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)
v3: Replaced i915 with intel_display (Suraj)
v4: Removed dithering enable/disable (Vandita)
New patch for histogram register definitions (Suraj)
Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx>
---
drivers/gpu/drm/i915/Makefile | 1 +
.../drm/i915/display/intel_display_types.h | 2 +
.../gpu/drm/i915/display/intel_histogram.c | 187 ++++++++++++++++++
.../gpu/drm/i915/display/intel_histogram.h | 35 ++++
4 files changed, 225 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 70771e521b1c..6317dbb46576 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -266,6 +266,7 @@ 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 7ff97e5b83dd..c5504f4c3178 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1407,6 +1407,8 @@ 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..86439636b490
--- /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 <drm/drm_vblank.h>
+
+#include "i915_reg.h"
+#include "i915_drv.h"
+#include "intel_display.h"
+#include "intel_histogram_reg.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 intel_crtc *crtc;
+ struct delayed_work work;
+ bool enable;
+ bool can_enable;
+ u32 bin_data[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 int intel_histogram_enable(struct intel_crtc *intel_crtc)
+{
+ struct intel_display *display = to_intel_display(intel_crtc);
+ 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;
+
+ /* enable histogram, clear DPST_BIN reg and select TC function */
+ intel_de_rmw(display, 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(display, 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(display, 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 intel_display *display = to_intel_display(intel_crtc);
+ struct intel_histogram *histogram = intel_crtc->histogram;
+ int pipe = intel_crtc->pipe;
+
+ if (!histogram)
+ return;
+
+ /* Clear pending interrupts and disable interrupts */
+ intel_de_rmw(display, DPST_GUARD(pipe),
+ DPST_GUARD_HIST_INT_EN | DPST_GUARD_HIST_EVENT_STATUS, 0);
+
+ /* disable DPST_CTL Histogram mode */
+ intel_de_rmw(display, 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 intel_display *display = to_intel_display(intel_crtc);
+ int pipe = intel_crtc->pipe;
+ int i = 0;
+
+ if (!histogram)
+ return -EINVAL;
+
+ if (!histogram->enable) {
+ drm_err(display->drm, "histogram not enabled");
+ return -EINVAL;
+ }
+
+ if (!data) {
+ drm_err(display->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(display, 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(display, DPST_BIN(pipe),
+ DPST_BIN_DATA_MASK, data[i]);
+ drm_dbg_atomic(display->drm, "iet_lut[%d]=%x\n", i, data[i]);
+ }
+
+ intel_de_rmw(display, 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(display, DPST_CTL(pipe),
+ DPST_CTL_BIN_REG_FUNC_SEL, DPST_CTL_BIN_REG_FUNC_TC);
+
+ return 0;
+}
+
+void intel_histogram_finish(struct intel_crtc *intel_crtc)
+{
+ struct intel_histogram *histogram = intel_crtc->histogram;
+
+ kfree(histogram);
+}
+
+int intel_histogram_init(struct intel_crtc *intel_crtc)
+{
+ struct intel_histogram *histogram;
+
+ /* Allocate histogram internal struct */
+ histogram = kzalloc(sizeof(*histogram), GFP_KERNEL);
+ if (!histogram) {
+ return -ENOMEM;
+ }
+
+ intel_crtc->histogram = histogram;
+ histogram->crtc = intel_crtc;
+ histogram->can_enable = false;
+
+ 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..9d66724f9c53
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_histogram.h
@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef __INTEL_HISTOGRAM_H__
+#define __INTEL_HISTOGRAM_H__
+
+#include <linux/types.h>
+
+struct intel_crtc;
+
+#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_finish(struct intel_crtc *intel_crtc);
+
+#endif /* __INTEL_HISTOGRAM_H__ */
--
2.25.1
