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

[Arun R Murthy <arun.r.murthy@intel.com>]

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.

Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
---
 drivers/gpu/drm/i915/Makefile                 |   1 +
 .../drm/i915/display/intel_display_types.h    |   3 +
 .../gpu/drm/i915/display/intel_histogram.c    | 187 ++++++++++++++++++
 .../gpu/drm/i915/display/intel_histogram.h    |  91 +++++++++
 drivers/gpu/drm/xe/Makefile                   |   1 +
 5 files changed, 283 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 8713835e2307..e0a9c6d8c9b2 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1537,6 +1537,9 @@ struct intel_crtc {
 	/* for loading single buffered registers during vblank */
 	struct pm_qos_request vblank_pm_qos;
 
+	/* histogram data */
+	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..1a603445fc29
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_histogram.c
@@ -0,0 +1,187 @@
+// 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_types.h"
+#include "intel_de.h"
+#include "intel_histogram.h"
+
+int intel_histogram_can_enable(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->can_enable) {
+		drm_err(&i915->drm,
+			"Histogram not supported, compute config failed\n");
+		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;
+
+	/* 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->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 (unlikely(!histogram)) {
+		drm_err(&i915->drm,
+			"Failed to allocate HISTOGRAM event\n");
+		kfree(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..632116c52882
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_histogram.h
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef __INTEL_HISTOGRAM_H__
+#define __INTEL_HISTOGRAM_H__
+
+#include <drm/drm_device.h>
+#include <drm/drm_file.h>
+#include "intel_display.h"
+#include "i915_reg.h"
+
+/* 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
+
+#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
+
+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,
+};
+
+struct intel_histogram {
+	struct drm_i915_private *i915;
+	bool enable;
+	bool can_enable;
+	enum pipe pipe;
+	u32 bindata[HISTOGRAM_BIN_COUNT];
+};
+
+int intel_histogram_can_enable(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 628c245c4822..1881e3e1f4a9 100644
--- a/drivers/gpu/drm/xe/Makefile
+++ b/drivers/gpu/drm/xe/Makefile
@@ -260,6 +260,7 @@ 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