From db56206e77d1a71c145669dc41d0ada496ea8e4f Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.com>
Date: Wed, 28 Apr 2021 12:32:10 +0200
Subject: [PATCH] drm/vc4: Add debugfs node that dumps the vc5 gamma
 PWL entries

This helps with debugging the conversion from a 256 point gamma LUT to
16 point PWL entries as used by the BCM2711.

Co-developed-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
 drivers/gpu/drm/vc4/vc4_hvs.c | 81 +++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

--- a/drivers/gpu/drm/vc4/vc4_hvs.c
+++ b/drivers/gpu/drm/vc4/vc4_hvs.c
@@ -134,6 +134,84 @@ static int vc4_hvs_debugfs_dlist(struct
 	return 0;
 }
 
+static int vc5_hvs_debugfs_gamma(struct seq_file *m, void *data)
+{
+	struct drm_info_node *node = m->private;
+	struct drm_device *dev = node->minor->dev;
+	struct vc4_dev *vc4 = to_vc4_dev(dev);
+	struct drm_printer p = drm_seq_file_printer(m);
+	unsigned int i, chan;
+	u32 dispstat, dispbkgndx;
+
+	for (chan = 0; chan < SCALER_CHANNELS_COUNT; chan++) {
+		u32 x_c, grad;
+		u32 offset = SCALER5_DSPGAMMA_START +
+			chan * SCALER5_DSPGAMMA_CHAN_OFFSET;
+
+		dispstat = VC4_GET_FIELD(HVS_READ(SCALER_DISPSTATX(chan)),
+					 SCALER_DISPSTATX_MODE);
+		if (dispstat == SCALER_DISPSTATX_MODE_DISABLED ||
+		    dispstat == SCALER_DISPSTATX_MODE_EOF) {
+			drm_printf(&p, "HVS channel %u: Channel disabled\n", chan);
+			continue;
+		}
+
+		dispbkgndx = HVS_READ(SCALER_DISPBKGNDX(chan));
+		if (!(dispbkgndx & SCALER_DISPBKGND_GAMMA)) {
+			drm_printf(&p, "HVS channel %u: Gamma disabled\n", chan);
+			continue;
+		}
+
+		drm_printf(&p, "HVS channel %u:\n", chan);
+		drm_printf(&p, "  red:\n");
+		for (i = 0; i < SCALER5_DSPGAMMA_NUM_POINTS; i++, offset += 8) {
+			x_c = HVS_READ(offset);
+			grad = HVS_READ(offset + 4);
+			drm_printf(&p, "  %08x %08x - x %u, c %u, grad %u\n",
+				   x_c, grad,
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_X),
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_C),
+				   grad);
+		}
+		drm_printf(&p, "  green:\n");
+		for (i = 0; i < SCALER5_DSPGAMMA_NUM_POINTS; i++, offset += 8) {
+			x_c = HVS_READ(offset);
+			grad = HVS_READ(offset + 4);
+			drm_printf(&p, "  %08x %08x - x %u, c %u, grad %u\n",
+				   x_c, grad,
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_X),
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_C),
+				   grad);
+		}
+		drm_printf(&p, "  blue:\n");
+		for (i = 0; i < SCALER5_DSPGAMMA_NUM_POINTS; i++, offset += 8) {
+			x_c = HVS_READ(offset);
+			grad = HVS_READ(offset + 4);
+			drm_printf(&p, "  %08x %08x - x %u, c %u, grad %u\n",
+				   x_c, grad,
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_X),
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_C),
+				   grad);
+		}
+
+		/* Alpha only valid on channel 2 */
+		if (chan != 2)
+			continue;
+
+		drm_printf(&p, "  alpha:\n");
+		for (i = 0; i < SCALER5_DSPGAMMA_NUM_POINTS; i++, offset += 8) {
+			x_c = HVS_READ(offset);
+			grad = HVS_READ(offset + 4);
+			drm_printf(&p, "  %08x %08x - x %u, c %u, grad %u\n",
+				   x_c, grad,
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_X),
+				   VC4_GET_FIELD(x_c, SCALER5_DSPGAMMA_OFF_C),
+				   grad);
+		}
+	}
+	return 0;
+}
+
 /* The filter kernel is composed of dwords each containing 3 9-bit
  * signed integers packed next to each other.
  */
@@ -848,6 +926,9 @@ static int vc4_hvs_bind(struct device *d
 			     NULL);
 	vc4_debugfs_add_file(drm, "hvs_dlists", vc4_hvs_debugfs_dlist,
 			     NULL);
+	if (hvs->hvs5)
+		vc4_debugfs_add_file(drm, "hvs_gamma", vc5_hvs_debugfs_gamma,
+				     NULL);
 
 	return 0;
 }
