[PATCH v9 11/20] drm/i915/histogram: histogram interrupt handling

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

Upon enabling histogram an interrupt is triggered after the generation
of the statistics. This patch registers the histogram interrupt and
handles the interrupt.

v2: Added intel_crtc backpointer to intel_histogram struct (Jani)
    Removed histogram_wq and instead use dev_priv->unodered_eq (Jani)
v3: Replaced drm_i915_private with intel_display (Suraj)
    Refactored the histogram read code (Jani)
v4: Rebased after addressing comments on patch 1
v5: removed the retry logic and moved to patch7 (Jani)

Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_irq.c  |   6 +-
 drivers/gpu/drm/i915/display/intel_display_regs.h |   5 +-
 drivers/gpu/drm/i915/display/intel_histogram.c    | 108 +++++++++++++++++++++-
 drivers/gpu/drm/i915/display/intel_histogram.h    |   3 +
 4 files changed, 117 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c b/drivers/gpu/drm/i915/display/intel_display_irq.c
index 9adeebb376b189ef72a97e0206e0c24b0f4e7117..ad1bf8c75fe1e33271ad054407b8ec1239c76064 100644
--- a/drivers/gpu/drm/i915/display/intel_display_irq.c
+++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
@@ -22,6 +22,7 @@
 #include "intel_fdi_regs.h"
 #include "intel_fifo_underrun.h"
 #include "intel_gmbus.h"
+#include "intel_histogram.h"
 #include "intel_hotplug_irq.h"
 #include "intel_parent.h"
 #include "intel_pipe_crc_regs.h"
@@ -1527,6 +1528,9 @@ void gen8_de_irq_handler(struct intel_display *display, u32 master_ctl)
 		if (iir & GEN8_PIPE_FIFO_UNDERRUN)
 			intel_cpu_fifo_underrun_irq_handler(display, pipe);
 
+		if (iir & GEN9_PIPE_HISTOGRAM_EVENT)
+			intel_histogram_irq_handler(display, pipe);
+
 		fault_errors = iir & gen8_de_pipe_fault_mask(display);
 		if (fault_errors)
 			intel_pipe_fault_irq_handler(display,
@@ -2315,7 +2319,7 @@ static void icp_irq_postinstall(struct intel_display *display);
 void gen8_de_irq_postinstall(struct intel_display *display)
 {
 	u32 de_pipe_masked = gen8_de_pipe_fault_mask(display) |
-		GEN8_PIPE_CDCLK_CRC_DONE;
+		GEN8_PIPE_CDCLK_CRC_DONE | GEN9_PIPE_HISTOGRAM_EVENT;
 	u32 de_pipe_enables;
 	u32 de_port_masked = gen8_de_port_aux_mask(display);
 	u32 de_port_enables;
diff --git a/drivers/gpu/drm/i915/display/intel_display_regs.h b/drivers/gpu/drm/i915/display/intel_display_regs.h
index c14d3caa73a7a3ffa86beca4b05700481c601899..7affc89fbe22fe8e09a733b16578136e96a3d1ba 100644
--- a/drivers/gpu/drm/i915/display/intel_display_regs.h
+++ b/drivers/gpu/drm/i915/display/intel_display_regs.h
@@ -799,7 +799,7 @@
 #define   PIPE_HOTPLUG_INTERRUPT_ENABLE		(1UL << 26)
 #define   PIPE_VSYNC_INTERRUPT_ENABLE		(1UL << 25)
 #define   PIPE_DISPLAY_LINE_COMPARE_ENABLE	(1UL << 24)
-#define   PIPE_DPST_EVENT_ENABLE		(1UL << 23)
+#define   PIPE_HISTOGRAM_EVENT_ENABLE		REG_BIT(23)
 #define   SPRITE0_FLIP_DONE_INT_EN_VLV		(1UL << 22)
 #define   PIPE_LEGACY_BLC_EVENT_ENABLE		(1UL << 22)
 #define   PIPE_ODD_FIELD_INTERRUPT_ENABLE	(1UL << 21)
@@ -822,7 +822,7 @@
 #define   PIPE_HOTPLUG_INTERRUPT_STATUS		(1UL << 10)
 #define   PIPE_VSYNC_INTERRUPT_STATUS		(1UL << 9)
 #define   PIPE_DISPLAY_LINE_COMPARE_STATUS	(1UL << 8)
-#define   PIPE_DPST_EVENT_STATUS		(1UL << 7)
+#define   PIPE_HISTOGRAM_EVENT_STATUS		REG_BIT(7)
 #define   PIPE_A_PSR_STATUS_VLV			(1UL << 6)
 #define   PIPE_LEGACY_BLC_EVENT_STATUS		(1UL << 6)
 #define   PIPE_ODD_FIELD_INTERRUPT_STATUS	(1UL << 5)
@@ -1255,6 +1255,7 @@
 #define  GEN12_DSB_1_INT		REG_BIT(14) /* tgl+ */
 #define  GEN12_DSB_0_INT		REG_BIT(13) /* tgl+ */
 #define  GEN12_DSB_INT(dsb_id)		REG_BIT(13 + (dsb_id))
+#define  GEN9_PIPE_HISTOGRAM_EVENT	REG_BIT(12) /* skl+ */
 #define  GEN9_PIPE_CURSOR_FAULT		REG_BIT(11) /* skl+ */
 #define  GEN9_PIPE_PLANE4_FAULT		REG_BIT(10) /* skl+ */
 #define  GEN8_PIPE_CURSOR_FAULT		REG_BIT(10) /* bdw */
diff --git a/drivers/gpu/drm/i915/display/intel_histogram.c b/drivers/gpu/drm/i915/display/intel_histogram.c
index 0d14cd88d1869583a3ade8ded9284425ab217d3e..b42edf7dae7c0b8d083dff81c41a7ed4f7938e84 100644
--- a/drivers/gpu/drm/i915/display/intel_histogram.c
+++ b/drivers/gpu/drm/i915/display/intel_histogram.c
@@ -21,7 +21,106 @@
 #define HISTOGRAM_GUARDBAND_THRESHOLD_DEFAULT 300
 /* Precision factor for threshold guardband */
 #define HISTOGRAM_GUARDBAND_PRECISION_FACTOR 10000
-#define HISTOGRAM_DEFAULT_GUARDBAND_DELAY 0x04
+#define HISTOGRAM_BIN_READ_RETRY_COUNT 5
+
+static bool intel_histogram_get_data(struct intel_crtc *intel_crtc)
+{
+	struct intel_display *display = to_intel_display(intel_crtc);
+	struct intel_histogram *histogram = intel_crtc->histogram;
+	int index;
+	u32 dpstbin;
+
+	for (index = 0; index < ARRAY_SIZE(histogram->bin_data); index++) {
+		dpstbin = intel_de_read(display, DPST_BIN(intel_crtc->pipe));
+		if (!(dpstbin & DPST_BIN_BUSY))
+			histogram->bin_data[index] = dpstbin & DPST_BIN_DATA_MASK;
+		else
+			return false;
+	}
+	return true;
+}
+
+static void intel_histogram_handle_int_work(struct work_struct *work)
+{
+	struct intel_histogram *histogram = container_of(work,
+		struct intel_histogram, work.work);
+	struct intel_crtc *intel_crtc = histogram->crtc;
+	struct intel_display *display = to_intel_display(intel_crtc);
+	struct drm_colorop *colorop;
+	char event[] = "HISTOGRAM=1", pipe_id[21];
+	char *histogram_event[] = { event, pipe_id, NULL };
+	int retry;
+
+	snprintf(pipe_id, sizeof(pipe_id),
+		 "PIPE=%u", intel_crtc->base.base.id);
+
+	/*
+	 * TODO: PSR to be exited while reading the Histogram data
+	 * Set DPST_CTL Bin Reg function select to TC
+	 * Set DPST_CTL Bin Register Index to 0
+	 */
+	intel_de_rmw(display, DPST_CTL(intel_crtc->pipe),
+		     DPST_CTL_BIN_REG_FUNC_SEL | DPST_CTL_BIN_REG_MASK, 0);
+	for (retry = 0; retry < HISTOGRAM_BIN_READ_RETRY_COUNT; retry++) {
+		if (intel_histogram_get_data(intel_crtc)) {
+			u32 *data;
+			struct drm_histogram *hist;
+
+			data = kzalloc(sizeof(data) * sizeof(histogram->bin_data), GFP_KERNEL);
+			if (!data)
+				return;
+			memcpy(histogram->bin_data, data, sizeof(histogram->bin_data));
+			hist = kzalloc(sizeof(*hist), GFP_KERNEL);
+			if (!hist)
+				return;
+			hist->data_ptr = *data;
+			hist->nr_elements = sizeof(histogram->bin_data);
+
+			colorop = intel_crtc->base.state->color_pipeline;
+			/* TODO: fill the drm_histogram_config data back this drm_histogram struct */
+			drm_property_replace_global_blob(display->drm,
+							 &colorop->state->histogram_data,
+							 sizeof(struct drm_histogram),
+							 hist, &intel_crtc->base.base,
+							 colorop->histogram_data_property);
+			/* Notify user for Histogram readiness */
+			if (kobject_uevent_env(&display->drm->primary->kdev->kobj,
+					       KOBJ_CHANGE, histogram_event))
+				drm_err(display->drm,
+					"Sending HISTOGRAM event failed\n");
+			break;
+		}
+	}
+	if (retry >= HISTOGRAM_BIN_READ_RETRY_COUNT) {
+		drm_err(display->drm, "Histogram bin read failed with max retry\n");
+		return;
+	}
+
+	/* Enable histogram interrupt */
+	intel_de_rmw(display, DPST_GUARD(intel_crtc->pipe), DPST_GUARD_HIST_INT_EN,
+		     DPST_GUARD_HIST_INT_EN);
+
+	/* Clear histogram interrupt by setting histogram interrupt status bit*/
+	intel_de_rmw(display, DPST_GUARD(intel_crtc->pipe),
+		     DPST_GUARD_HIST_EVENT_STATUS, 1);
+}
+
+void intel_histogram_irq_handler(struct intel_display *display, enum pipe pipe)
+{
+	struct intel_crtc *intel_crtc =
+		to_intel_crtc(drm_crtc_from_index(display->drm, pipe));
+	struct intel_histogram *histogram = intel_crtc->histogram;
+	struct drm_i915_private *i915 = to_i915(intel_crtc->base.dev);
+
+	if (!histogram->enable) {
+		drm_err(display->drm,
+			"Spurious interrupt, histogram not enabled\n");
+		return;
+	}
+
+	queue_delayed_work(i915->unordered_wq,
+			   &histogram->work, 0);
+}
 
 int intel_histogram_atomic_check(struct intel_crtc *intel_crtc)
 {
@@ -73,7 +172,7 @@ static int intel_histogram_enable(struct intel_crtc *intel_crtc, u8 mode)
 		     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_INTERRUPT_DELAY(0x04) |
 		     DPST_GUARD_HIST_INT_EN);
 
 	/* Clear pending interrupts has to be done on separate write */
@@ -106,6 +205,7 @@ static void intel_histogram_disable(struct intel_crtc *intel_crtc)
 	intel_de_rmw(display, DPST_CTL(pipe),
 		     DPST_CTL_IE_HIST_EN, 0);
 
+	cancel_delayed_work(&histogram->work);
 	histogram->enable = false;
 }
 
@@ -131,6 +231,7 @@ void intel_histogram_finish(struct intel_crtc *intel_crtc)
 {
 	struct intel_histogram *histogram = intel_crtc->histogram;
 
+	cancel_delayed_work_sync(&histogram->work);
 	kfree(histogram);
 }
 
@@ -155,5 +256,8 @@ int intel_histogram_init(struct intel_crtc *crtc)
 	histogram->can_enable = false;
 	histogram->caps = histogram_caps;
 
+	INIT_DEFERRABLE_WORK(&histogram->work,
+			     intel_histogram_handle_int_work);
+
 	return 0;
 }
diff --git a/drivers/gpu/drm/i915/display/intel_histogram.h b/drivers/gpu/drm/i915/display/intel_histogram.h
index 71ca706ebef9873c482f9714f614f6f6cc1eb2f0..bd559d90e9b9fc8f5afdbc31c47702a99569b712 100644
--- a/drivers/gpu/drm/i915/display/intel_histogram.h
+++ b/drivers/gpu/drm/i915/display/intel_histogram.h
@@ -12,6 +12,8 @@ struct drm_property_blob;
 struct drm_histogram_config;
 struct drm_histogram_caps;
 struct intel_crtc;
+struct intel_display;
+enum pipe;
 
 #define HISTOGRAM_BIN_COUNT                    32
 
@@ -37,6 +39,7 @@ enum intel_global_hist_lut {
 	INTEL_HISTOGRAM_PIXEL_FACTOR,
 };
 
+void intel_histogram_irq_handler(struct intel_display *display, enum pipe pipe);
 int intel_histogram_atomic_check(struct intel_crtc *intel_crtc);
 int intel_histogram_update(struct intel_crtc *intel_crtc,
 			   struct drm_histogram_config *config);

-- 
2.25.1