > +	intel_de_rmw(i915, DPST_GUARD(pipe),
> > +		     DPST_GUARD_THRESHOLD_GB_MASK |
> > +		     DPST_GUARD_INTERRUPT_DELAY_MASK |
> > DPST_GUARD_HIST_INT_EN,
> > +		     DPST_GUARD_THRESHOLD_GB(gbandthreshold) |
> > +
> >
> DPST_GUARD_INTERRUPT_DELAY(HISTOGRAM_DEFAULT_GUARDBAND_DELA
> Y)
> > |
> > +		     DPST_GUARD_HIST_INT_EN);
> > +
> > +	/* Clear pending interrupts has to be done on separate write */
> > +	intel_de_rmw(i915, DPST_GUARD(pipe),
> > +		     DPST_GUARD_HIST_EVENT_STATUS, 1);
> > +
> > +	histogram->enable = true;
> > +
> > +	return 0;
> > +}
> > +
> > +static void intel_histogram_disable(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	int pipe = intel_crtc->pipe;
> > +
> > +	if (!histogram)
> > +		return;
> > +
> > +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> > +	intel_histogram_enable_dithering(i915, pipe);
> > +
> > +	/* Clear pending interrupts and disable interrupts */
> > +	intel_de_rmw(i915, DPST_GUARD(pipe),
> > +		     DPST_GUARD_HIST_INT_EN |
> > DPST_GUARD_HIST_EVENT_STATUS, 0);
> > +
> > +	/* disable DPST_CTL Histogram mode */
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_IE_HIST_EN, 0);
> > +
> > +	histogram->enable = false;
> > +}
> > +
> > +int intel_histogram_update(struct intel_crtc *intel_crtc, bool
> > +enable) {
> > +	if (enable)
> > +		return intel_histogram_enable(intel_crtc);
> > +
> > +	intel_histogram_disable(intel_crtc);
> > +	return 0;
> > +}
> > +
> > +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32
> > +*data) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	int pipe = intel_crtc->pipe;
> > +	int i = 0;
> > +
> > +	if (!histogram)
> > +		return -EINVAL;
> > +
> > +	if (!histogram->enable) {
> > +		drm_err(&i915->drm, "histogram not enabled");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (!data) {
> > +		drm_err(&i915->drm, "enhancement LUT data is NULL");
> > +		return -EINVAL;
> > +	}
> > +
> > +	/*
> > +	 * Set DPST_CTL Bin Reg function select to IE
> > +	 * Set DPST_CTL Bin Register Index to 0
> > +	 */
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_BIN_REG_FUNC_SEL |
> DPST_CTL_BIN_REG_MASK,
> > +		     DPST_CTL_BIN_REG_FUNC_IE |
> DPST_CTL_BIN_REG_CLEAR);
> > +
> > +	for (i = 0; i < HISTOGRAM_IET_LENGTH; i++) {
> > +		intel_de_rmw(i915, DPST_BIN(pipe),
> > +			     DPST_BIN_DATA_MASK, data[i]);
> > +		drm_dbg_atomic(&i915->drm, "iet_lut[%d]=%x\n", i, data[i]);
> > +	}
> > +
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_ENHANCEMENT_MODE_MASK |
> > DPST_CTL_IE_MODI_TABLE_EN,
> > +		     DPST_CTL_EN_MULTIPLICATIVE |
> > DPST_CTL_IE_MODI_TABLE_EN);
> > +
> > +	/* Once IE is applied, change DPST CTL to TC */
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_BIN_REG_FUNC_SEL,
> > DPST_CTL_BIN_REG_FUNC_TC);
> > +
> > +	return 0;
> > +}
> > +
> > +void intel_histogram_deinit(struct intel_crtc *intel_crtc) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +
> > +	kfree(histogram);
> > +}
> > +
> > +int intel_histogram_init(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram;
> > +
> > +	/* Allocate histogram internal struct */
> > +	histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
> > +	if (!histogram) {
> > +		return -ENOMEM;
> > +	}
> > +
> > +	intel_crtc->histogram = histogram;
> > +	histogram->pipe = intel_crtc->pipe;
> > +	histogram->can_enable = false;
> > +
> > +	histogram->i915 = i915;
> > +
> > +	return 0;
> > +}
> > diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h
> > b/drivers/gpu/drm/i915/display/intel_histogram.h
> > new file mode 100644
> > index 000000000000..b25091732274
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_histogram.h
> > @@ -0,0 +1,78 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2024 Intel Corporation  */
> > +
> > +#ifndef __INTEL_HISTOGRAM_H__
> > +#define __INTEL_HISTOGRAM_H__
> > +
> > +#include <linux/types.h>
> > +
> > +struct intel_crtc;
> > +
> > +/* GLOBAL_HIST related registers */
> > +#define _DPST_CTL_A					0x490C0
> > +#define _DPST_CTL_B					0x491C0
> > +#define DPST_CTL(pipe)
> > 	_MMIO_PIPE(pipe, _DPST_CTL_A, _DPST_CTL_B)
> > +#define DPST_CTL_IE_HIST_EN				REG_BIT(31)
> > +#define DPST_CTL_RESTORE				REG_BIT(28)
> > +#define DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
> > +#define DPST_CTL_HIST_MODE				REG_BIT(24)
> > +#define DPST_CTL_ENHANCEMENT_MODE_MASK
> > 	REG_GENMASK(14, 13)
> > +#define DPST_CTL_EN_MULTIPLICATIVE
> > 	REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
> > +#define DPST_CTL_IE_TABLE_VALUE_FORMAT
> 	REG_BIT(15)
> > +#define DPST_CTL_BIN_REG_FUNC_SEL			REG_BIT(11)
> > +#define DPST_CTL_BIN_REG_FUNC_TC
> > 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 0)
> > +#define DPST_CTL_BIN_REG_FUNC_IE
> > 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 1)
> > +#define DPST_CTL_BIN_REG_MASK
> > 	REG_GENMASK(6, 0)
> > +#define DPST_CTL_BIN_REG_CLEAR
> > 	REG_FIELD_PREP(DPST_CTL_BIN_REG_MASK, 0)
> > +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_2INT_8FRAC
> > 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 1)
> > +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC
> > 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 0)
> > +#define DPST_CTL_HIST_MODE_YUV
> > 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 0)
> > +#define DPST_CTL_HIST_MODE_HSV
> > 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 1)
> > +
> > +#define _DPST_GUARD_A					0x490C8
> > +#define _DPST_GUARD_B					0x491C8
> > +#define DPST_GUARD(pipe)				_MMIO_PIPE(pipe,
> > _DPST_GUARD_A, _DPST_GUARD_B)
> > +#define DPST_GUARD_HIST_INT_EN				REG_BIT(31)
> > +#define DPST_GUARD_HIST_EVENT_STATUS			REG_BIT(30)
> > +#define DPST_GUARD_INTERRUPT_DELAY_MASK
> > 	REG_GENMASK(29, 22)
> > +#define DPST_GUARD_INTERRUPT_DELAY(val)
> > 	REG_FIELD_PREP(DPST_GUARD_INTERRUPT_DELAY_MASK, val)
> > +#define DPST_GUARD_THRESHOLD_GB_MASK
> > 	REG_GENMASK(21, 0)
> > +#define DPST_GUARD_THRESHOLD_GB(val)
> > 	REG_FIELD_PREP(DPST_GUARD_THRESHOLD_GB_MASK, val)
> > +
> > +#define _DPST_BIN_A					0x490C4
> > +#define _DPST_BIN_B					0x491C4
> > +#define DPST_BIN(pipe)
> > 	_MMIO_PIPE(pipe, _DPST_BIN_A, _DPST_BIN_B)
> > +#define DPST_BIN_DATA_MASK
> > 	REG_GENMASK(23, 0)
> > +#define DPST_BIN_BUSY					REG_BIT(31)
> > +
> > +#define INTEL_HISTOGRAM_PIPEA			0x90000000
> > +#define INTEL_HISTOGRAM_PIPEB			0x90000002
> > +#define INTEL_HISTOGRAM_EVENT(pipe)		PIPE(pipe, \
> > +						     INTEL_HISTOGRAM_PIPEA,
> \
> > +						     INTEL_HISTOGRAM_PIPEB)
> 
> I don't think this is the right way. Lets have a file for intel_histogram_regs.h
> and intel_histogram.h That will look a lot cleaner.
> 
> > +
> > +#define HISTOGRAM_BIN_COUNT			32
> > +#define HISTOGRAM_IET_LENGTH			33
> > +
> > +enum intel_global_hist_status {
> > +	INTEL_HISTOGRAM_ENABLE,
> > +	INTEL_HISTOGRAM_DISABLE,
> > +};
> > +
> > +enum intel_global_histogram {
> > +	INTEL_HISTOGRAM,
> > +};
> > +
> > +enum intel_global_hist_lut {
> > +	INTEL_HISTOGRAM_PIXEL_FACTOR,
> > +};
> > +
> > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc); int
> > +intel_histogram_update(struct intel_crtc *intel_crtc, bool enable);
> > +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32
> > +*data); int intel_histogram_init(struct intel_crtc *intel_crtc); void
> > +intel_histogram_deinit(struct intel_crtc *intel_crtc);
> > +
> > +#endif /* __INTEL_HISTOGRAM_H__ */
> > diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> > index b9670ae09a9e..424ea43016dd 100644
> > --- a/drivers/gpu/drm/xe/Makefile
> > +++ b/drivers/gpu/drm/xe/Makefile
> > @@ -238,6 +238,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
> >  	i915-display/intel_hdcp.o \
> >  	i915-display/intel_hdcp_gsc_message.o \
> >  	i915-display/intel_hdmi.o \
> > +	i915-display/intel_histogram.o \
> >  	i915-display/intel_hotplug.o \
> >  	i915-display/intel_hotplug_irq.o \
> >  	i915-display/intel_hti.o \
> 
> Lets try to separate xe and i915 changes into different patches as well as we
> can I know its tough to decouple some Changes but the ones that can be
> done should be.
> 
> Regards,
> Suraj Kandpal
> 
> > --
> > 2.25.1
Murthy, Arun R Sept. 12, 2024, 9:08 a.m. UTC | #4 
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of
> > Arun R Murthy
> > Sent: Wednesday, August 21, 2024 3:54 PM
> > To: intel-gfx@lists.freedesktop.org
> > Cc: Murthy, Arun R <arun.r.murthy@intel.com>
> > Subject: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> >
> > Statistics is generated from the image frame that is coming to display
> > and an event is sent to user after reading this histogram data.
> > This statistics/histogram is then shared with the user upon getting a
> > request from user. User can then use this histogram and generate an
> > enhancement factor. This enhancement factor can be multiplied/added
> > with the incoming pixel data frame.
> >
> > v2: forward declaration in header file along with error handling
> > (Jani)
> >
> > Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> > ---
> >  drivers/gpu/drm/i915/Makefile                 |   1 +
> >  .../drm/i915/display/intel_display_types.h    |   2 +
> >  .../gpu/drm/i915/display/intel_histogram.c    | 205 ++++++++++++++++++
> >  .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
> >  drivers/gpu/drm/xe/Makefile                   |   1 +
> >  5 files changed, 287 insertions(+)
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
> >  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h
> >
> > diff --git a/drivers/gpu/drm/i915/Makefile
> > b/drivers/gpu/drm/i915/Makefile index c63fa2133ccb..03caf3a24966
> > 100644
> > --- a/drivers/gpu/drm/i915/Makefile
> > +++ b/drivers/gpu/drm/i915/Makefile
> > @@ -264,6 +264,7 @@ i915-y += \
> >  	display/intel_hdcp.o \
> >  	display/intel_hdcp_gsc.o \
> >  	display/intel_hdcp_gsc_message.o \
> > +	display/intel_histogram.o \
> >  	display/intel_hotplug.o \
> >  	display/intel_hotplug_irq.o \
> >  	display/intel_hti.o \
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index bd290536a1b7..79d34d6d537d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1537,6 +1537,8 @@ struct intel_crtc {
> >  	/* for loading single buffered registers during vblank */
> >  	struct pm_qos_request vblank_pm_qos;
> >
> > +	struct intel_histogram *histogram;
> > +
> >  #ifdef CONFIG_DEBUG_FS
> >  	struct intel_pipe_crc pipe_crc;
> >  #endif
> > diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c
> > b/drivers/gpu/drm/i915/display/intel_histogram.c
> > new file mode 100644
> > index 000000000000..45e968e00af6
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> > @@ -0,0 +1,205 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2024 Intel Corporation  */
> > +
> > +#include <drm/drm_device.h>
> > +#include <drm/drm_file.h>
> > +
> > +#include "i915_reg.h"
> > +#include "i915_drv.h"
> > +#include "intel_display.h"
> > +#include "intel_histogram.h"
> > +#include "intel_display_types.h"
> > +#include "intel_de.h"
> > +
> > +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    // 3.0% of
> > the pipe's current pixel count.
> > +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   // Precision
> > factor for threshold guardband.
> > +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> > +
> > +struct intel_histogram {
> > +	struct drm_i915_private *i915;
> > +	bool enable;
> > +	bool can_enable;
> > +	enum pipe pipe;
> > +	u32 bindata[HISTOGRAM_BIN_COUNT];
> > +};
> > +
> > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +
> > +	/* TODO: Restrictions for enabling histogram */
> > +	histogram->can_enable = true;
> > +
> > +	return 0;
> > +}
> > +
> Looks like we are totally bypassing crtc_state->dither.
> Also I see some comments on dither not being enabled on anything which is
> not 6bpc. Is that constraint resolved now?
> 

Crtc_state->dither is used for enabling dithering during the crtc_enable and at this point we are far ahead of that.
That restriction is for older platforms(ironlake) and we don't have any such for ADLP+

> > +static void intel_histogram_enable_dithering(struct drm_i915_private
> > *dev_priv,
> > +					     enum pipe pipe)
> > +{
> > +	intel_de_rmw(dev_priv, PIPE_MISC(pipe),
> > PIPE_MISC_DITHER_ENABLE,
> > +		     PIPE_MISC_DITHER_ENABLE);
> > +}
> > +
> > +static int intel_histogram_enable(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	int pipe = intel_crtc->pipe;
> > +	u64 res;
> > +	u32 gbandthreshold;
> > +
> > +	if (!histogram)
> > +		return -EINVAL;
> > +
> > +	if (!histogram->can_enable) {
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (histogram->enable)
> > +		return 0;
> > +
> I don't see in the spec that dither should be enabled, any quick bspec
> references?
Dithering should be enabled by default for ADL+ for DPST. This is an enhancement to avoid artifacts.

Thanks and Regards,
Arun R Murthy
--------------------
Jani Nikula Sept. 12, 2024, 9:45 a.m. UTC | #5 
On Wed, 21 Aug 2024, Arun R Murthy <arun.r.murthy@intel.com> wrote:
> Statistics is generated from the image frame that is coming to display
> and an event is sent to user after reading this histogram data.
> This statistics/histogram is then shared with the user upon getting a
> request from user. User can then use this histogram and generate an
> enhancement factor. This enhancement factor can be multiplied/added with
> the incoming pixel data frame.
>
> v2: forward declaration in header file along with error handling (Jani)
>
> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile                 |   1 +
>  .../drm/i915/display/intel_display_types.h    |   2 +
>  .../gpu/drm/i915/display/intel_histogram.c    | 205 ++++++++++++++++++
>  .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
>  drivers/gpu/drm/xe/Makefile                   |   1 +
>  5 files changed, 287 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
>  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h
>
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index c63fa2133ccb..03caf3a24966 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -264,6 +264,7 @@ i915-y += \
>  	display/intel_hdcp.o \
>  	display/intel_hdcp_gsc.o \
>  	display/intel_hdcp_gsc_message.o \
> +	display/intel_histogram.o \
>  	display/intel_hotplug.o \
>  	display/intel_hotplug_irq.o \
>  	display/intel_hti.o \
> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
> index bd290536a1b7..79d34d6d537d 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> @@ -1537,6 +1537,8 @@ struct intel_crtc {
>  	/* for loading single buffered registers during vblank */
>  	struct pm_qos_request vblank_pm_qos;
>  
> +	struct intel_histogram *histogram;
> +
>  #ifdef CONFIG_DEBUG_FS
>  	struct intel_pipe_crc pipe_crc;
>  #endif
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c b/drivers/gpu/drm/i915/display/intel_histogram.c
> new file mode 100644
> index 000000000000..45e968e00af6
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> @@ -0,0 +1,205 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#include <drm/drm_device.h>
> +#include <drm/drm_file.h>
> +
> +#include "i915_reg.h"
> +#include "i915_drv.h"
> +#include "intel_display.h"
> +#include "intel_histogram.h"
> +#include "intel_display_types.h"
> +#include "intel_de.h"
> +
> +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    // 3.0% of the pipe's current pixel count.
> +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   // Precision factor for threshold guardband.
> +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> +
> +struct intel_histogram {
> +	struct drm_i915_private *i915;
> +	bool enable;
> +	bool can_enable;
> +	enum pipe pipe;
> +	u32 bindata[HISTOGRAM_BIN_COUNT];
> +};
> +
> +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc)
> +{
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +
> +	/* TODO: Restrictions for enabling histogram */
> +	histogram->can_enable = true;
> +
> +	return 0;
> +}
> +
> +static void intel_histogram_enable_dithering(struct drm_i915_private *dev_priv,
> +					     enum pipe pipe)
> +{
> +	intel_de_rmw(dev_priv, PIPE_MISC(pipe), PIPE_MISC_DITHER_ENABLE,
> +		     PIPE_MISC_DITHER_ENABLE);
> +}
> +
> +static int intel_histogram_enable(struct intel_crtc *intel_crtc)
> +{
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	int pipe = intel_crtc->pipe;
> +	u64 res;
> +	u32 gbandthreshold;
> +
> +	if (!histogram)
> +		return -EINVAL;
> +
> +	if (!histogram->can_enable) {
> +		return -EINVAL;
> +	}
> +
> +	if (histogram->enable)
> +		return 0;
> +
> +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> +	intel_histogram_enable_dithering(i915, pipe);
> +
> +	/*
> +	 * enable DPST_CTL Histogram mode
> +	 * Clear DPST_CTL Bin Reg function select to TC
> +	 */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_IE_HIST_EN |
> +		     DPST_CTL_HIST_MODE | DPST_CTL_IE_TABLE_VALUE_FORMAT,
> +		     DPST_CTL_BIN_REG_FUNC_TC | DPST_CTL_IE_HIST_EN |
> +		     DPST_CTL_HIST_MODE_HSV |
> +		     DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC);
> +
> +	/* Re-Visit: check if wait for one vblank is required */
> +	drm_crtc_wait_one_vblank(&intel_crtc->base);
> +
> +	/* TODO: one time programming: Program GuardBand Threshold */
> +	res = (intel_crtc->config->hw.adjusted_mode.vtotal *
> +				intel_crtc->config->hw.adjusted_mode.htotal);
> +	gbandthreshold = (res *	HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT) /
> +				HISTOGRAM_GUARDBAND_PRECISION_FACTOR;
> +
> +	/* Enable histogram interrupt mode */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_THRESHOLD_GB_MASK |
> +		     DPST_GUARD_INTERRUPT_DELAY_MASK | DPST_GUARD_HIST_INT_EN,
> +		     DPST_GUARD_THRESHOLD_GB(gbandthreshold) |
> +		     DPST_GUARD_INTERRUPT_DELAY(HISTOGRAM_DEFAULT_GUARDBAND_DELAY) |
> +		     DPST_GUARD_HIST_INT_EN);
> +
> +	/* Clear pending interrupts has to be done on separate write */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_HIST_EVENT_STATUS, 1);
> +
> +	histogram->enable = true;
> +
> +	return 0;
> +}
> +
> +static void intel_histogram_disable(struct intel_crtc *intel_crtc)
> +{
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	int pipe = intel_crtc->pipe;
> +
> +	if (!histogram)
> +		return;
> +
> +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> +	intel_histogram_enable_dithering(i915, pipe);
> +
> +	/* Clear pending interrupts and disable interrupts */
> +	intel_de_rmw(i915, DPST_GUARD(pipe),
> +		     DPST_GUARD_HIST_INT_EN | DPST_GUARD_HIST_EVENT_STATUS, 0);
> +
> +	/* disable DPST_CTL Histogram mode */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_IE_HIST_EN, 0);
> +
> +	histogram->enable = false;
> +}
> +
> +int intel_histogram_update(struct intel_crtc *intel_crtc, bool enable)
> +{
> +	if (enable)
> +		return intel_histogram_enable(intel_crtc);
> +
> +	intel_histogram_disable(intel_crtc);
> +	return 0;
> +}
> +
> +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32 *data)
> +{
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	int pipe = intel_crtc->pipe;
> +	int i = 0;
> +
> +	if (!histogram)
> +		return -EINVAL;
> +
> +	if (!histogram->enable) {
> +		drm_err(&i915->drm, "histogram not enabled");
> +		return -EINVAL;
> +	}
> +
> +	if (!data) {
> +		drm_err(&i915->drm, "enhancement LUT data is NULL");
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * Set DPST_CTL Bin Reg function select to IE
> +	 * Set DPST_CTL Bin Register Index to 0
> +	 */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_BIN_REG_MASK,
> +		     DPST_CTL_BIN_REG_FUNC_IE | DPST_CTL_BIN_REG_CLEAR);
> +
> +	for (i = 0; i < HISTOGRAM_IET_LENGTH; i++) {
> +		intel_de_rmw(i915, DPST_BIN(pipe),
> +			     DPST_BIN_DATA_MASK, data[i]);
> +		drm_dbg_atomic(&i915->drm, "iet_lut[%d]=%x\n", i, data[i]);
> +	}
> +
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_ENHANCEMENT_MODE_MASK | DPST_CTL_IE_MODI_TABLE_EN,
> +		     DPST_CTL_EN_MULTIPLICATIVE | DPST_CTL_IE_MODI_TABLE_EN);
> +
> +	/* Once IE is applied, change DPST CTL to TC */
> +	intel_de_rmw(i915, DPST_CTL(pipe),
> +		     DPST_CTL_BIN_REG_FUNC_SEL, DPST_CTL_BIN_REG_FUNC_TC);
> +
> +	return 0;
> +}
> +
> +void intel_histogram_deinit(struct intel_crtc *intel_crtc)
> +{
> +	struct intel_histogram *histogram = intel_crtc->histogram;
> +
> +	kfree(histogram);
> +}
> +
> +int intel_histogram_init(struct intel_crtc *intel_crtc)
> +{
> +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> +	struct intel_histogram *histogram;
> +
> +	/* Allocate histogram internal struct */
> +	histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
> +	if (!histogram) {
> +		return -ENOMEM;
> +	}
> +
> +	intel_crtc->histogram = histogram;
> +	histogram->pipe = intel_crtc->pipe;
> +	histogram->can_enable = false;
> +
> +	histogram->i915 = i915;
> +
> +	return 0;
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h b/drivers/gpu/drm/i915/display/intel_histogram.h
> new file mode 100644
> index 000000000000..b25091732274
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/display/intel_histogram.h
> @@ -0,0 +1,78 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#ifndef __INTEL_HISTOGRAM_H__
> +#define __INTEL_HISTOGRAM_H__
> +
> +#include <linux/types.h>
> +
> +struct intel_crtc;
> +
> +/* GLOBAL_HIST related registers */
> +#define _DPST_CTL_A					0x490C0
> +#define _DPST_CTL_B					0x491C0
> +#define DPST_CTL(pipe)					_MMIO_PIPE(pipe, _DPST_CTL_A, _DPST_CTL_B)
> +#define DPST_CTL_IE_HIST_EN				REG_BIT(31)
> +#define DPST_CTL_RESTORE				REG_BIT(28)
> +#define DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
> +#define DPST_CTL_HIST_MODE				REG_BIT(24)
> +#define DPST_CTL_ENHANCEMENT_MODE_MASK			REG_GENMASK(14, 13)
> +#define DPST_CTL_EN_MULTIPLICATIVE			REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT			REG_BIT(15)
> +#define DPST_CTL_BIN_REG_FUNC_SEL			REG_BIT(11)
> +#define DPST_CTL_BIN_REG_FUNC_TC			REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 0)
> +#define DPST_CTL_BIN_REG_FUNC_IE			REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 1)
> +#define DPST_CTL_BIN_REG_MASK				REG_GENMASK(6, 0)
> +#define DPST_CTL_BIN_REG_CLEAR				REG_FIELD_PREP(DPST_CTL_BIN_REG_MASK, 0)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_2INT_8FRAC	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 1)
> +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 0)
> +#define DPST_CTL_HIST_MODE_YUV				REG_FIELD_PREP(DPST_CTL_HIST_MODE, 0)
> +#define DPST_CTL_HIST_MODE_HSV				REG_FIELD_PREP(DPST_CTL_HIST_MODE, 1)
> +
> +#define _DPST_GUARD_A					0x490C8
> +#define _DPST_GUARD_B					0x491C8
> +#define DPST_GUARD(pipe)				_MMIO_PIPE(pipe, _DPST_GUARD_A, _DPST_GUARD_B)
> +#define DPST_GUARD_HIST_INT_EN				REG_BIT(31)
> +#define DPST_GUARD_HIST_EVENT_STATUS			REG_BIT(30)
> +#define DPST_GUARD_INTERRUPT_DELAY_MASK			REG_GENMASK(29, 22)
> +#define DPST_GUARD_INTERRUPT_DELAY(val)			REG_FIELD_PREP(DPST_GUARD_INTERRUPT_DELAY_MASK, val)
> +#define DPST_GUARD_THRESHOLD_GB_MASK			REG_GENMASK(21, 0)
> +#define DPST_GUARD_THRESHOLD_GB(val)			REG_FIELD_PREP(DPST_GUARD_THRESHOLD_GB_MASK, val)
> +
> +#define _DPST_BIN_A					0x490C4
> +#define _DPST_BIN_B					0x491C4
> +#define DPST_BIN(pipe)					_MMIO_PIPE(pipe, _DPST_BIN_A, _DPST_BIN_B)
> +#define DPST_BIN_DATA_MASK				REG_GENMASK(23, 0)
> +#define DPST_BIN_BUSY					REG_BIT(31)
> +
> +#define INTEL_HISTOGRAM_PIPEA			0x90000000
> +#define INTEL_HISTOGRAM_PIPEB			0x90000002
> +#define INTEL_HISTOGRAM_EVENT(pipe)		PIPE(pipe, \
> +						     INTEL_HISTOGRAM_PIPEA, \
> +						     INTEL_HISTOGRAM_PIPEB)
> +
> +#define HISTOGRAM_BIN_COUNT			32
> +#define HISTOGRAM_IET_LENGTH			33
> +

Please put registers in a separate _regs.h file.

> +enum intel_global_hist_status {
> +	INTEL_HISTOGRAM_ENABLE,
> +	INTEL_HISTOGRAM_DISABLE,
> +};
> +
> +enum intel_global_histogram {
> +	INTEL_HISTOGRAM,
> +};
> +
> +enum intel_global_hist_lut {
> +	INTEL_HISTOGRAM_PIXEL_FACTOR,
> +};
> +
> +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc);
> +int intel_histogram_update(struct intel_crtc *intel_crtc, bool enable);
> +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32 *data);
> +int intel_histogram_init(struct intel_crtc *intel_crtc);
> +void intel_histogram_deinit(struct intel_crtc *intel_crtc);
> +
> +#endif /* __INTEL_HISTOGRAM_H__ */
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index b9670ae09a9e..424ea43016dd 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -238,6 +238,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
>  	i915-display/intel_hdcp.o \
>  	i915-display/intel_hdcp_gsc_message.o \
>  	i915-display/intel_hdmi.o \
> +	i915-display/intel_histogram.o \
>  	i915-display/intel_hotplug.o \
>  	i915-display/intel_hotplug_irq.o \
>  	i915-display/intel_hti.o \
Kulkarni, Vandita Sept. 12, 2024, 10:17 a.m. UTC | #6 
> -----Original Message-----
> From: Murthy, Arun R <arun.r.murthy@intel.com>
> Sent: Thursday, September 12, 2024 2:39 PM
> To: Kulkarni, Vandita <vandita.kulkarni@intel.com>; intel-
> gfx@lists.freedesktop.org
> Subject: RE: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> 
> > > -----Original Message-----
> > > From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf
> > > Of Arun R Murthy
> > > Sent: Wednesday, August 21, 2024 3:54 PM
> > > To: intel-gfx@lists.freedesktop.org
> > > Cc: Murthy, Arun R <arun.r.murthy@intel.com>
> > > Subject: [PATCHv2 1/5] drm/i915/display: Add support for histogram
> > >
> > > Statistics is generated from the image frame that is coming to
> > > display and an event is sent to user after reading this histogram data.
> > > This statistics/histogram is then shared with the user upon getting
> > > a request from user. User can then use this histogram and generate
> > > an enhancement factor. This enhancement factor can be
> > > multiplied/added with the incoming pixel data frame.
> > >
> > > v2: forward declaration in header file along with error handling
> > > (Jani)
> > >
> > > Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/Makefile                 |   1 +
> > >  .../drm/i915/display/intel_display_types.h    |   2 +
> > >  .../gpu/drm/i915/display/intel_histogram.c    | 205
> ++++++++++++++++++
> > >  .../gpu/drm/i915/display/intel_histogram.h    |  78 +++++++
> > >  drivers/gpu/drm/xe/Makefile                   |   1 +
> > >  5 files changed, 287 insertions(+)
> > >  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.c
> > >  create mode 100644 drivers/gpu/drm/i915/display/intel_histogram.h
> > >
> > > diff --git a/drivers/gpu/drm/i915/Makefile
> > > b/drivers/gpu/drm/i915/Makefile index c63fa2133ccb..03caf3a24966
> > > 100644
> > > --- a/drivers/gpu/drm/i915/Makefile
> > > +++ b/drivers/gpu/drm/i915/Makefile
> > > @@ -264,6 +264,7 @@ i915-y += \
> > >  	display/intel_hdcp.o \
> > >  	display/intel_hdcp_gsc.o \
> > >  	display/intel_hdcp_gsc_message.o \
> > > +	display/intel_histogram.o \
> > >  	display/intel_hotplug.o \
> > >  	display/intel_hotplug_irq.o \
> > >  	display/intel_hti.o \
> > > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > index bd290536a1b7..79d34d6d537d 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > > @@ -1537,6 +1537,8 @@ struct intel_crtc {
> > >  	/* for loading single buffered registers during vblank */
> > >  	struct pm_qos_request vblank_pm_qos;
> > >
> > > +	struct intel_histogram *histogram;
> > > +
> > >  #ifdef CONFIG_DEBUG_FS
> > >  	struct intel_pipe_crc pipe_crc;
> > >  #endif
> > > diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c
> > > b/drivers/gpu/drm/i915/display/intel_histogram.c
> > > new file mode 100644
> > > index 000000000000..45e968e00af6
> > > --- /dev/null
> > > +++ b/drivers/gpu/drm/i915/display/intel_histogram.c
> > > @@ -0,0 +1,205 @@
> > > +// SPDX-License-Identifier: MIT
> > > +/*
> > > + * Copyright © 2024 Intel Corporation  */
> > > +
> > > +#include <drm/drm_device.h>
> > > +#include <drm/drm_file.h>
> > > +
> > > +#include "i915_reg.h"
> > > +#include "i915_drv.h"
> > > +#include "intel_display.h"
> > > +#include "intel_histogram.h"
> > > +#include "intel_display_types.h"
> > > +#include "intel_de.h"
> > > +
> > > +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    //
> 3.0% of
> > > the pipe's current pixel count.
> > > +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   //
> Precision
> > > factor for threshold guardband.
> > > +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> > > +
> > > +struct intel_histogram {
> > > +	struct drm_i915_private *i915;
> > > +	bool enable;
> > > +	bool can_enable;
> > > +	enum pipe pipe;
> > > +	u32 bindata[HISTOGRAM_BIN_COUNT];
> > > +};
> > > +
> > > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> > > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > > +
> > > +	/* TODO: Restrictions for enabling histogram */
> > > +	histogram->can_enable = true;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > Looks like we are totally bypassing crtc_state->dither.
> > Also I see some comments on dither not being enabled on anything which
> > is not 6bpc. Is that constraint resolved now?
> >
> 
> Crtc_state->dither is used for enabling dithering during the crtc_enable and
> at this point we are far ahead of that.
> That restriction is for older platforms(ironlake) and we don't have any such
> for ADLP+

My first point was why do you need to enable it again separately, if it has been already taken care by crtc_state->dither
And second point was, can you please share the bsepc link where we have this requirement of enabling it again, even it it was enabled.

Thanks
Vandita
> 
> > > +static void intel_histogram_enable_dithering(struct
> > > +drm_i915_private
> > > *dev_priv,
> > > +					     enum pipe pipe)
> > > +{
> > > +	intel_de_rmw(dev_priv, PIPE_MISC(pipe),
> > > PIPE_MISC_DITHER_ENABLE,
> > > +		     PIPE_MISC_DITHER_ENABLE);
> > > +}
> > > +
> > > +static int intel_histogram_enable(struct intel_crtc *intel_crtc) {
> > > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > > +	int pipe = intel_crtc->pipe;
> > > +	u64 res;
> > > +	u32 gbandthreshold;
> > > +
> > > +	if (!histogram)
> > > +		return -EINVAL;
> > > +
> > > +	if (!histogram->can_enable) {
> > > +		return -EINVAL;
> > > +	}
> > > +
> > > +	if (histogram->enable)
> > > +		return 0;
> > > +
> > I don't see in the spec that dither should be enabled, any quick bspec
> > references?
> Dithering should be enabled by default for ADL+ for DPST. This is an
> enhancement to avoid artifacts.
> 
> Thanks and Regards,
> Arun R Murthy
> --------------------
Murthy, Arun R Sept. 15, 2024, 4:59 a.m. UTC | #7 
> > pipe's current pixel count.
> > +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   // Precision
> > factor for threshold guardband.
> > +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> > +
> > +struct intel_histogram {
> > +	struct drm_i915_private *i915;
> 
> Lets use intel_display here instead of i915 as I can see this is mostly being used
> for reg read/writes Read/write/rmw also work with intel_display well.
> 
Sure!

> > +	bool enable;
> > +	bool can_enable;
> > +	enum pipe pipe;
> > +	u32 bindata[HISTOGRAM_BIN_COUNT];
> > +};
> > +
> > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +
> > +	/* TODO: Restrictions for enabling histogram */
> > +	histogram->can_enable = true;
> > +
> > +	return 0;
> > +}
> > +
> > +static void intel_histogram_enable_dithering(struct drm_i915_private
> > *dev_priv,
> 
> Use intel_display here
Done

> > +					     enum pipe pipe)
> > +{
> > +	intel_de_rmw(dev_priv, PIPE_MISC(pipe), PIPE_MISC_DITHER_ENABLE,
> > +		     PIPE_MISC_DITHER_ENABLE);
> 
> So every where below drm_i915_private can be replaced with intel_display
> Ditto.
> 
Done
> > +}
> > +
> > +static int intel_histogram_enable(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	int pipe = intel_crtc->pipe;
> > +	u64 res;
> > +	u32 gbandthreshold;
> > +
> > +	if (!histogram)
> > +		return -EINVAL;
> > +
> > +	if (!histogram->can_enable) {
> > +		return -EINVAL;
> > +	}
> 
> No need for brackets here now atleast
> 
Done

> > +
> > +	if (histogram->enable)
> > +		return 0;
> > +
> > +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> > +	intel_histogram_enable_dithering(i915, pipe);
> > +
> > +	/*
> > +	 * enable DPST_CTL Histogram mode
> > +	 * Clear DPST_CTL Bin Reg function select to TC
> > +	 */
> 
> Nit: maybe make it Enable DPST... and If we are mentioning the steps lets add
> some number or points(-)
> 
Done

> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_IE_HIST_EN |
> > +		     DPST_CTL_HIST_MODE |
> > DPST_CTL_IE_TABLE_VALUE_FORMAT,
> > +		     DPST_CTL_BIN_REG_FUNC_TC | DPST_CTL_IE_HIST_EN |
> > +		     DPST_CTL_HIST_MODE_HSV |
> > +		     DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC);
> > +
> > +	/* Re-Visit: check if wait for one vblank is required */
> > +	drm_crtc_wait_one_vblank(&intel_crtc->base);
> > +
> > +	/* TODO: one time programming: Program GuardBand Threshold */
> > +	res = (intel_crtc->config->hw.adjusted_mode.vtotal *
> > +				intel_crtc->config->hw.adjusted_mode.htotal);
> > +	gbandthreshold = (res *
> > 	HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT) /
> > +
> > 	HISTOGRAM_GUARDBAND_PRECISION_FACTOR;
> > +
> > +	/* Enable histogram interrupt mode */
> > +	intel_de_rmw(i915, DPST_GUARD(pipe),
> > +		     DPST_GUARD_THRESHOLD_GB_MASK |
> > +		     DPST_GUARD_INTERRUPT_DELAY_MASK |
> > DPST_GUARD_HIST_INT_EN,
> > +		     DPST_GUARD_THRESHOLD_GB(gbandthreshold) |
> > +
> >
> DPST_GUARD_INTERRUPT_DELAY(HISTOGRAM_DEFAULT_GUARDBAND_DELAY)
> > |
> > +		     DPST_GUARD_HIST_INT_EN);
> > +
> > +	/* Clear pending interrupts has to be done on separate write */
> > +	intel_de_rmw(i915, DPST_GUARD(pipe),
> > +		     DPST_GUARD_HIST_EVENT_STATUS, 1);
> > +
> > +	histogram->enable = true;
> > +
> > +	return 0;
> > +}
> > +
> > +static void intel_histogram_disable(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	int pipe = intel_crtc->pipe;
> > +
> > +	if (!histogram)
> > +		return;
> > +
> > +	/* Pipe Dithering should be enabled with GLOBAL_HIST */
> > +	intel_histogram_enable_dithering(i915, pipe);
> > +
> > +	/* Clear pending interrupts and disable interrupts */
> > +	intel_de_rmw(i915, DPST_GUARD(pipe),
> > +		     DPST_GUARD_HIST_INT_EN |
> > DPST_GUARD_HIST_EVENT_STATUS, 0);
> > +
> > +	/* disable DPST_CTL Histogram mode */
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_IE_HIST_EN, 0);
> > +
> > +	histogram->enable = false;
> > +}
> > +
> > +int intel_histogram_update(struct intel_crtc *intel_crtc, bool
> > +enable) {
> > +	if (enable)
> > +		return intel_histogram_enable(intel_crtc);
> > +
> > +	intel_histogram_disable(intel_crtc);
> > +	return 0;
> > +}
> > +
> > +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32
> > +*data) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	int pipe = intel_crtc->pipe;
> > +	int i = 0;
> > +
> > +	if (!histogram)
> > +		return -EINVAL;
> > +
> > +	if (!histogram->enable) {
> > +		drm_err(&i915->drm, "histogram not enabled");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (!data) {
> > +		drm_err(&i915->drm, "enhancement LUT data is NULL");
> > +		return -EINVAL;
> > +	}
> > +
> > +	/*
> > +	 * Set DPST_CTL Bin Reg function select to IE
> > +	 * Set DPST_CTL Bin Register Index to 0
> > +	 */
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_BIN_REG_FUNC_SEL |
> DPST_CTL_BIN_REG_MASK,
> > +		     DPST_CTL_BIN_REG_FUNC_IE |
> DPST_CTL_BIN_REG_CLEAR);
> > +
> > +	for (i = 0; i < HISTOGRAM_IET_LENGTH; i++) {
> > +		intel_de_rmw(i915, DPST_BIN(pipe),
> > +			     DPST_BIN_DATA_MASK, data[i]);
> > +		drm_dbg_atomic(&i915->drm, "iet_lut[%d]=%x\n", i, data[i]);
> > +	}
> > +
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_ENHANCEMENT_MODE_MASK |
> > DPST_CTL_IE_MODI_TABLE_EN,
> > +		     DPST_CTL_EN_MULTIPLICATIVE |
> > DPST_CTL_IE_MODI_TABLE_EN);
> > +
> > +	/* Once IE is applied, change DPST CTL to TC */
> > +	intel_de_rmw(i915, DPST_CTL(pipe),
> > +		     DPST_CTL_BIN_REG_FUNC_SEL,
> > DPST_CTL_BIN_REG_FUNC_TC);
> > +
> > +	return 0;
> > +}
> > +
> > +void intel_histogram_deinit(struct intel_crtc *intel_crtc) {
> > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > +
> > +	kfree(histogram);
> > +}
> > +
> > +int intel_histogram_init(struct intel_crtc *intel_crtc) {
> > +	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
> > +	struct intel_histogram *histogram;
> > +
> > +	/* Allocate histogram internal struct */
> > +	histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
> > +	if (!histogram) {
> > +		return -ENOMEM;
> > +	}
> > +
> > +	intel_crtc->histogram = histogram;
> > +	histogram->pipe = intel_crtc->pipe;
> > +	histogram->can_enable = false;
> > +
> > +	histogram->i915 = i915;
> > +
> > +	return 0;
> > +}
> > diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h
> > b/drivers/gpu/drm/i915/display/intel_histogram.h
> > new file mode 100644
> > index 000000000000..b25091732274
> > --- /dev/null
> > +++ b/drivers/gpu/drm/i915/display/intel_histogram.h
> > @@ -0,0 +1,78 @@
> > +// SPDX-License-Identifier: MIT
> > +/*
> > + * Copyright © 2024 Intel Corporation  */
> > +
> > +#ifndef __INTEL_HISTOGRAM_H__
> > +#define __INTEL_HISTOGRAM_H__
> > +
> > +#include <linux/types.h>
> > +
> > +struct intel_crtc;
> > +
> > +/* GLOBAL_HIST related registers */
> > +#define _DPST_CTL_A					0x490C0
> > +#define _DPST_CTL_B					0x491C0
> > +#define DPST_CTL(pipe)
> > 	_MMIO_PIPE(pipe, _DPST_CTL_A, _DPST_CTL_B)
> > +#define DPST_CTL_IE_HIST_EN				REG_BIT(31)
> > +#define DPST_CTL_RESTORE				REG_BIT(28)
> > +#define DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
> > +#define DPST_CTL_HIST_MODE				REG_BIT(24)
> > +#define DPST_CTL_ENHANCEMENT_MODE_MASK
> > 	REG_GENMASK(14, 13)
> > +#define DPST_CTL_EN_MULTIPLICATIVE
> > 	REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
> > +#define DPST_CTL_IE_TABLE_VALUE_FORMAT			REG_BIT(15)
> > +#define DPST_CTL_BIN_REG_FUNC_SEL			REG_BIT(11)
> > +#define DPST_CTL_BIN_REG_FUNC_TC
> > 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 0)
> > +#define DPST_CTL_BIN_REG_FUNC_IE
> > 	REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 1)
> > +#define DPST_CTL_BIN_REG_MASK
> > 	REG_GENMASK(6, 0)
> > +#define DPST_CTL_BIN_REG_CLEAR
> > 	REG_FIELD_PREP(DPST_CTL_BIN_REG_MASK, 0)
> > +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_2INT_8FRAC
> > 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 1)
> > +#define DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC
> > 	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 0)
> > +#define DPST_CTL_HIST_MODE_YUV
> > 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 0)
> > +#define DPST_CTL_HIST_MODE_HSV
> > 	REG_FIELD_PREP(DPST_CTL_HIST_MODE, 1)
> > +
> > +#define _DPST_GUARD_A					0x490C8
> > +#define _DPST_GUARD_B					0x491C8
> > +#define DPST_GUARD(pipe)				_MMIO_PIPE(pipe,
> > _DPST_GUARD_A, _DPST_GUARD_B)
> > +#define DPST_GUARD_HIST_INT_EN				REG_BIT(31)
> > +#define DPST_GUARD_HIST_EVENT_STATUS			REG_BIT(30)
> > +#define DPST_GUARD_INTERRUPT_DELAY_MASK
> > 	REG_GENMASK(29, 22)
> > +#define DPST_GUARD_INTERRUPT_DELAY(val)
> > 	REG_FIELD_PREP(DPST_GUARD_INTERRUPT_DELAY_MASK, val)
> > +#define DPST_GUARD_THRESHOLD_GB_MASK
> > 	REG_GENMASK(21, 0)
> > +#define DPST_GUARD_THRESHOLD_GB(val)
> > 	REG_FIELD_PREP(DPST_GUARD_THRESHOLD_GB_MASK, val)
> > +
> > +#define _DPST_BIN_A					0x490C4
> > +#define _DPST_BIN_B					0x491C4
> > +#define DPST_BIN(pipe)
> > 	_MMIO_PIPE(pipe, _DPST_BIN_A, _DPST_BIN_B)
> > +#define DPST_BIN_DATA_MASK
> > 	REG_GENMASK(23, 0)
> > +#define DPST_BIN_BUSY					REG_BIT(31)
> > +
> > +#define INTEL_HISTOGRAM_PIPEA			0x90000000
> > +#define INTEL_HISTOGRAM_PIPEB			0x90000002
> > +#define INTEL_HISTOGRAM_EVENT(pipe)		PIPE(pipe, \
> > +						     INTEL_HISTOGRAM_PIPEA,
> \
> > +						     INTEL_HISTOGRAM_PIPEB)
> 
> I don't think this is the right way. Lets have a file for intel_histogram_regs.h and
> intel_histogram.h That will look a lot cleaner.
> 
Done

> > +
> > +#define HISTOGRAM_BIN_COUNT			32
> > +#define HISTOGRAM_IET_LENGTH			33
> > +
> > +enum intel_global_hist_status {
> > +	INTEL_HISTOGRAM_ENABLE,
> > +	INTEL_HISTOGRAM_DISABLE,
> > +};
> > +
> > +enum intel_global_histogram {
> > +	INTEL_HISTOGRAM,
> > +};
> > +
> > +enum intel_global_hist_lut {
> > +	INTEL_HISTOGRAM_PIXEL_FACTOR,
> > +};
> > +
> > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc); int
> > +intel_histogram_update(struct intel_crtc *intel_crtc, bool enable);
> > +int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32
> > +*data); int intel_histogram_init(struct intel_crtc *intel_crtc); void
> > +intel_histogram_deinit(struct intel_crtc *intel_crtc);
> > +
> > +#endif /* __INTEL_HISTOGRAM_H__ */
> > diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> > index b9670ae09a9e..424ea43016dd 100644
> > --- a/drivers/gpu/drm/xe/Makefile
> > +++ b/drivers/gpu/drm/xe/Makefile
> > @@ -238,6 +238,7 @@ xe-$(CONFIG_DRM_XE_DISPLAY) += \
> >  	i915-display/intel_hdcp.o \
> >  	i915-display/intel_hdcp_gsc_message.o \
> >  	i915-display/intel_hdmi.o \
> > +	i915-display/intel_histogram.o \
> >  	i915-display/intel_hotplug.o \
> >  	i915-display/intel_hotplug_irq.o \
> >  	i915-display/intel_hti.o \
> 
> Lets try to separate xe and i915 changes into different patches as well as we can
> I know its tough to decouple some Changes but the ones that can be done
> should be.
> 
Done

Thanks and Regards,
Arun R Murthy
--------------------
Murthy, Arun R Sept. 15, 2024, 12:47 p.m. UTC | #8 
> > > > +#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    //
> > 3.0% of
> > > > the pipe's current pixel count.
> > > > +#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   //
> > Precision
> > > > factor for threshold guardband.
> > > > +#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
> > > > +
> > > > +struct intel_histogram {
> > > > +	struct drm_i915_private *i915;
> > > > +	bool enable;
> > > > +	bool can_enable;
> > > > +	enum pipe pipe;
> > > > +	u32 bindata[HISTOGRAM_BIN_COUNT]; };
> > > > +
> > > > +int intel_histogram_atomic_check(struct intel_crtc *intel_crtc) {
> > > > +	struct intel_histogram *histogram = intel_crtc->histogram;
> > > > +
> > > > +	/* TODO: Restrictions for enabling histogram */
> > > > +	histogram->can_enable = true;
> > > > +
> > > > +	return 0;
> > > > +}
> > > > +
> > > Looks like we are totally bypassing crtc_state->dither.
> > > Also I see some comments on dither not being enabled on anything
> > > which is not 6bpc. Is that constraint resolved now?
> > >
> >
> > Crtc_state->dither is used for enabling dithering during the
> > crtc_enable and at this point we are far ahead of that.
> > That restriction is for older platforms(ironlake) and we don't have
> > any such for ADLP+
> 
> My first point was why do you need to enable it again separately, if it has been
> already taken care by crtc_state->dither And second point was, can you please
> share the bsepc link where we have this requirement of enabling it again, even
> it it was enabled.
> 
Enabling dithering helps in removing the artifacts in the image and is done as part of improvement.
As communicated earlier histogram is a pipe configuration and dithering is a trigger point for histogram.

Thanks and Regards
Arun R Murthy
--------------------
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index c63fa2133ccb..03caf3a24966 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -264,6 +264,7 @@  i915-y += \
 	display/intel_hdcp.o \
 	display/intel_hdcp_gsc.o \
 	display/intel_hdcp_gsc_message.o \
+	display/intel_histogram.o \
 	display/intel_hotplug.o \
 	display/intel_hotplug_irq.o \
 	display/intel_hti.o \
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index bd290536a1b7..79d34d6d537d 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1537,6 +1537,8 @@  struct intel_crtc {
 	/* for loading single buffered registers during vblank */
 	struct pm_qos_request vblank_pm_qos;
 
+	struct intel_histogram *histogram;
+
 #ifdef CONFIG_DEBUG_FS
 	struct intel_pipe_crc pipe_crc;
 #endif
diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c b/drivers/gpu/drm/i915/display/intel_histogram.c
new file mode 100644
index 000000000000..45e968e00af6
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_histogram.c
@@ -0,0 +1,205 @@ 
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include <drm/drm_device.h>
+#include <drm/drm_file.h>
+
+#include "i915_reg.h"
+#include "i915_drv.h"
+#include "intel_display.h"
+#include "intel_histogram.h"
+#include "intel_display_types.h"
+#include "intel_de.h"
+
+#define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300    // 3.0% of the pipe's current pixel count.
+#define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000   // Precision factor for threshold guardband.
+#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
+
+struct intel_histogram {
+	struct drm_i915_private *i915;
+	bool enable;
+	bool can_enable;
+	enum pipe pipe;
+	u32 bindata[HISTOGRAM_BIN_COUNT];
+};
+
+int intel_histogram_atomic_check(struct intel_crtc *intel_crtc)
+{
+	struct intel_histogram *histogram = intel_crtc->histogram;
+
+	/* TODO: Restrictions for enabling histogram */
+	histogram->can_enable = true;
+
+	return 0;
+}
+
+static void intel_histogram_enable_dithering(struct drm_i915_private *dev_priv,
+					     enum pipe pipe)
+{
+	intel_de_rmw(dev_priv, PIPE_MISC(pipe), PIPE_MISC_DITHER_ENABLE,
+		     PIPE_MISC_DITHER_ENABLE);
+}
+
+static int intel_histogram_enable(struct intel_crtc *intel_crtc)
+{
+	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
+	struct intel_histogram *histogram = intel_crtc->histogram;
+	int pipe = intel_crtc->pipe;
+	u64 res;
+	u32 gbandthreshold;
+
+	if (!histogram)
+		return -EINVAL;
+
+	if (!histogram->can_enable) {
+		return -EINVAL;
+	}
+
+	if (histogram->enable)
+		return 0;
+
+	/* Pipe Dithering should be enabled with GLOBAL_HIST */
+	intel_histogram_enable_dithering(i915, pipe);
+
+	/*
+	 * enable DPST_CTL Histogram mode
+	 * Clear DPST_CTL Bin Reg function select to TC
+	 */
+	intel_de_rmw(i915, DPST_CTL(pipe),
+		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_IE_HIST_EN |
+		     DPST_CTL_HIST_MODE | DPST_CTL_IE_TABLE_VALUE_FORMAT,
+		     DPST_CTL_BIN_REG_FUNC_TC | DPST_CTL_IE_HIST_EN |
+		     DPST_CTL_HIST_MODE_HSV |
+		     DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC);
+
+	/* Re-Visit: check if wait for one vblank is required */
+	drm_crtc_wait_one_vblank(&intel_crtc->base);
+
+	/* TODO: one time programming: Program GuardBand Threshold */
+	res = (intel_crtc->config->hw.adjusted_mode.vtotal *
+				intel_crtc->config->hw.adjusted_mode.htotal);
+	gbandthreshold = (res *	HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT) /
+				HISTOGRAM_GUARDBAND_PRECISION_FACTOR;
+
+	/* Enable histogram interrupt mode */
+	intel_de_rmw(i915, DPST_GUARD(pipe),
+		     DPST_GUARD_THRESHOLD_GB_MASK |
+		     DPST_GUARD_INTERRUPT_DELAY_MASK | DPST_GUARD_HIST_INT_EN,
+		     DPST_GUARD_THRESHOLD_GB(gbandthreshold) |
+		     DPST_GUARD_INTERRUPT_DELAY(HISTOGRAM_DEFAULT_GUARDBAND_DELAY) |
+		     DPST_GUARD_HIST_INT_EN);
+
+	/* Clear pending interrupts has to be done on separate write */
+	intel_de_rmw(i915, DPST_GUARD(pipe),
+		     DPST_GUARD_HIST_EVENT_STATUS, 1);
+
+	histogram->enable = true;
+
+	return 0;
+}
+
+static void intel_histogram_disable(struct intel_crtc *intel_crtc)
+{
+	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
+	struct intel_histogram *histogram = intel_crtc->histogram;
+	int pipe = intel_crtc->pipe;
+
+	if (!histogram)
+		return;
+
+	/* Pipe Dithering should be enabled with GLOBAL_HIST */
+	intel_histogram_enable_dithering(i915, pipe);
+
+	/* Clear pending interrupts and disable interrupts */
+	intel_de_rmw(i915, DPST_GUARD(pipe),
+		     DPST_GUARD_HIST_INT_EN | DPST_GUARD_HIST_EVENT_STATUS, 0);
+
+	/* disable DPST_CTL Histogram mode */
+	intel_de_rmw(i915, DPST_CTL(pipe),
+		     DPST_CTL_IE_HIST_EN, 0);
+
+	histogram->enable = false;
+}
+
+int intel_histogram_update(struct intel_crtc *intel_crtc, bool enable)
+{
+	if (enable)
+		return intel_histogram_enable(intel_crtc);
+
+	intel_histogram_disable(intel_crtc);
+	return 0;
+}
+
+int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32 *data)
+{
+	struct intel_histogram *histogram = intel_crtc->histogram;
+	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
+	int pipe = intel_crtc->pipe;
+	int i = 0;
+
+	if (!histogram)
+		return -EINVAL;
+
+	if (!histogram->enable) {
+		drm_err(&i915->drm, "histogram not enabled");
+		return -EINVAL;
+	}
+
+	if (!data) {
+		drm_err(&i915->drm, "enhancement LUT data is NULL");
+		return -EINVAL;
+	}
+
+	/*
+	 * Set DPST_CTL Bin Reg function select to IE
+	 * Set DPST_CTL Bin Register Index to 0
+	 */
+	intel_de_rmw(i915, DPST_CTL(pipe),
+		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_BIN_REG_MASK,
+		     DPST_CTL_BIN_REG_FUNC_IE | DPST_CTL_BIN_REG_CLEAR);
+
+	for (i = 0; i < HISTOGRAM_IET_LENGTH; i++) {
+		intel_de_rmw(i915, DPST_BIN(pipe),
+			     DPST_BIN_DATA_MASK, data[i]);
+		drm_dbg_atomic(&i915->drm, "iet_lut[%d]=%x\n", i, data[i]);
+	}
+
+	intel_de_rmw(i915, DPST_CTL(pipe),
+		     DPST_CTL_ENHANCEMENT_MODE_MASK | DPST_CTL_IE_MODI_TABLE_EN,
+		     DPST_CTL_EN_MULTIPLICATIVE | DPST_CTL_IE_MODI_TABLE_EN);
+
+	/* Once IE is applied, change DPST CTL to TC */
+	intel_de_rmw(i915, DPST_CTL(pipe),
+		     DPST_CTL_BIN_REG_FUNC_SEL, DPST_CTL_BIN_REG_FUNC_TC);
+
+	return 0;
+}
+
+void intel_histogram_deinit(struct intel_crtc *intel_crtc)
+{
+	struct intel_histogram *histogram = intel_crtc->histogram;
+
+	kfree(histogram);
+}
+
+int intel_histogram_init(struct intel_crtc *intel_crtc)
+{
+	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
+	struct intel_histogram *histogram;
+
+	/* Allocate histogram internal struct */
+	histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
+	if (!histogram) {
+		return -ENOMEM;
+	}
+
+	intel_crtc->histogram = histogram;
+	histogram->pipe = intel_crtc->pipe;
+	histogram->can_enable = false;
+
+	histogram->i915 = i915;
+
+	return 0;
+}
diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h b/drivers/gpu/drm/i915/display/intel_histogram.h
new file mode 100644
index 000000000000..b25091732274
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_histogram.h
@@ -0,0 +1,78 @@ 
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef __INTEL_HISTOGRAM_H__
+#define __INTEL_HISTOGRAM_H__
+
+#include <linux/types.h>
+
+struct intel_crtc;
+
+/* GLOBAL_HIST related registers */
+#define _DPST_CTL_A					0x490C0
+#define _DPST_CTL_B					0x491C0
+#define DPST_CTL(pipe)					_MMIO_PIPE(pipe, _DPST_CTL_A, _DPST_CTL_B)
+#define DPST_CTL_IE_HIST_EN				REG_BIT(31)
+#define DPST_CTL_RESTORE				REG_BIT(28)
+#define DPST_CTL_IE_MODI_TABLE_EN			REG_BIT(27)
+#define DPST_CTL_HIST_MODE				REG_BIT(24)
+#define DPST_CTL_ENHANCEMENT_MODE_MASK			REG_GENMASK(14, 13)
+#define DPST_CTL_EN_MULTIPLICATIVE			REG_FIELD_PREP(DPST_CTL_ENHANCEMENT_MODE_MASK, 2)
+#define DPST_CTL_IE_TABLE_VALUE_FORMAT			REG_BIT(15)
+#define DPST_CTL_BIN_REG_FUNC_SEL			REG_BIT(11)
+#define DPST_CTL_BIN_REG_FUNC_TC			REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 0)
+#define DPST_CTL_BIN_REG_FUNC_IE			REG_FIELD_PREP(DPST_CTL_BIN_REG_FUNC_SEL, 1)
+#define DPST_CTL_BIN_REG_MASK				REG_GENMASK(6, 0)
+#define DPST_CTL_BIN_REG_CLEAR				REG_FIELD_PREP(DPST_CTL_BIN_REG_MASK, 0)
+#define DPST_CTL_IE_TABLE_VALUE_FORMAT_2INT_8FRAC	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 1)
+#define DPST_CTL_IE_TABLE_VALUE_FORMAT_1INT_9FRAC	REG_FIELD_PREP(DPST_CTL_IE_TABLE_VALUE_FORMAT, 0)
+#define DPST_CTL_HIST_MODE_YUV				REG_FIELD_PREP(DPST_CTL_HIST_MODE, 0)
+#define DPST_CTL_HIST_MODE_HSV				REG_FIELD_PREP(DPST_CTL_HIST_MODE, 1)
+
+#define _DPST_GUARD_A					0x490C8
+#define _DPST_GUARD_B					0x491C8
+#define DPST_GUARD(pipe)				_MMIO_PIPE(pipe, _DPST_GUARD_A, _DPST_GUARD_B)
+#define DPST_GUARD_HIST_INT_EN				REG_BIT(31)
+#define DPST_GUARD_HIST_EVENT_STATUS			REG_BIT(30)
+#define DPST_GUARD_INTERRUPT_DELAY_MASK			REG_GENMASK(29, 22)
+#define DPST_GUARD_INTERRUPT_DELAY(val)			REG_FIELD_PREP(DPST_GUARD_INTERRUPT_DELAY_MASK, val)
+#define DPST_GUARD_THRESHOLD_GB_MASK			REG_GENMASK(21, 0)
+#define DPST_GUARD_THRESHOLD_GB(val)			REG_FIELD_PREP(DPST_GUARD_THRESHOLD_GB_MASK, val)
+
+#define _DPST_BIN_A					0x490C4
+#define _DPST_BIN_B					0x491C4
+#define DPST_BIN(pipe)					_MMIO_PIPE(pipe, _DPST_BIN_A, _DPST_BIN_B)
+#define DPST_BIN_DATA_MASK				REG_GENMASK(23, 0)
+#define DPST_BIN_BUSY					REG_BIT(31)
+
+#define INTEL_HISTOGRAM_PIPEA			0x90000000
+#define INTEL_HISTOGRAM_PIPEB			0x90000002
+#define INTEL_HISTOGRAM_EVENT(pipe)		PIPE(pipe, \
+						     INTEL_HISTOGRAM_PIPEA, \
+						     INTEL_HISTOGRAM_PIPEB)
+
+#define HISTOGRAM_BIN_COUNT			32
+#define HISTOGRAM_IET_LENGTH			33
+
+enum intel_global_hist_status {
+	INTEL_HISTOGRAM_ENABLE,
+	INTEL_HISTOGRAM_DISABLE,
+};
+
+enum intel_global_histogram {
+	INTEL_HISTOGRAM,
+};
+
+enum intel_global_hist_lut {
+	INTEL_HISTOGRAM_PIXEL_FACTOR,
+};
+
+int intel_histogram_atomic_check(struct intel_crtc *intel_crtc);
+int intel_histogram_update(struct intel_crtc *intel_crtc, bool enable);
+int intel_histogram_set_iet_lut(struct intel_crtc *intel_crtc, u32 *data);
+int intel_histogram_init(struct intel_crtc *intel_crtc);
+void intel_histogram_deinit(struct intel_crtc *intel_crtc);
+
+#endif /* __INTEL_HISTOGRAM_H__ */
diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
index b9670ae09a9e..424ea43016dd 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -238,6 +238,7 @@  xe-$(CONFIG_DRM_XE_DISPLAY) += \
 	i915-display/intel_hdcp.o \
 	i915-display/intel_hdcp_gsc_message.o \
 	i915-display/intel_hdmi.o \
+	i915-display/intel_histogram.o \
 	i915-display/intel_hotplug.o \
 	i915-display/intel_hotplug_irq.o \
 	i915-display/intel_hti.o \