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author | Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com> | 2015-10-23 13:01:48 +0300 |
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committer | Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com> | 2015-11-05 15:14:56 +0200 |
commit | 94223d041b0716cee45240cdcd635357d7302021 (patch) | |
tree | 833a761440f6d15a25ea5ff52836d2fc14d90078 /drivers/gpu/drm/i915/intel_dp_link_training.c | |
parent | b905a9155db6fd51bfdb7625b7d0c5c3047d49f2 (diff) | |
download | op-kernel-dev-94223d041b0716cee45240cdcd635357d7302021.zip op-kernel-dev-94223d041b0716cee45240cdcd635357d7302021.tar.gz |
drm/i915: Move generic link training code to a separate file
No functional changes, just moving code around.
v2: Rebase
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1445594525-7174-6-git-send-email-ander.conselvan.de.oliveira@intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/intel_dp_link_training.c')
-rw-r--r-- | drivers/gpu/drm/i915/intel_dp_link_training.c | 327 |
1 files changed, 327 insertions, 0 deletions
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..53f9c14 --- /dev/null +++ b/drivers/gpu/drm/i915/intel_dp_link_training.c @@ -0,0 +1,327 @@ +/* + * 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_set_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_set_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 void +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; + + 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; + } + + voltage = 0xff; + voltage_tries = 0; + loop_tries = 0; + for (;;) { + uint8_t link_status[DP_LINK_STATUS_SIZE]; + + 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; + } + 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; + } + } +} + +static void +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; + } + + 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"); + } +} + +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) +{ + intel_dp_link_training_clock_recovery(intel_dp); + intel_dp_link_training_channel_equalization(intel_dp); +} |