LibreELEC.tv/packages/linux/patches/rockchip/rockchip-0097-WIP-SCRAMB-drm-bridge-dw-hdmi-qp-Add-high-TMDS-clock.patch

From b1b2d3346cc84581f57a77c7f4d28bda6aa88c46 Mon Sep 17 00:00:00 2001
From: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
Date: Fri, 13 Sep 2024 17:30:35 +0300
Subject: [PATCH 097/110] [WIP-SCRAMB] drm/bridge: dw-hdmi-qp: Add high TMDS
 clock ratio and scrambling support

Enable use of HDMI 2.0 display modes, e.g. 4K@60Hz, by permitting TMDS
character rates above the 340 MHz limit of HDMI 1.4b.

Hence, add the required support for SCDC management, including the high
TMDS clock ratio and scrambling setup.

Additionally, filter out HDMI 2.1 display modes.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@collabora.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c | 214 ++++++++++++++++++-
 1 file changed, 203 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
index 54377ba3a607..16736bcf26e1 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c
@@ -20,6 +20,7 @@
 #include <drm/display/drm_hdmi_helper.h>
 #include <drm/display/drm_hdmi_cec_helper.h>
 #include <drm/display/drm_hdmi_state_helper.h>
+#include <drm/display/drm_scdc_helper.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
@@ -36,7 +37,10 @@
 #define DDC_CI_ADDR		0x37
 #define DDC_SEGMENT_ADDR	0x30
 
+#define SCDC_MIN_SOURCE_VERSION	0x1
+
 #define HDMI14_MAX_TMDSCLK	340000000
+#define HDMI20_MAX_TMDSRATE	600000000
 
 #define SCRAMB_POLL_DELAY_MS	3000
 
@@ -162,6 +166,11 @@ struct dw_hdmi_qp {
 	} phy;
 
 	unsigned long ref_clk_rate;
+
+	struct drm_connector *connector;
+	struct delayed_work scramb_work;
+	bool scramb_enabled;
+
 	struct regmap *regm;
 
 	unsigned long tmds_char_rate;
@@ -850,28 +859,103 @@ static int dw_hdmi_qp_config_audio_infoframe(struct dw_hdmi_qp *hdmi,
 	return 0;
 }
 
+static bool dw_hdmi_qp_supports_scrambling(struct dw_hdmi_qp *hdmi)
+{
+	struct drm_display_info *display = &hdmi->connector->display_info;
+
+	if (!display->is_hdmi)
+		return false;
+
+	if (!display->hdmi.scdc.supported ||
+	    !display->hdmi.scdc.scrambling.supported)
+		return false;
+
+	return true;
+}
+
+static void dw_hdmi_qp_set_scramb(struct dw_hdmi_qp *hdmi)
+{
+	dev_dbg(hdmi->dev, "set scrambling\n");
+
+	drm_scdc_set_high_tmds_clock_ratio(hdmi->connector, true);
+	drm_scdc_set_scrambling(hdmi->connector, true);
+
+	schedule_delayed_work(&hdmi->scramb_work,
+			      msecs_to_jiffies(SCRAMB_POLL_DELAY_MS));
+}
+
+static void dw_hdmi_qp_scramb_work(struct work_struct *work)
+{
+	struct dw_hdmi_qp *hdmi = container_of(to_delayed_work(work),
+					       struct dw_hdmi_qp,
+					       scramb_work);
+	if (!drm_scdc_get_scrambling_status(hdmi->connector))
+		dw_hdmi_qp_set_scramb(hdmi);
+}
+
+static void dw_hdmi_qp_enable_scramb(struct dw_hdmi_qp *hdmi)
+{
+	u8 ver;
+
+	if (!dw_hdmi_qp_supports_scrambling(hdmi))
+		return;
+
+	drm_scdc_readb(hdmi->bridge.ddc, SCDC_SINK_VERSION, &ver);
+	drm_scdc_writeb(hdmi->bridge.ddc, SCDC_SOURCE_VERSION,
+			min_t(u8, ver, SCDC_MIN_SOURCE_VERSION));
+
+	dw_hdmi_qp_set_scramb(hdmi);
+	dw_hdmi_qp_write(hdmi, 1, SCRAMB_CONFIG0);
+
+	hdmi->scramb_enabled = true;
+
+	/* Wait for resuming transmission of TMDS clock and data */
+	msleep(100);
+}
+
+static void dw_hdmi_qp_disable_scramb(struct dw_hdmi_qp *hdmi)
+{
+	if (!hdmi->scramb_enabled)
+		return;
+
+	dev_dbg(hdmi->dev, "disable scrambling\n");
+
+	hdmi->scramb_enabled = false;
+	cancel_delayed_work_sync(&hdmi->scramb_work);
+
+	dw_hdmi_qp_write(hdmi, 0, SCRAMB_CONFIG0);
+
+	if (hdmi->connector->status != connector_status_disconnected) {
+		drm_scdc_set_scrambling(hdmi->connector, false);
+		drm_scdc_set_high_tmds_clock_ratio(hdmi->connector, false);
+	}
+}
+
 static void dw_hdmi_qp_bridge_atomic_enable(struct drm_bridge *bridge,
 					    struct drm_atomic_state *state)
 {
 	struct dw_hdmi_qp *hdmi = bridge->driver_private;
 	struct drm_connector_state *conn_state;
-	struct drm_connector *connector;
 	unsigned int op_mode;
 
-	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
-	if (WARN_ON(!connector))
+	hdmi->connector = drm_atomic_get_new_connector_for_encoder(state,
+								   bridge->encoder);
+	if (WARN_ON(!hdmi->connector))
 		return;
 
-	conn_state = drm_atomic_get_new_connector_state(state, connector);
+	conn_state = drm_atomic_get_new_connector_state(state, hdmi->connector);
 	if (WARN_ON(!conn_state))
 		return;
 
-	if (connector->display_info.is_hdmi) {
+	if (hdmi->connector->display_info.is_hdmi) {
 		dev_dbg(hdmi->dev, "%s mode=HDMI %s rate=%llu bpc=%u\n", __func__,
 			drm_hdmi_connector_get_output_format_name(conn_state->hdmi.output_format),
 			conn_state->hdmi.tmds_char_rate, conn_state->hdmi.output_bpc);
 		op_mode = 0;
 		hdmi->tmds_char_rate = conn_state->hdmi.tmds_char_rate;
+
+		if (conn_state->hdmi.tmds_char_rate > HDMI14_MAX_TMDSCLK)
+			dw_hdmi_qp_enable_scramb(hdmi);
 	} else {
 		dev_dbg(hdmi->dev, "%s mode=DVI\n", __func__);
 		op_mode = OPMODE_DVI;
@@ -882,7 +966,7 @@ static void dw_hdmi_qp_bridge_atomic_enable(struct drm_bridge *bridge,
 	dw_hdmi_qp_mod(hdmi, HDCP2_BYPASS, HDCP2_BYPASS, HDCP2LOGIC_CONFIG0);
 	dw_hdmi_qp_mod(hdmi, op_mode, OPMODE_DVI, LINK_CONFIG0);
 
-	drm_atomic_helper_connector_hdmi_update_infoframes(connector, state);
+	drm_atomic_helper_connector_hdmi_update_infoframes(hdmi->connector, state);
 }
 
 static void dw_hdmi_qp_bridge_atomic_disable(struct drm_bridge *bridge,
@@ -892,15 +976,121 @@ static void dw_hdmi_qp_bridge_atomic_disable(struct drm_bridge *bridge,
 
 	hdmi->tmds_char_rate = 0;
 
+	dw_hdmi_qp_disable_scramb(hdmi);
+
+	hdmi->connector = NULL;
 	hdmi->phy.ops->disable(hdmi, hdmi->phy.data);
 }
 
-static enum drm_connector_status
-dw_hdmi_qp_bridge_detect(struct drm_bridge *bridge, struct drm_connector *connector)
+static int dw_hdmi_qp_reset_link(struct drm_connector *conn,
+				 struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_crtc_state *crtc_state;
+	struct drm_atomic_state *state;
+	struct drm_crtc *crtc;
+	int ret;
+
+	ret = drm_modeset_lock(&conn->dev->mode_config.connection_mutex, ctx);
+	if (ret)
+		return ret;
+
+	crtc = conn->state->crtc;
+	if (!crtc)
+		return 0;
+
+	ret = drm_modeset_lock(&crtc->mutex, ctx);
+	if (ret)
+		return ret;
+
+	if (!crtc->state->active)
+		return 0;
+
+	if (conn->state->commit &&
+	    !try_wait_for_completion(&conn->state->commit->hw_done))
+		return 0;
+
+	state = drm_atomic_state_alloc(crtc->dev);
+	if (!state)
+		return -ENOMEM;
+
+	state->acquire_ctx = ctx;
+retry:
+	crtc_state = drm_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto out;
+	}
+
+	crtc_state->connectors_changed = true;
+
+	ret = drm_atomic_commit(state);
+out:
+	if (ret == -EDEADLK) {
+		drm_atomic_state_clear(state);
+		drm_modeset_backoff(ctx);
+		goto retry;
+	}
+
+	drm_atomic_state_put(state);
+
+	return ret;
+}
+
+static int dw_hdmi_qp_bridge_detect(struct drm_bridge *bridge,
+				    struct drm_modeset_acquire_ctx *ctx)
 {
 	struct dw_hdmi_qp *hdmi = bridge->driver_private;
+	enum drm_connector_status status;
+	const struct drm_edid *drm_edid;
+
+	status = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
+
+	dev_dbg(hdmi->dev, "%s conn=%d scramb=%d\n", __func__,
+		status, hdmi->scramb_enabled);
+
+	if (hdmi->scramb_enabled)
+		cancel_delayed_work_sync(&hdmi->scramb_work);
+
+	if (status == connector_status_disconnected || !hdmi->connector)
+		return status;
+
+	dev_dbg(hdmi->dev, "reading DDC\n");
+	//TODO: also read via dw_hdmi_qp_bridge_edid_read()
+	// and drm_bridge_connector_read_edid()
+	drm_edid = drm_edid_read_ddc(hdmi->connector, bridge->ddc);
+
+	drm_edid_connector_update(hdmi->connector, drm_edid);
+
+	if (!drm_edid) {
+		dev_dbg(hdmi->dev, "got no EDID\n");
+		return status;
+	}
+
+	drm_edid_free(drm_edid);
+
+	/* if (!hdmi->scramb_enabled || !dw_hdmi_qp_supports_scrambling(hdmi) || */
+	/*     drm_scdc_get_scrambling_status(hdmi->connector)) */
+	/* 	return status; */
+
+	if (!hdmi->scramb_enabled)
+		return status;
+
+	if (!dw_hdmi_qp_supports_scrambling(hdmi)) {
+		dev_dbg(hdmi->dev, "scramb not supported\n");
+		return status;
+	}
+
+	if (drm_scdc_get_scrambling_status(hdmi->connector)) {
+		dev_dbg(hdmi->dev, "scramb already enabled\n");
+		return status;
+	}
 
-	return hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
+	//FIXME: disable output before scramb setup - see vc4_hdmi_reset_link()
+	dev_dbg(hdmi->dev, "%s reset link\n", __func__);
+	dw_hdmi_qp_reset_link(hdmi->connector, ctx);
+	/* dw_hdmi_qp_set_scramb(hdmi); */
+
+	return status;
 }
 
 static const struct drm_edid *
@@ -924,7 +1114,7 @@ dw_hdmi_qp_bridge_tmds_char_rate_valid(const struct drm_bridge *bridge,
 {
 	struct dw_hdmi_qp *hdmi = bridge->driver_private;
 
-	if (rate > HDMI14_MAX_TMDSCLK) {
+	if (rate > HDMI20_MAX_TMDSRATE) {
 		dev_dbg(hdmi->dev, "Unsupported TMDS char rate: %lld\n", rate);
 		return MODE_CLOCK_HIGH;
 	}
@@ -1164,7 +1354,7 @@ static const struct drm_bridge_funcs dw_hdmi_qp_bridge_funcs = {
 	.atomic_reset = drm_atomic_helper_bridge_reset,
 	.atomic_enable = dw_hdmi_qp_bridge_atomic_enable,
 	.atomic_disable = dw_hdmi_qp_bridge_atomic_disable,
-	.detect = dw_hdmi_qp_bridge_detect,
+	.detect_ctx = dw_hdmi_qp_bridge_detect,
 	.edid_read = dw_hdmi_qp_bridge_edid_read,
 	.hdmi_tmds_char_rate_valid = dw_hdmi_qp_bridge_tmds_char_rate_valid,
 	.hdmi_clear_infoframe = dw_hdmi_qp_bridge_clear_infoframe,
@@ -1246,6 +1436,8 @@ struct dw_hdmi_qp *dw_hdmi_qp_bind(struct platform_device *pdev,
 	if (IS_ERR(hdmi))
 		return ERR_CAST(hdmi);
 
+	INIT_DELAYED_WORK(&hdmi->scramb_work, dw_hdmi_qp_scramb_work);
+
 	hdmi->dev = dev;
 
 	regs = devm_platform_ioremap_resource(pdev, 0);
-- 
2.34.1