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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 | { | |
34511dce | 88 | memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set)); |
94223d04 ACO |
89 | intel_dp_set_signal_levels(intel_dp); |
90 | return intel_dp_set_link_train(intel_dp, dp_train_pat); | |
91 | } | |
92 | ||
93 | static bool | |
94 | intel_dp_update_link_train(struct intel_dp *intel_dp) | |
95 | { | |
96 | int ret; | |
97 | ||
98 | intel_dp_set_signal_levels(intel_dp); | |
99 | ||
100 | ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET, | |
101 | intel_dp->train_set, intel_dp->lane_count); | |
102 | ||
103 | return ret == intel_dp->lane_count; | |
104 | } | |
105 | ||
106 | /* Enable corresponding port and start training pattern 1 */ | |
107 | static void | |
108 | intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp) | |
109 | { | |
94223d04 ACO |
110 | int i; |
111 | uint8_t voltage; | |
112 | int voltage_tries, loop_tries; | |
113 | uint8_t link_config[2]; | |
114 | uint8_t link_bw, rate_select; | |
115 | ||
ad64217b ACO |
116 | if (intel_dp->prepare_link_retrain) |
117 | intel_dp->prepare_link_retrain(intel_dp); | |
94223d04 ACO |
118 | |
119 | intel_dp_compute_rate(intel_dp, intel_dp->link_rate, | |
120 | &link_bw, &rate_select); | |
121 | ||
122 | /* Write the link configuration data */ | |
123 | link_config[0] = link_bw; | |
124 | link_config[1] = intel_dp->lane_count; | |
125 | if (drm_dp_enhanced_frame_cap(intel_dp->dpcd)) | |
126 | link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN; | |
127 | drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2); | |
128 | if (intel_dp->num_sink_rates) | |
129 | drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET, | |
130 | &rate_select, 1); | |
131 | ||
132 | link_config[0] = 0; | |
133 | link_config[1] = DP_SET_ANSI_8B10B; | |
134 | drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2); | |
135 | ||
136 | intel_dp->DP |= DP_PORT_EN; | |
137 | ||
138 | /* clock recovery */ | |
139 | if (!intel_dp_reset_link_train(intel_dp, | |
140 | DP_TRAINING_PATTERN_1 | | |
141 | DP_LINK_SCRAMBLING_DISABLE)) { | |
142 | DRM_ERROR("failed to enable link training\n"); | |
143 | return; | |
144 | } | |
145 | ||
146 | voltage = 0xff; | |
147 | voltage_tries = 0; | |
148 | loop_tries = 0; | |
149 | for (;;) { | |
150 | uint8_t link_status[DP_LINK_STATUS_SIZE]; | |
151 | ||
152 | drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd); | |
153 | if (!intel_dp_get_link_status(intel_dp, link_status)) { | |
154 | DRM_ERROR("failed to get link status\n"); | |
155 | break; | |
156 | } | |
157 | ||
158 | if (drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count)) { | |
159 | DRM_DEBUG_KMS("clock recovery OK\n"); | |
160 | break; | |
161 | } | |
162 | ||
94223d04 ACO |
163 | /* Check to see if we've tried the max voltage */ |
164 | for (i = 0; i < intel_dp->lane_count; i++) | |
165 | if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0) | |
166 | break; | |
167 | if (i == intel_dp->lane_count) { | |
168 | ++loop_tries; | |
169 | if (loop_tries == 5) { | |
170 | DRM_ERROR("too many full retries, give up\n"); | |
171 | break; | |
172 | } | |
173 | intel_dp_reset_link_train(intel_dp, | |
174 | DP_TRAINING_PATTERN_1 | | |
175 | DP_LINK_SCRAMBLING_DISABLE); | |
176 | voltage_tries = 0; | |
177 | continue; | |
178 | } | |
179 | ||
180 | /* Check to see if we've tried the same voltage 5 times */ | |
181 | if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) { | |
182 | ++voltage_tries; | |
183 | if (voltage_tries == 5) { | |
184 | DRM_ERROR("too many voltage retries, give up\n"); | |
185 | break; | |
186 | } | |
187 | } else | |
188 | voltage_tries = 0; | |
189 | voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK; | |
190 | ||
191 | /* Update training set as requested by target */ | |
192 | intel_get_adjust_train(intel_dp, link_status); | |
193 | if (!intel_dp_update_link_train(intel_dp)) { | |
194 | DRM_ERROR("failed to update link training\n"); | |
195 | break; | |
196 | } | |
197 | } | |
198 | } | |
199 | ||
bf039fa9 JN |
200 | /* |
201 | * Pick training pattern for channel equalization. Training Pattern 3 for HBR2 | |
202 | * or 1.2 devices that support it, Training Pattern 2 otherwise. | |
203 | */ | |
204 | static u32 intel_dp_training_pattern(struct intel_dp *intel_dp) | |
94223d04 | 205 | { |
bf039fa9 | 206 | u32 training_pattern = DP_TRAINING_PATTERN_2; |
0fd64e82 | 207 | bool source_tps3, sink_tps3; |
94223d04 ACO |
208 | |
209 | /* | |
94223d04 | 210 | * Intel platforms that support HBR2 also support TPS3. TPS3 support is |
0fd64e82 JN |
211 | * also mandatory for downstream devices that support HBR2. However, not |
212 | * all sinks follow the spec. | |
94223d04 ACO |
213 | * |
214 | * Due to WaDisableHBR2 SKL < B0 is the only exception where TPS3 is | |
0fd64e82 | 215 | * supported in source but still not enabled. |
94223d04 | 216 | */ |
0fd64e82 JN |
217 | source_tps3 = intel_dp_source_supports_hbr2(intel_dp); |
218 | sink_tps3 = drm_dp_tps3_supported(intel_dp->dpcd); | |
219 | ||
220 | if (source_tps3 && sink_tps3) { | |
94223d04 | 221 | training_pattern = DP_TRAINING_PATTERN_3; |
0fd64e82 JN |
222 | } else if (intel_dp->link_rate == 540000) { |
223 | if (!source_tps3) | |
224 | DRM_DEBUG_KMS("5.4 Gbps link rate without source HBR2/TPS3 support\n"); | |
225 | if (!sink_tps3) | |
226 | DRM_DEBUG_KMS("5.4 Gbps link rate without sink TPS3 support\n"); | |
227 | } | |
94223d04 | 228 | |
bf039fa9 JN |
229 | return training_pattern; |
230 | } | |
231 | ||
232 | static void | |
233 | intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp) | |
234 | { | |
235 | bool channel_eq = false; | |
236 | int tries, cr_tries; | |
237 | u32 training_pattern; | |
238 | ||
239 | training_pattern = intel_dp_training_pattern(intel_dp); | |
240 | ||
94223d04 ACO |
241 | /* channel equalization */ |
242 | if (!intel_dp_set_link_train(intel_dp, | |
243 | training_pattern | | |
244 | DP_LINK_SCRAMBLING_DISABLE)) { | |
245 | DRM_ERROR("failed to start channel equalization\n"); | |
246 | return; | |
247 | } | |
248 | ||
249 | tries = 0; | |
250 | cr_tries = 0; | |
251 | channel_eq = false; | |
252 | for (;;) { | |
253 | uint8_t link_status[DP_LINK_STATUS_SIZE]; | |
254 | ||
255 | if (cr_tries > 5) { | |
256 | DRM_ERROR("failed to train DP, aborting\n"); | |
257 | break; | |
258 | } | |
259 | ||
260 | drm_dp_link_train_channel_eq_delay(intel_dp->dpcd); | |
261 | if (!intel_dp_get_link_status(intel_dp, link_status)) { | |
262 | DRM_ERROR("failed to get link status\n"); | |
263 | break; | |
264 | } | |
265 | ||
266 | /* Make sure clock is still ok */ | |
267 | if (!drm_dp_clock_recovery_ok(link_status, | |
268 | intel_dp->lane_count)) { | |
94223d04 ACO |
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) { | |
94223d04 ACO |
285 | intel_dp_link_training_clock_recovery(intel_dp); |
286 | intel_dp_set_link_train(intel_dp, | |
287 | training_pattern | | |
288 | DP_LINK_SCRAMBLING_DISABLE); | |
289 | tries = 0; | |
290 | cr_tries++; | |
291 | continue; | |
292 | } | |
293 | ||
294 | /* Update training set as requested by target */ | |
295 | intel_get_adjust_train(intel_dp, link_status); | |
296 | if (!intel_dp_update_link_train(intel_dp)) { | |
297 | DRM_ERROR("failed to update link training\n"); | |
298 | break; | |
299 | } | |
300 | ++tries; | |
301 | } | |
302 | ||
303 | intel_dp_set_idle_link_train(intel_dp); | |
304 | ||
34511dce | 305 | if (channel_eq) |
94223d04 | 306 | DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n"); |
94223d04 ACO |
307 | } |
308 | ||
309 | void intel_dp_stop_link_train(struct intel_dp *intel_dp) | |
310 | { | |
311 | intel_dp_set_link_train(intel_dp, | |
312 | DP_TRAINING_PATTERN_DISABLE); | |
313 | } | |
314 | ||
315 | void | |
316 | intel_dp_start_link_train(struct intel_dp *intel_dp) | |
317 | { | |
318 | intel_dp_link_training_clock_recovery(intel_dp); | |
319 | intel_dp_link_training_channel_equalization(intel_dp); | |
320 | } |