xref: /linux/drivers/gpu/drm/i915/display/intel_alpm.c (revision 55d0969c451159cff86949b38c39171cab962069)
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
139 _lnl_compute_aux_less_alpm_params(struct intel_dp *intel_dp,
140 				  const struct intel_crtc_state *crtc_state)
141 {
142 	struct intel_display *display = to_intel_display(intel_dp);
143 	int aux_less_wake_time, aux_less_wake_lines, silence_period,
144 		lfps_half_cycle;
145 
146 	aux_less_wake_time =
147 		_lnl_compute_aux_less_wake_time(crtc_state->port_clock);
148 	aux_less_wake_lines = intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode,
149 						       aux_less_wake_time);
150 
151 	if (!_lnl_get_silence_period_and_lfps_half_cycle(crtc_state->port_clock,
152 							 &silence_period,
153 							 &lfps_half_cycle))
154 		return false;
155 
156 	if (aux_less_wake_lines > ALPM_CTL_AUX_LESS_WAKE_TIME_MASK ||
157 	    silence_period > PORT_ALPM_CTL_SILENCE_PERIOD_MASK ||
158 	    lfps_half_cycle > PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION_MASK)
159 		return false;
160 
161 	if (display->params.psr_safest_params)
162 		aux_less_wake_lines = ALPM_CTL_AUX_LESS_WAKE_TIME_MASK;
163 
164 	intel_dp->alpm_parameters.aux_less_wake_lines = aux_less_wake_lines;
165 	intel_dp->alpm_parameters.silence_period_sym_clocks = silence_period;
166 	intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms = lfps_half_cycle;
167 
168 	return true;
169 }
170 
171 static bool _lnl_compute_alpm_params(struct intel_dp *intel_dp,
172 				     const struct intel_crtc_state *crtc_state)
173 {
174 	struct intel_display *display = to_intel_display(intel_dp);
175 	int check_entry_lines;
176 
177 	if (DISPLAY_VER(display) < 20)
178 		return true;
179 
180 	/* ALPM Entry Check = 2 + CEILING( 5us /tline ) */
181 	check_entry_lines = 2 +
182 		intel_usecs_to_scanlines(&crtc_state->hw.adjusted_mode, 5);
183 
184 	if (check_entry_lines > 15)
185 		return false;
186 
187 	if (!_lnl_compute_aux_less_alpm_params(intel_dp, crtc_state))
188 		return false;
189 
190 	if (display->params.psr_safest_params)
191 		check_entry_lines = 15;
192 
193 	intel_dp->alpm_parameters.check_entry_lines = check_entry_lines;
194 
195 	return true;
196 }
197 
198 /*
199  * IO wake time for DISPLAY_VER < 12 is not directly mentioned in Bspec. There
200  * are 50 us io wake time and 32 us fast wake time. Clearly preharge pulses are
201  * not (improperly) included in 32 us fast wake time. 50 us - 32 us = 18 us.
202  */
203 static int skl_io_buffer_wake_time(void)
204 {
205 	return 18;
206 }
207 
208 static int tgl_io_buffer_wake_time(void)
209 {
210 	return 10;
211 }
212 
213 static int io_buffer_wake_time(const struct intel_crtc_state *crtc_state)
214 {
215 	struct intel_display *display = to_intel_display(crtc_state);
216 
217 	if (DISPLAY_VER(display) >= 12)
218 		return tgl_io_buffer_wake_time();
219 	else
220 		return skl_io_buffer_wake_time();
221 }
222 
223 bool intel_alpm_compute_params(struct intel_dp *intel_dp,
224 			       const struct intel_crtc_state *crtc_state)
225 {
226 	struct intel_display *display = to_intel_display(intel_dp);
227 	int io_wake_lines, io_wake_time, fast_wake_lines, fast_wake_time;
228 	int tfw_exit_latency = 20; /* eDP spec */
229 	int phy_wake = 4;	   /* eDP spec */
230 	int preamble = 8;	   /* eDP spec */
231 	int precharge = intel_dp_aux_fw_sync_len(intel_dp) - preamble;
232 	u8 max_wake_lines;
233 
234 	io_wake_time = max(precharge, io_buffer_wake_time(crtc_state)) +
235 		preamble + phy_wake + tfw_exit_latency;
236 	fast_wake_time = precharge + preamble + phy_wake +
237 		tfw_exit_latency;
238 
239 	if (DISPLAY_VER(display) >= 20)
240 		max_wake_lines = 68;
241 	else if (DISPLAY_VER(display) >= 12)
242 		max_wake_lines = 12;
243 	else
244 		max_wake_lines = 8;
245 
246 	io_wake_lines = intel_usecs_to_scanlines(
247 		&crtc_state->hw.adjusted_mode, io_wake_time);
248 	fast_wake_lines = intel_usecs_to_scanlines(
249 		&crtc_state->hw.adjusted_mode, fast_wake_time);
250 
251 	if (io_wake_lines > max_wake_lines ||
252 	    fast_wake_lines > max_wake_lines)
253 		return false;
254 
255 	if (!_lnl_compute_alpm_params(intel_dp, crtc_state))
256 		return false;
257 
258 	if (display->params.psr_safest_params)
259 		io_wake_lines = fast_wake_lines = max_wake_lines;
260 
261 	/* According to Bspec lower limit should be set as 7 lines. */
262 	intel_dp->alpm_parameters.io_wake_lines = max(io_wake_lines, 7);
263 	intel_dp->alpm_parameters.fast_wake_lines = max(fast_wake_lines, 7);
264 
265 	return true;
266 }
267 
268 void intel_alpm_lobf_compute_config(struct intel_dp *intel_dp,
269 				    struct intel_crtc_state *crtc_state,
270 				    struct drm_connector_state *conn_state)
271 {
272 	struct intel_display *display = to_intel_display(intel_dp);
273 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
274 	int waketime_in_lines, first_sdp_position;
275 	int context_latency, guardband;
276 
277 	if (!intel_dp_is_edp(intel_dp))
278 		return;
279 
280 	if (DISPLAY_VER(display) < 20)
281 		return;
282 
283 	if (!intel_dp->as_sdp_supported)
284 		return;
285 
286 	if (crtc_state->has_psr)
287 		return;
288 
289 	if (!(intel_alpm_aux_wake_supported(intel_dp) ||
290 	      intel_alpm_aux_less_wake_supported(intel_dp)))
291 		return;
292 
293 	if (!intel_alpm_compute_params(intel_dp, crtc_state))
294 		return;
295 
296 	context_latency = adjusted_mode->crtc_vblank_start - adjusted_mode->crtc_vdisplay;
297 	guardband = adjusted_mode->crtc_vtotal -
298 		    adjusted_mode->crtc_vdisplay - context_latency;
299 	first_sdp_position = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_start;
300 	if (intel_alpm_aux_less_wake_supported(intel_dp))
301 		waketime_in_lines = intel_dp->alpm_parameters.io_wake_lines;
302 	else
303 		waketime_in_lines = intel_dp->alpm_parameters.aux_less_wake_lines;
304 
305 	crtc_state->has_lobf = (context_latency + guardband) >
306 		(first_sdp_position + waketime_in_lines);
307 }
308 
309 static void lnl_alpm_configure(struct intel_dp *intel_dp,
310 			       const struct intel_crtc_state *crtc_state)
311 {
312 	struct intel_display *display = to_intel_display(intel_dp);
313 	enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
314 	enum port port = dp_to_dig_port(intel_dp)->base.port;
315 	u32 alpm_ctl;
316 
317 	if (DISPLAY_VER(display) < 20 ||
318 	    (!intel_dp->psr.sel_update_enabled && !intel_dp_is_edp(intel_dp)))
319 		return;
320 
321 	/*
322 	 * Panel Replay on eDP is always using ALPM aux less. I.e. no need to
323 	 * check panel support at this point.
324 	 */
325 	if ((intel_dp->psr.panel_replay_enabled && intel_dp_is_edp(intel_dp)) ||
326 	    (crtc_state->has_lobf && intel_alpm_aux_less_wake_supported(intel_dp))) {
327 		alpm_ctl = ALPM_CTL_ALPM_ENABLE |
328 			ALPM_CTL_ALPM_AUX_LESS_ENABLE |
329 			ALPM_CTL_AUX_LESS_SLEEP_HOLD_TIME_50_SYMBOLS |
330 			ALPM_CTL_AUX_LESS_WAKE_TIME(intel_dp->alpm_parameters.aux_less_wake_lines);
331 
332 		intel_de_write(display,
333 			       PORT_ALPM_CTL(display, port),
334 			       PORT_ALPM_CTL_ALPM_AUX_LESS_ENABLE |
335 			       PORT_ALPM_CTL_MAX_PHY_SWING_SETUP(15) |
336 			       PORT_ALPM_CTL_MAX_PHY_SWING_HOLD(0) |
337 			       PORT_ALPM_CTL_SILENCE_PERIOD(
338 				       intel_dp->alpm_parameters.silence_period_sym_clocks));
339 
340 		intel_de_write(display,
341 			       PORT_ALPM_LFPS_CTL(display, port),
342 			       PORT_ALPM_LFPS_CTL_LFPS_CYCLE_COUNT(10) |
343 			       PORT_ALPM_LFPS_CTL_LFPS_HALF_CYCLE_DURATION(
344 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms) |
345 			       PORT_ALPM_LFPS_CTL_FIRST_LFPS_HALF_CYCLE_DURATION(
346 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms) |
347 			       PORT_ALPM_LFPS_CTL_LAST_LFPS_HALF_CYCLE_DURATION(
348 				       intel_dp->alpm_parameters.lfps_half_cycle_num_of_syms));
349 	} else {
350 		alpm_ctl = ALPM_CTL_EXTENDED_FAST_WAKE_ENABLE |
351 			ALPM_CTL_EXTENDED_FAST_WAKE_TIME(intel_dp->alpm_parameters.fast_wake_lines);
352 	}
353 
354 	if (crtc_state->has_lobf)
355 		alpm_ctl |= ALPM_CTL_LOBF_ENABLE;
356 
357 	alpm_ctl |= ALPM_CTL_ALPM_ENTRY_CHECK(intel_dp->alpm_parameters.check_entry_lines);
358 
359 	intel_de_write(display, ALPM_CTL(display, cpu_transcoder), alpm_ctl);
360 }
361 
362 void intel_alpm_configure(struct intel_dp *intel_dp,
363 			  const struct intel_crtc_state *crtc_state)
364 {
365 	lnl_alpm_configure(intel_dp, crtc_state);
366 }
367 
368 static int i915_edp_lobf_info_show(struct seq_file *m, void *data)
369 {
370 	struct intel_connector *connector = m->private;
371 	struct intel_display *display = to_intel_display(connector);
372 	struct drm_crtc *crtc;
373 	struct intel_crtc_state *crtc_state;
374 	enum transcoder cpu_transcoder;
375 	u32 alpm_ctl;
376 	int ret;
377 
378 	ret = drm_modeset_lock_single_interruptible(&display->drm->mode_config.connection_mutex);
379 	if (ret)
380 		return ret;
381 
382 	crtc = connector->base.state->crtc;
383 	if (connector->base.status != connector_status_connected || !crtc) {
384 		ret = -ENODEV;
385 		goto out;
386 	}
387 
388 	crtc_state = to_intel_crtc_state(crtc->state);
389 	cpu_transcoder = crtc_state->cpu_transcoder;
390 	alpm_ctl = intel_de_read(display, ALPM_CTL(display, cpu_transcoder));
391 	seq_printf(m, "LOBF status: %s\n", str_enabled_disabled(alpm_ctl & ALPM_CTL_LOBF_ENABLE));
392 	seq_printf(m, "Aux-wake alpm status: %s\n",
393 		   str_enabled_disabled(!(alpm_ctl & ALPM_CTL_ALPM_AUX_LESS_ENABLE)));
394 	seq_printf(m, "Aux-less alpm status: %s\n",
395 		   str_enabled_disabled(alpm_ctl & ALPM_CTL_ALPM_AUX_LESS_ENABLE));
396 out:
397 	drm_modeset_unlock(&display->drm->mode_config.connection_mutex);
398 
399 	return ret;
400 }
401 
402 DEFINE_SHOW_ATTRIBUTE(i915_edp_lobf_info);
403 
404 void intel_alpm_lobf_debugfs_add(struct intel_connector *connector)
405 {
406 	struct intel_display *display = to_intel_display(connector);
407 	struct dentry *root = connector->base.debugfs_entry;
408 
409 	if (DISPLAY_VER(display) < 20 ||
410 	    connector->base.connector_type != DRM_MODE_CONNECTOR_eDP)
411 		return;
412 
413 	debugfs_create_file("i915_edp_lobf_info", 0444, root,
414 			    connector, &i915_edp_lobf_info_fops);
415 }
416