[PATCH 6/8] drm/i915: Move generic link training code to a separate file

Ander Conselvan de Oliveira
2015-09-08T12:28:46Z

No functional changes, just moving code around.
---
drivers/gpu/drm/i915/Makefile | 1 +
drivers/gpu/drm/i915/intel_dp.c | 328 +------------------------
drivers/gpu/drm/i915/intel_dp_link_training.c | 336 ++++++++++++++++++++++++++
drivers/gpu/drm/i915/intel_drv.h | 16 ++
4 files changed, 362 insertions(+), 319 deletions(-)
create mode 100644 drivers/gpu/drm/i915/intel_dp_link_training.c

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 44d290a..0851de07 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -77,6 +77,7 @@ i915-y += dvo_ch7017.o \
dvo_tfp410.o \
intel_crt.o \
intel_ddi.o \
+ intel_dp_link_training.o \
intel_dp_mst.o \
intel_dp.o \
intel_dsi.o \
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d5c1b0a..5778059 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1188,7 +1188,7 @@ intel_dp_sink_rates(struct intel_dp *intel_dp, const int **sink_rates)
return (intel_dp_max_link_bw(intel_dp) >> 3) + 1;
}

-static bool intel_dp_source_supports_hbr2(struct drm_device *dev)
+bool intel_dp_source_supports_hbr2(struct drm_device *dev)
{
/* WaDisableHBR2:skl */
if (IS_SKYLAKE(dev) && INTEL_REVID(dev) <= SKL_REVID_B0)
@@ -1364,8 +1364,8 @@ int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
return rate_to_index(rate, intel_dp->sink_rates);
}

-static void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
- uint8_t *link_bw, uint8_t *rate_select)
+void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
+ uint8_t *link_bw, uint8_t *rate_select)
{
if (intel_dp->num_sink_rates) {
*link_bw = 0;
@@ -3045,7 +3045,7 @@ intel_dp_dpcd_read_wake(struct drm_dp_aux *aux, unsigned int offset,
* Fetch AUX CH registers 0x202 - 0x207 which contain
* link status information
*/
-static bool
+bool
intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE])
{
return intel_dp_dpcd_read_wake(&intel_dp->aux,
@@ -3055,7 +3055,7 @@ intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_
}

/* These are source-specific values. */
-static uint8_t
+uint8_t
intel_dp_voltage_max(struct intel_dp *intel_dp)
{
struct drm_device *dev = intel_dp_to_dev(intel_dp);
@@ -3078,7 +3078,7 @@ intel_dp_voltage_max(struct intel_dp *intel_dp)
return DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
}

-static uint8_t
+uint8_t
intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
{
struct drm_device *dev = intel_dp_to_dev(intel_dp);
@@ -3425,38 +3425,6 @@ static uint32_t chv_signal_levels(struct intel_dp *intel_dp)
return 0;
}

-static void
-intel_get_adjust_train(struct intel_dp *intel_dp,
- const uint8_t link_status[DP_LINK_STATUS_SIZE])
-{
- uint8_t v = 0;
- uint8_t p = 0;
- int lane;
- uint8_t voltage_max;
- uint8_t preemph_max;
-
- for (lane = 0; lane < intel_dp->lane_count; lane++) {
- uint8_t this_v = drm_dp_get_adjust_request_voltage(link_status, lane);
- uint8_t this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
-
- if (this_v > v)
- v = this_v;
- if (this_p > p)
- p = this_p;
- }
-
- voltage_max = intel_dp_voltage_max(intel_dp);
- if (v >= voltage_max)
- v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
-
- preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
- if (p >= preemph_max)
- p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
-
- for (lane = 0; lane < 4; lane++)
- intel_dp->train_set[lane] = v | p;
-}
-
static uint32_t
gen4_signal_levels(uint8_t train_set)
{
@@ -3598,7 +3566,7 @@ intel_dp_set_signal_levels(struct intel_dp *intel_dp, uint32_t *DP)
*DP = (*DP & ~mask) | signal_levels;
}

-static void
+void
intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
uint8_t dp_train_pat)
{
@@ -3612,33 +3580,7 @@ intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
POSTING_READ(intel_dp->output_reg);
}

-static bool
-intel_dp_set_link_train(struct intel_dp *intel_dp,
- uint8_t dp_train_pat)
-{
- uint8_t buf[sizeof(intel_dp->train_set) + 1];
- int ret, len;
-
- intel_dp_program_link_training_pattern(intel_dp, dp_train_pat);
-
- buf[0] = dp_train_pat;
- if ((dp_train_pat & DP_TRAINING_PATTERN_MASK) ==
- DP_TRAINING_PATTERN_DISABLE) {
- /* don't write DP_TRAINING_LANEx_SET on disable */
- len = 1;
- } else {
- /* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
- memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
- len = intel_dp->lane_count + 1;
- }
-
- ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
- buf, len);
-
- return ret == len;
-}
-
-static void
+void
intel_dp_update_signal_levels(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -3651,30 +3593,7 @@ intel_dp_update_signal_levels(struct intel_dp *intel_dp)
POSTING_READ(intel_dp->output_reg);
}

-static bool
-intel_dp_reset_link_train(struct intel_dp *intel_dp,
- uint8_t dp_train_pat)
-{
- if (!intel_dp->train_set_valid)
- memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
- intel_dp_update_signal_levels(intel_dp);
- return intel_dp_set_link_train(intel_dp, dp_train_pat);
-}
-
-static bool
-intel_dp_update_link_train(struct intel_dp *intel_dp)
-{
- int ret;
-
- intel_dp_update_signal_levels(intel_dp);
-
- ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET,
- intel_dp->train_set, intel_dp->lane_count);
-
- return ret == intel_dp->lane_count;
-}
-
-static void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
+void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
struct drm_device *dev = intel_dig_port->base.base.dev;
@@ -3705,235 +3624,6 @@ static void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
DRM_ERROR("Timed out waiting for DP idle patterns\n");
}

-/* Enable corresponding port and start training pattern 1 */
-static bool
-intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
-{
- struct drm_encoder *encoder = &dp_to_dig_port(intel_dp)->base.base;
- struct drm_device *dev = encoder->dev;
- int i;
- uint8_t voltage;
- int voltage_tries, loop_tries;
- uint8_t link_config[2];
- uint8_t link_bw, rate_select;
- uint8_t link_status[DP_LINK_STATUS_SIZE];
-
- if (HAS_DDI(dev))
- intel_ddi_prepare_link_retrain(encoder);
-
- intel_dp_compute_rate(intel_dp, intel_dp->link_rate,
- &link_bw, &rate_select);
-
- /* Write the link configuration data */
- link_config[0] = link_bw;
- link_config[1] = intel_dp->lane_count;
- if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
- link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
- drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2);
- if (intel_dp->num_sink_rates)
- drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET,
- &rate_select, 1);
-
- link_config[0] = 0;
- link_config[1] = DP_SET_ANSI_8B10B;
- drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2);
-
- intel_dp->DP |= DP_PORT_EN;
-
- /* clock recovery */
- if (!intel_dp_reset_link_train(intel_dp,
- DP_TRAINING_PATTERN_1 |
- DP_LINK_SCRAMBLING_DISABLE)) {
- DRM_ERROR("failed to enable link training\n");
- return false;
- }
-
- voltage = 0xff;
- voltage_tries = 0;
- loop_tries = 0;
- for (;;) {
- drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
- if (!intel_dp_get_link_status(intel_dp, link_status)) {
- DRM_ERROR("failed to get link status\n");
- break;
- }
-
- if (drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) {
- DRM_DEBUG_KMS("clock recovery OK\n");
- break;
- }
-
- /*
- * if we used previously trained voltage and pre-emphasis values
- * and we don't get clock recovery, reset link training values
- */
- if (intel_dp->train_set_valid) {
- DRM_DEBUG_KMS("clock recovery not ok, reset");
- /* clear the flag as we are not reusing train set */
- intel_dp->train_set_valid = false;
- if (!intel_dp_reset_link_train(intel_dp,
- DP_TRAINING_PATTERN_1 |
- DP_LINK_SCRAMBLING_DISABLE)) {
- DRM_ERROR("failed to enable link training\n");
- return false;
- }
- continue;
- }
-
- /* Check to see if we've tried the max voltage */
- for (i = 0; i < intel_dp->lane_count; i++)
- if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
- break;
- if (i == intel_dp->lane_count) {
- ++loop_tries;
- if (loop_tries == 5) {
- DRM_ERROR("too many full retries, give up\n");
- break;
- }
- intel_dp_reset_link_train(intel_dp,
- DP_TRAINING_PATTERN_1 |
- DP_LINK_SCRAMBLING_DISABLE);
- voltage_tries = 0;
- continue;
- }
-
- /* Check to see if we've tried the same voltage 5 times */
- if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
- ++voltage_tries;
- if (voltage_tries == 5) {
- DRM_ERROR("too many voltage retries, give up\n");
- break;
- }
- } else
- voltage_tries = 0;
- voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
-
- /* Update training set as requested by target */
- intel_get_adjust_train(intel_dp, link_status);
- if (!intel_dp_update_link_train(intel_dp)) {
- DRM_ERROR("failed to update link training\n");
- break;
- }
- }
-
- return drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count);
-}
-
-static bool
-intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
-{
- struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
- struct drm_device *dev = dig_port->base.base.dev;
- bool channel_eq = false;
- int tries, cr_tries;
- uint32_t training_pattern = DP_TRAINING_PATTERN_2;
-
- /*
- * Training Pattern 3 for HBR2 or 1.2 devices that support it.
- *
- * Intel platforms that support HBR2 also support TPS3. TPS3 support is
- * also mandatory for downstream devices that support HBR2.
- *
- * Due to WaDisableHBR2 SKL < B0 is the only exception where TPS3 is
- * supported but still not enabled.
- */
- if (intel_dp_source_supports_hbr2(dev) &&
- drm_dp_tps3_supported(intel_dp->dpcd))
- training_pattern = DP_TRAINING_PATTERN_3;
- else if (intel_dp->link_rate == 540000)
- DRM_ERROR("5.4 Gbps link rate without HBR2/TPS3 support\n");
-
- /* channel equalization */
- if (!intel_dp_set_link_train(intel_dp,
- training_pattern |
- DP_LINK_SCRAMBLING_DISABLE)) {
- DRM_ERROR("failed to start channel equalization\n");
- return false;
- }
-
- tries = 0;
- cr_tries = 0;
- channel_eq = false;
- for (;;) {
- uint8_t link_status[DP_LINK_STATUS_SIZE];
-
- if (cr_tries > 5) {
- DRM_ERROR("failed to train DP, aborting\n");
- break;
- }
-
- drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
- if (!intel_dp_get_link_status(intel_dp, link_status)) {
- DRM_ERROR("failed to get link status\n");
- break;
- }
-
- /* Make sure clock is still ok */
- if (!drm_dp_clock_recovery_ok(link_status,
- intel_dp->lane_count)) {
- intel_dp->train_set_valid = false;
- intel_dp_link_training_clock_recovery(intel_dp);
- intel_dp_set_link_train(intel_dp,
- training_pattern |
- DP_LINK_SCRAMBLING_DISABLE);
- cr_tries++;
- continue;
- }
-
- if (drm_dp_channel_eq_ok(link_status,
- intel_dp->lane_count)) {
- channel_eq = true;
- break;
- }
-
- /* Try 5 times, then try clock recovery if that fails */
- if (tries > 5) {
- intel_dp->train_set_valid = false;
- intel_dp_link_training_clock_recovery(intel_dp);
- intel_dp_set_link_train(intel_dp,
- training_pattern |
- DP_LINK_SCRAMBLING_DISABLE);
- tries = 0;
- cr_tries++;
- continue;
- }
-
- /* Update training set as requested by target */
- intel_get_adjust_train(intel_dp, link_status);
- if (!intel_dp_update_link_train(intel_dp)) {
- DRM_ERROR("failed to update link training\n");
- break;
- }
- ++tries;
- }
-
- intel_dp_set_idle_link_train(intel_dp);
-
- if (channel_eq) {
- intel_dp->train_set_valid = true;
- DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n");
- return true;
- } else {
- return false;
- }
-}
-
-void intel_dp_stop_link_train(struct intel_dp *intel_dp)
-{
- intel_dp_set_link_train(intel_dp,
- DP_TRAINING_PATTERN_DISABLE);
-}
-
-void
-intel_dp_start_link_train(struct intel_dp *intel_dp)
-{
- uint32_t DP = intel_dp->DP;
-
- if (!intel_dp_link_training_clock_recovery(intel_dp) ||
- !intel_dp_link_training_channel_equalization(intel_dp))
- intel_dp->DP = DP;
-}
-
static void
intel_dp_link_down(struct intel_dp *intel_dp)
{
diff --git a/drivers/gpu/drm/i915/intel_dp_link_training.c b/drivers/gpu/drm/i915/intel_dp_link_training.c
new file mode 100644
index 0000000..f33cbbb
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_dp_link_training.c
@@ -0,0 +1,336 @@
+/*
+ * Copyright © 2008-2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "intel_drv.h"
+
+static void
+intel_get_adjust_train(struct intel_dp *intel_dp,
+ const uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+ uint8_t v = 0;
+ uint8_t p = 0;
+ int lane;
+ uint8_t voltage_max;
+ uint8_t preemph_max;
+
+ for (lane = 0; lane < intel_dp->lane_count; lane++) {
+ uint8_t this_v = drm_dp_get_adjust_request_voltage(link_status, lane);
+ uint8_t this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane);
+
+ if (this_v > v)
+ v = this_v;
+ if (this_p > p)
+ p = this_p;
+ }
+
+ voltage_max = intel_dp_voltage_max(intel_dp);
+ if (v >= voltage_max)
+ v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
+
+ preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
+ if (p >= preemph_max)
+ p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
+
+ for (lane = 0; lane < 4; lane++)
+ intel_dp->train_set[lane] = v | p;
+}
+
+static bool
+intel_dp_set_link_train(struct intel_dp *intel_dp,
+ uint8_t dp_train_pat)
+{
+ uint8_t buf[sizeof(intel_dp->train_set) + 1];
+ int ret, len;
+
+ intel_dp_program_link_training_pattern(intel_dp, dp_train_pat);
+
+ buf[0] = dp_train_pat;
+ if ((dp_train_pat & DP_TRAINING_PATTERN_MASK) ==
+ DP_TRAINING_PATTERN_DISABLE) {
+ /* don't write DP_TRAINING_LANEx_SET on disable */
+ len = 1;
+ } else {
+ /* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */
+ memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count);
+ len = intel_dp->lane_count + 1;
+ }
+
+ ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET,
+ buf, len);
+
+ return ret == len;
+}
+
+static bool
+intel_dp_reset_link_train(struct intel_dp *intel_dp,
+ uint8_t dp_train_pat)
+{
+ if (!intel_dp->train_set_valid)
+ memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
+ intel_dp_update_signal_levels(intel_dp);
+ return intel_dp_set_link_train(intel_dp, dp_train_pat);
+}
+
+static bool
+intel_dp_update_link_train(struct intel_dp *intel_dp)
+{
+ int ret;
+
+ intel_dp_update_signal_levels(intel_dp);
+
+ ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET,
+ intel_dp->train_set, intel_dp->lane_count);
+
+ return ret == intel_dp->lane_count;
+}
+
+/* Enable corresponding port and start training pattern 1 */
+static bool
+intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
+{
+ struct drm_encoder *encoder = &dp_to_dig_port(intel_dp)->base.base;
+ struct drm_device *dev = encoder->dev;
+ int i;
+ uint8_t voltage;
+ int voltage_tries, loop_tries;
+ uint8_t link_config[2];
+ uint8_t link_bw, rate_select;
+ uint8_t link_status[DP_LINK_STATUS_SIZE];
+
+ if (HAS_DDI(dev))
+ intel_ddi_prepare_link_retrain(encoder);
+
+ intel_dp_compute_rate(intel_dp, intel_dp->link_rate,
+ &link_bw, &rate_select);
+
+ /* Write the link configuration data */
+ link_config[0] = link_bw;
+ link_config[1] = intel_dp->lane_count;
+ if (drm_dp_enhanced_frame_cap(intel_dp->dpcd))
+ link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
+ drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2);
+ if (intel_dp->num_sink_rates)
+ drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET,
+ &rate_select, 1);
+
+ link_config[0] = 0;
+ link_config[1] = DP_SET_ANSI_8B10B;
+ drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2);
+
+ intel_dp->DP |= DP_PORT_EN;
+
+ /* clock recovery */
+ if (!intel_dp_reset_link_train(intel_dp,
+ DP_TRAINING_PATTERN_1 |
+ DP_LINK_SCRAMBLING_DISABLE)) {
+ DRM_ERROR("failed to enable link training\n");
+ return false;
+ }
+
+ voltage = 0xff;
+ voltage_tries = 0;
+ loop_tries = 0;
+ for (;;) {
+ drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
+ if (!intel_dp_get_link_status(intel_dp, link_status)) {
+ DRM_ERROR("failed to get link status\n");
+ break;
+ }
+
+ if (drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) {
+ DRM_DEBUG_KMS("clock recovery OK\n");
+ break;
+ }
+
+ /*
+ * if we used previously trained voltage and pre-emphasis values
+ * and we don't get clock recovery, reset link training values
+ */
+ if (intel_dp->train_set_valid) {
+ DRM_DEBUG_KMS("clock recovery not ok, reset");
+ /* clear the flag as we are not reusing train set */
+ intel_dp->train_set_valid = false;
+ if (!intel_dp_reset_link_train(intel_dp,
+ DP_TRAINING_PATTERN_1 |
+ DP_LINK_SCRAMBLING_DISABLE)) {
+ DRM_ERROR("failed to enable link training\n");
+ return false;
+ }
+ continue;
+ }
+
+ /* Check to see if we've tried the max voltage */
+ for (i = 0; i < intel_dp->lane_count; i++)
+ if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
+ break;
+ if (i == intel_dp->lane_count) {
+ ++loop_tries;
+ if (loop_tries == 5) {
+ DRM_ERROR("too many full retries, give up\n");
+ break;
+ }
+ intel_dp_reset_link_train(intel_dp,
+ DP_TRAINING_PATTERN_1 |
+ DP_LINK_SCRAMBLING_DISABLE);
+ voltage_tries = 0;
+ continue;
+ }
+
+ /* Check to see if we've tried the same voltage 5 times */
+ if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
+ ++voltage_tries;
+ if (voltage_tries == 5) {
+ DRM_ERROR("too many voltage retries, give up\n");
+ break;
+ }
+ } else
+ voltage_tries = 0;
+ voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
+
+ /* Update training set as requested by target */
+ intel_get_adjust_train(intel_dp, link_status);
+ if (!intel_dp_update_link_train(intel_dp)) {
+ DRM_ERROR("failed to update link training\n");
+ break;
+ }
+ }
+
+ return drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count);
+}
+
+static bool
+intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
+{
+ struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+ struct drm_device *dev = dig_port->base.base.dev;
+ bool channel_eq = false;
+ int tries, cr_tries;
+ uint32_t training_pattern = DP_TRAINING_PATTERN_2;
+
+ /*
+ * Training Pattern 3 for HBR2 or 1.2 devices that support it.
+ *
+ * Intel platforms that support HBR2 also support TPS3. TPS3 support is
+ * also mandatory for downstream devices that support HBR2.
+ *
+ * Due to WaDisableHBR2 SKL < B0 is the only exception where TPS3 is
+ * supported but still not enabled.
+ */
+ if (intel_dp_source_supports_hbr2(dev) &&
+ drm_dp_tps3_supported(intel_dp->dpcd))
+ training_pattern = DP_TRAINING_PATTERN_3;
+ else if (intel_dp->link_rate == 540000)
+ DRM_ERROR("5.4 Gbps link rate without HBR2/TPS3 support\n");
+
+ /* channel equalization */
+ if (!intel_dp_set_link_train(intel_dp,
+ training_pattern |
+ DP_LINK_SCRAMBLING_DISABLE)) {
+ DRM_ERROR("failed to start channel equalization\n");
+ return false;
+ }
+
+ tries = 0;
+ cr_tries = 0;
+ channel_eq = false;
+ for (;;) {
+ uint8_t link_status[DP_LINK_STATUS_SIZE];
+
+ if (cr_tries > 5) {
+ DRM_ERROR("failed to train DP, aborting\n");
+ break;
+ }
+
+ drm_dp_link_train_channel_eq_delay(intel_dp->dpcd);
+ if (!intel_dp_get_link_status(intel_dp, link_status)) {
+ DRM_ERROR("failed to get link status\n");
+ break;
+ }
+
+ /* Make sure clock is still ok */
+ if (!drm_dp_clock_recovery_ok(link_status,
+ intel_dp->lane_count)) {
+ intel_dp->train_set_valid = false;
+ intel_dp_link_training_clock_recovery(intel_dp);
+ intel_dp_set_link_train(intel_dp,
+ training_pattern |
+ DP_LINK_SCRAMBLING_DISABLE);
+ cr_tries++;
+ continue;
+ }
+
+ if (drm_dp_channel_eq_ok(link_status,
+ intel_dp->lane_count)) {
+ channel_eq = true;
+ break;
+ }
+
+ /* Try 5 times, then try clock recovery if that fails */
+ if (tries > 5) {
+ intel_dp->train_set_valid = false;
+ intel_dp_link_training_clock_recovery(intel_dp);
+ intel_dp_set_link_train(intel_dp,
+ training_pattern |
+ DP_LINK_SCRAMBLING_DISABLE);
+ tries = 0;
+ cr_tries++;
+ continue;
+ }
+
+ /* Update training set as requested by target */
+ intel_get_adjust_train(intel_dp, link_status);
+ if (!intel_dp_update_link_train(intel_dp)) {
+ DRM_ERROR("failed to update link training\n");
+ break;
+ }
+ ++tries;
+ }
+
+ intel_dp_set_idle_link_train(intel_dp);
+
+ if (channel_eq) {
+ intel_dp->train_set_valid = true;
+ DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n");
+ return true;
+ } else {
+ return false;
+ }
+}
+
+void intel_dp_stop_link_train(struct intel_dp *intel_dp)
+{
+ intel_dp_set_link_train(intel_dp,
+ DP_TRAINING_PATTERN_DISABLE);
+}
+
+void
+intel_dp_start_link_train(struct intel_dp *intel_dp)
+{
+ uint32_t DP = intel_dp->DP;
+
+ if (!intel_dp_link_training_clock_recovery(intel_dp) ||
+ !intel_dp_link_training_channel_equalization(intel_dp))
+ intel_dp->DP = DP;
+}
+
+
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 6bac79b..29ae4bb 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -1210,6 +1210,22 @@ void intel_edp_drrs_invalidate(struct drm_device *dev,
void intel_edp_drrs_flush(struct drm_device *dev, unsigned frontbuffer_bits);
void hsw_dp_set_ddi_pll_sel(struct intel_crtc_state *pipe_config);

+void
+intel_dp_program_link_training_pattern(struct intel_dp *intel_dp,
+ uint8_t dp_train_pat);
+void
+intel_dp_update_signal_levels(struct intel_dp *intel_dp);
+void intel_dp_set_idle_link_train(struct intel_dp *intel_dp);
+uint8_t
+intel_dp_voltage_max(struct intel_dp *intel_dp);
+uint8_t
+intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing);
+void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
+ uint8_t *link_bw, uint8_t *rate_select);
+bool intel_dp_source_supports_hbr2(struct drm_device *dev);
+bool
+intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE]);
+
/* intel_dp_mst.c */
int intel_dp_mst_encoder_init(struct intel_digital_port *intel_dig_port, int conn_id);
void intel_dp_mst_encoder_cleanup(struct intel_digital_port *intel_dig_port);
--
2.4.3