HDMI support for modes that require the scrambler (4k @ 60Hz, most importantly)

drivers/clk/clk.c

@@ -2498,6 +2498,9 @@ void clk_request_done(struct clk_request *req)
 {
 	struct clk_core *core = req->clk->core;
 
+	if (!req)
+		return;
+
 	clk_prepare_lock();
 
 	list_del(&req->list);

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -272,6 +272,19 @@ static u32 vc4_crtc_get_fifo_full_level_bits(struct vc4_crtc *vc4_crtc,
 				   PV_CONTROL_FIFO_LEVEL);
 }
 
+static struct drm_encoder *vc4_get_connector_encoder(struct drm_connector *connector)
+{
+	struct drm_encoder *encoder;
+
+	if (drm_WARN_ON(connector->dev, hweight32(connector->possible_encoders) != 1))
+		return NULL;
+
+	drm_connector_for_each_possible_encoder(connector, encoder)
+		return encoder;
+
+	return NULL;
+}
+
 /*
  * Returns the encoder attached to the CRTC.
  *
@@ -286,9 +299,17 @@ static struct drm_encoder *vc4_get_crtc_encoder(struct drm_crtc *crtc)
 
 	drm_connector_list_iter_begin(crtc->dev, &conn_iter);
 	drm_for_each_connector_iter(connector, &conn_iter) {
-		if (connector->state->crtc == crtc) {
+		struct drm_encoder *encoder;
+		struct vc4_encoder *vc4_encoder;
+
+		encoder = vc4_get_connector_encoder(connector);
+		if (!encoder)
+			continue;
+
+		vc4_encoder = to_vc4_encoder(encoder);
+		if (vc4_encoder->crtc == crtc) {
 			drm_connector_list_iter_end(&conn_iter);
-			return connector->encoder;
+			return encoder;
 		}
 	}
 	drm_connector_list_iter_end(&conn_iter);
@@ -1049,6 +1070,9 @@ static void vc4_set_crtc_possible_masks(struct drm_device *drm,
 		struct vc4_encoder *vc4_encoder;
 		int i;
 
+		if (encoder->encoder_type == DRM_MODE_ENCODER_VIRTUAL)
+			continue;
+
 		vc4_encoder = to_vc4_encoder(encoder);
 		for (i = 0; i < ARRAY_SIZE(pv_data->encoder_types); i++) {
 			if (vc4_encoder->type == encoder_types[i]) {

drivers/gpu/drm/vc4/vc4_drv.c

@@ -226,6 +226,41 @@ static int compare_dev(struct device *dev, void *data)
 	return dev == data;
 }
 
+static struct drm_crtc *vc4_drv_find_crtc(struct drm_device *drm,
+					  struct drm_encoder *encoder)
+{
+	struct drm_crtc *crtc;
+
+	if (WARN_ON(hweight32(encoder->possible_crtcs) != 1))
+		return NULL;
+
+	drm_for_each_crtc(crtc, drm) {
+		if (!drm_encoder_crtc_ok(encoder, crtc))
+			continue;
+
+		return crtc;
+	}
+
+	return NULL;
+}
+
+static void vc4_drv_set_encoder_data(struct drm_device *drm)
+{
+	struct drm_encoder *encoder;
+
+	drm_for_each_encoder(encoder, drm) {
+		struct vc4_encoder *vc4_encoder;
+		struct drm_crtc *crtc;
+
+		crtc = vc4_drv_find_crtc(drm, encoder);
+		if (WARN_ON(!crtc))
+			return;
+
+		vc4_encoder = to_vc4_encoder(encoder);
+		vc4_encoder->crtc = crtc;
+	}
+}
+
 static void vc4_match_add_drivers(struct device *dev,
 				  struct component_match **match,
 				  struct platform_driver *const *drivers,
@@ -308,6 +343,7 @@ static int vc4_drm_bind(struct device *dev)
 	ret = component_bind_all(dev, drm);
 	if (ret)
 		return ret;
+	vc4_drv_set_encoder_data(drm);
 
 	if (!vc4->firmware_kms) {
 		ret = vc4_plane_create_additional_planes(drm);
@@ -354,12 +390,21 @@ static const struct component_master_ops vc4_drm_ops = {
 	.unbind = vc4_drm_unbind,
 };
 
+/*
+ * This list determines the binding order of our components, and we have
+ * a few constraints:
+ *   - The TXP driver needs to be bound before the PixelValves (CRTC)
+ *     but after the HVS to set the possible_crtc field properly
+ *   - The HDMI driver needs to be bound after the HVS so that we can
+ *     lookup the HVS maximum core clock rate and figure out if we
+ *     support 4kp60 or not.
+ */
 static struct platform_driver *const component_drivers[] = {
+	&vc4_hvs_driver,
 	&vc4_hdmi_driver,
 	&vc4_vec_driver,
 	&vc4_dpi_driver,
 	&vc4_dsi_driver,
-	&vc4_hvs_driver,
 	&vc4_txp_driver,
 	&vc4_crtc_driver,
 	&vc4_firmware_kms_driver,

drivers/gpu/drm/vc4/vc4_drv.h

@@ -447,6 +447,16 @@ enum vc4_encoder_type {
 
 struct vc4_encoder {
 	struct drm_encoder base;
+
+	/*
+	 * At boot time, we need to be able to retrieve the CRTC for a given
+	 * connector in order to run the disable hooks below to avoid the stuck
+	 * pixel issue. Unfortunately the drm_connector->encoder pointer is
+	 * NULL at that time so we can't move up the chain, so we'll store it
+	 * ourselves here.
+	 */
+	struct drm_crtc *crtc;
+
 	enum vc4_encoder_type type;
 	u32 clock_select;
 

drivers/gpu/drm/vc4/vc4_hdmi.c

@@ -35,6 +35,7 @@
 #include <drm/drm_edid.h>
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>
+#include <drm/drm_scdc_helper.h>
 #include <linux/clk.h>
 #include <linux/component.h>
 #include <linux/i2c.h>
@@ -78,6 +79,8 @@
 #define VC5_HDMI_VERTB_VSPO_SHIFT		16
 #define VC5_HDMI_VERTB_VSPO_MASK		VC4_MASK(29, 16)
 
+#define VC5_HDMI_SCRAMBLER_CTL_ENABLE		BIT(0)
+
 #define VC5_HDMI_DEEP_COLOR_CONFIG_1_INIT_PACK_PHASE_SHIFT	8
 #define VC5_HDMI_DEEP_COLOR_CONFIG_1_INIT_PACK_PHASE_MASK	VC4_MASK(10, 8)
 
@@ -93,7 +96,6 @@
 # define VC4_HD_M_ENABLE			BIT(0)
 
 #define CEC_CLOCK_FREQ 40000
-#define VC4_HSM_MID_CLOCK 149985000
 
 #define HDMI_CODEC_CHMAP_IDX_UNKNOWN  -1
 
@@ -402,6 +404,11 @@ static void hdmi_codec_eld_chmap(struct vc4_hdmi *vc4_hdmi)
 
 #define HDMI_14_MAX_TMDS_CLK   (340 * 1000 * 1000)
 
+static bool vc4_hdmi_mode_needs_scrambling(const struct drm_display_mode *mode)
+{
+	return (mode->clock * 1000) > HDMI_14_MAX_TMDS_CLK;
+}
+
 static int vc4_hdmi_debugfs_regs(struct seq_file *m, void *unused)
 {
 	struct drm_info_node *node = (struct drm_info_node *)m->private;
@@ -524,6 +531,18 @@ static int vc4_hdmi_connector_get_modes(struct drm_connector *connector)
 	ret = drm_add_edid_modes(connector, edid);
 	kfree(edid);
 
+	if (vc4_hdmi->disable_4kp60) {
+		struct drm_device *drm = connector->dev;
+		struct drm_display_mode *mode;
+
+		list_for_each_entry(mode, &connector->probed_modes, head) {
+			if (vc4_hdmi_mode_needs_scrambling(mode)) {
+				drm_warn_once(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
+				drm_warn_once(drm, "Please change your config.txt file to add hdmi_enable_4kp60.");
+			}
+		}
+	}
+
 	return ret;
 }
 
@@ -825,6 +844,64 @@ static void vc4_hdmi_set_infoframes(struct drm_encoder *encoder)
 	vc4_hdmi_set_hdr_infoframe(encoder);
 }
 
+static bool vc4_hdmi_supports_scrambling(struct drm_encoder *encoder,
+					 struct drm_display_mode *mode)
+{
+	struct vc4_hdmi_encoder *vc4_encoder = to_vc4_hdmi_encoder(encoder);
+	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
+	struct drm_display_info *display = &vc4_hdmi->connector.display_info;
+
+	if (!vc4_encoder->hdmi_monitor)
+		return false;
+
+	if (!display->hdmi.scdc.supported ||
+	    !display->hdmi.scdc.scrambling.supported)
+		return false;
+
+	return true;
+}
+
+static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
+{
+	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
+	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
+
+	if (!vc4_hdmi_supports_scrambling(encoder, mode))
+		return;
+
+	if (!vc4_hdmi_mode_needs_scrambling(mode))
+		return;
+
+	drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, true);
+	drm_scdc_set_scrambling(vc4_hdmi->ddc, true);
+
+	HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) |
+		   VC5_HDMI_SCRAMBLER_CTL_ENABLE);
+}
+
+static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
+{
+	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
+	struct drm_crtc *crtc = encoder->crtc;
+
+	/*
+	 * At boot, encoder->crtc will be NULL. Since we don't know the
+	 * state of the scrambler and in order to avoid any
+	 * inconsistency, let's disable it all the time.
+	 */
+	if (crtc && !vc4_hdmi_supports_scrambling(encoder, &crtc->mode))
+		return;
+
+	if (crtc && !vc4_hdmi_mode_needs_scrambling(&crtc->mode))
+		return;
+
+	HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) &
+		   ~VC5_HDMI_SCRAMBLER_CTL_ENABLE);
+
+	drm_scdc_set_scrambling(vc4_hdmi->ddc, false);
+	drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, false);
+}
+
 static void vc4_hdmi_encoder_post_crtc_disable(struct drm_encoder *encoder,
 					       struct drm_atomic_state *state)
 {
@@ -837,6 +914,8 @@ static void vc4_hdmi_encoder_post_crtc_disable(struct drm_encoder *encoder,
 
 	HDMI_WRITE(HDMI_VID_CTL,
 		   HDMI_READ(HDMI_VID_CTL) | VC4_HD_VID_CTL_BLANKPIX);
+
+	vc4_hdmi_disable_scrambling(encoder);
 }
 
 static void vc4_hdmi_encoder_post_crtc_powerdown(struct drm_encoder *encoder,
@@ -1120,7 +1199,7 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder,
 		conn_state_to_vc4_hdmi_conn_state(conn_state);
 	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
 	struct vc4_hdmi *vc4_hdmi = encoder_to_vc4_hdmi(encoder);
-	unsigned long pixel_rate, hsm_rate;
+	unsigned long bvb_rate, pixel_rate, hsm_rate;
 	int ret;
 
 	ret = pm_runtime_get_sync(&vc4_hdmi->pdev->dev);
@@ -1174,12 +1253,14 @@ static void vc4_hdmi_encoder_pre_crtc_configure(struct drm_encoder *encoder,
 
 	vc4_hdmi_cec_update_clk_div(vc4_hdmi);
 
-	/*
-	 * FIXME: When the pixel freq is 594MHz (4k60), this needs to be setup
-	 * at 300MHz.
-	 */
-	vc4_hdmi->bvb_req = clk_request_start(vc4_hdmi->pixel_bvb_clock,
-					      (hsm_rate > VC4_HSM_MID_CLOCK ? 150000000 : 75000000));
+	if (pixel_rate > 297000000)
+		bvb_rate = 300000000;
+	else if (pixel_rate > 148500000)
+		bvb_rate = 150000000;
+	else
+		bvb_rate = 75000000;
+
+	vc4_hdmi->bvb_req = clk_request_start(vc4_hdmi->pixel_bvb_clock, bvb_rate);
 	if (IS_ERR(vc4_hdmi->bvb_req)) {
 		DRM_ERROR("Failed to set pixel bvb clock rate: %ld\n", PTR_ERR(vc4_hdmi->bvb_req));
 		clk_request_done(vc4_hdmi->hsm_req);
@@ -1290,6 +1371,7 @@ static void vc4_hdmi_encoder_post_crtc_enable(struct drm_encoder *encoder,
 	}
 
 	vc4_hdmi_recenter_fifo(vc4_hdmi);
+	vc4_hdmi_enable_scrambling(encoder);
 }
 
 static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
@@ -1342,6 +1424,9 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder,
 	if (pixel_rate > vc4_hdmi->variant->max_pixel_clock)
 		return -EINVAL;
 
+	if (vc4_hdmi->disable_4kp60 && (pixel_rate > HDMI_14_MAX_TMDS_CLK))
+		return -EINVAL;
+
 	vc4_state->pixel_rate = pixel_rate;
 
 	return 0;
@@ -1361,6 +1446,9 @@ vc4_hdmi_encoder_mode_valid(struct drm_encoder *encoder,
 	if ((mode->clock * 1000) > vc4_hdmi->variant->max_pixel_clock)
 		return MODE_CLOCK_HIGH;
 
+	if (vc4_hdmi->disable_4kp60 && vc4_hdmi_mode_needs_scrambling(mode))
+		return MODE_CLOCK_HIGH;
+
 	return MODE_OK;
 }
 
@@ -2623,9 +2711,25 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 	vc4_hdmi->disable_wifi_frequencies =
 		of_property_read_bool(dev->of_node, "wifi-2.4ghz-coexistence");
 
+	if (variant->max_pixel_clock == 600000000) {
+		struct vc4_dev *vc4 = to_vc4_dev(drm);
+		long max_rate = clk_round_rate(vc4->hvs->core_clk, 550000000);
+
+		if (max_rate < 550000000)
+			vc4_hdmi->disable_4kp60 = true;
+	}
+
 	if (vc4_hdmi->variant->reset)
 		vc4_hdmi->variant->reset(vc4_hdmi);
 
+	if ((of_device_is_compatible(dev->of_node, "brcm,bcm2711-hdmi0") ||
+	     of_device_is_compatible(dev->of_node, "brcm,bcm2711-hdmi1")) &&
+	    HDMI_READ(HDMI_VID_CTL) & VC4_HD_VID_CTL_ENABLE) {
+		clk_prepare_enable(vc4_hdmi->pixel_clock);
+		clk_prepare_enable(vc4_hdmi->hsm_clock);
+		clk_prepare_enable(vc4_hdmi->pixel_bvb_clock);
+	}
+
 	pm_runtime_enable(dev);
 
 	drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_TMDS);
@@ -2740,7 +2844,7 @@ static const struct vc4_hdmi_variant bcm2711_hdmi0_variant = {
 	.encoder_type		= VC4_ENCODER_TYPE_HDMI0,
 	.debugfs_name		= "hdmi0_regs",
 	.card_name		= "vc4-hdmi-0",
-	.max_pixel_clock	= HDMI_14_MAX_TMDS_CLK,
+	.max_pixel_clock	= 600000000,
 	.registers		= vc5_hdmi_hdmi0_fields,
 	.num_registers		= ARRAY_SIZE(vc5_hdmi_hdmi0_fields),
 	.phy_lane_mapping	= {

drivers/gpu/drm/vc4/vc4_hdmi.h

@@ -162,6 +162,14 @@ struct vc4_hdmi {
 	 */
 	bool disable_wifi_frequencies;
 
+	/*
+	 * Even if HDMI0 on the RPi4 can output modes requiring a pixel
+	 * rate higher than 297MHz, it needs some adjustments in the
+	 * config.txt file to be able to do so and thus won't always be
+	 * available.
+	 */
+	bool disable_4kp60;
+
 	struct cec_adapter *cec_adap;
 	struct cec_msg cec_rx_msg;
 	bool cec_tx_ok;