xref: /linux/drivers/gpu/drm/i915/display/intel_dp_aux.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0)
1 // SPDX-License-Identifier: MIT
2 /*
3  * Copyright © 2020-2021 Intel Corporation
4  */
5 
6 #include "i915_drv.h"
7 #include "i915_reg.h"
8 #include "i915_trace.h"
9 #include "intel_bios.h"
10 #include "intel_de.h"
11 #include "intel_display_types.h"
12 #include "intel_dp.h"
13 #include "intel_dp_aux.h"
14 #include "intel_dp_aux_regs.h"
15 #include "intel_pps.h"
16 #include "intel_quirks.h"
17 #include "intel_tc.h"
18 
19 #define AUX_CH_NAME_BUFSIZE	6
20 
21 static const char *aux_ch_name(struct intel_display *display,
22 			       char *buf, int size, enum aux_ch aux_ch)
23 {
24 	if (DISPLAY_VER(display) >= 13 && aux_ch >= AUX_CH_D_XELPD)
25 		snprintf(buf, size, "%c", 'A' + aux_ch - AUX_CH_D_XELPD + AUX_CH_D);
26 	else if (DISPLAY_VER(display) >= 12 && aux_ch >= AUX_CH_USBC1)
27 		snprintf(buf, size, "USBC%c", '1' + aux_ch - AUX_CH_USBC1);
28 	else
29 		snprintf(buf, size, "%c", 'A' + aux_ch);
30 
31 	return buf;
32 }
33 
34 u32 intel_dp_aux_pack(const u8 *src, int src_bytes)
35 {
36 	int i;
37 	u32 v = 0;
38 
39 	if (src_bytes > 4)
40 		src_bytes = 4;
41 	for (i = 0; i < src_bytes; i++)
42 		v |= ((u32)src[i]) << ((3 - i) * 8);
43 	return v;
44 }
45 
46 static void intel_dp_aux_unpack(u32 src, u8 *dst, int dst_bytes)
47 {
48 	int i;
49 
50 	if (dst_bytes > 4)
51 		dst_bytes = 4;
52 	for (i = 0; i < dst_bytes; i++)
53 		dst[i] = src >> ((3 - i) * 8);
54 }
55 
56 static u32
57 intel_dp_aux_wait_done(struct intel_dp *intel_dp)
58 {
59 	struct intel_display *display = to_intel_display(intel_dp);
60 	i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
61 	const unsigned int timeout_ms = 10;
62 	u32 status;
63 	int ret;
64 
65 	ret = intel_de_wait_custom(display, ch_ctl, DP_AUX_CH_CTL_SEND_BUSY,
66 				   0,
67 				   2, timeout_ms, &status);
68 
69 	if (ret == -ETIMEDOUT)
70 		drm_err(display->drm,
71 			"%s: did not complete or timeout within %ums (status 0x%08x)\n",
72 			intel_dp->aux.name, timeout_ms, status);
73 
74 	return status;
75 }
76 
77 static u32 g4x_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
78 {
79 	struct intel_display *display = to_intel_display(intel_dp);
80 
81 	if (index)
82 		return 0;
83 
84 	/*
85 	 * The clock divider is based off the hrawclk, and would like to run at
86 	 * 2MHz.  So, take the hrawclk value and divide by 2000 and use that
87 	 */
88 	return DIV_ROUND_CLOSEST(DISPLAY_RUNTIME_INFO(display)->rawclk_freq, 2000);
89 }
90 
91 static u32 ilk_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
92 {
93 	struct intel_display *display = to_intel_display(intel_dp);
94 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
95 	u32 freq;
96 
97 	if (index)
98 		return 0;
99 
100 	/*
101 	 * The clock divider is based off the cdclk or PCH rawclk, and would
102 	 * like to run at 2MHz.  So, take the cdclk or PCH rawclk value and
103 	 * divide by 2000 and use that
104 	 */
105 	if (dig_port->aux_ch == AUX_CH_A)
106 		freq = display->cdclk.hw.cdclk;
107 	else
108 		freq = DISPLAY_RUNTIME_INFO(display)->rawclk_freq;
109 	return DIV_ROUND_CLOSEST(freq, 2000);
110 }
111 
112 static u32 hsw_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
113 {
114 	struct intel_display *display = to_intel_display(intel_dp);
115 	struct drm_i915_private *i915 = to_i915(display->drm);
116 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
117 
118 	if (dig_port->aux_ch != AUX_CH_A && HAS_PCH_LPT_H(i915)) {
119 		/* Workaround for non-ULT HSW */
120 		switch (index) {
121 		case 0: return 63;
122 		case 1: return 72;
123 		default: return 0;
124 		}
125 	}
126 
127 	return ilk_get_aux_clock_divider(intel_dp, index);
128 }
129 
130 static u32 skl_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
131 {
132 	/*
133 	 * SKL doesn't need us to program the AUX clock divider (Hardware will
134 	 * derive the clock from CDCLK automatically). We still implement the
135 	 * get_aux_clock_divider vfunc to plug-in into the existing code.
136 	 */
137 	return index ? 0 : 1;
138 }
139 
140 static int intel_dp_aux_sync_len(void)
141 {
142 	int precharge = 16; /* 10-16 */
143 	int preamble = 16;
144 
145 	return precharge + preamble;
146 }
147 
148 int intel_dp_aux_fw_sync_len(struct intel_dp *intel_dp)
149 {
150 	int precharge = 10; /* 10-16 */
151 	int preamble = 8;
152 
153 	/*
154 	 * We faced some glitches on Dell Precision 5490 MTL laptop with panel:
155 	 * "Manufacturer: AUO, Model: 63898" when using HW default 18. Using 20
156 	 * is fixing these problems with the panel. It is still within range
157 	 * mentioned in eDP specification. Increasing Fast Wake sync length is
158 	 * causing problems with other panels: increase length as a quirk for
159 	 * this specific laptop.
160 	 */
161 	if (intel_has_dpcd_quirk(intel_dp, QUIRK_FW_SYNC_LEN))
162 		precharge += 2;
163 
164 	return precharge + preamble;
165 }
166 
167 static int g4x_dp_aux_precharge_len(void)
168 {
169 	int precharge_min = 10;
170 	int preamble = 16;
171 
172 	/* HW wants the length of the extra precharge in 2us units */
173 	return (intel_dp_aux_sync_len() -
174 		precharge_min - preamble) / 2;
175 }
176 
177 static u32 g4x_get_aux_send_ctl(struct intel_dp *intel_dp,
178 				int send_bytes,
179 				u32 aux_clock_divider)
180 {
181 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
182 	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
183 	u32 timeout;
184 
185 	/* Max timeout value on G4x-BDW: 1.6ms */
186 	if (IS_BROADWELL(i915))
187 		timeout = DP_AUX_CH_CTL_TIME_OUT_600us;
188 	else
189 		timeout = DP_AUX_CH_CTL_TIME_OUT_400us;
190 
191 	return DP_AUX_CH_CTL_SEND_BUSY |
192 		DP_AUX_CH_CTL_DONE |
193 		DP_AUX_CH_CTL_INTERRUPT |
194 		DP_AUX_CH_CTL_TIME_OUT_ERROR |
195 		timeout |
196 		DP_AUX_CH_CTL_RECEIVE_ERROR |
197 		DP_AUX_CH_CTL_MESSAGE_SIZE(send_bytes) |
198 		DP_AUX_CH_CTL_PRECHARGE_2US(g4x_dp_aux_precharge_len()) |
199 		DP_AUX_CH_CTL_BIT_CLOCK_2X(aux_clock_divider);
200 }
201 
202 static u32 skl_get_aux_send_ctl(struct intel_dp *intel_dp,
203 				int send_bytes,
204 				u32 unused)
205 {
206 	struct intel_display *display = to_intel_display(intel_dp);
207 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
208 	u32 ret;
209 
210 	/*
211 	 * Max timeout values:
212 	 * SKL-GLK: 1.6ms
213 	 * ICL+: 4ms
214 	 */
215 	ret = DP_AUX_CH_CTL_SEND_BUSY |
216 		DP_AUX_CH_CTL_DONE |
217 		DP_AUX_CH_CTL_INTERRUPT |
218 		DP_AUX_CH_CTL_TIME_OUT_ERROR |
219 		DP_AUX_CH_CTL_TIME_OUT_MAX |
220 		DP_AUX_CH_CTL_RECEIVE_ERROR |
221 		DP_AUX_CH_CTL_MESSAGE_SIZE(send_bytes) |
222 		DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(intel_dp_aux_fw_sync_len(intel_dp)) |
223 		DP_AUX_CH_CTL_SYNC_PULSE_SKL(intel_dp_aux_sync_len());
224 
225 	if (intel_tc_port_in_tbt_alt_mode(dig_port))
226 		ret |= DP_AUX_CH_CTL_TBT_IO;
227 
228 	/*
229 	 * Power request bit is already set during aux power well enable.
230 	 * Preserve the bit across aux transactions.
231 	 */
232 	if (DISPLAY_VER(display) >= 14)
233 		ret |= XELPDP_DP_AUX_CH_CTL_POWER_REQUEST;
234 
235 	return ret;
236 }
237 
238 static int
239 intel_dp_aux_xfer(struct intel_dp *intel_dp,
240 		  const u8 *send, int send_bytes,
241 		  u8 *recv, int recv_size,
242 		  u32 aux_send_ctl_flags)
243 {
244 	struct intel_display *display = to_intel_display(intel_dp);
245 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
246 	struct intel_encoder *encoder = &dig_port->base;
247 	struct drm_i915_private *i915 = to_i915(dig_port->base.base.dev);
248 	i915_reg_t ch_ctl, ch_data[5];
249 	u32 aux_clock_divider;
250 	enum intel_display_power_domain aux_domain;
251 	intel_wakeref_t aux_wakeref;
252 	intel_wakeref_t pps_wakeref;
253 	int i, ret, recv_bytes;
254 	int try, clock = 0;
255 	u32 status;
256 	bool vdd;
257 
258 	ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
259 	for (i = 0; i < ARRAY_SIZE(ch_data); i++)
260 		ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
261 
262 	intel_digital_port_lock(encoder);
263 	/*
264 	 * Abort transfers on a disconnected port as required by
265 	 * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
266 	 * timeouts that would otherwise happen.
267 	 */
268 	if (!intel_dp_is_edp(intel_dp) &&
269 	    !intel_digital_port_connected_locked(&dig_port->base)) {
270 		ret = -ENXIO;
271 		goto out_unlock;
272 	}
273 
274 	aux_domain = intel_aux_power_domain(dig_port);
275 
276 	aux_wakeref = intel_display_power_get(i915, aux_domain);
277 	pps_wakeref = intel_pps_lock(intel_dp);
278 
279 	/*
280 	 * We will be called with VDD already enabled for dpcd/edid/oui reads.
281 	 * In such cases we want to leave VDD enabled and it's up to upper layers
282 	 * to turn it off. But for eg. i2c-dev access we need to turn it on/off
283 	 * ourselves.
284 	 */
285 	vdd = intel_pps_vdd_on_unlocked(intel_dp);
286 
287 	/*
288 	 * dp aux is extremely sensitive to irq latency, hence request the
289 	 * lowest possible wakeup latency and so prevent the cpu from going into
290 	 * deep sleep states.
291 	 */
292 	cpu_latency_qos_update_request(&intel_dp->pm_qos, 0);
293 
294 	intel_pps_check_power_unlocked(intel_dp);
295 
296 	/*
297 	 * FIXME PSR should be disabled here to prevent
298 	 * it using the same AUX CH simultaneously
299 	 */
300 
301 	/* Try to wait for any previous AUX channel activity */
302 	for (try = 0; try < 3; try++) {
303 		status = intel_de_read_notrace(display, ch_ctl);
304 		if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
305 			break;
306 		msleep(1);
307 	}
308 	/* just trace the final value */
309 	trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true);
310 
311 	if (try == 3) {
312 		const u32 status = intel_de_read(display, ch_ctl);
313 
314 		if (status != intel_dp->aux_busy_last_status) {
315 			drm_WARN(display->drm, 1,
316 				 "%s: not started (status 0x%08x)\n",
317 				 intel_dp->aux.name, status);
318 			intel_dp->aux_busy_last_status = status;
319 		}
320 
321 		ret = -EBUSY;
322 		goto out;
323 	}
324 
325 	/* Only 5 data registers! */
326 	if (drm_WARN_ON(display->drm, send_bytes > 20 || recv_size > 20)) {
327 		ret = -E2BIG;
328 		goto out;
329 	}
330 
331 	while ((aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, clock++))) {
332 		u32 send_ctl = intel_dp->get_aux_send_ctl(intel_dp,
333 							  send_bytes,
334 							  aux_clock_divider);
335 
336 		send_ctl |= aux_send_ctl_flags;
337 
338 		/* Must try at least 3 times according to DP spec */
339 		for (try = 0; try < 5; try++) {
340 			/* Load the send data into the aux channel data registers */
341 			for (i = 0; i < send_bytes; i += 4)
342 				intel_de_write(display, ch_data[i >> 2],
343 					       intel_dp_aux_pack(send + i,
344 								 send_bytes - i));
345 
346 			/* Send the command and wait for it to complete */
347 			intel_de_write(display, ch_ctl, send_ctl);
348 
349 			status = intel_dp_aux_wait_done(intel_dp);
350 
351 			/* Clear done status and any errors */
352 			intel_de_write(display, ch_ctl,
353 				       status | DP_AUX_CH_CTL_DONE |
354 				       DP_AUX_CH_CTL_TIME_OUT_ERROR |
355 				       DP_AUX_CH_CTL_RECEIVE_ERROR);
356 
357 			/*
358 			 * DP CTS 1.2 Core Rev 1.1, 4.2.1.1 & 4.2.1.2
359 			 *   400us delay required for errors and timeouts
360 			 *   Timeout errors from the HW already meet this
361 			 *   requirement so skip to next iteration
362 			 */
363 			if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR)
364 				continue;
365 
366 			if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
367 				usleep_range(400, 500);
368 				continue;
369 			}
370 			if (status & DP_AUX_CH_CTL_DONE)
371 				goto done;
372 		}
373 	}
374 
375 	if ((status & DP_AUX_CH_CTL_DONE) == 0) {
376 		drm_err(display->drm, "%s: not done (status 0x%08x)\n",
377 			intel_dp->aux.name, status);
378 		ret = -EBUSY;
379 		goto out;
380 	}
381 
382 done:
383 	/*
384 	 * Check for timeout or receive error. Timeouts occur when the sink is
385 	 * not connected.
386 	 */
387 	if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
388 		drm_err(display->drm, "%s: receive error (status 0x%08x)\n",
389 			intel_dp->aux.name, status);
390 		ret = -EIO;
391 		goto out;
392 	}
393 
394 	/*
395 	 * Timeouts occur when the device isn't connected, so they're "normal"
396 	 * -- don't fill the kernel log with these
397 	 */
398 	if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
399 		drm_dbg_kms(display->drm, "%s: timeout (status 0x%08x)\n",
400 			    intel_dp->aux.name, status);
401 		ret = -ETIMEDOUT;
402 		goto out;
403 	}
404 
405 	/* Unload any bytes sent back from the other side */
406 	recv_bytes = REG_FIELD_GET(DP_AUX_CH_CTL_MESSAGE_SIZE_MASK, status);
407 
408 	/*
409 	 * By BSpec: "Message sizes of 0 or >20 are not allowed."
410 	 * We have no idea of what happened so we return -EBUSY so
411 	 * drm layer takes care for the necessary retries.
412 	 */
413 	if (recv_bytes == 0 || recv_bytes > 20) {
414 		drm_dbg_kms(display->drm,
415 			    "%s: Forbidden recv_bytes = %d on aux transaction\n",
416 			    intel_dp->aux.name, recv_bytes);
417 		ret = -EBUSY;
418 		goto out;
419 	}
420 
421 	if (recv_bytes > recv_size)
422 		recv_bytes = recv_size;
423 
424 	for (i = 0; i < recv_bytes; i += 4)
425 		intel_dp_aux_unpack(intel_de_read(display, ch_data[i >> 2]),
426 				    recv + i, recv_bytes - i);
427 
428 	ret = recv_bytes;
429 out:
430 	cpu_latency_qos_update_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
431 
432 	if (vdd)
433 		intel_pps_vdd_off_unlocked(intel_dp, false);
434 
435 	intel_pps_unlock(intel_dp, pps_wakeref);
436 	intel_display_power_put_async(i915, aux_domain, aux_wakeref);
437 out_unlock:
438 	intel_digital_port_unlock(encoder);
439 
440 	return ret;
441 }
442 
443 #define BARE_ADDRESS_SIZE	3
444 #define HEADER_SIZE		(BARE_ADDRESS_SIZE + 1)
445 
446 static void
447 intel_dp_aux_header(u8 txbuf[HEADER_SIZE],
448 		    const struct drm_dp_aux_msg *msg)
449 {
450 	txbuf[0] = (msg->request << 4) | ((msg->address >> 16) & 0xf);
451 	txbuf[1] = (msg->address >> 8) & 0xff;
452 	txbuf[2] = msg->address & 0xff;
453 	txbuf[3] = msg->size - 1;
454 }
455 
456 static u32 intel_dp_aux_xfer_flags(const struct drm_dp_aux_msg *msg)
457 {
458 	/*
459 	 * If we're trying to send the HDCP Aksv, we need to set a the Aksv
460 	 * select bit to inform the hardware to send the Aksv after our header
461 	 * since we can't access that data from software.
462 	 */
463 	if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_WRITE &&
464 	    msg->address == DP_AUX_HDCP_AKSV)
465 		return DP_AUX_CH_CTL_AUX_AKSV_SELECT;
466 
467 	return 0;
468 }
469 
470 static ssize_t
471 intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
472 {
473 	struct intel_dp *intel_dp = container_of(aux, struct intel_dp, aux);
474 	struct intel_display *display = to_intel_display(intel_dp);
475 	u8 txbuf[20], rxbuf[20];
476 	size_t txsize, rxsize;
477 	u32 flags = intel_dp_aux_xfer_flags(msg);
478 	int ret;
479 
480 	intel_dp_aux_header(txbuf, msg);
481 
482 	switch (msg->request & ~DP_AUX_I2C_MOT) {
483 	case DP_AUX_NATIVE_WRITE:
484 	case DP_AUX_I2C_WRITE:
485 	case DP_AUX_I2C_WRITE_STATUS_UPDATE:
486 		txsize = msg->size ? HEADER_SIZE + msg->size : BARE_ADDRESS_SIZE;
487 		rxsize = 2; /* 0 or 1 data bytes */
488 
489 		if (drm_WARN_ON(display->drm, txsize > 20))
490 			return -E2BIG;
491 
492 		drm_WARN_ON(display->drm, !msg->buffer != !msg->size);
493 
494 		if (msg->buffer)
495 			memcpy(txbuf + HEADER_SIZE, msg->buffer, msg->size);
496 
497 		ret = intel_dp_aux_xfer(intel_dp, txbuf, txsize,
498 					rxbuf, rxsize, flags);
499 		if (ret > 0) {
500 			msg->reply = rxbuf[0] >> 4;
501 
502 			if (ret > 1) {
503 				/* Number of bytes written in a short write. */
504 				ret = clamp_t(int, rxbuf[1], 0, msg->size);
505 			} else {
506 				/* Return payload size. */
507 				ret = msg->size;
508 			}
509 		}
510 		break;
511 
512 	case DP_AUX_NATIVE_READ:
513 	case DP_AUX_I2C_READ:
514 		txsize = msg->size ? HEADER_SIZE : BARE_ADDRESS_SIZE;
515 		rxsize = msg->size + 1;
516 
517 		if (drm_WARN_ON(display->drm, rxsize > 20))
518 			return -E2BIG;
519 
520 		ret = intel_dp_aux_xfer(intel_dp, txbuf, txsize,
521 					rxbuf, rxsize, flags);
522 		if (ret > 0) {
523 			msg->reply = rxbuf[0] >> 4;
524 			/*
525 			 * Assume happy day, and copy the data. The caller is
526 			 * expected to check msg->reply before touching it.
527 			 *
528 			 * Return payload size.
529 			 */
530 			ret--;
531 			memcpy(msg->buffer, rxbuf + 1, ret);
532 		}
533 		break;
534 
535 	default:
536 		ret = -EINVAL;
537 		break;
538 	}
539 
540 	return ret;
541 }
542 
543 static i915_reg_t vlv_aux_ctl_reg(struct intel_dp *intel_dp)
544 {
545 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
546 	enum aux_ch aux_ch = dig_port->aux_ch;
547 
548 	switch (aux_ch) {
549 	case AUX_CH_B:
550 	case AUX_CH_C:
551 	case AUX_CH_D:
552 		return VLV_DP_AUX_CH_CTL(aux_ch);
553 	default:
554 		MISSING_CASE(aux_ch);
555 		return VLV_DP_AUX_CH_CTL(AUX_CH_B);
556 	}
557 }
558 
559 static i915_reg_t vlv_aux_data_reg(struct intel_dp *intel_dp, int index)
560 {
561 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
562 	enum aux_ch aux_ch = dig_port->aux_ch;
563 
564 	switch (aux_ch) {
565 	case AUX_CH_B:
566 	case AUX_CH_C:
567 	case AUX_CH_D:
568 		return VLV_DP_AUX_CH_DATA(aux_ch, index);
569 	default:
570 		MISSING_CASE(aux_ch);
571 		return VLV_DP_AUX_CH_DATA(AUX_CH_B, index);
572 	}
573 }
574 
575 static i915_reg_t g4x_aux_ctl_reg(struct intel_dp *intel_dp)
576 {
577 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
578 	enum aux_ch aux_ch = dig_port->aux_ch;
579 
580 	switch (aux_ch) {
581 	case AUX_CH_B:
582 	case AUX_CH_C:
583 	case AUX_CH_D:
584 		return DP_AUX_CH_CTL(aux_ch);
585 	default:
586 		MISSING_CASE(aux_ch);
587 		return DP_AUX_CH_CTL(AUX_CH_B);
588 	}
589 }
590 
591 static i915_reg_t g4x_aux_data_reg(struct intel_dp *intel_dp, int index)
592 {
593 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
594 	enum aux_ch aux_ch = dig_port->aux_ch;
595 
596 	switch (aux_ch) {
597 	case AUX_CH_B:
598 	case AUX_CH_C:
599 	case AUX_CH_D:
600 		return DP_AUX_CH_DATA(aux_ch, index);
601 	default:
602 		MISSING_CASE(aux_ch);
603 		return DP_AUX_CH_DATA(AUX_CH_B, index);
604 	}
605 }
606 
607 static i915_reg_t ilk_aux_ctl_reg(struct intel_dp *intel_dp)
608 {
609 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
610 	enum aux_ch aux_ch = dig_port->aux_ch;
611 
612 	switch (aux_ch) {
613 	case AUX_CH_A:
614 		return DP_AUX_CH_CTL(aux_ch);
615 	case AUX_CH_B:
616 	case AUX_CH_C:
617 	case AUX_CH_D:
618 		return PCH_DP_AUX_CH_CTL(aux_ch);
619 	default:
620 		MISSING_CASE(aux_ch);
621 		return DP_AUX_CH_CTL(AUX_CH_A);
622 	}
623 }
624 
625 static i915_reg_t ilk_aux_data_reg(struct intel_dp *intel_dp, int index)
626 {
627 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
628 	enum aux_ch aux_ch = dig_port->aux_ch;
629 
630 	switch (aux_ch) {
631 	case AUX_CH_A:
632 		return DP_AUX_CH_DATA(aux_ch, index);
633 	case AUX_CH_B:
634 	case AUX_CH_C:
635 	case AUX_CH_D:
636 		return PCH_DP_AUX_CH_DATA(aux_ch, index);
637 	default:
638 		MISSING_CASE(aux_ch);
639 		return DP_AUX_CH_DATA(AUX_CH_A, index);
640 	}
641 }
642 
643 static i915_reg_t skl_aux_ctl_reg(struct intel_dp *intel_dp)
644 {
645 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
646 	enum aux_ch aux_ch = dig_port->aux_ch;
647 
648 	switch (aux_ch) {
649 	case AUX_CH_A:
650 	case AUX_CH_B:
651 	case AUX_CH_C:
652 	case AUX_CH_D:
653 	case AUX_CH_E:
654 	case AUX_CH_F:
655 		return DP_AUX_CH_CTL(aux_ch);
656 	default:
657 		MISSING_CASE(aux_ch);
658 		return DP_AUX_CH_CTL(AUX_CH_A);
659 	}
660 }
661 
662 static i915_reg_t skl_aux_data_reg(struct intel_dp *intel_dp, int index)
663 {
664 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
665 	enum aux_ch aux_ch = dig_port->aux_ch;
666 
667 	switch (aux_ch) {
668 	case AUX_CH_A:
669 	case AUX_CH_B:
670 	case AUX_CH_C:
671 	case AUX_CH_D:
672 	case AUX_CH_E:
673 	case AUX_CH_F:
674 		return DP_AUX_CH_DATA(aux_ch, index);
675 	default:
676 		MISSING_CASE(aux_ch);
677 		return DP_AUX_CH_DATA(AUX_CH_A, index);
678 	}
679 }
680 
681 static i915_reg_t tgl_aux_ctl_reg(struct intel_dp *intel_dp)
682 {
683 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
684 	enum aux_ch aux_ch = dig_port->aux_ch;
685 
686 	switch (aux_ch) {
687 	case AUX_CH_A:
688 	case AUX_CH_B:
689 	case AUX_CH_C:
690 	case AUX_CH_USBC1:
691 	case AUX_CH_USBC2:
692 	case AUX_CH_USBC3:
693 	case AUX_CH_USBC4:
694 	case AUX_CH_USBC5:  /* aka AUX_CH_D_XELPD */
695 	case AUX_CH_USBC6:  /* aka AUX_CH_E_XELPD */
696 		return DP_AUX_CH_CTL(aux_ch);
697 	default:
698 		MISSING_CASE(aux_ch);
699 		return DP_AUX_CH_CTL(AUX_CH_A);
700 	}
701 }
702 
703 static i915_reg_t tgl_aux_data_reg(struct intel_dp *intel_dp, int index)
704 {
705 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
706 	enum aux_ch aux_ch = dig_port->aux_ch;
707 
708 	switch (aux_ch) {
709 	case AUX_CH_A:
710 	case AUX_CH_B:
711 	case AUX_CH_C:
712 	case AUX_CH_USBC1:
713 	case AUX_CH_USBC2:
714 	case AUX_CH_USBC3:
715 	case AUX_CH_USBC4:
716 	case AUX_CH_USBC5:  /* aka AUX_CH_D_XELPD */
717 	case AUX_CH_USBC6:  /* aka AUX_CH_E_XELPD */
718 		return DP_AUX_CH_DATA(aux_ch, index);
719 	default:
720 		MISSING_CASE(aux_ch);
721 		return DP_AUX_CH_DATA(AUX_CH_A, index);
722 	}
723 }
724 
725 static i915_reg_t xelpdp_aux_ctl_reg(struct intel_dp *intel_dp)
726 {
727 	struct intel_display *display = to_intel_display(intel_dp);
728 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
729 	enum aux_ch aux_ch = dig_port->aux_ch;
730 
731 	switch (aux_ch) {
732 	case AUX_CH_A:
733 	case AUX_CH_B:
734 	case AUX_CH_USBC1:
735 	case AUX_CH_USBC2:
736 	case AUX_CH_USBC3:
737 	case AUX_CH_USBC4:
738 		return XELPDP_DP_AUX_CH_CTL(display, aux_ch);
739 	default:
740 		MISSING_CASE(aux_ch);
741 		return XELPDP_DP_AUX_CH_CTL(display, AUX_CH_A);
742 	}
743 }
744 
745 static i915_reg_t xelpdp_aux_data_reg(struct intel_dp *intel_dp, int index)
746 {
747 	struct intel_display *display = to_intel_display(intel_dp);
748 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
749 	enum aux_ch aux_ch = dig_port->aux_ch;
750 
751 	switch (aux_ch) {
752 	case AUX_CH_A:
753 	case AUX_CH_B:
754 	case AUX_CH_USBC1:
755 	case AUX_CH_USBC2:
756 	case AUX_CH_USBC3:
757 	case AUX_CH_USBC4:
758 		return XELPDP_DP_AUX_CH_DATA(display, aux_ch, index);
759 	default:
760 		MISSING_CASE(aux_ch);
761 		return XELPDP_DP_AUX_CH_DATA(display, AUX_CH_A, index);
762 	}
763 }
764 
765 void intel_dp_aux_fini(struct intel_dp *intel_dp)
766 {
767 	if (cpu_latency_qos_request_active(&intel_dp->pm_qos))
768 		cpu_latency_qos_remove_request(&intel_dp->pm_qos);
769 
770 	kfree(intel_dp->aux.name);
771 }
772 
773 void intel_dp_aux_init(struct intel_dp *intel_dp)
774 {
775 	struct intel_display *display = to_intel_display(intel_dp);
776 	struct drm_i915_private *i915 = to_i915(display->drm);
777 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
778 	struct intel_encoder *encoder = &dig_port->base;
779 	enum aux_ch aux_ch = dig_port->aux_ch;
780 	char buf[AUX_CH_NAME_BUFSIZE];
781 
782 	if (DISPLAY_VER(display) >= 14) {
783 		intel_dp->aux_ch_ctl_reg = xelpdp_aux_ctl_reg;
784 		intel_dp->aux_ch_data_reg = xelpdp_aux_data_reg;
785 	} else if (DISPLAY_VER(display) >= 12) {
786 		intel_dp->aux_ch_ctl_reg = tgl_aux_ctl_reg;
787 		intel_dp->aux_ch_data_reg = tgl_aux_data_reg;
788 	} else if (DISPLAY_VER(display) >= 9) {
789 		intel_dp->aux_ch_ctl_reg = skl_aux_ctl_reg;
790 		intel_dp->aux_ch_data_reg = skl_aux_data_reg;
791 	} else if (HAS_PCH_SPLIT(i915)) {
792 		intel_dp->aux_ch_ctl_reg = ilk_aux_ctl_reg;
793 		intel_dp->aux_ch_data_reg = ilk_aux_data_reg;
794 	} else if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) {
795 		intel_dp->aux_ch_ctl_reg = vlv_aux_ctl_reg;
796 		intel_dp->aux_ch_data_reg = vlv_aux_data_reg;
797 	} else {
798 		intel_dp->aux_ch_ctl_reg = g4x_aux_ctl_reg;
799 		intel_dp->aux_ch_data_reg = g4x_aux_data_reg;
800 	}
801 
802 	if (DISPLAY_VER(display) >= 9)
803 		intel_dp->get_aux_clock_divider = skl_get_aux_clock_divider;
804 	else if (IS_BROADWELL(i915) || IS_HASWELL(i915))
805 		intel_dp->get_aux_clock_divider = hsw_get_aux_clock_divider;
806 	else if (HAS_PCH_SPLIT(i915))
807 		intel_dp->get_aux_clock_divider = ilk_get_aux_clock_divider;
808 	else
809 		intel_dp->get_aux_clock_divider = g4x_get_aux_clock_divider;
810 
811 	if (DISPLAY_VER(display) >= 9)
812 		intel_dp->get_aux_send_ctl = skl_get_aux_send_ctl;
813 	else
814 		intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl;
815 
816 	intel_dp->aux.drm_dev = display->drm;
817 	drm_dp_aux_init(&intel_dp->aux);
818 
819 	/* Failure to allocate our preferred name is not critical */
820 	intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX %s/%s",
821 				       aux_ch_name(display, buf, sizeof(buf), aux_ch),
822 				       encoder->base.name);
823 
824 	intel_dp->aux.transfer = intel_dp_aux_transfer;
825 	cpu_latency_qos_add_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
826 }
827 
828 static enum aux_ch default_aux_ch(struct intel_encoder *encoder)
829 {
830 	struct intel_display *display = to_intel_display(encoder);
831 
832 	/* SKL has DDI E but no AUX E */
833 	if (DISPLAY_VER(display) == 9 && encoder->port == PORT_E)
834 		return AUX_CH_A;
835 
836 	return (enum aux_ch)encoder->port;
837 }
838 
839 static struct intel_encoder *
840 get_encoder_by_aux_ch(struct intel_encoder *encoder,
841 		      enum aux_ch aux_ch)
842 {
843 	struct intel_display *display = to_intel_display(encoder);
844 	struct intel_encoder *other;
845 
846 	for_each_intel_encoder(display->drm, other) {
847 		if (other == encoder)
848 			continue;
849 
850 		if (!intel_encoder_is_dig_port(other))
851 			continue;
852 
853 		if (enc_to_dig_port(other)->aux_ch == aux_ch)
854 			return other;
855 	}
856 
857 	return NULL;
858 }
859 
860 enum aux_ch intel_dp_aux_ch(struct intel_encoder *encoder)
861 {
862 	struct intel_display *display = to_intel_display(encoder);
863 	struct intel_encoder *other;
864 	const char *source;
865 	enum aux_ch aux_ch;
866 	char buf[AUX_CH_NAME_BUFSIZE];
867 
868 	aux_ch = intel_bios_dp_aux_ch(encoder->devdata);
869 	source = "VBT";
870 
871 	if (aux_ch == AUX_CH_NONE) {
872 		aux_ch = default_aux_ch(encoder);
873 		source = "platform default";
874 	}
875 
876 	if (aux_ch == AUX_CH_NONE)
877 		return AUX_CH_NONE;
878 
879 	/* FIXME validate aux_ch against platform caps */
880 
881 	other = get_encoder_by_aux_ch(encoder, aux_ch);
882 	if (other) {
883 		drm_dbg_kms(display->drm,
884 			    "[ENCODER:%d:%s] AUX CH %s already claimed by [ENCODER:%d:%s]\n",
885 			    encoder->base.base.id, encoder->base.name,
886 			    aux_ch_name(display, buf, sizeof(buf), aux_ch),
887 			    other->base.base.id, other->base.name);
888 		return AUX_CH_NONE;
889 	}
890 
891 	drm_dbg_kms(display->drm,
892 		    "[ENCODER:%d:%s] Using AUX CH %s (%s)\n",
893 		    encoder->base.base.id, encoder->base.name,
894 		    aux_ch_name(display, buf, sizeof(buf), aux_ch), source);
895 
896 	return aux_ch;
897 }
898 
899 void intel_dp_aux_irq_handler(struct intel_display *display)
900 {
901 	wake_up_all(&display->gmbus.wait_queue);
902 }
903