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94223d04 ACO |
1 | /* |
2 | * Copyright © 2008-2015 Intel Corporation | |
3 | * | |
4 | * Permission is hereby granted, free of charge, to any person obtaining a | |
5 | * copy of this software and associated documentation files (the "Software"), | |
6 | * to deal in the Software without restriction, including without limitation | |
7 | * the rights to use, copy, modify, merge, publish, distribute, sublicense, | |
8 | * and/or sell copies of the Software, and to permit persons to whom the | |
9 | * Software is furnished to do so, subject to the following conditions: | |
10 | * | |
11 | * The above copyright notice and this permission notice (including the next | |
12 | * paragraph) shall be included in all copies or substantial portions of the | |
13 | * Software. | |
14 | * | |
15 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
16 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
17 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL | |
18 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
19 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
20 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
21 | * IN THE SOFTWARE. | |
22 | */ | |
23 | ||
24 | #include "intel_drv.h" | |
25 | ||
26 | static void | |
27 | intel_get_adjust_train(struct intel_dp *intel_dp, | |
28 | const uint8_t link_status[DP_LINK_STATUS_SIZE]) | |
29 | { | |
30 | uint8_t v = 0; | |
31 | uint8_t p = 0; | |
32 | int lane; | |
33 | uint8_t voltage_max; | |
34 | uint8_t preemph_max; | |
35 | ||
36 | for (lane = 0; lane < intel_dp->lane_count; lane++) { | |
37 | uint8_t this_v = drm_dp_get_adjust_request_voltage(link_status, lane); | |
38 | uint8_t this_p = drm_dp_get_adjust_request_pre_emphasis(link_status, lane); | |
39 | ||
40 | if (this_v > v) | |
41 | v = this_v; | |
42 | if (this_p > p) | |
43 | p = this_p; | |
44 | } | |
45 | ||
46 | voltage_max = intel_dp_voltage_max(intel_dp); | |
47 | if (v >= voltage_max) | |
48 | v = voltage_max | DP_TRAIN_MAX_SWING_REACHED; | |
49 | ||
50 | preemph_max = intel_dp_pre_emphasis_max(intel_dp, v); | |
51 | if (p >= preemph_max) | |
52 | p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED; | |
53 | ||
54 | for (lane = 0; lane < 4; lane++) | |
55 | intel_dp->train_set[lane] = v | p; | |
56 | } | |
57 | ||
58 | static bool | |
59 | intel_dp_set_link_train(struct intel_dp *intel_dp, | |
60 | uint8_t dp_train_pat) | |
61 | { | |
62 | uint8_t buf[sizeof(intel_dp->train_set) + 1]; | |
63 | int ret, len; | |
64 | ||
65 | intel_dp_program_link_training_pattern(intel_dp, dp_train_pat); | |
66 | ||
67 | buf[0] = dp_train_pat; | |
68 | if ((dp_train_pat & DP_TRAINING_PATTERN_MASK) == | |
69 | DP_TRAINING_PATTERN_DISABLE) { | |
70 | /* don't write DP_TRAINING_LANEx_SET on disable */ | |
71 | len = 1; | |
72 | } else { | |
73 | /* DP_TRAINING_LANEx_SET follow DP_TRAINING_PATTERN_SET */ | |
74 | memcpy(buf + 1, intel_dp->train_set, intel_dp->lane_count); | |
75 | len = intel_dp->lane_count + 1; | |
76 | } | |
77 | ||
78 | ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_PATTERN_SET, | |
79 | buf, len); | |
80 | ||
81 | return ret == len; | |
82 | } | |
83 | ||
84 | static bool | |
85 | intel_dp_reset_link_train(struct intel_dp *intel_dp, | |
86 | uint8_t dp_train_pat) | |
87 | { | |
88 | if (!intel_dp->train_set_valid) | |
89 | memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set)); | |
90 | intel_dp_set_signal_levels(intel_dp); | |
91 | return intel_dp_set_link_train(intel_dp, dp_train_pat); | |
92 | } | |
93 | ||
94 | static bool | |
95 | intel_dp_update_link_train(struct intel_dp *intel_dp) | |
96 | { | |
97 | int ret; | |
98 | ||
99 | intel_dp_set_signal_levels(intel_dp); | |
100 | ||
101 | ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET, | |
102 | intel_dp->train_set, intel_dp->lane_count); | |
103 | ||
104 | return ret == intel_dp->lane_count; | |
105 | } | |
106 | ||
107 | /* Enable corresponding port and start training pattern 1 */ | |
108 | static void | |
109 | intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp) | |
110 | { | |
94223d04 ACO |
111 | int i; |
112 | uint8_t voltage; | |
113 | int voltage_tries, loop_tries; | |
114 | uint8_t link_config[2]; | |
115 | uint8_t link_bw, rate_select; | |
116 | ||
ad64217b ACO |
117 | if (intel_dp->prepare_link_retrain) |
118 | intel_dp->prepare_link_retrain(intel_dp); | |
94223d04 ACO |
119 | |
120 | intel_dp_compute_rate(intel_dp, intel_dp->link_rate, | |
121 | &link_bw, &rate_select); | |
122 | ||
123 | /* Write the link configuration data */ | |
124 | link_config[0] = link_bw; | |
125 | link_config[1] = intel_dp->lane_count; | |
126 | if (drm_dp_enhanced_frame_cap(intel_dp->dpcd)) | |
127 | link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN; | |
128 | drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2); | |
129 | if (intel_dp->num_sink_rates) | |
130 | drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET, | |
131 | &rate_select, 1); | |
132 | ||
133 | link_config[0] = 0; | |
134 | link_config[1] = DP_SET_ANSI_8B10B; | |
135 | drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2); | |
136 | ||
137 | intel_dp->DP |= DP_PORT_EN; | |
138 | ||
139 | /* clock recovery */ | |
140 | if (!intel_dp_reset_link_train(intel_dp, | |
141 | DP_TRAINING_PATTERN_1 | | |
142 | DP_LINK_SCRAMBLING_DISABLE)) { | |
143 | DRM_ERROR("failed to enable link training\n"); | |
144 | return; | |
145 | } | |
146 | ||
147 | voltage = 0xff; | |
148 | voltage_tries = 0; | |
149 | loop_tries = 0; | |
150 | for (;;) { | |
151 | uint8_t link_status[DP_LINK_STATUS_SIZE]; | |
152 | ||
153 | drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd); | |
154 | if (!intel_dp_get_link_status(intel_dp, link_status)) { | |
155 | DRM_ERROR("failed to get link status\n"); | |
156 | break; | |
157 | } | |
158 | ||
159 | if (drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) { | |
160 | DRM_DEBUG_KMS("clock recovery OK\n"); | |
161 | break; | |
162 | } | |
163 | ||
164 | /* | |
165 | * if we used previously trained voltage and pre-emphasis values | |
166 | * and we don't get clock recovery, reset link training values | |
167 | */ | |
168 | if (intel_dp->train_set_valid) { | |
169 | DRM_DEBUG_KMS("clock recovery not ok, reset"); | |
170 | /* clear the flag as we are not reusing train set */ | |
171 | intel_dp->train_set_valid = false; | |
172 | if (!intel_dp_reset_link_train(intel_dp, | |
173 | DP_TRAINING_PATTERN_1 | | |
174 | DP_LINK_SCRAMBLING_DISABLE)) { | |
175 | DRM_ERROR("failed to enable link training\n"); | |
176 | return; | |
177 | } | |
178 | continue; | |
179 | } | |
180 | ||
181 | /* Check to see if we've tried the max voltage */ | |
182 | for (i = 0; i < intel_dp->lane_count; i++) | |
183 | if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0) | |
184 | break; | |
185 | if (i == intel_dp->lane_count) { | |
186 | ++loop_tries; | |
187 | if (loop_tries == 5) { | |
188 | DRM_ERROR("too many full retries, give up\n"); | |
189 | break; | |
190 | } | |
191 | intel_dp_reset_link_train(intel_dp, | |
192 | DP_TRAINING_PATTERN_1 | | |
193 | DP_LINK_SCRAMBLING_DISABLE); | |
194 | voltage_tries = 0; | |
195 | continue; | |
196 | } | |
197 | ||
198 | /* Check to see if we've tried the same voltage 5 times */ | |
199 | if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) { | |
200 | ++voltage_tries; | |
201 | if (voltage_tries == 5) { | |
202 | DRM_ERROR("too many voltage retries, give up\n"); | |
203 | break; | |
204 | } | |
205 | } else | |
206 | voltage_tries = 0; | |
207 | voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK; | |
208 | ||
209 | /* Update training set as requested by target */ | |
210 | intel_get_adjust_train(intel_dp, link_status); | |
211 | if (!intel_dp_update_link_train(intel_dp)) { | |
212 | DRM_ERROR("failed to update link training\n"); | |
213 | break; | |
214 | } | |
215 | } | |
216 | } | |
217 | ||
218 | static void | |
219 | intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) | |
220 | { | |
94223d04 ACO |
221 | bool channel_eq = false; |
222 | int tries, cr_tries; | |
223 | uint32_t training_pattern = DP_TRAINING_PATTERN_2; | |
224 | ||
225 | /* | |
226 | * Training Pattern 3 for HBR2 or 1.2 devices that support it. | |
227 | * | |
228 | * Intel platforms that support HBR2 also support TPS3. TPS3 support is | |
229 | * also mandatory for downstream devices that support HBR2. | |
230 | * | |
231 | * Due to WaDisableHBR2 SKL < B0 is the only exception where TPS3 is | |
232 | * supported but still not enabled. | |
233 | */ | |
e588fa18 | 234 | if (intel_dp_source_supports_hbr2(intel_dp) && |
94223d04 ACO |
235 | drm_dp_tps3_supported(intel_dp->dpcd)) |
236 | training_pattern = DP_TRAINING_PATTERN_3; | |
237 | else if (intel_dp->link_rate == 540000) | |
238 | DRM_ERROR("5.4 Gbps link rate without HBR2/TPS3 support\n"); | |
239 | ||
240 | /* channel equalization */ | |
241 | if (!intel_dp_set_link_train(intel_dp, | |
242 | training_pattern | | |
243 | DP_LINK_SCRAMBLING_DISABLE)) { | |
244 | DRM_ERROR("failed to start channel equalization\n"); | |
245 | return; | |
246 | } | |
247 | ||
248 | tries = 0; | |
249 | cr_tries = 0; | |
250 | channel_eq = false; | |
251 | for (;;) { | |
252 | uint8_t link_status[DP_LINK_STATUS_SIZE]; | |
253 | ||
254 | if (cr_tries > 5) { | |
255 | DRM_ERROR("failed to train DP, aborting\n"); | |
256 | break; | |
257 | } | |
258 | ||
259 | drm_dp_link_train_channel_eq_delay(intel_dp->dpcd); | |
260 | if (!intel_dp_get_link_status(intel_dp, link_status)) { | |
261 | DRM_ERROR("failed to get link status\n"); | |
262 | break; | |
263 | } | |
264 | ||
265 | /* Make sure clock is still ok */ | |
266 | if (!drm_dp_clock_recovery_ok(link_status, | |
267 | intel_dp->lane_count)) { | |
268 | intel_dp->train_set_valid = false; | |
269 | intel_dp_link_training_clock_recovery(intel_dp); | |
270 | intel_dp_set_link_train(intel_dp, | |
271 | training_pattern | | |
272 | DP_LINK_SCRAMBLING_DISABLE); | |
273 | cr_tries++; | |
274 | continue; | |
275 | } | |
276 | ||
277 | if (drm_dp_channel_eq_ok(link_status, | |
278 | intel_dp->lane_count)) { | |
279 | channel_eq = true; | |
280 | break; | |
281 | } | |
282 | ||
283 | /* Try 5 times, then try clock recovery if that fails */ | |
284 | if (tries > 5) { | |
285 | intel_dp->train_set_valid = false; | |
286 | intel_dp_link_training_clock_recovery(intel_dp); | |
287 | intel_dp_set_link_train(intel_dp, | |
288 | training_pattern | | |
289 | DP_LINK_SCRAMBLING_DISABLE); | |
290 | tries = 0; | |
291 | cr_tries++; | |
292 | continue; | |
293 | } | |
294 | ||
295 | /* Update training set as requested by target */ | |
296 | intel_get_adjust_train(intel_dp, link_status); | |
297 | if (!intel_dp_update_link_train(intel_dp)) { | |
298 | DRM_ERROR("failed to update link training\n"); | |
299 | break; | |
300 | } | |
301 | ++tries; | |
302 | } | |
303 | ||
304 | intel_dp_set_idle_link_train(intel_dp); | |
305 | ||
306 | if (channel_eq) { | |
307 | intel_dp->train_set_valid = true; | |
308 | DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n"); | |
309 | } | |
310 | } | |
311 | ||
312 | void intel_dp_stop_link_train(struct intel_dp *intel_dp) | |
313 | { | |
314 | intel_dp_set_link_train(intel_dp, | |
315 | DP_TRAINING_PATTERN_DISABLE); | |
316 | } | |
317 | ||
318 | void | |
319 | intel_dp_start_link_train(struct intel_dp *intel_dp) | |
320 | { | |
321 | intel_dp_link_training_clock_recovery(intel_dp); | |
322 | intel_dp_link_training_channel_equalization(intel_dp); | |
323 | } |