xref: /linux/drivers/gpu/drm/i915/display/intel_alpm.c (revision 569d7db70e5dcf13fbf072f10e9096577ac1e565)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright 2024, Intel Corporation.
4  */
5 
6 #include "intel_alpm.h"
7 #include "intel_crtc.h"
8 #include "intel_de.h"
9 #include "intel_display_types.h"
10 #include "intel_dp.h"
11 #include "intel_dp_aux.h"
12 #include "intel_psr_regs.h"
13 
14 bool intel_alpm_aux_wake_supported(struct intel_dp *intel_dp)
15 {
16 	return intel_dp->alpm_dpcd & DP_ALPM_CAP;
17 }
18 
19 bool intel_alpm_aux_less_wake_supported(struct intel_dp *intel_dp)
20 {
21 	return intel_dp->alpm_dpcd & DP_ALPM_AUX_LESS_CAP;
22 }
23 
24 void intel_alpm_init_dpcd(struct intel_dp *intel_dp)
25 {
26 	u8 dpcd;
27 
28 	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_RECEIVER_ALPM_CAP, &dpcd) < 0)
29 		return;
30 
31 	intel_dp->alpm_dpcd = dpcd;
32 }
33 
34 /*
35  * See Bspec: 71632 for the table
36  *
37  * Silence_period = tSilence,Min + ((tSilence,Max - tSilence,Min) / 2)
38  *
39  * Half cycle duration:
40  *
41  * Link rates 1.62 - 4.32 and tLFPS_Cycle = 70 ns
42  * FLOOR( (Link Rate * tLFPS_Cycle) / (2 * 10) )
43  *
44  * Link rates 5.4 - 8.1
45  * PORT_ALPM_LFPS_CTL[ LFPS Cycle Count ] = 10
46  * LFPS Period chosen is the mid-point of the min:max values from the table
47  * FLOOR( LFPS Period in Symbol clocks /
48  * (2 * PORT_ALPM_LFPS_CTL[ LFPS Cycle Count ]) )
49  */
50 static bool _lnl_get_silence_period_and_lfps_half_cycle(int link_rate,
51 							int *silence_period,
52 							int *lfps_half_cycle)
53 {
54 	switch (link_rate) {
55 	case 162000:
56 		*silence_period = 20;
57 		*lfps_half_cycle = 5;
58 		break;
59 	case 216000:
60 		*silence_period = 27;
61 		*lfps_half_cycle = 7;
62 		break;
63 	case 243000:
64 		*silence_period = 31;
65 		*lfps_half_cycle = 8;
66 		break;
67 	case 270000:
68 		*silence_period = 34;
69 		*lfps_half_cycle = 9;
70 		break;
71 	case 324000:
72 		*silence_period = 41;
73 		*lfps_half_cycle = 11;
74 		break;
75 	case 432000:
76 		*silence_period = 56;
77 		*lfps_half_cycle = 15;
78 		break;
79 	case 540000:
80 		*silence_period = 69;
81 		*lfps_half_cycle = 12;
82 		break;
83 	case 648000:
84 		*silence_period = 84;
85 		*lfps_half_cycle = 15;
86 		break;
87 	case 675000:
88 		*silence_period = 87;
89 		*lfps_half_cycle = 15;
90 		break;
91 	case 810000:
92 		*silence_period = 104;
93 		*lfps_half_cycle = 19;
94 		break;
95 	default:
96 		*silence_period = *lfps_half_cycle = -1;
97 		return false;
98 	}
99 	return true;
100 }
101 
102 /*
103  * AUX-Less Wake Time = CEILING( ((PHY P2 to P0) + tLFPS_Period, Max+
104  * tSilence, Max+ tPHY Establishment + tCDS) / tline)
105  * For the "PHY P2 to P0" latency see the PHY Power Control page
106  * (PHY P2 to P0) : https://gfxspecs.intel.com/Predator/Home/Index/68965
107  * : 12 us
108  * The tLFPS_Period, Max term is 800ns
109  * The tSilence, Max term is 180ns
110  * The tPHY Establishment (a.k.a. t1) term is 50us
111  * The tCDS term is 1 or 2 times t2
112  * t2 = Number ML_PHY_LOCK * tML_PHY_LOCK
113  * Number ML_PHY_LOCK = ( 7 + CEILING( 6.5us / tML_PHY_LOCK ) + 1)
114  * Rounding up the 6.5us padding to the next ML_PHY_LOCK boundary and
115  * adding the "+ 1" term ensures all ML_PHY_LOCK sequences that start
116  * within the CDS period complete within the CDS period regardless of
117  * entry into the period
118  * tML_PHY_LOCK = TPS4 Length * ( 10 / (Link Rate in MHz) )
119  * TPS4 Length = 252 Symbols
120  */
121 static int _lnl_compute_aux_less_wake_time(int port_clock)
122 {
123 	int tphy2_p2_to_p0 = 12 * 1000;
124 	int tlfps_period_max = 800;
125 	int tsilence_max = 180;
126 	int t1 = 50 * 1000;
127 	int tps4 = 252;
128 	/* port_clock is link rate in 10kbit/s units */
129 	int tml_phy_lock = 1000 * 1000 * tps4 / port_clock;
130 	int num_ml_phy_lock = 7 + DIV_ROUND_UP(6500, tml_phy_lock) + 1;
131 	int t2 = num_ml_phy_lock * tml_phy_lock;
132 	int tcds = 1 * t2;
133 
134 	return DIV_ROUND_UP(tphy2_p2_to_p0 + tlfps_period_max + tsilence_max +
135 			    t1 + tcds, 1000);
136 }
137 
138 static int _lnl_compute_aux_less_alpm_params(struct intel_dp *intel_dp,
139 					     struct intel_crtc_state *crtc_state)
140 {
141 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
142 	int aux_less_wake_time, aux_less_wake_lines, silence_period,
143 		lfps_half_cycle;
144 
145 	aux_less_wake_time =
146 		_lnl_compute_aux_less_wake_time(crtc_state->port_clock);
147 	aux_less_wake_lines = intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode,
148 						       aux_less_wake_time);
149 
150 	if (!_lnl_get_silence_period_and_lfps_half_cycle(crtc_state->port_clock,
151 							 &silence_period,
152 							 &lfps_half_cycle))
153 		return false;
154 
155 	if (aux_less_wake_lines > ALPM_CTL_AUX_LESS_WAKE_TIME_MASK ||
156 	    silence_period > PORT_ALPM_CTL_SILENCE_PERIOD_MASK ||
157 	    lfps_half_cycle > PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION_MASK)
158 		return false;
159 
160 	if (i915->display.params.psr_safest_params)
161 		aux_less_wake_lines = ALPM_CTL_AUX_LESS_WAKE_TIME_MASK;
162 
163 	intel_dp->alpm_parameters.aux_less_wake_lines = aux_less_wake_lines;
164 	intel_dp->alpm_parameters.silence_period_sym_clocks = silence_period;
165 	intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms = lfps_half_cycle;
166 
167 	return true;
168 }
169 
170 static bool _lnl_compute_alpm_params(struct intel_dp *intel_dp,
171 				     struct intel_crtc_state *crtc_state)
172 {
173 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
174 	int check_entry_lines;
175 
176 	if (DISPLAY_VER(i915) < 20)
177 		return true;
178 
179 	/* ALPM Entry Check = 2 + CEILING( 5us /tline ) */
180 	check_entry_lines = 2 +
181 		intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode, 5);
182 
183 	if (check_entry_lines > 15)
184 		return false;
185 
186 	if (!_lnl_compute_aux_less_alpm_params(intel_dp, crtc_state))
187 		return false;
188 
189 	if (i915->display.params.psr_safest_params)
190 		check_entry_lines = 15;
191 
192 	intel_dp->alpm_parameters.check_entry_lines = check_entry_lines;
193 
194 	return true;
195 }
196 
197 /*
198  * IO wake time for DISPLAY_VER < 12 is not directly mentioned in Bspec. There
199  * are 50 us io wake time and 32 us fast wake time. Clearly preharge pulses are
200  * not (improperly) included in 32 us fast wake time. 50 us - 32 us = 18 us.
201  */
202 static int skl_io_buffer_wake_time(void)
203 {
204 	return 18;
205 }
206 
207 static int tgl_io_buffer_wake_time(void)
208 {
209 	return 10;
210 }
211 
212 static int io_buffer_wake_time(const struct intel_crtc_state *crtc_state)
213 {
214 	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
215 
216 	if (DISPLAY_VER(i915) >= 12)
217 		return tgl_io_buffer_wake_time();
218 	else
219 		return skl_io_buffer_wake_time();
220 }
221 
222 bool intel_alpm_compute_params(struct intel_dp *intel_dp,
223 				      struct intel_crtc_state *crtc_state)
224 {
225 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
226 	int io_wake_lines, io_wake_time, fast_wake_lines, fast_wake_time;
227 	int tfw_exit_latency = 20; /* eDP spec */
228 	int phy_wake = 4;	   /* eDP spec */
229 	int preamble = 8;	   /* eDP spec */
230 	int precharge = intel_dp_aux_fw_sync_len() - preamble;
231 	u8 max_wake_lines;
232 
233 	io_wake_time = max(precharge, io_buffer_wake_time(crtc_state)) +
234 		preamble + phy_wake + tfw_exit_latency;
235 	fast_wake_time = precharge + preamble + phy_wake +
236 		tfw_exit_latency;
237 
238 	if (DISPLAY_VER(i915) >= 20)
239 		max_wake_lines = 68;
240 	else if (DISPLAY_VER(i915) >= 12)
241 		max_wake_lines = 12;
242 	else
243 		max_wake_lines = 8;
244 
245 	io_wake_lines = intel_usecs_to_scanlines(
246 		&crtc_state->hw.adjusted_mode, io_wake_time);
247 	fast_wake_lines = intel_usecs_to_scanlines(
248 		&crtc_state->hw.adjusted_mode, fast_wake_time);
249 
250 	if (io_wake_lines > max_wake_lines ||
251 	    fast_wake_lines > max_wake_lines)
252 		return false;
253 
254 	if (!_lnl_compute_alpm_params(intel_dp, crtc_state))
255 		return false;
256 
257 	if (i915->display.params.psr_safest_params)
258 		io_wake_lines = fast_wake_lines = max_wake_lines;
259 
260 	/* According to Bspec lower limit should be set as 7 lines. */
261 	intel_dp->alpm_parameters.io_wake_lines = max(io_wake_lines, 7);
262 	intel_dp->alpm_parameters.fast_wake_lines = max(fast_wake_lines, 7);
263 
264 	return true;
265 }
266 
267 void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp,
268 				    struct intel_crtc_state *crtc_state,
269 				    struct drm_connector_state *conn_state)
270 {
271 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
272 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
273 	int waketime_in_lines, first_sdp_position;
274 	int context_latency, guardband;
275 
276 	if (!intel_dp_is_edp(intel_dp))
277 		return;
278 
279 	if (DISPLAY_VER(i915) < 20)
280 		return;
281 
282 	if (!intel_dp_as_sdp_supported(intel_dp))
283 		return;
284 
285 	if (crtc_state->has_psr)
286 		return;
287 
288 	if (!(intel_alpm_aux_wake_supported(intel_dp) ||
289 	      intel_alpm_aux_less_wake_supported(intel_dp)))
290 		return;
291 
292 	if (!intel_alpm_compute_params(intel_dp, crtc_state))
293 		return;
294 
295 	context_latency = adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay;
296 	guardband = adjusted_mode->crtc_vtotal -
297 		    adjusted_mode->crtc_vdisplay - context_latency;
298 	first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start;
299 	if (intel_alpm_aux_less_wake_supported(intel_dp))
300 		waketime_in_lines = intel_dp->alpm_parameters.io_wake_lines;
301 	else
302 		waketime_in_lines = intel_dp->alpm_parameters.aux_less_wake_lines;
303 
304 	crtc_state->has_lobf = (context_latency + guardband) >
305 		(first_sdp_position + waketime_in_lines);
306 }
307 
308 static void lnl_alpm_configure(struct intel_dp *intel_dp,
309 			       const struct intel_crtc_state *crtc_state)
310 {
311 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
312 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
313 	enum port port = dp_to_dig_port(intel_dp)->base.port;
314 	u32 alpm_ctl;
315 
316 	if (DISPLAY_VER(dev_priv) < 20 || (!intel_dp->psr.sel_update_enabled &&
317 					   !intel_dp_is_edp(intel_dp)))
318 		return;
319 
320 	/*
321 	 * Panel Replay on eDP is always using ALPM aux less. I.e. no need to
322 	 * check panel support at this point.
323 	 */
324 	if ((intel_dp->psr.panel_replay_enabled && intel_dp_is_edp(intel_dp)) ||
325 	    (crtc_state->has_lobf && intel_alpm_aux_less_wake_supported(intel_dp))) {
326 		alpm_ctl = ALPM_CTL_ALPM_ENABLE |
327 			ALPM_CTL_ALPM_AUX_LESS_ENABLE |
328 			ALPM_CTL_AUX_LESS_SLEEP_HOLD_TIME_50_SYMBOLS |
329 			ALPM_CTL_AUX_LESS_WAKE_TIME(intel_dp->alpm_parameters.aux_less_wake_lines);
330 
331 		intel_de_write(dev_priv,
332 			       PORT_ALPM_CTL(dev_priv, port),
333 			       PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE |
334 			       PORT_ALPM_CTL_MAX_PHY_SWING_SETUP(15) |
335 			       PORT_ALPM_CTL_MAX_PHY_SWING_HOLD(0) |
336 			       PORT_ALPM_CTL_SILENCE_PERIOD(
337 				       intel_dp->alpm_parameters.silence_period_sym_clocks));
338 
339 		intel_de_write(dev_priv,
340 			       PORT_ALPM_LFPS_CTL(dev_priv, port),
341 			       PORT_ALPM_LFPS_CTL_LFPS_CYCLE_COUNT(10) |
342 			       PORT_ALPM_LFPS_CTL_LFPS_HALF_CYCLE_DURATION(
343 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms) |
344 			       PORT_ALPM_LFPS_CTL_FIRST_LFPS_HALF_CYCLE_DURATION(
345 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms) |
346 			       PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION(
347 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms));
348 	} else {
349 		alpm_ctl = ALPM_CTL_EXTENDED_FAST_WAKE_ENABLE |
350 			ALPM_CTL_EXTENDED_FAST_WAKE_TIME(intel_dp->alpm_parameters.fast_wake_lines);
351 	}
352 
353 	if (crtc_state->has_lobf)
354 		alpm_ctl |= ALPM_CTL_LOBF_ENABLE;
355 
356 	alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp->alpm_parameters.check_entry_lines);
357 
358 	intel_de_write(dev_priv, ALPM_CTL(dev_priv, cpu_transcoder), alpm_ctl);
359 }
360 
361 void intel_alpm_configure(struct intel_dp *intel_dp,
362 			  const struct intel_crtc_state *crtc_state)
363 {
364 	lnl_alpm_configure(intel_dp, crtc_state);
365 }
366 
367 static int i915_edp_lobf_info_show(struct seq_file *m, void *data)
368 {
369 	struct intel_connector *connector = m->private;
370 	struct drm_i915_private *dev_priv = to_i915(connector->base.dev);
371 	struct drm_crtc *crtc;
372 	struct intel_crtc_state *crtc_state;
373 	enum transcoder cpu_transcoder;
374 	u32 alpm_ctl;
375 	int ret;
376 
377 	ret = drm_modeset_lock_single_interruptible(&dev_priv->drm.mode_config.connection_mutex);
378 	if (ret)
379 		return ret;
380 
381 	crtc = connector->base.state->crtc;
382 	if (connector->base.status != connector_status_connected || !crtc) {
383 		ret = -ENODEV;
384 		goto out;
385 	}
386 
387 	crtc_state = to_intel_crtc_state(crtc->state);
388 	cpu_transcoder = crtc_state->cpu_transcoder;
389 	alpm_ctl = intel_de_read(dev_priv, ALPM_CTL(dev_priv, cpu_transcoder));
390 	seq_printf(m, "LOBF status: %s\n", str_enabled_disabled(alpm_ctl & ALPM_CTL_LOBF_ENABLE));
391 	seq_printf(m, "Aux-wake alpm status: %s\n",
392 		   str_enabled_disabled(!(alpm_ctl & ALPM_CTL_ALPM_AUX_LESS_ENABLE)));
393 	seq_printf(m, "Aux-less alpm status: %s\n",
394 		   str_enabled_disabled(alpm_ctl & ALPM_CTL_ALPM_AUX_LESS_ENABLE));
395 out:
396 	drm_modeset_unlock(&dev_priv->drm.mode_config.connection_mutex);
397 
398 	return ret;
399 }
400 
401 DEFINE_SHOW_ATTRIBUTE(i915_edp_lobf_info);
402 
403 void intel_alpm_lobf_debugfs_add(struct intel_connector *connector)
404 {
405 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
406 	struct dentry *root = connector->base.debugfs_entry;
407 
408 	if (DISPLAY_VER(i915) < 20 ||
409 	    connector->base.connector_type != DRM_MODE_CONNECTOR_eDP)
410 		return;
411 
412 	debugfs_create_file("i915_edp_lobf_info", 0444, root,
413 			    connector, &i915_edp_lobf_info_fops);
414 }
415