[RFC 0/8] Add support for DP-HDMI2.1 PCON

[RFC 0/8] Add support for DP-HDMI2.1 PCON

[Ankit Nautiyal]

This patch series attempts to add support for a DP-HDMI2.1 Protocol
Convertor. The VESA spec for the HDMI2.1 PCON are proposed in Errata
E5 to DisplayPort_v2.0:
https://vesa.org/join-vesamemberships/member-downloads/?action=stamp&fileid=42299
The details are mentioned in DP to HDMI2.1 PCON Enum/Config
improvement slide decks:
https://groups.vesa.org/wg/DP/document/folder/1316

This RFC series starts with adding support for FRL (Fixed Rate Link)
Training between the PCON and HDMI2.1 sink.
As per HDMI2.1 specification, a new data-channel or lane is added in
FRL mode, by repurposing the TMDS clock Channel. Through FRL, higher
bit-rate can be supported, ie. up to 12 Gbps/lane (48 Gbps over 4
lanes).

With these patches, the HDMI2.1 PCON can be configured to achieve FRL
training based on the maximum FRL rate supported by the panel, source
and the PCON.
The approach is to add the support for FRL training between PCON and
HDMI2.1 sink and gradually add other blocks for supporting higher
resolutions and other HDMI2.1 features, that can be supported by pcon
for the sources that do not natively support HDMI2.1.

This is done before the DP Link training between the source and PCON
is started. In case of FRL training is not achieved, the PCON will
work in the regular TMDS mode, without HDMI2.1 feature support.
Any interruption in FRL training between the PCON and HDMI2.1 sink is
notified through IRQ_HPD. On receiving the IRQ_HPD the concerned DPCD
registers are read and FRL training is re-attempted.

Currently, we have tested the FRL training and are able to enable 4K
display with TGL Platform + Realtek PCON RTD2173 with HDMI2.1 supporting
panel.

v2: Added patch to capture the PCON FRL caps in downstream facing port
cap structure.

Ankit Nautiyal (4):
  drm/dp_helper: Add FRL training support for a DP-HDMI2.1 PCON
  drm/i915: Capture max frl rate for PCON in dfp cap structure
  drm/i915: Add support for starting FRL training for HDMI2.1 via PCON
  drm/i915: Check for FRL training before DP Link training

Swati Sharma (4):
  drm/edid: Add additional HFVSDB fields for HDMI2.1
  drm/edid: Parse MAX_FRL field from HFVSDB block
  drm/dp_helper: Add support for link status and link recovery
  drm/i915: Add support for enabling link status and recovery

 drivers/gpu/drm/drm_dp_helper.c               | 338 ++++++++++++++++++
 drivers/gpu/drm/drm_edid.c                    |  50 +++
 drivers/gpu/drm/i915/display/intel_ddi.c      |   2 +
 .../drm/i915/display/intel_display_types.h    |   7 +
 drivers/gpu/drm/i915/display/intel_dp.c       | 282 ++++++++++++++-
 drivers/gpu/drm/i915/display/intel_dp.h       |   2 +
 include/drm/drm_connector.h                   |   6 +
 include/drm/drm_dp_helper.h                   |  96 +++++
 include/drm/drm_edid.h                        |  30 ++
 9 files changed, 808 insertions(+), 5 deletions(-)

-- 
2.17.1

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[RFC 1/8] drm/edid: Add additional HFVSDB fields for HDMI2.1

[Ankit Nautiyal]

From: Swati Sharma <swati2.sharma@intel.com>

The HDMI2.1 extends HFVSBD (HDMI Forum Vendor Specific
Data block) to have fields related to newly defined methods of FRL
(Fixed Rate Link) levels, number of lanes supported, DSC Color bit
depth, VRR min/max, FVA (Fast Vactive), ALLM etc.

This patch adds the new HFVSDB fields that are required for
HDMI2.1.

Signed-off-by: Sharma, Swati2 <swati2.sharma@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 include/drm/drm_edid.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index b27a0e2169c8..3b6371f36676 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -229,6 +229,36 @@ struct detailed_timing {
 				    DRM_EDID_YCBCR420_DC_36 | \
 				    DRM_EDID_YCBCR420_DC_30)
 
+/* HDMI 2.1 additional fields */
+#define DRM_EDID_MAX_FRL_RATE_MASK		0xf0
+#define DRM_EDID_FAPA_START_LOCATION		(1 << 0)
+#define DRM_EDID_ALLM				(1 << 1)
+#define DRM_EDID_FVA				(1 << 2)
+
+/* Deep Color specific */
+#define DRM_EDID_DC_30BIT_420			(1 << 0)
+#define DRM_EDID_DC_36BIT_420			(1 << 1)
+#define DRM_EDID_DC_48BIT_420			(1 << 2)
+
+/* VRR specific */
+#define DRM_EDID_CNMVRR				(1 << 3)
+#define DRM_EDID_CINEMA_VRR			(1 << 4)
+#define DRM_EDID_MDELTA				(1 << 5)
+#define DRM_EDID_VRR_MAX_UPPER_MASK		0xc0
+#define DRM_EDID_VRR_MAX_LOWER_MASK		0xff
+#define DRM_EDID_VRR_MIN_MASK			0x3f
+
+/* DSC specific */
+#define DRM_EDID_DSC_10				(1 << 0)
+#define DRM_EDID_DSC_12				(1 << 1)
+#define DRM_EDID_DSC_16				(1 << 2)
+#define DRM_EDID_DSC_ALL			(1 << 3)
+#define DRM_EDID_DSC_NATIVE_420			(1 << 6)
+#define DRM_EDID_1P2				(1 << 7)
+#define DRM_EDID_DSC_MAX_FRL_RATE		0xf
+#define DRM_EDID_DSC_MAX_SLICES			0xf
+#define DRM_EDID_DSC_TOTAL_CHUNK_KBYTES		0x3f
+
 /* ELD Header Block */
 #define DRM_ELD_HEADER_BLOCK_SIZE	4
 
-- 
2.17.1

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[RFC 2/8] drm/edid: Parse MAX_FRL field from HFVSDB block

[Ankit Nautiyal]

From: Swati Sharma <swati2.sharma@intel.com>

This patch parses MAX_FRL field to get the MAX rate in Gbps that
the HDMI 2.1 panel can support in FRL mode. Source need this
field to determine the optimal rate between the source and sink
during FRL training.

Signed-off-by: Sharma, Swati2 <swati2.sharma@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/drm_edid.c  | 50 +++++++++++++++++++++++++++++++++++++
 include/drm/drm_connector.h |  6 +++++
 2 files changed, 56 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 631125b46e04..d468ac91abb6 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -4849,6 +4849,51 @@ static void drm_parse_vcdb(struct drm_connector *connector, const u8 *db)
 		info->rgb_quant_range_selectable = true;
 }
 
+static void drm_parse_hdmi_21_additional_fields(struct drm_connector *connector,
+						const u8 *db)
+{
+     /* hf_vsdb 7:14 support needs to be added */
+
+    u8 max_frl_rate_per_lane;
+    struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+
+    max_frl_rate_per_lane = (db[7] & DRM_EDID_MAX_FRL_RATE_MASK) >> 4;
+
+    switch(max_frl_rate_per_lane) {
+    case 0:
+	    hdmi->max_lane = 0;
+	    hdmi->max_frl_rate_per_lane = 0;
+	    break;
+    case 1:
+	    hdmi->max_lane = 3;
+	    hdmi->max_frl_rate_per_lane = 3;
+	    break;
+    case 2:
+	    hdmi->max_lane = 3;
+	    hdmi->max_frl_rate_per_lane = 6;
+	    break;
+    case 3:
+	    hdmi->max_lane = 4;
+	    hdmi->max_frl_rate_per_lane = 6;
+	    break;
+    case 4:
+	    hdmi->max_lane = 4;
+	    hdmi->max_frl_rate_per_lane = 8;
+	    break;
+    case 5:
+	    hdmi->max_lane = 4;
+	    hdmi->max_frl_rate_per_lane = 10;
+	    break;
+    case 6:
+	    hdmi->max_lane = 4;
+	    hdmi->max_frl_rate_per_lane = 12;
+	    break;
+    default:
+	    DRM_DEBUG_KMS("max frl rate per lane 0x%x, reserved\n", max_frl_rate_per_lane);
+	    break;
+    }
+}
+
 static void drm_parse_ycbcr420_deep_color_info(struct drm_connector *connector,
 					       const u8 *db)
 {
@@ -4902,6 +4947,11 @@ static void drm_parse_hdmi_forum_vsdb(struct drm_connector *connector,
 		}
 	}
 
+	if (hf_vsdb[7]) {
+		    DRM_DEBUG_KMS("hdmi_21 sink detected. parsing edid\n");
+		    drm_parse_hdmi_21_additional_fields(connector, hf_vsdb);
+	}
+
 	drm_parse_ycbcr420_deep_color_info(connector, hf_vsdb);
 }
 
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 928136556174..aa6ae9c17ca4 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -207,6 +207,12 @@ struct drm_hdmi_info {
 
 	/** @y420_dc_modes: bitmap of deep color support index */
 	u8 y420_dc_modes;
+
+	/** @max_frl_rate_per_lane: support fixed rate link */
+	u8 max_frl_rate_per_lane;
+
+	/** @max_lane: supported by sink */
+	u8 max_lane;
 };
 
 /**
-- 
2.17.1

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[RFC 3/8] drm/dp_helper: Add FRL training support for a DP-HDMI2.1 PCON

[Ankit Nautiyal]

This patch adds support for configuring a PCON device,
connected as a DP branched device to enable FRL Link training
with a HDMI2.1 + sink.

v2: Minor changes:
-removed unnecessary argument supplied to a drm helper function.
-fixed return value for max frl read from pcon.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 305 ++++++++++++++++++++++++++++++++
 include/drm/drm_dp_helper.h     |  80 +++++++++
 2 files changed, 385 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 478dd51f738d..39d8e4d665b7 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -2366,3 +2366,308 @@ void drm_dp_vsc_sdp_log(const char *level, struct device *dev,
 #undef DP_SDP_LOG
 }
 EXPORT_SYMBOL(drm_dp_vsc_sdp_log);
+
+/**
+ * drm_dp_get_pcon_max_frl_bw() - maximum frl supported by PCON
+ * @dpcd: DisplayPort configuration data
+ * @port_cap: port capabilities
+ *
+ * Returns maximum frl bandwidth supported by PCON in GBPS,
+ * returns 0 if not supported.
+ **/
+int drm_dp_get_pcon_max_frl_bw(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+			       const u8 port_cap[4])
+{
+	int bw;
+	u8 buf;
+
+	buf = port_cap[2];
+	bw = buf & DP_PCON_MAX_FRL_BW;
+
+	switch (bw) {
+	case DP_PCON_MAX_9GBPS:
+		return 9;
+	case DP_PCON_MAX_18GBPS:
+		return 18;
+	case DP_PCON_MAX_24GBPS:
+		return 24;
+	case DP_PCON_MAX_32GBPS:
+		return 32;
+	case DP_PCON_MAX_40GBPS:
+		return 40;
+	case DP_PCON_MAX_48GBPS:
+		return 48;
+	case DP_PCON_MAX_0GBPS:
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_get_pcon_max_frl_bw);
+
+/**
+ * drm_dp_get_hdmi_max_frl_bw() - maximum frl supported by HDMI Sink
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns maximum frl bandwidth supported by HDMI in Gbps on success,
+ * returns 0, if not supported.
+ **/
+int drm_dp_get_hdmi_max_frl_bw(struct drm_dp_aux *aux)
+{
+	u8 buf;
+	int bw, ret;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_SINK, &buf);
+	if (ret < 0)
+		return 0;
+	bw = buf & DP_HDMI_SINK_LINK_BW;
+
+	switch (bw) {
+	case DP_HDMI_SINK_BW_9GBPS:
+		return 9;
+	case DP_HDMI_SINK_BW_18GBPS:
+		return 18;
+	case DP_HDMI_SINK_BW_24GBPS:
+		return 24;
+	case DP_HDMI_SINK_BW_32GBPS:
+		return 32;
+	case DP_HDMI_SINK_BW_40GBPS:
+		return 40;
+	case DP_HDMI_SINK_BW_48GBPS:
+		return 48;
+	case DP_HDMI_SINK_BW_0GBPS:
+	default:
+		return 0;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_get_hdmi_max_frl_bw);
+
+/**
+ * drm_dp_pcon_frl_prepare() - Prepare PCON for FRL.
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns 0 if success, else returns negative error code.
+ **/
+int drm_dp_pcon_frl_prepare(struct drm_dp_aux *aux, bool enable_frl_ready_hpd)
+{
+	int ret;
+	u8 buf = DP_PCON_ENABLE_SOURCE_CTL_MODE |
+		 DP_PCON_ENABLE_LINK_FRL_MODE;
+
+	if (enable_frl_ready_hpd)
+		buf |= DP_PCON_ENABLE_HPD_READY;
+
+	ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_dp_pcon_frl_prepare);
+
+/**
+ * drm_dp_pcon_is_frl_ready() - Is PCON ready for FRL
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns true if success, else returns false.
+ **/
+bool drm_dp_pcon_is_frl_ready(struct drm_dp_aux *aux)
+{
+	int ret;
+	u8 buf;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_TX_LINK_STATUS, &buf);
+	if (ret < 0)
+		return false;
+
+	if (buf & DP_PCON_FRL_READY)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL(drm_dp_pcon_is_frl_ready);
+
+/**
+ * drm_dp_pcon_frl_configure_1() - Set HDMI LINK Configuration-Step1
+ * @aux: DisplayPort AUX channel
+ * max_frl_mask: mask for selecting the bandwidths supported by source,
+ * to be tried by Pcon f/w.
+ * @concurrent_mode: true if concurrent mode or operation is required,
+ * false otherwise.
+ *
+ * Returns 0 if success, else returns negative error code.
+ **/
+
+int drm_dp_pcon_frl_configure_1(struct drm_dp_aux *aux, int max_frl_gbps,
+				bool concurrent_mode)
+{
+	int ret;
+	u8 buf;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf);
+	if (ret < 0)
+		return ret;
+
+	if (concurrent_mode)
+		buf |= DP_PCON_ENABLE_CONCURRENT_LINK;
+	else
+		buf &= ~DP_PCON_ENABLE_CONCURRENT_LINK;
+
+	switch (max_frl_gbps) {
+	case 9:
+		buf |=  DP_PCON_ENABLE_MAX_BW_9GBPS;
+		break;
+	case 18:
+		buf |=  DP_PCON_ENABLE_MAX_BW_18GBPS;
+		break;
+	case 24:
+		buf |=  DP_PCON_ENABLE_MAX_BW_24GBPS;
+		break;
+	case 32:
+		buf |=  DP_PCON_ENABLE_MAX_BW_32GBPS;
+		break;
+	case 40:
+		buf |=  DP_PCON_ENABLE_MAX_BW_40GBPS;
+		break;
+	case 48:
+		buf |=  DP_PCON_ENABLE_MAX_BW_48GBPS;
+		break;
+	case 0:
+		buf |=  DP_PCON_ENABLE_MAX_BW_0GBPS;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_frl_configure_1);
+
+/**
+ * drm_dp_pcon_frl_configure_2() - Set HDMI Link configuration Step-2
+ * @aux: DisplayPort AUX channel
+ * @max_frl_mask : Max FRL BW to be tried by the PCON with HDMI Sink
+ * @extended_train_mode : true for Extended Mode, false for Normal Mode.
+ * In Normal mode, the PCON tries each frl bw from the max_frl_mask starting
+ * from min, and stops when link training is successful. In Extended mode, all
+ * frl bw selected in the mask are trained by the PCON.
+ *
+ * Returns 0 if success, else returns negative error code.
+ **/
+int drm_dp_pcon_frl_configure_2(struct drm_dp_aux *aux, int max_frl_mask,
+				bool extended_train_mode)
+{
+	int ret;
+	u8 buf = 0;
+
+	buf |= max_frl_mask;
+
+	if (extended_train_mode)
+		buf |= DP_PCON_FRL_LINK_TRAIN_EXTENDED;
+
+	ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_2, buf);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_frl_configure_2);
+
+/**
+ * drm_dp_pcon_reset_frl_config() - Re-Set HDMI Link configuration.
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns 0 if success, else returns negative error code.
+ **/
+int drm_dp_pcon_reset_frl_config(struct drm_dp_aux *aux)
+{
+	int ret;
+
+	ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, 0x0);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_reset_frl_config);
+
+/**
+ * drm_dp_pcon_frl_enable() - Enable HDMI link through FRL
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns 0 if success, else returns negative error code.
+ **/
+int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux)
+{
+	int ret;
+	u8 buf = 0;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf);
+	if (ret < 0)
+		return ret;
+	if (!(buf & DP_PCON_ENABLE_SOURCE_CTL_MODE)) {
+		DRM_DEBUG_KMS("PCON in Autonomous mode, can't enable FRL\n");
+		return -EINVAL;
+	}
+	buf |= DP_PCON_ENABLE_HDMI_LINK;
+	ret = drm_dp_dpcd_writeb(aux, DP_PCON_HDMI_LINK_CONFIG_1, buf);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_dp_pcon_frl_enable);
+
+/**
+ * drm_dp_pcon_hdmi_link_active() - check if the PCON HDMI LINK status is active.
+ * @aux: DisplayPort AUX channel
+ *
+ * Returns true if link is active else returns false.
+ **/
+bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux)
+{
+	u8 buf;
+	int ret;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_TX_LINK_STATUS, &buf);
+	if (ret < 0)
+		return false;
+
+	return buf & DP_PCON_HDMI_TX_LINK_ACTIVE;
+}
+EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_active);
+
+/**
+ * drm_dp_pcon_hdmi_link_mode() - get the PCON HDMI LINK MODE
+ * @aux: DisplayPort AUX channel
+ * @frl_trained_mask: pointer to store bitmask of the trained bw configuration.
+ * Valid only if the MODE returned is FRL. For Normal Link training mode
+ * only 1 of the bits will be set, but in case of Extended mode, more than
+ * one bits can be set.
+ *
+ * Returns the link mode : TMDS or FRL on success, else retunes negative error
+ * code.
+ **/
+int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask)
+{
+	u8 buf;
+	int mode;
+	int ret;
+
+	ret = drm_dp_dpcd_readb(aux, DP_PCON_HDMI_POST_FRL_STATUS, &buf);
+	if (ret < 0)
+		return ret;
+
+	mode = buf & DP_PCON_HDMI_LINK_MODE;
+
+	if (frl_trained_mask && DP_PCON_HDMI_MODE_FRL == mode)
+		*frl_trained_mask = (buf & DP_PCON_HDMI_FRL_TRAINED_BW) >> 1;
+
+	return mode;
+}
+EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_mode);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 159191c1ae75..82fa75f6cc86 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -411,6 +411,17 @@ struct drm_device;
 # define DP_DS_10BPC		            1
 # define DP_DS_12BPC		            2
 # define DP_DS_16BPC		            3
+/* HDMI2.1 PCON FRL CONFIGURATION */
+# define DP_PCON_MAX_FRL_BW                 (7 << 2)
+# define DP_PCON_MAX_0GBPS                  (0 << 2)
+# define DP_PCON_MAX_9GBPS                  (1 << 2)
+# define DP_PCON_MAX_18GBPS                 (2 << 2)
+# define DP_PCON_MAX_24GBPS                 (3 << 2)
+# define DP_PCON_MAX_32GBPS                 (4 << 2)
+# define DP_PCON_MAX_40GBPS                 (5 << 2)
+# define DP_PCON_MAX_48GBPS                 (6 << 2)
+# define DP_PCON_SOURCE_CTL_MODE            (1 << 5)
+
 /* offset 3 for DVI */
 # define DP_DS_DVI_DUAL_LINK		    (1 << 1)
 # define DP_DS_DVI_HIGH_COLOR_DEPTH	    (1 << 2)
@@ -1053,6 +1064,61 @@ struct drm_device;
 #define DP_CEC_RX_MESSAGE_BUFFER               0x3010
 #define DP_CEC_TX_MESSAGE_BUFFER               0x3020
 #define DP_CEC_MESSAGE_BUFFER_LENGTH             0x10
+/* PROTOCOL CONVERSION HDMI SINK */
+#define DP_PCON_HDMI_SINK                      0x3035
+# define DP_HDMI_SINK_LINK_BW                  (7 << 0)
+# define DP_HDMI_SINK_BW_0GBPS		       0
+# define DP_HDMI_SINK_BW_9GBPS		       1
+# define DP_HDMI_SINK_BW_18GBPS		       2
+# define DP_HDMI_SINK_BW_24GBPS		       3
+# define DP_HDMI_SINK_BW_32GBPS		       4
+# define DP_HDMI_SINK_BW_40GBPS		       5
+# define DP_HDMI_SINK_BW_48GBPS		       6
+
+/* PCON CONFIGURE-1 FRL FOR HDMI SINK */
+#define DP_PCON_HDMI_LINK_CONFIG_1             0x305A
+# define DP_PCON_ENABLE_MAX_FRL_BW             (7 << 0)
+# define DP_PCON_ENABLE_MAX_BW_0GBPS	       0
+# define DP_PCON_ENABLE_MAX_BW_9GBPS	       1
+# define DP_PCON_ENABLE_MAX_BW_18GBPS	       2
+# define DP_PCON_ENABLE_MAX_BW_24GBPS	       3
+# define DP_PCON_ENABLE_MAX_BW_32GBPS	       4
+# define DP_PCON_ENABLE_MAX_BW_40GBPS	       5
+# define DP_PCON_ENABLE_MAX_BW_48GBPS	       6
+# define DP_PCON_ENABLE_SOURCE_CTL_MODE       (1 << 3)
+# define DP_PCON_ENABLE_CONCURRENT_LINK       (1 << 4)
+# define DP_PCON_ENABLE_LINK_FRL_MODE         (1 << 5)
+# define DP_PCON_ENABLE_HPD_READY	      (1 << 6)
+# define DP_PCON_ENABLE_HDMI_LINK             (1 << 7)
+
+/* PCON CONFIGURE-2 FRL FOR HDMI SINK */
+#define DP_PCON_HDMI_LINK_CONFIG_2            0x305B
+# define DP_PCON_MAX_LINK_BW_MASK             (0x3F << 0)
+# define DP_PCON_FRL_BW_MASK_9GBPS            (1 << 0)
+# define DP_PCON_FRL_BW_MASK_18GBPS           (1 << 1)
+# define DP_PCON_FRL_BW_MASK_24GBPS           (1 << 2)
+# define DP_PCON_FRL_BW_MASK_32GBPS           (1 << 3)
+# define DP_PCON_FRL_BW_MASK_40GBPS           (1 << 4)
+# define DP_PCON_FRL_BW_MASK_48GBPS           (1 << 5)
+# define DP_PCON_FRL_LINK_TRAIN_EXTENDED      (1 << 6)
+
+/* PCON HDMI LINK STATUS */
+#define DP_PCON_HDMI_TX_LINK_STATUS           0x303B
+# define DP_PCON_HDMI_TX_LINK_ACTIVE          (1 << 0)
+# define DP_PCON_FRL_READY		      (1 << 1)
+
+/* PCON HDMI POST FRL STATUS */
+#define DP_PCON_HDMI_POST_FRL_STATUS          0x3036
+# define DP_PCON_HDMI_LINK_MODE               (1 << 0)
+# define DP_PCON_HDMI_MODE_TMDS               0
+# define DP_PCON_HDMI_MODE_FRL                1
+# define DP_PCON_HDMI_FRL_TRAINED_BW          (0x3F << 1)
+# define DP_PCON_FRL_TRAINED_BW_9GBPS	      (1 << 1)
+# define DP_PCON_FRL_TRAINED_BW_18GBPS	      (1 << 2)
+# define DP_PCON_FRL_TRAINED_BW_24GBPS	      (1 << 3)
+# define DP_PCON_FRL_TRAINED_BW_32GBPS	      (1 << 4)
+# define DP_PCON_FRL_TRAINED_BW_40GBPS	      (1 << 5)
+# define DP_PCON_FRL_TRAINED_BW_48GBPS	      (1 << 6)
 
 #define DP_PROTOCOL_CONVERTER_CONTROL_0		0x3050 /* DP 1.3 */
 # define DP_HDMI_DVI_OUTPUT_CONFIG		(1 << 0) /* DP 1.3 */
@@ -1905,4 +1971,18 @@ int drm_dp_get_phy_test_pattern(struct drm_dp_aux *aux,
 				struct drm_dp_phy_test_params *data);
 int drm_dp_set_phy_test_pattern(struct drm_dp_aux *aux,
 				struct drm_dp_phy_test_params *data, u8 dp_rev);
+int drm_dp_get_pcon_max_frl_bw(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
+			       const u8 port_cap[4]);
+int drm_dp_get_hdmi_max_frl_bw(struct drm_dp_aux *aux);
+int drm_dp_pcon_frl_prepare(struct drm_dp_aux *aux, bool enable_frl_ready_hpd);
+bool drm_dp_pcon_is_frl_ready(struct drm_dp_aux *aux);
+int drm_dp_pcon_frl_configure_1(struct drm_dp_aux *aux, int max_frl_gbps,
+				bool concurrent_mode);
+int drm_dp_pcon_frl_configure_2(struct drm_dp_aux *aux, int max_frl_mask,
+				bool extended_train_mode);
+int drm_dp_pcon_reset_frl_config(struct drm_dp_aux *aux);
+int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux);
+
+bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux);
+int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask);
 #endif /* _DRM_DP_HELPER_H_ */
-- 
2.17.1

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[RFC 4/8] drm/i915: Capture max frl rate for PCON in dfp cap structure

[Ankit Nautiyal]

HDMI2.1 PCON advertises Max FRL bandwidth supported by the PCON and
by the sink.

This patch captures these in dfp cap structure in intel_dp and uses
these to prune connector modes that cannot be supported by the PCON
and sink FRL bandwidth.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 .../drm/i915/display/intel_display_types.h    |  1 +
 drivers/gpu/drm/i915/display/intel_dp.c       | 33 +++++++++++++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index d5dc18cb8c39..77e486d78b7c 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1378,6 +1378,7 @@ struct intel_dp {
 	struct {
 		int min_tmds_clock, max_tmds_clock;
 		int max_dotclock;
+		int pcon_max_frl, sink_max_frl;
 		u8 max_bpc;
 		bool ycbcr_444_to_420;
 	} dfp;
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 7429597b57be..b28583ed6559 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -667,6 +667,24 @@ intel_dp_mode_valid_downstream(struct intel_connector *connector,
 	const struct drm_display_info *info = &connector->base.display_info;
 	int tmds_clock;
 
+	/* If PCON and HDMI2.1 sink both support FRL MODE, check FRL
+	 * bandwidth constraints.
+	 */
+	if (intel_dp->dfp.pcon_max_frl) {
+		int target_bw;
+		int max_frl_bw;
+		int bpp = intel_dp_mode_min_output_bpp(&connector->base, mode);
+
+		target_bw = bpp * DIV_ROUND_UP(target_clock, 1000000);
+
+		max_frl_bw = min(intel_dp->dfp.pcon_max_frl,
+				 intel_dp->dfp.sink_max_frl);
+		if (target_bw > max_frl_bw)
+			return MODE_CLOCK_HIGH;
+
+		return MODE_OK;
+	}
+
 	if (intel_dp->dfp.max_dotclock &&
 	    target_clock > intel_dp->dfp.max_dotclock)
 		return MODE_CLOCK_HIGH;
@@ -6355,13 +6373,21 @@ intel_dp_update_dfp(struct intel_dp *intel_dp,
 						 intel_dp->downstream_ports,
 						 edid);
 
+	intel_dp->dfp.pcon_max_frl =
+		drm_dp_get_pcon_max_frl_bw(intel_dp->dpcd,
+					   intel_dp->downstream_ports);
+
+	intel_dp->dfp.sink_max_frl = drm_dp_get_hdmi_max_frl_bw(&intel_dp->aux);
+
 	drm_dbg_kms(&i915->drm,
-		    "[CONNECTOR:%d:%s] DFP max bpc %d, max dotclock %d, TMDS clock %d-%d\n",
+		    "[CONNECTOR:%d:%s] DFP max bpc %d, max dotclock %d, TMDS clock %d-%d, PCON Max FRL BW %dGbps, Sink Max FRL BW %dGbps\n",
 		    connector->base.base.id, connector->base.name,
 		    intel_dp->dfp.max_bpc,
 		    intel_dp->dfp.max_dotclock,
 		    intel_dp->dfp.min_tmds_clock,
-		    intel_dp->dfp.max_tmds_clock);
+		    intel_dp->dfp.max_tmds_clock,
+		    intel_dp->dfp.pcon_max_frl,
+		    intel_dp->dfp.sink_max_frl);
 }
 
 static void
@@ -6451,6 +6477,9 @@ intel_dp_unset_edid(struct intel_dp *intel_dp)
 	intel_dp->dfp.min_tmds_clock = 0;
 	intel_dp->dfp.max_tmds_clock = 0;
 
+	intel_dp->dfp.pcon_max_frl = 0;
+	intel_dp->dfp.sink_max_frl = 0;
+
 	intel_dp->dfp.ycbcr_444_to_420 = false;
 	connector->base.ycbcr_420_allowed = false;
 }
-- 
2.17.1

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[RFC 5/8] drm/i915: Add support for starting FRL training for HDMI2.1 via PCON

[Ankit Nautiyal]

This patch adds functions to start FRL training for an HDMI2.1 sink,
connected via a PCON as a DP branch device.
This patch also adds a new structure for storing frl training related
data, when FRL training is completed.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 .../drm/i915/display/intel_display_types.h    |   6 +
 drivers/gpu/drm/i915/display/intel_dp.c       | 200 ++++++++++++++++++
 drivers/gpu/drm/i915/display/intel_dp.h       |   2 +
 3 files changed, 208 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 77e486d78b7c..e667caf90eb9 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1267,6 +1267,11 @@ struct intel_dp_compliance {
 	u8 test_lane_count;
 };
 
+struct intel_dp_pcon_frl {
+	bool is_trained;
+	int trained_rate_gbps;
+};
+
 struct intel_dp {
 	i915_reg_t output_reg;
 	u32 DP;
@@ -1314,6 +1319,7 @@ struct intel_dp {
 	unsigned long last_backlight_off;
 	ktime_t panel_power_off_time;
 
+	struct intel_dp_pcon_frl frl;
 	struct notifier_block edp_notifier;
 
 	/*
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index b28583ed6559..fd30e025a09e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2904,6 +2904,9 @@ static void intel_dp_prepare(struct intel_encoder *encoder,
 			intel_dp->DP |= DP_PIPE_SEL_CHV(crtc->pipe);
 		else
 			intel_dp->DP |= DP_PIPE_SEL(crtc->pipe);
+
+		intel_dp->frl.is_trained = false;
+		intel_dp->frl.trained_rate_gbps = 0;
 	}
 }
 
@@ -3740,6 +3743,9 @@ static void intel_disable_dp(struct intel_atomic_state *state,
 	intel_edp_backlight_off(old_conn_state);
 	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
 	intel_edp_panel_off(intel_dp);
+
+	intel_dp->frl.is_trained = false;
+	intel_dp->frl.trained_rate_gbps = 0;
 }
 
 static void g4x_disable_dp(struct intel_atomic_state *state,
@@ -3835,6 +3841,200 @@ cpt_set_link_train(struct intel_dp *intel_dp,
 	intel_de_posting_read(dev_priv, intel_dp->output_reg);
 }
 
+static int intel_dp_get_max_rate_gbps(struct intel_dp *intel_dp)
+{
+	int max_link_clock, max_lanes, max_rate_khz, max_rate_gbps;
+
+	max_link_clock = intel_dp_max_link_rate(intel_dp);
+	max_lanes = intel_dp_max_lane_count(intel_dp);
+	max_rate_khz = intel_dp_max_data_rate(max_link_clock, max_lanes);
+	max_rate_gbps = 8 * DIV_ROUND_UP(max_rate_khz, 1000000);
+
+	return max_rate_gbps;
+}
+
+static int intel_dp_pcon_get_frl_mask(u8 frl_bw_mask)
+{
+	int bw_gbps[] = {9, 18, 24, 32, 40, 48};
+	int i;
+
+	for (i = ARRAY_SIZE(bw_gbps) - 1; i >= 0; i--) {
+		if (frl_bw_mask & (1 << i))
+			return bw_gbps[i];
+	}
+	return 0;
+}
+
+static int intel_dp_pcon_set_frl_mask(int max_frl)
+{
+	int max_frl_mask = 0;
+
+	switch (max_frl) {
+	case 48:
+		max_frl_mask |= DP_PCON_FRL_BW_MASK_48GBPS;
+		break;
+	case 40:
+		max_frl_mask |= DP_PCON_FRL_BW_MASK_40GBPS;
+		break;
+	case 32:
+		max_frl_mask |= DP_PCON_FRL_BW_MASK_32GBPS;
+		break;
+	case 24:
+		max_frl_mask |= DP_PCON_FRL_BW_MASK_24GBPS;
+		break;
+	case 18:
+		max_frl_mask |= DP_PCON_FRL_BW_MASK_18GBPS;
+		break;
+	case 9:
+		max_frl_mask |= DP_PCON_FRL_BW_MASK_9GBPS;
+		break;
+	default:
+		max_frl_mask = 0;
+	}
+
+	return max_frl_mask;
+}
+
+static int intel_dp_hdmi_sink_max_frl(struct intel_dp *intel_dp)
+{
+	struct intel_connector *intel_connector = intel_dp->attached_connector;
+	struct drm_connector *connector = &intel_connector->base;
+
+	return (connector->display_info.hdmi.max_frl_rate_per_lane *
+		connector->display_info.hdmi.max_lane);
+}
+
+static int intel_dp_pcon_start_frl_training(struct intel_dp *intel_dp)
+{
+#define PCON_EXTENDED_TRAIN_MODE true
+#define PCON_CONCURRENT_MODE true
+#define PCON_SEQUENTIAL_MODE !PCON_CONCURRENT_MODE
+#define PCON_NORMAL_TRAIN_MODE !PCON_EXTENDED_TRAIN_MODE
+#define TIMEOUT_FRL_READY_MS 500
+#define TIMEOUT_HDMI_LINK_ACTIVE_MS 1000
+
+	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
+	int max_frl, max_pcon_frl, max_sink_frl, max_rate_gbps, max_frl_edid, ret;
+	u8 max_frl_mask = 0, frl_trained_mask;
+	bool is_active;
+
+	ret = drm_dp_pcon_reset_frl_config(&intel_dp->aux);
+	if (ret < 0)
+		return ret;
+
+	max_rate_gbps = intel_dp_get_max_rate_gbps(intel_dp);
+	drm_dbg(&i915->drm, "Source max rate = %d Gbps\n", max_rate_gbps);
+
+	max_pcon_frl = intel_dp->dfp.pcon_max_frl;
+	drm_dbg(&i915->drm, "PCON max rate = %d Gbps\n", max_pcon_frl);
+
+	/* Double Check from HDMI SINK EDID */
+	max_frl_edid = intel_dp_hdmi_sink_max_frl(intel_dp);
+	drm_dbg(&i915->drm, "Sink max rate from EDID = %d Gbps\n", max_frl_edid);
+
+	max_sink_frl = intel_dp->dfp.sink_max_frl;
+	drm_dbg(&i915->drm, "Sink max rate from PCON = %d Gbps\n", max_sink_frl);
+
+	/* TODO MAX SINK FRL from PCON is not enumerated. Using MAX FRL value
+	 * directly from EDID. Need to confirm from Spec.
+	 */
+	max_frl = min(max_rate_gbps, min(max_frl_edid, max_pcon_frl));
+
+	if (max_frl <= 0)
+		return -EINVAL;
+
+	ret = drm_dp_pcon_frl_prepare(&intel_dp->aux, false);
+	if (ret < 0)
+		return ret;
+	/* Wait for PCON to be FRL Ready */
+	wait_for(is_active = drm_dp_pcon_is_frl_ready(&intel_dp->aux) == true, TIMEOUT_FRL_READY_MS);
+
+	if (!is_active)
+		return -ETIMEDOUT;
+
+	max_frl_mask = intel_dp_pcon_set_frl_mask(max_frl);
+	ret = drm_dp_pcon_frl_configure_1(&intel_dp->aux, max_frl, PCON_SEQUENTIAL_MODE);
+	if (ret < 0)
+		return ret;
+	ret = drm_dp_pcon_frl_configure_2(&intel_dp->aux, max_frl_mask, PCON_NORMAL_TRAIN_MODE);
+	if (ret < 0)
+		return ret;
+	ret = drm_dp_pcon_frl_enable(&intel_dp->aux);
+	if (ret < 0)
+		return ret;
+	/*
+	 * Wait for FRL to be completed
+	 * Check if the HDMI Link is up and active.
+	 */
+	wait_for(is_active = drm_dp_pcon_hdmi_link_active(&intel_dp->aux) == true, TIMEOUT_HDMI_LINK_ACTIVE_MS);
+
+	if (!is_active)
+		return -ETIMEDOUT;
+	/*
+	 * Verify HDMI Link configuration shows FRL Mode.
+	 */
+	if (DP_PCON_HDMI_MODE_FRL != drm_dp_pcon_hdmi_link_mode(&intel_dp->aux, &frl_trained_mask)) {
+		drm_dbg(&i915->drm, "HDMI couldn't be trained in FRL Mode\n");
+		return -EINVAL;
+	}
+	drm_dbg(&i915->drm, "MAX_FRL_MASK = %u, FRL_TRAINED_MASK = %u\n", max_frl_mask, frl_trained_mask);
+
+	/*
+	 * Read HDMI_LINK_STATUS_TRAINED 0x2005 bit 5
+	 * TODO: Details not mentioned in spec. Need to check.
+	 */
+
+	intel_dp->frl.trained_rate_gbps = intel_dp_pcon_get_frl_mask(frl_trained_mask);
+	intel_dp->frl.is_trained = true;
+	drm_dbg(&i915->drm, "FRL trained with : %d Gbps\n", intel_dp->frl.trained_rate_gbps);
+
+	return 0;
+}
+
+static bool intel_dp_is_frl_required(struct intel_dp *intel_dp)
+{
+	if (!intel_dp->frl.is_trained)
+		return true;
+	/*
+	 * #TODO check if the mode really required FRL or can work
+	 * with TMDS mode.
+	 */
+
+	return false;
+}
+
+static bool intel_dp_is_hdmi_2_1_sink(struct intel_dp *intel_dp)
+{
+	if (drm_dp_is_branch(intel_dp->dpcd) &&
+	    intel_dp_hdmi_sink_max_frl(intel_dp) > 0)
+		return true;
+
+	return false;
+}
+
+void intel_dp_check_frl_training(struct intel_dp *intel_dp)
+{
+	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
+
+	if (!intel_dp_is_hdmi_2_1_sink(intel_dp) ||
+	    !intel_dp_is_frl_required(intel_dp))
+		return;
+
+	if (intel_dp_pcon_start_frl_training(intel_dp) < 0) {
+		int ret, mode;
+
+		drm_dbg(&dev_priv->drm, "Couldnt set FRL mode, continuing with TMDS mode\n");
+		ret = drm_dp_pcon_reset_frl_config(&intel_dp->aux);
+		mode = drm_dp_pcon_hdmi_link_mode(&intel_dp->aux, NULL);
+
+		if (ret < 0 || mode != DP_PCON_HDMI_MODE_TMDS)
+			drm_dbg(&dev_priv->drm, "Issue with PCON, cannot set TMDS mode\n");
+	}
+
+	else
+		drm_dbg(&dev_priv->drm, "FRL training Completed\n");
+}
+
 static void
 g4x_set_link_train(struct intel_dp *intel_dp,
 		   const struct intel_crtc_state *crtc_state,
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 66854aab9887..45d15fecbfe7 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -141,4 +141,6 @@ void intel_ddi_update_pipe(struct intel_atomic_state *state,
 int intel_dp_init_hdcp(struct intel_digital_port *dig_port,
 		       struct intel_connector *intel_connector);
 
+void intel_dp_check_frl_training(struct intel_dp *intel_dp);
+
 #endif /* __INTEL_DP_H__ */
-- 
2.17.1

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[RFC 6/8] drm/i915: Check for FRL training before DP Link training

[Ankit Nautiyal]

This patch calls functions to check FRL training requirements
for an HDMI2.1 sink, when connected through PCON.
The call is made before the DP link training. In case FRL is not
required or failure during FRL training, the TMDS mode is selected
for the pcon.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c | 2 ++
 drivers/gpu/drm/i915/display/intel_dp.c  | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index b4c520348b3b..94c8a7dab97b 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3489,6 +3489,8 @@ static void tgl_ddi_pre_enable_dp(struct intel_atomic_state *state,
 	if (!is_mst)
 		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
 
+	intel_dp_check_frl_training(intel_dp);
+
 	intel_dp_sink_set_decompression_state(intel_dp, crtc_state, true);
 	/*
 	 * DDI FEC: "anticipates enabling FEC encoding sets the FEC_READY bit
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index fd30e025a09e..d3b67c7123d8 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4165,6 +4165,7 @@ static void intel_enable_dp(struct intel_atomic_state *state,
 
 	intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
 	intel_dp_configure_protocol_converter(intel_dp);
+	intel_dp_check_frl_training(intel_dp);
 	intel_dp_start_link_train(intel_dp, pipe_config);
 	intel_dp_stop_link_train(intel_dp, pipe_config);
 
@@ -6099,6 +6100,7 @@ int intel_dp_retrain_link(struct intel_encoder *encoder,
 		    !intel_dp_mst_is_master_trans(crtc_state))
 			continue;
 
+		intel_dp_check_frl_training(intel_dp);
 		intel_dp_start_link_train(intel_dp, crtc_state);
 		intel_dp_stop_link_train(intel_dp, crtc_state);
 		break;
-- 
2.17.1

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[RFC 7/8] drm/dp_helper: Add support for link status and link recovery

[Ankit Nautiyal]

From: Swati Sharma <swati2.sharma@intel.com>

This patch adds support for link status and link recovery. There
are specific DPCD’s defined for link status check and recovery in
case of any issues. PCON will communicate the same using an IRQ_HPD
to source. HDMI sink would have indicated the same to PCON using
SCDC interrupt mechanism. While source can always read final HDMI
sink’s status using I2C over AUX, it’s easier and faster to read
the PCON’s already read HDMI sink’s status registers.

Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/drm_dp_helper.c | 33 +++++++++++++++++++++++++++++++++
 include/drm/drm_dp_helper.h     | 16 ++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index 39d8e4d665b7..131ea604321b 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -2671,3 +2671,36 @@ int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask)
 	return mode;
 }
 EXPORT_SYMBOL(drm_dp_pcon_hdmi_link_mode);
+
+void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux,
+					   struct drm_connector *connector)
+{
+	u8 buf, error_count;
+	int i, num_error;
+	struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
+
+	for (i = 0; i < hdmi->max_lane; i++)
+	{
+		if (drm_dp_dpcd_readb(aux, DP_PCON_HDMI_ERROR_STATUS_LN0 + i , &buf) < 0)
+			return;
+
+		error_count = buf & DP_PCON_HDMI_ERROR_COUNT_MASK;
+
+	switch(error_count) {
+	case DP_PCON_HDMI_ERROR_COUNT_HUNDRED_PLUS:
+		num_error = 100;
+		break;
+	case DP_PCON_HDMI_ERROR_COUNT_TEN_PLUS:
+		num_error = 10;
+		break;
+	case DP_PCON_HDMI_ERROR_COUNT_THREE_PLUS:
+		num_error = 3;
+		break;
+	default:
+		num_error = 0;
+	}
+
+		DRM_ERROR("More than %d errors since the last read for lane %d", num_error, i);
+	}
+}
+EXPORT_SYMBOL(drm_dp_pcon_hdmi_frl_link_error_count);
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 82fa75f6cc86..9397410390e7 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -946,6 +946,11 @@ struct drm_device;
 # define DP_CEC_IRQ                          (1 << 2)
 
 #define DP_LINK_SERVICE_IRQ_VECTOR_ESI0     0x2005   /* 1.2 */
+# define RX_CAP_CHANGED                      (1 << 0)
+# define LINK_STATUS_CHANGED                 (1 << 1)
+# define STREAM_STATUS_CHANGED               (1 << 2)
+# define HDMI_LINK_STATUS_CHANGED            (1 << 3)
+# define CONNECTED_OFF_ENTRY_REQUESTED       (1 << 4)
 
 #define DP_PSR_ERROR_STATUS                 0x2006  /* XXX 1.2? */
 # define DP_PSR_LINK_CRC_ERROR              (1 << 0)
@@ -1130,6 +1135,16 @@ struct drm_device;
 #define DP_PROTOCOL_CONVERTER_CONTROL_2		0x3052 /* DP 1.3 */
 # define DP_CONVERSION_TO_YCBCR422_ENABLE	(1 << 0) /* DP 1.3 */
 
+/* PCON Downstream HDMI ERROR Status per Lane */
+#define DP_PCON_HDMI_ERROR_STATUS_LN0          0x3037
+#define DP_PCON_HDMI_ERROR_STATUS_LN1          0x3038
+#define DP_PCON_HDMI_ERROR_STATUS_LN2          0x3039
+#define DP_PCON_HDMI_ERROR_STATUS_LN3          0x303A
+# define DP_PCON_HDMI_ERROR_COUNT_MASK         (0x7 << 0)
+# define DP_PCON_HDMI_ERROR_COUNT_THREE_PLUS   (1 << 0)
+# define DP_PCON_HDMI_ERROR_COUNT_TEN_PLUS     (1 << 1)
+# define DP_PCON_HDMI_ERROR_COUNT_HUNDRED_PLUS (1 << 2)
+
 /* HDCP 1.3 and HDCP 2.2 */
 #define DP_AUX_HDCP_BKSV		0x68000
 #define DP_AUX_HDCP_RI_PRIME		0x68005
@@ -1985,4 +2000,5 @@ int drm_dp_pcon_frl_enable(struct drm_dp_aux *aux);
 
 bool drm_dp_pcon_hdmi_link_active(struct drm_dp_aux *aux);
 int drm_dp_pcon_hdmi_link_mode(struct drm_dp_aux *aux, u8 *frl_trained_mask);
+void drm_dp_pcon_hdmi_frl_link_error_count(struct drm_dp_aux *aux, struct drm_connector *connector);
 #endif /* _DRM_DP_HELPER_H_ */
-- 
2.17.1

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[RFC 8/8] drm/i915: Add support for enabling link status and recovery

[Ankit Nautiyal]

From: Swati Sharma <swati2.sharma@intel.com>

In this patch enabled support for link status and recovery in i915
driver. HDMI link loss indication to upstream DP source is indicated
via IRQ_HPD. This is followed by reading of HDMI link configuration
status (HDMI_TX_LINK_ACTIVE_STATUS). If the PCON → HDMI 2.1 link status
is off; reinitiate frl link training to recover.
Also, HDMI FRL link error count range for each individual FRL
active lane is indicated by DOWNSTREAM_HDMI_ERROR_STATUS_LN registers.

Signed-off-by: Swati Sharma <swati2.sharma@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 47 +++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index d3b67c7123d8..c8cbef8d9c98 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5928,6 +5928,29 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
 	return link_ok;
 }
 
+static void
+intel_dp_handle_hdmi_link_status_change(struct intel_dp *intel_dp)
+{
+	bool is_active;
+	u8 buf = 0;
+
+	is_active = drm_dp_pcon_hdmi_link_active(&intel_dp->aux);
+	if (intel_dp->frl.is_trained && !is_active) {
+		if (drm_dp_dpcd_readb(&intel_dp->aux, DP_PCON_HDMI_LINK_CONFIG_1, &buf) < 0)
+			return;
+
+		buf &=  ~DP_PCON_ENABLE_HDMI_LINK;
+		if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_PCON_HDMI_LINK_CONFIG_1, buf) < 0)
+			return;
+
+		intel_dp->frl.is_trained = false;
+		intel_dp->frl.trained_rate_gbps = 0;
+
+		intel_dp_check_frl_training(intel_dp);
+		drm_dp_pcon_hdmi_frl_link_error_count(&intel_dp->aux, &intel_dp->attached_connector->base);
+	}
+}
+
 static bool
 intel_dp_needs_link_retrain(struct intel_dp *intel_dp)
 {
@@ -6292,7 +6315,7 @@ intel_dp_hotplug(struct intel_encoder *encoder,
 	return state;
 }
 
-static void intel_dp_check_service_irq(struct intel_dp *intel_dp)
+static void intel_dp_check_device_service_irq(struct intel_dp *intel_dp)
 {
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 	u8 val;
@@ -6316,6 +6339,23 @@ static void intel_dp_check_service_irq(struct intel_dp *intel_dp)
 		drm_dbg_kms(&i915->drm, "Sink specific irq unhandled\n");
 }
 
+static void intel_dp_check_link_service_irq(struct intel_dp *intel_dp)
+{
+	u8 val;
+
+	if (intel_dp->dpcd[DP_DPCD_REV] < 0x11)
+		return;
+
+	if (drm_dp_dpcd_readb(&intel_dp->aux,
+			      DP_LINK_SERVICE_IRQ_VECTOR_ESI0, &val) != 1 || !val)
+		return;
+
+	drm_dp_dpcd_writeb(&intel_dp->aux, DP_LINK_SERVICE_IRQ_VECTOR_ESI0, val);
+
+	if (val & HDMI_LINK_STATUS_CHANGED)
+		intel_dp_handle_hdmi_link_status_change(intel_dp);
+}
+
 /*
  * According to DP spec
  * 5.1.2:
@@ -6355,7 +6395,8 @@ intel_dp_short_pulse(struct intel_dp *intel_dp)
 		return false;
 	}
 
-	intel_dp_check_service_irq(intel_dp);
+	intel_dp_check_device_service_irq(intel_dp);
+	intel_dp_check_link_service_irq(intel_dp);
 
 	/* Handle CEC interrupts, if any */
 	drm_dp_cec_irq(&intel_dp->aux);
@@ -6787,7 +6828,7 @@ intel_dp_detect(struct drm_connector *connector,
 	    to_intel_connector(connector)->detect_edid)
 		status = connector_status_connected;
 
-	intel_dp_check_service_irq(intel_dp);
+	intel_dp_check_device_service_irq(intel_dp);
 
 out:
 	if (status != connector_status_connected && !intel_dp->is_mst)
-- 
2.17.1

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