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_aux.h"
13 #include "intel_dp_aux_regs.h"
14 #include "intel_pps.h"
15 #include "intel_tc.h"
16 
17 u32 intel_dp_aux_pack(const u8 *src, int src_bytes)
18 {
19 	int i;
20 	u32 v = 0;
21 
22 	if (src_bytes > 4)
23 		src_bytes = 4;
24 	for (i = 0; i < src_bytes; i++)
25 		v |= ((u32)src[i]) << ((3 - i) * 8);
26 	return v;
27 }
28 
29 static void intel_dp_aux_unpack(u32 src, u8 *dst, int dst_bytes)
30 {
31 	int i;
32 
33 	if (dst_bytes > 4)
34 		dst_bytes = 4;
35 	for (i = 0; i < dst_bytes; i++)
36 		dst[i] = src >> ((3 - i) * 8);
37 }
38 
39 static u32
40 intel_dp_aux_wait_done(struct intel_dp *intel_dp)
41 {
42 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
43 	i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
44 	const unsigned int timeout_ms = 10;
45 	u32 status;
46 	int ret;
47 
48 	ret = __intel_de_wait_for_register(i915, ch_ctl,
49 					   DP_AUX_CH_CTL_SEND_BUSY, 0,
50 					   2, timeout_ms, &status);
51 
52 	if (ret == -ETIMEDOUT)
53 		drm_err(&i915->drm,
54 			"%s: did not complete or timeout within %ums (status 0x%08x)\n",
55 			intel_dp->aux.name, timeout_ms, status);
56 
57 	return status;
58 }
59 
60 static u32 g4x_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
61 {
62 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
63 
64 	if (index)
65 		return 0;
66 
67 	/*
68 	 * The clock divider is based off the hrawclk, and would like to run at
69 	 * 2MHz.  So, take the hrawclk value and divide by 2000 and use that
70 	 */
71 	return DIV_ROUND_CLOSEST(RUNTIME_INFO(dev_priv)->rawclk_freq, 2000);
72 }
73 
74 static u32 ilk_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
75 {
76 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
77 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
78 	u32 freq;
79 
80 	if (index)
81 		return 0;
82 
83 	/*
84 	 * The clock divider is based off the cdclk or PCH rawclk, and would
85 	 * like to run at 2MHz.  So, take the cdclk or PCH rawclk value and
86 	 * divide by 2000 and use that
87 	 */
88 	if (dig_port->aux_ch == AUX_CH_A)
89 		freq = dev_priv->display.cdclk.hw.cdclk;
90 	else
91 		freq = RUNTIME_INFO(dev_priv)->rawclk_freq;
92 	return DIV_ROUND_CLOSEST(freq, 2000);
93 }
94 
95 static u32 hsw_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
96 {
97 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
98 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
99 
100 	if (dig_port->aux_ch != AUX_CH_A && HAS_PCH_LPT_H(dev_priv)) {
101 		/* Workaround for non-ULT HSW */
102 		switch (index) {
103 		case 0: return 63;
104 		case 1: return 72;
105 		default: return 0;
106 		}
107 	}
108 
109 	return ilk_get_aux_clock_divider(intel_dp, index);
110 }
111 
112 static u32 skl_get_aux_clock_divider(struct intel_dp *intel_dp, int index)
113 {
114 	/*
115 	 * SKL doesn't need us to program the AUX clock divider (Hardware will
116 	 * derive the clock from CDCLK automatically). We still implement the
117 	 * get_aux_clock_divider vfunc to plug-in into the existing code.
118 	 */
119 	return index ? 0 : 1;
120 }
121 
122 static int intel_dp_aux_sync_len(void)
123 {
124 	int precharge = 16; /* 10-16 */
125 	int preamble = 16;
126 
127 	return precharge + preamble;
128 }
129 
130 static int intel_dp_aux_fw_sync_len(void)
131 {
132 	int precharge = 10; /* 10-16 */
133 	int preamble = 8;
134 
135 	return precharge + preamble;
136 }
137 
138 static int g4x_dp_aux_precharge_len(void)
139 {
140 	int precharge_min = 10;
141 	int preamble = 16;
142 
143 	/* HW wants the length of the extra precharge in 2us units */
144 	return (intel_dp_aux_sync_len() -
145 		precharge_min - preamble) / 2;
146 }
147 
148 static u32 g4x_get_aux_send_ctl(struct intel_dp *intel_dp,
149 				int send_bytes,
150 				u32 aux_clock_divider)
151 {
152 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
153 	struct drm_i915_private *dev_priv =
154 			to_i915(dig_port->base.base.dev);
155 	u32 timeout;
156 
157 	/* Max timeout value on G4x-BDW: 1.6ms */
158 	if (IS_BROADWELL(dev_priv))
159 		timeout = DP_AUX_CH_CTL_TIME_OUT_600us;
160 	else
161 		timeout = DP_AUX_CH_CTL_TIME_OUT_400us;
162 
163 	return DP_AUX_CH_CTL_SEND_BUSY |
164 		DP_AUX_CH_CTL_DONE |
165 		DP_AUX_CH_CTL_INTERRUPT |
166 		DP_AUX_CH_CTL_TIME_OUT_ERROR |
167 		timeout |
168 		DP_AUX_CH_CTL_RECEIVE_ERROR |
169 		DP_AUX_CH_CTL_MESSAGE_SIZE(send_bytes) |
170 		DP_AUX_CH_CTL_PRECHARGE_2US(g4x_dp_aux_precharge_len()) |
171 		DP_AUX_CH_CTL_BIT_CLOCK_2X(aux_clock_divider);
172 }
173 
174 static u32 skl_get_aux_send_ctl(struct intel_dp *intel_dp,
175 				int send_bytes,
176 				u32 unused)
177 {
178 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
179 	struct drm_i915_private *i915 =	to_i915(dig_port->base.base.dev);
180 	u32 ret;
181 
182 	/*
183 	 * Max timeout values:
184 	 * SKL-GLK: 1.6ms
185 	 * ICL+: 4ms
186 	 */
187 	ret = DP_AUX_CH_CTL_SEND_BUSY |
188 		DP_AUX_CH_CTL_DONE |
189 		DP_AUX_CH_CTL_INTERRUPT |
190 		DP_AUX_CH_CTL_TIME_OUT_ERROR |
191 		DP_AUX_CH_CTL_TIME_OUT_MAX |
192 		DP_AUX_CH_CTL_RECEIVE_ERROR |
193 		DP_AUX_CH_CTL_MESSAGE_SIZE(send_bytes) |
194 		DP_AUX_CH_CTL_FW_SYNC_PULSE_SKL(intel_dp_aux_fw_sync_len()) |
195 		DP_AUX_CH_CTL_SYNC_PULSE_SKL(intel_dp_aux_sync_len());
196 
197 	if (intel_tc_port_in_tbt_alt_mode(dig_port))
198 		ret |= DP_AUX_CH_CTL_TBT_IO;
199 
200 	/*
201 	 * Power request bit is already set during aux power well enable.
202 	 * Preserve the bit across aux transactions.
203 	 */
204 	if (DISPLAY_VER(i915) >= 14)
205 		ret |= XELPDP_DP_AUX_CH_CTL_POWER_REQUEST;
206 
207 	return ret;
208 }
209 
210 static int
211 intel_dp_aux_xfer(struct intel_dp *intel_dp,
212 		  const u8 *send, int send_bytes,
213 		  u8 *recv, int recv_size,
214 		  u32 aux_send_ctl_flags)
215 {
216 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
217 	struct drm_i915_private *i915 =
218 			to_i915(dig_port->base.base.dev);
219 	enum phy phy = intel_port_to_phy(i915, dig_port->base.port);
220 	bool is_tc_port = intel_phy_is_tc(i915, phy);
221 	i915_reg_t ch_ctl, ch_data[5];
222 	u32 aux_clock_divider;
223 	enum intel_display_power_domain aux_domain;
224 	intel_wakeref_t aux_wakeref;
225 	intel_wakeref_t pps_wakeref;
226 	int i, ret, recv_bytes;
227 	int try, clock = 0;
228 	u32 status;
229 	bool vdd;
230 
231 	ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp);
232 	for (i = 0; i < ARRAY_SIZE(ch_data); i++)
233 		ch_data[i] = intel_dp->aux_ch_data_reg(intel_dp, i);
234 
235 	if (is_tc_port) {
236 		intel_tc_port_lock(dig_port);
237 		/*
238 		 * Abort transfers on a disconnected port as required by
239 		 * DP 1.4a link CTS 4.2.1.5, also avoiding the long AUX
240 		 * timeouts that would otherwise happen.
241 		 * TODO: abort the transfer on non-TC ports as well.
242 		 */
243 		if (!intel_tc_port_connected_locked(&dig_port->base)) {
244 			ret = -ENXIO;
245 			goto out_unlock;
246 		}
247 	}
248 
249 	aux_domain = intel_aux_power_domain(dig_port);
250 
251 	aux_wakeref = intel_display_power_get(i915, aux_domain);
252 	pps_wakeref = intel_pps_lock(intel_dp);
253 
254 	/*
255 	 * We will be called with VDD already enabled for dpcd/edid/oui reads.
256 	 * In such cases we want to leave VDD enabled and it's up to upper layers
257 	 * to turn it off. But for eg. i2c-dev access we need to turn it on/off
258 	 * ourselves.
259 	 */
260 	vdd = intel_pps_vdd_on_unlocked(intel_dp);
261 
262 	/*
263 	 * dp aux is extremely sensitive to irq latency, hence request the
264 	 * lowest possible wakeup latency and so prevent the cpu from going into
265 	 * deep sleep states.
266 	 */
267 	cpu_latency_qos_update_request(&intel_dp->pm_qos, 0);
268 
269 	intel_pps_check_power_unlocked(intel_dp);
270 
271 	/*
272 	 * FIXME PSR should be disabled here to prevent
273 	 * it using the same AUX CH simultaneously
274 	 */
275 
276 	/* Try to wait for any previous AUX channel activity */
277 	for (try = 0; try < 3; try++) {
278 		status = intel_de_read_notrace(i915, ch_ctl);
279 		if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
280 			break;
281 		msleep(1);
282 	}
283 	/* just trace the final value */
284 	trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true);
285 
286 	if (try == 3) {
287 		const u32 status = intel_de_read(i915, ch_ctl);
288 
289 		if (status != intel_dp->aux_busy_last_status) {
290 			drm_WARN(&i915->drm, 1,
291 				 "%s: not started (status 0x%08x)\n",
292 				 intel_dp->aux.name, status);
293 			intel_dp->aux_busy_last_status = status;
294 		}
295 
296 		ret = -EBUSY;
297 		goto out;
298 	}
299 
300 	/* Only 5 data registers! */
301 	if (drm_WARN_ON(&i915->drm, send_bytes > 20 || recv_size > 20)) {
302 		ret = -E2BIG;
303 		goto out;
304 	}
305 
306 	while ((aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, clock++))) {
307 		u32 send_ctl = intel_dp->get_aux_send_ctl(intel_dp,
308 							  send_bytes,
309 							  aux_clock_divider);
310 
311 		send_ctl |= aux_send_ctl_flags;
312 
313 		/* Must try at least 3 times according to DP spec */
314 		for (try = 0; try < 5; try++) {
315 			/* Load the send data into the aux channel data registers */
316 			for (i = 0; i < send_bytes; i += 4)
317 				intel_de_write(i915, ch_data[i >> 2],
318 					       intel_dp_aux_pack(send + i,
319 								 send_bytes - i));
320 
321 			/* Send the command and wait for it to complete */
322 			intel_de_write(i915, ch_ctl, send_ctl);
323 
324 			status = intel_dp_aux_wait_done(intel_dp);
325 
326 			/* Clear done status and any errors */
327 			intel_de_write(i915, ch_ctl,
328 				       status | DP_AUX_CH_CTL_DONE |
329 				       DP_AUX_CH_CTL_TIME_OUT_ERROR |
330 				       DP_AUX_CH_CTL_RECEIVE_ERROR);
331 
332 			/*
333 			 * DP CTS 1.2 Core Rev 1.1, 4.2.1.1 & 4.2.1.2
334 			 *   400us delay required for errors and timeouts
335 			 *   Timeout errors from the HW already meet this
336 			 *   requirement so skip to next iteration
337 			 */
338 			if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR)
339 				continue;
340 
341 			if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
342 				usleep_range(400, 500);
343 				continue;
344 			}
345 			if (status & DP_AUX_CH_CTL_DONE)
346 				goto done;
347 		}
348 	}
349 
350 	if ((status & DP_AUX_CH_CTL_DONE) == 0) {
351 		drm_err(&i915->drm, "%s: not done (status 0x%08x)\n",
352 			intel_dp->aux.name, status);
353 		ret = -EBUSY;
354 		goto out;
355 	}
356 
357 done:
358 	/*
359 	 * Check for timeout or receive error. Timeouts occur when the sink is
360 	 * not connected.
361 	 */
362 	if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
363 		drm_err(&i915->drm, "%s: receive error (status 0x%08x)\n",
364 			intel_dp->aux.name, status);
365 		ret = -EIO;
366 		goto out;
367 	}
368 
369 	/*
370 	 * Timeouts occur when the device isn't connected, so they're "normal"
371 	 * -- don't fill the kernel log with these
372 	 */
373 	if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
374 		drm_dbg_kms(&i915->drm, "%s: timeout (status 0x%08x)\n",
375 			    intel_dp->aux.name, status);
376 		ret = -ETIMEDOUT;
377 		goto out;
378 	}
379 
380 	/* Unload any bytes sent back from the other side */
381 	recv_bytes = REG_FIELD_GET(DP_AUX_CH_CTL_MESSAGE_SIZE_MASK, status);
382 
383 	/*
384 	 * By BSpec: "Message sizes of 0 or >20 are not allowed."
385 	 * We have no idea of what happened so we return -EBUSY so
386 	 * drm layer takes care for the necessary retries.
387 	 */
388 	if (recv_bytes == 0 || recv_bytes > 20) {
389 		drm_dbg_kms(&i915->drm,
390 			    "%s: Forbidden recv_bytes = %d on aux transaction\n",
391 			    intel_dp->aux.name, recv_bytes);
392 		ret = -EBUSY;
393 		goto out;
394 	}
395 
396 	if (recv_bytes > recv_size)
397 		recv_bytes = recv_size;
398 
399 	for (i = 0; i < recv_bytes; i += 4)
400 		intel_dp_aux_unpack(intel_de_read(i915, ch_data[i >> 2]),
401 				    recv + i, recv_bytes - i);
402 
403 	ret = recv_bytes;
404 out:
405 	cpu_latency_qos_update_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
406 
407 	if (vdd)
408 		intel_pps_vdd_off_unlocked(intel_dp, false);
409 
410 	intel_pps_unlock(intel_dp, pps_wakeref);
411 	intel_display_power_put_async(i915, aux_domain, aux_wakeref);
412 out_unlock:
413 	if (is_tc_port)
414 		intel_tc_port_unlock(dig_port);
415 
416 	return ret;
417 }
418 
419 #define BARE_ADDRESS_SIZE	3
420 #define HEADER_SIZE		(BARE_ADDRESS_SIZE + 1)
421 
422 static void
423 intel_dp_aux_header(u8 txbuf[HEADER_SIZE],
424 		    const struct drm_dp_aux_msg *msg)
425 {
426 	txbuf[0] = (msg->request << 4) | ((msg->address >> 16) & 0xf);
427 	txbuf[1] = (msg->address >> 8) & 0xff;
428 	txbuf[2] = msg->address & 0xff;
429 	txbuf[3] = msg->size - 1;
430 }
431 
432 static u32 intel_dp_aux_xfer_flags(const struct drm_dp_aux_msg *msg)
433 {
434 	/*
435 	 * If we're trying to send the HDCP Aksv, we need to set a the Aksv
436 	 * select bit to inform the hardware to send the Aksv after our header
437 	 * since we can't access that data from software.
438 	 */
439 	if ((msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_WRITE &&
440 	    msg->address == DP_AUX_HDCP_AKSV)
441 		return DP_AUX_CH_CTL_AUX_AKSV_SELECT;
442 
443 	return 0;
444 }
445 
446 static ssize_t
447 intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
448 {
449 	struct intel_dp *intel_dp = container_of(aux, struct intel_dp, aux);
450 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
451 	u8 txbuf[20], rxbuf[20];
452 	size_t txsize, rxsize;
453 	u32 flags = intel_dp_aux_xfer_flags(msg);
454 	int ret;
455 
456 	intel_dp_aux_header(txbuf, msg);
457 
458 	switch (msg->request & ~DP_AUX_I2C_MOT) {
459 	case DP_AUX_NATIVE_WRITE:
460 	case DP_AUX_I2C_WRITE:
461 	case DP_AUX_I2C_WRITE_STATUS_UPDATE:
462 		txsize = msg->size ? HEADER_SIZE + msg->size : BARE_ADDRESS_SIZE;
463 		rxsize = 2; /* 0 or 1 data bytes */
464 
465 		if (drm_WARN_ON(&i915->drm, txsize > 20))
466 			return -E2BIG;
467 
468 		drm_WARN_ON(&i915->drm, !msg->buffer != !msg->size);
469 
470 		if (msg->buffer)
471 			memcpy(txbuf + HEADER_SIZE, msg->buffer, msg->size);
472 
473 		ret = intel_dp_aux_xfer(intel_dp, txbuf, txsize,
474 					rxbuf, rxsize, flags);
475 		if (ret > 0) {
476 			msg->reply = rxbuf[0] >> 4;
477 
478 			if (ret > 1) {
479 				/* Number of bytes written in a short write. */
480 				ret = clamp_t(int, rxbuf[1], 0, msg->size);
481 			} else {
482 				/* Return payload size. */
483 				ret = msg->size;
484 			}
485 		}
486 		break;
487 
488 	case DP_AUX_NATIVE_READ:
489 	case DP_AUX_I2C_READ:
490 		txsize = msg->size ? HEADER_SIZE : BARE_ADDRESS_SIZE;
491 		rxsize = msg->size + 1;
492 
493 		if (drm_WARN_ON(&i915->drm, rxsize > 20))
494 			return -E2BIG;
495 
496 		ret = intel_dp_aux_xfer(intel_dp, txbuf, txsize,
497 					rxbuf, rxsize, flags);
498 		if (ret > 0) {
499 			msg->reply = rxbuf[0] >> 4;
500 			/*
501 			 * Assume happy day, and copy the data. The caller is
502 			 * expected to check msg->reply before touching it.
503 			 *
504 			 * Return payload size.
505 			 */
506 			ret--;
507 			memcpy(msg->buffer, rxbuf + 1, ret);
508 		}
509 		break;
510 
511 	default:
512 		ret = -EINVAL;
513 		break;
514 	}
515 
516 	return ret;
517 }
518 
519 static i915_reg_t g4x_aux_ctl_reg(struct intel_dp *intel_dp)
520 {
521 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
522 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
523 	enum aux_ch aux_ch = dig_port->aux_ch;
524 
525 	switch (aux_ch) {
526 	case AUX_CH_B:
527 	case AUX_CH_C:
528 	case AUX_CH_D:
529 		return DP_AUX_CH_CTL(aux_ch);
530 	default:
531 		MISSING_CASE(aux_ch);
532 		return DP_AUX_CH_CTL(AUX_CH_B);
533 	}
534 }
535 
536 static i915_reg_t g4x_aux_data_reg(struct intel_dp *intel_dp, int index)
537 {
538 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
539 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
540 	enum aux_ch aux_ch = dig_port->aux_ch;
541 
542 	switch (aux_ch) {
543 	case AUX_CH_B:
544 	case AUX_CH_C:
545 	case AUX_CH_D:
546 		return DP_AUX_CH_DATA(aux_ch, index);
547 	default:
548 		MISSING_CASE(aux_ch);
549 		return DP_AUX_CH_DATA(AUX_CH_B, index);
550 	}
551 }
552 
553 static i915_reg_t ilk_aux_ctl_reg(struct intel_dp *intel_dp)
554 {
555 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
556 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
557 	enum aux_ch aux_ch = dig_port->aux_ch;
558 
559 	switch (aux_ch) {
560 	case AUX_CH_A:
561 		return DP_AUX_CH_CTL(aux_ch);
562 	case AUX_CH_B:
563 	case AUX_CH_C:
564 	case AUX_CH_D:
565 		return PCH_DP_AUX_CH_CTL(aux_ch);
566 	default:
567 		MISSING_CASE(aux_ch);
568 		return DP_AUX_CH_CTL(AUX_CH_A);
569 	}
570 }
571 
572 static i915_reg_t ilk_aux_data_reg(struct intel_dp *intel_dp, int index)
573 {
574 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
575 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
576 	enum aux_ch aux_ch = dig_port->aux_ch;
577 
578 	switch (aux_ch) {
579 	case AUX_CH_A:
580 		return DP_AUX_CH_DATA(aux_ch, index);
581 	case AUX_CH_B:
582 	case AUX_CH_C:
583 	case AUX_CH_D:
584 		return PCH_DP_AUX_CH_DATA(aux_ch, index);
585 	default:
586 		MISSING_CASE(aux_ch);
587 		return DP_AUX_CH_DATA(AUX_CH_A, index);
588 	}
589 }
590 
591 static i915_reg_t skl_aux_ctl_reg(struct intel_dp *intel_dp)
592 {
593 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
594 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
595 	enum aux_ch aux_ch = dig_port->aux_ch;
596 
597 	switch (aux_ch) {
598 	case AUX_CH_A:
599 	case AUX_CH_B:
600 	case AUX_CH_C:
601 	case AUX_CH_D:
602 	case AUX_CH_E:
603 	case AUX_CH_F:
604 		return DP_AUX_CH_CTL(aux_ch);
605 	default:
606 		MISSING_CASE(aux_ch);
607 		return DP_AUX_CH_CTL(AUX_CH_A);
608 	}
609 }
610 
611 static i915_reg_t skl_aux_data_reg(struct intel_dp *intel_dp, int index)
612 {
613 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
614 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
615 	enum aux_ch aux_ch = dig_port->aux_ch;
616 
617 	switch (aux_ch) {
618 	case AUX_CH_A:
619 	case AUX_CH_B:
620 	case AUX_CH_C:
621 	case AUX_CH_D:
622 	case AUX_CH_E:
623 	case AUX_CH_F:
624 		return DP_AUX_CH_DATA(aux_ch, index);
625 	default:
626 		MISSING_CASE(aux_ch);
627 		return DP_AUX_CH_DATA(AUX_CH_A, index);
628 	}
629 }
630 
631 static i915_reg_t tgl_aux_ctl_reg(struct intel_dp *intel_dp)
632 {
633 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
634 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
635 	enum aux_ch aux_ch = dig_port->aux_ch;
636 
637 	switch (aux_ch) {
638 	case AUX_CH_A:
639 	case AUX_CH_B:
640 	case AUX_CH_C:
641 	case AUX_CH_USBC1:
642 	case AUX_CH_USBC2:
643 	case AUX_CH_USBC3:
644 	case AUX_CH_USBC4:
645 	case AUX_CH_USBC5:  /* aka AUX_CH_D_XELPD */
646 	case AUX_CH_USBC6:  /* aka AUX_CH_E_XELPD */
647 		return DP_AUX_CH_CTL(aux_ch);
648 	default:
649 		MISSING_CASE(aux_ch);
650 		return DP_AUX_CH_CTL(AUX_CH_A);
651 	}
652 }
653 
654 static i915_reg_t tgl_aux_data_reg(struct intel_dp *intel_dp, int index)
655 {
656 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
657 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
658 	enum aux_ch aux_ch = dig_port->aux_ch;
659 
660 	switch (aux_ch) {
661 	case AUX_CH_A:
662 	case AUX_CH_B:
663 	case AUX_CH_C:
664 	case AUX_CH_USBC1:
665 	case AUX_CH_USBC2:
666 	case AUX_CH_USBC3:
667 	case AUX_CH_USBC4:
668 	case AUX_CH_USBC5:  /* aka AUX_CH_D_XELPD */
669 	case AUX_CH_USBC6:  /* aka AUX_CH_E_XELPD */
670 		return DP_AUX_CH_DATA(aux_ch, index);
671 	default:
672 		MISSING_CASE(aux_ch);
673 		return DP_AUX_CH_DATA(AUX_CH_A, index);
674 	}
675 }
676 
677 static i915_reg_t xelpdp_aux_ctl_reg(struct intel_dp *intel_dp)
678 {
679 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
680 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
681 	enum aux_ch aux_ch = dig_port->aux_ch;
682 
683 	switch (aux_ch) {
684 	case AUX_CH_A:
685 	case AUX_CH_B:
686 	case AUX_CH_USBC1:
687 	case AUX_CH_USBC2:
688 	case AUX_CH_USBC3:
689 	case AUX_CH_USBC4:
690 		return XELPDP_DP_AUX_CH_CTL(aux_ch);
691 	default:
692 		MISSING_CASE(aux_ch);
693 		return XELPDP_DP_AUX_CH_CTL(AUX_CH_A);
694 	}
695 }
696 
697 static i915_reg_t xelpdp_aux_data_reg(struct intel_dp *intel_dp, int index)
698 {
699 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
700 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
701 	enum aux_ch aux_ch = dig_port->aux_ch;
702 
703 	switch (aux_ch) {
704 	case AUX_CH_A:
705 	case AUX_CH_B:
706 	case AUX_CH_USBC1:
707 	case AUX_CH_USBC2:
708 	case AUX_CH_USBC3:
709 	case AUX_CH_USBC4:
710 		return XELPDP_DP_AUX_CH_DATA(aux_ch, index);
711 	default:
712 		MISSING_CASE(aux_ch);
713 		return XELPDP_DP_AUX_CH_DATA(AUX_CH_A, index);
714 	}
715 }
716 
717 void intel_dp_aux_fini(struct intel_dp *intel_dp)
718 {
719 	if (cpu_latency_qos_request_active(&intel_dp->pm_qos))
720 		cpu_latency_qos_remove_request(&intel_dp->pm_qos);
721 
722 	kfree(intel_dp->aux.name);
723 }
724 
725 void intel_dp_aux_init(struct intel_dp *intel_dp)
726 {
727 	struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
728 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
729 	struct intel_encoder *encoder = &dig_port->base;
730 	enum aux_ch aux_ch = dig_port->aux_ch;
731 
732 	if (DISPLAY_VER(dev_priv) >= 14) {
733 		intel_dp->aux_ch_ctl_reg = xelpdp_aux_ctl_reg;
734 		intel_dp->aux_ch_data_reg = xelpdp_aux_data_reg;
735 	} else if (DISPLAY_VER(dev_priv) >= 12) {
736 		intel_dp->aux_ch_ctl_reg = tgl_aux_ctl_reg;
737 		intel_dp->aux_ch_data_reg = tgl_aux_data_reg;
738 	} else if (DISPLAY_VER(dev_priv) >= 9) {
739 		intel_dp->aux_ch_ctl_reg = skl_aux_ctl_reg;
740 		intel_dp->aux_ch_data_reg = skl_aux_data_reg;
741 	} else if (HAS_PCH_SPLIT(dev_priv)) {
742 		intel_dp->aux_ch_ctl_reg = ilk_aux_ctl_reg;
743 		intel_dp->aux_ch_data_reg = ilk_aux_data_reg;
744 	} else {
745 		intel_dp->aux_ch_ctl_reg = g4x_aux_ctl_reg;
746 		intel_dp->aux_ch_data_reg = g4x_aux_data_reg;
747 	}
748 
749 	if (DISPLAY_VER(dev_priv) >= 9)
750 		intel_dp->get_aux_clock_divider = skl_get_aux_clock_divider;
751 	else if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
752 		intel_dp->get_aux_clock_divider = hsw_get_aux_clock_divider;
753 	else if (HAS_PCH_SPLIT(dev_priv))
754 		intel_dp->get_aux_clock_divider = ilk_get_aux_clock_divider;
755 	else
756 		intel_dp->get_aux_clock_divider = g4x_get_aux_clock_divider;
757 
758 	if (DISPLAY_VER(dev_priv) >= 9)
759 		intel_dp->get_aux_send_ctl = skl_get_aux_send_ctl;
760 	else
761 		intel_dp->get_aux_send_ctl = g4x_get_aux_send_ctl;
762 
763 	intel_dp->aux.drm_dev = &dev_priv->drm;
764 	drm_dp_aux_init(&intel_dp->aux);
765 
766 	/* Failure to allocate our preferred name is not critical */
767 	if (DISPLAY_VER(dev_priv) >= 13 && aux_ch >= AUX_CH_D_XELPD)
768 		intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX %c/%s",
769 					       aux_ch_name(aux_ch - AUX_CH_D_XELPD + AUX_CH_D),
770 					       encoder->base.name);
771 	else if (DISPLAY_VER(dev_priv) >= 12 && aux_ch >= AUX_CH_USBC1)
772 		intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX USBC%c/%s",
773 					       aux_ch - AUX_CH_USBC1 + '1',
774 					       encoder->base.name);
775 	else
776 		intel_dp->aux.name = kasprintf(GFP_KERNEL, "AUX %c/%s",
777 					       aux_ch_name(aux_ch),
778 					       encoder->base.name);
779 
780 	intel_dp->aux.transfer = intel_dp_aux_transfer;
781 	cpu_latency_qos_add_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
782 }
783 
784 static enum aux_ch default_aux_ch(struct intel_encoder *encoder)
785 {
786 	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
787 
788 	/* SKL has DDI E but no AUX E */
789 	if (DISPLAY_VER(i915) == 9 && encoder->port == PORT_E)
790 		return AUX_CH_A;
791 
792 	return (enum aux_ch)encoder->port;
793 }
794 
795 static struct intel_encoder *
796 get_encoder_by_aux_ch(struct intel_encoder *encoder,
797 		      enum aux_ch aux_ch)
798 {
799 	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
800 	struct intel_encoder *other;
801 
802 	for_each_intel_encoder(&i915->drm, other) {
803 		if (other == encoder)
804 			continue;
805 
806 		if (!intel_encoder_is_dig_port(other))
807 			continue;
808 
809 		if (enc_to_dig_port(other)->aux_ch == aux_ch)
810 			return other;
811 	}
812 
813 	return NULL;
814 }
815 
816 enum aux_ch intel_dp_aux_ch(struct intel_encoder *encoder)
817 {
818 	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
819 	struct intel_encoder *other;
820 	const char *source;
821 	enum aux_ch aux_ch;
822 
823 	aux_ch = intel_bios_dp_aux_ch(encoder->devdata);
824 	source = "VBT";
825 
826 	if (aux_ch == AUX_CH_NONE) {
827 		aux_ch = default_aux_ch(encoder);
828 		source = "platform default";
829 	}
830 
831 	if (aux_ch == AUX_CH_NONE)
832 		return AUX_CH_NONE;
833 
834 	/* FIXME validate aux_ch against platform caps */
835 
836 	other = get_encoder_by_aux_ch(encoder, aux_ch);
837 	if (other) {
838 		drm_dbg_kms(&i915->drm,
839 			    "[ENCODER:%d:%s] AUX CH %c already claimed by [ENCODER:%d:%s]\n",
840 			    encoder->base.base.id, encoder->base.name, aux_ch_name(aux_ch),
841 			    other->base.base.id, other->base.name);
842 		return AUX_CH_NONE;
843 	}
844 
845 	drm_dbg_kms(&i915->drm,
846 		    "[ENCODER:%d:%s] Using AUX CH %c (%s)\n",
847 		    encoder->base.base.id, encoder->base.name,
848 		    aux_ch_name(aux_ch), source);
849 
850 	return aux_ch;
851 }
852 
853 void intel_dp_aux_irq_handler(struct drm_i915_private *i915)
854 {
855 	wake_up_all(&i915->display.gmbus.wait_queue);
856 }
857