1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (c) 2012-2020, The Linux Foundation. All rights reserved.
4 */
5
6 #include <linux/delay.h>
7 #include <linux/phy/phy.h>
8 #include <drm/drm_print.h>
9
10 #include "dp_reg.h"
11 #include "dp_aux.h"
12
13 enum msm_dp_aux_err {
14 DP_AUX_ERR_NONE,
15 DP_AUX_ERR_ADDR,
16 DP_AUX_ERR_TOUT,
17 DP_AUX_ERR_NACK,
18 DP_AUX_ERR_DEFER,
19 DP_AUX_ERR_NACK_DEFER,
20 DP_AUX_ERR_PHY,
21 };
22
23 struct dp_aux_private {
24 struct device *dev;
25 struct dp_catalog *catalog;
26
27 struct phy *phy;
28
29 struct mutex mutex;
30 struct completion comp;
31
32 enum msm_dp_aux_err aux_error_num;
33 u32 retry_cnt;
34 bool cmd_busy;
35 bool native;
36 bool read;
37 bool no_send_addr;
38 bool no_send_stop;
39 bool initted;
40 bool is_edp;
41 bool enable_xfers;
42 u32 offset;
43 u32 segment;
44
45 struct drm_dp_aux dp_aux;
46 };
47
48 #define MAX_AUX_RETRIES 5
49
dp_aux_write(struct dp_aux_private * aux,struct drm_dp_aux_msg * msg)50 static ssize_t dp_aux_write(struct dp_aux_private *aux,
51 struct drm_dp_aux_msg *msg)
52 {
53 u8 data[4];
54 u32 reg;
55 ssize_t len;
56 u8 *msgdata = msg->buffer;
57 int const AUX_CMD_FIFO_LEN = 128;
58 int i = 0;
59
60 if (aux->read)
61 len = 0;
62 else
63 len = msg->size;
64
65 /*
66 * cmd fifo only has depth of 144 bytes
67 * limit buf length to 128 bytes here
68 */
69 if (len > AUX_CMD_FIFO_LEN - 4) {
70 DRM_ERROR("buf size greater than allowed size of 128 bytes\n");
71 return -EINVAL;
72 }
73
74 /* Pack cmd and write to HW */
75 data[0] = (msg->address >> 16) & 0xf; /* addr[19:16] */
76 if (aux->read)
77 data[0] |= BIT(4); /* R/W */
78
79 data[1] = msg->address >> 8; /* addr[15:8] */
80 data[2] = msg->address; /* addr[7:0] */
81 data[3] = msg->size - 1; /* len[7:0] */
82
83 for (i = 0; i < len + 4; i++) {
84 reg = (i < 4) ? data[i] : msgdata[i - 4];
85 reg <<= DP_AUX_DATA_OFFSET;
86 reg &= DP_AUX_DATA_MASK;
87 reg |= DP_AUX_DATA_WRITE;
88 /* index = 0, write */
89 if (i == 0)
90 reg |= DP_AUX_DATA_INDEX_WRITE;
91 dp_catalog_aux_write_data(aux->catalog, reg);
92 }
93
94 dp_catalog_aux_clear_trans(aux->catalog, false);
95 dp_catalog_aux_clear_hw_interrupts(aux->catalog);
96
97 reg = 0; /* Transaction number == 1 */
98 if (!aux->native) { /* i2c */
99 reg |= DP_AUX_TRANS_CTRL_I2C;
100
101 if (aux->no_send_addr)
102 reg |= DP_AUX_TRANS_CTRL_NO_SEND_ADDR;
103
104 if (aux->no_send_stop)
105 reg |= DP_AUX_TRANS_CTRL_NO_SEND_STOP;
106 }
107
108 reg |= DP_AUX_TRANS_CTRL_GO;
109 dp_catalog_aux_write_trans(aux->catalog, reg);
110
111 return len;
112 }
113
dp_aux_cmd_fifo_tx(struct dp_aux_private * aux,struct drm_dp_aux_msg * msg)114 static ssize_t dp_aux_cmd_fifo_tx(struct dp_aux_private *aux,
115 struct drm_dp_aux_msg *msg)
116 {
117 ssize_t ret;
118 unsigned long time_left;
119
120 reinit_completion(&aux->comp);
121
122 ret = dp_aux_write(aux, msg);
123 if (ret < 0)
124 return ret;
125
126 time_left = wait_for_completion_timeout(&aux->comp,
127 msecs_to_jiffies(250));
128 if (!time_left)
129 return -ETIMEDOUT;
130
131 return ret;
132 }
133
dp_aux_cmd_fifo_rx(struct dp_aux_private * aux,struct drm_dp_aux_msg * msg)134 static ssize_t dp_aux_cmd_fifo_rx(struct dp_aux_private *aux,
135 struct drm_dp_aux_msg *msg)
136 {
137 u32 data;
138 u8 *dp;
139 u32 i, actual_i;
140 u32 len = msg->size;
141
142 dp_catalog_aux_clear_trans(aux->catalog, true);
143
144 data = DP_AUX_DATA_INDEX_WRITE; /* INDEX_WRITE */
145 data |= DP_AUX_DATA_READ; /* read */
146
147 dp_catalog_aux_write_data(aux->catalog, data);
148
149 dp = msg->buffer;
150
151 /* discard first byte */
152 data = dp_catalog_aux_read_data(aux->catalog);
153
154 for (i = 0; i < len; i++) {
155 data = dp_catalog_aux_read_data(aux->catalog);
156 *dp++ = (u8)((data >> DP_AUX_DATA_OFFSET) & 0xff);
157
158 actual_i = (data >> DP_AUX_DATA_INDEX_OFFSET) & 0xFF;
159 if (i != actual_i)
160 break;
161 }
162
163 return i;
164 }
165
dp_aux_update_offset_and_segment(struct dp_aux_private * aux,struct drm_dp_aux_msg * input_msg)166 static void dp_aux_update_offset_and_segment(struct dp_aux_private *aux,
167 struct drm_dp_aux_msg *input_msg)
168 {
169 u32 edid_address = 0x50;
170 u32 segment_address = 0x30;
171 bool i2c_read = input_msg->request &
172 (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
173 u8 *data;
174
175 if (aux->native || i2c_read || ((input_msg->address != edid_address) &&
176 (input_msg->address != segment_address)))
177 return;
178
179
180 data = input_msg->buffer;
181 if (input_msg->address == segment_address)
182 aux->segment = *data;
183 else
184 aux->offset = *data;
185 }
186
187 /**
188 * dp_aux_transfer_helper() - helper function for EDID read transactions
189 *
190 * @aux: DP AUX private structure
191 * @input_msg: input message from DRM upstream APIs
192 * @send_seg: send the segment to sink
193 *
194 * return: void
195 *
196 * This helper function is used to fix EDID reads for non-compliant
197 * sinks that do not handle the i2c middle-of-transaction flag correctly.
198 */
dp_aux_transfer_helper(struct dp_aux_private * aux,struct drm_dp_aux_msg * input_msg,bool send_seg)199 static void dp_aux_transfer_helper(struct dp_aux_private *aux,
200 struct drm_dp_aux_msg *input_msg,
201 bool send_seg)
202 {
203 struct drm_dp_aux_msg helper_msg;
204 u32 message_size = 0x10;
205 u32 segment_address = 0x30;
206 u32 const edid_block_length = 0x80;
207 bool i2c_mot = input_msg->request & DP_AUX_I2C_MOT;
208 bool i2c_read = input_msg->request &
209 (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
210
211 if (!i2c_mot || !i2c_read || (input_msg->size == 0))
212 return;
213
214 /*
215 * Sending the segment value and EDID offset will be performed
216 * from the DRM upstream EDID driver for each block. Avoid
217 * duplicate AUX transactions related to this while reading the
218 * first 16 bytes of each block.
219 */
220 if (!(aux->offset % edid_block_length) || !send_seg)
221 goto end;
222
223 aux->read = false;
224 aux->cmd_busy = true;
225 aux->no_send_addr = true;
226 aux->no_send_stop = true;
227
228 /*
229 * Send the segment address for every i2c read in which the
230 * middle-of-tranaction flag is set. This is required to support EDID
231 * reads of more than 2 blocks as the segment address is reset to 0
232 * since we are overriding the middle-of-transaction flag for read
233 * transactions.
234 */
235
236 if (aux->segment) {
237 memset(&helper_msg, 0, sizeof(helper_msg));
238 helper_msg.address = segment_address;
239 helper_msg.buffer = &aux->segment;
240 helper_msg.size = 1;
241 dp_aux_cmd_fifo_tx(aux, &helper_msg);
242 }
243
244 /*
245 * Send the offset address for every i2c read in which the
246 * middle-of-transaction flag is set. This will ensure that the sink
247 * will update its read pointer and return the correct portion of the
248 * EDID buffer in the subsequent i2c read trasntion triggered in the
249 * native AUX transfer function.
250 */
251 memset(&helper_msg, 0, sizeof(helper_msg));
252 helper_msg.address = input_msg->address;
253 helper_msg.buffer = &aux->offset;
254 helper_msg.size = 1;
255 dp_aux_cmd_fifo_tx(aux, &helper_msg);
256
257 end:
258 aux->offset += message_size;
259 if (aux->offset == 0x80 || aux->offset == 0x100)
260 aux->segment = 0x0; /* reset segment at end of block */
261 }
262
263 /*
264 * This function does the real job to process an AUX transaction.
265 * It will call aux_reset() function to reset the AUX channel,
266 * if the waiting is timeout.
267 */
dp_aux_transfer(struct drm_dp_aux * dp_aux,struct drm_dp_aux_msg * msg)268 static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
269 struct drm_dp_aux_msg *msg)
270 {
271 ssize_t ret;
272 int const aux_cmd_native_max = 16;
273 int const aux_cmd_i2c_max = 128;
274 struct dp_aux_private *aux;
275
276 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
277
278 aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);
279
280 /* Ignore address only message */
281 if (msg->size == 0 || !msg->buffer) {
282 msg->reply = aux->native ?
283 DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
284 return msg->size;
285 }
286
287 /* msg sanity check */
288 if ((aux->native && msg->size > aux_cmd_native_max) ||
289 msg->size > aux_cmd_i2c_max) {
290 DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n",
291 __func__, msg->size, msg->request);
292 return -EINVAL;
293 }
294
295 ret = pm_runtime_resume_and_get(dp_aux->dev);
296 if (ret)
297 return ret;
298
299 mutex_lock(&aux->mutex);
300 if (!aux->initted) {
301 ret = -EIO;
302 goto exit;
303 }
304
305 /*
306 * If we're using DP and an external display isn't connected then the
307 * transfer won't succeed. Return right away. If we don't do this we
308 * can end up with long timeouts if someone tries to access the DP AUX
309 * character device when no DP device is connected.
310 */
311 if (!aux->is_edp && !aux->enable_xfers) {
312 ret = -ENXIO;
313 goto exit;
314 }
315
316 dp_aux_update_offset_and_segment(aux, msg);
317 dp_aux_transfer_helper(aux, msg, true);
318
319 aux->read = msg->request & (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
320 aux->cmd_busy = true;
321
322 if (aux->read) {
323 aux->no_send_addr = true;
324 aux->no_send_stop = false;
325 } else {
326 aux->no_send_addr = true;
327 aux->no_send_stop = true;
328 }
329
330 ret = dp_aux_cmd_fifo_tx(aux, msg);
331 if (ret < 0) {
332 if (aux->native) {
333 aux->retry_cnt++;
334 if (!(aux->retry_cnt % MAX_AUX_RETRIES))
335 phy_calibrate(aux->phy);
336 }
337 /* reset aux if link is in connected state */
338 if (dp_catalog_link_is_connected(aux->catalog))
339 dp_catalog_aux_reset(aux->catalog);
340 } else {
341 aux->retry_cnt = 0;
342 switch (aux->aux_error_num) {
343 case DP_AUX_ERR_NONE:
344 if (aux->read)
345 ret = dp_aux_cmd_fifo_rx(aux, msg);
346 msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
347 break;
348 case DP_AUX_ERR_DEFER:
349 msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_DEFER : DP_AUX_I2C_REPLY_DEFER;
350 break;
351 case DP_AUX_ERR_PHY:
352 case DP_AUX_ERR_ADDR:
353 case DP_AUX_ERR_NACK:
354 case DP_AUX_ERR_NACK_DEFER:
355 msg->reply = aux->native ? DP_AUX_NATIVE_REPLY_NACK : DP_AUX_I2C_REPLY_NACK;
356 break;
357 case DP_AUX_ERR_TOUT:
358 ret = -ETIMEDOUT;
359 break;
360 }
361 }
362
363 aux->cmd_busy = false;
364
365 exit:
366 mutex_unlock(&aux->mutex);
367 pm_runtime_put_sync(dp_aux->dev);
368
369 return ret;
370 }
371
dp_aux_isr(struct drm_dp_aux * dp_aux)372 irqreturn_t dp_aux_isr(struct drm_dp_aux *dp_aux)
373 {
374 u32 isr;
375 struct dp_aux_private *aux;
376
377 if (!dp_aux) {
378 DRM_ERROR("invalid input\n");
379 return IRQ_NONE;
380 }
381
382 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
383
384 isr = dp_catalog_aux_get_irq(aux->catalog);
385
386 /* no interrupts pending, return immediately */
387 if (!isr)
388 return IRQ_NONE;
389
390 if (!aux->cmd_busy) {
391 DRM_ERROR("Unexpected DP AUX IRQ %#010x when not busy\n", isr);
392 return IRQ_NONE;
393 }
394
395 /*
396 * The logic below assumes only one error bit is set (other than "done"
397 * which can apparently be set at the same time as some of the other
398 * bits). Warn if more than one get set so we know we need to improve
399 * the logic.
400 */
401 if (hweight32(isr & ~DP_INTR_AUX_XFER_DONE) > 1)
402 DRM_WARN("Some DP AUX interrupts unhandled: %#010x\n", isr);
403
404 if (isr & DP_INTR_AUX_ERROR) {
405 aux->aux_error_num = DP_AUX_ERR_PHY;
406 dp_catalog_aux_clear_hw_interrupts(aux->catalog);
407 } else if (isr & DP_INTR_NACK_DEFER) {
408 aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
409 } else if (isr & DP_INTR_WRONG_ADDR) {
410 aux->aux_error_num = DP_AUX_ERR_ADDR;
411 } else if (isr & DP_INTR_TIMEOUT) {
412 aux->aux_error_num = DP_AUX_ERR_TOUT;
413 } else if (!aux->native && (isr & DP_INTR_I2C_NACK)) {
414 aux->aux_error_num = DP_AUX_ERR_NACK;
415 } else if (!aux->native && (isr & DP_INTR_I2C_DEFER)) {
416 if (isr & DP_INTR_AUX_XFER_DONE)
417 aux->aux_error_num = DP_AUX_ERR_NACK;
418 else
419 aux->aux_error_num = DP_AUX_ERR_DEFER;
420 } else if (isr & DP_INTR_AUX_XFER_DONE) {
421 aux->aux_error_num = DP_AUX_ERR_NONE;
422 } else {
423 DRM_WARN("Unexpected interrupt: %#010x\n", isr);
424 return IRQ_NONE;
425 }
426
427 complete(&aux->comp);
428
429 return IRQ_HANDLED;
430 }
431
dp_aux_enable_xfers(struct drm_dp_aux * dp_aux,bool enabled)432 void dp_aux_enable_xfers(struct drm_dp_aux *dp_aux, bool enabled)
433 {
434 struct dp_aux_private *aux;
435
436 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
437 aux->enable_xfers = enabled;
438 }
439
dp_aux_reconfig(struct drm_dp_aux * dp_aux)440 void dp_aux_reconfig(struct drm_dp_aux *dp_aux)
441 {
442 struct dp_aux_private *aux;
443
444 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
445
446 phy_calibrate(aux->phy);
447 dp_catalog_aux_reset(aux->catalog);
448 }
449
dp_aux_init(struct drm_dp_aux * dp_aux)450 void dp_aux_init(struct drm_dp_aux *dp_aux)
451 {
452 struct dp_aux_private *aux;
453
454 if (!dp_aux) {
455 DRM_ERROR("invalid input\n");
456 return;
457 }
458
459 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
460
461 mutex_lock(&aux->mutex);
462
463 dp_catalog_aux_enable(aux->catalog, true);
464 aux->retry_cnt = 0;
465 aux->initted = true;
466
467 mutex_unlock(&aux->mutex);
468 }
469
dp_aux_deinit(struct drm_dp_aux * dp_aux)470 void dp_aux_deinit(struct drm_dp_aux *dp_aux)
471 {
472 struct dp_aux_private *aux;
473
474 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
475
476 mutex_lock(&aux->mutex);
477
478 aux->initted = false;
479 dp_catalog_aux_enable(aux->catalog, false);
480
481 mutex_unlock(&aux->mutex);
482 }
483
dp_aux_register(struct drm_dp_aux * dp_aux)484 int dp_aux_register(struct drm_dp_aux *dp_aux)
485 {
486 int ret;
487
488 if (!dp_aux) {
489 DRM_ERROR("invalid input\n");
490 return -EINVAL;
491 }
492
493 ret = drm_dp_aux_register(dp_aux);
494 if (ret) {
495 DRM_ERROR("%s: failed to register drm aux: %d\n", __func__,
496 ret);
497 return ret;
498 }
499
500 return 0;
501 }
502
dp_aux_unregister(struct drm_dp_aux * dp_aux)503 void dp_aux_unregister(struct drm_dp_aux *dp_aux)
504 {
505 drm_dp_aux_unregister(dp_aux);
506 }
507
dp_wait_hpd_asserted(struct drm_dp_aux * dp_aux,unsigned long wait_us)508 static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux,
509 unsigned long wait_us)
510 {
511 int ret;
512 struct dp_aux_private *aux;
513
514 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
515
516 ret = pm_runtime_resume_and_get(aux->dev);
517 if (ret)
518 return ret;
519
520 ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog, wait_us);
521 pm_runtime_put_sync(aux->dev);
522
523 return ret;
524 }
525
dp_aux_get(struct device * dev,struct dp_catalog * catalog,struct phy * phy,bool is_edp)526 struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog,
527 struct phy *phy,
528 bool is_edp)
529 {
530 struct dp_aux_private *aux;
531
532 if (!catalog) {
533 DRM_ERROR("invalid input\n");
534 return ERR_PTR(-ENODEV);
535 }
536
537 aux = devm_kzalloc(dev, sizeof(*aux), GFP_KERNEL);
538 if (!aux)
539 return ERR_PTR(-ENOMEM);
540
541 init_completion(&aux->comp);
542 aux->cmd_busy = false;
543 aux->is_edp = is_edp;
544 mutex_init(&aux->mutex);
545
546 aux->dev = dev;
547 aux->catalog = catalog;
548 aux->phy = phy;
549 aux->retry_cnt = 0;
550
551 /*
552 * Use the drm_dp_aux_init() to use the aux adapter
553 * before registering AUX with the DRM device so that
554 * msm eDP panel can be detected by generic_dep_panel_probe().
555 */
556 aux->dp_aux.name = "dpu_dp_aux";
557 aux->dp_aux.dev = dev;
558 aux->dp_aux.transfer = dp_aux_transfer;
559 aux->dp_aux.wait_hpd_asserted = dp_wait_hpd_asserted;
560 drm_dp_aux_init(&aux->dp_aux);
561
562 return &aux->dp_aux;
563 }
564
dp_aux_put(struct drm_dp_aux * dp_aux)565 void dp_aux_put(struct drm_dp_aux *dp_aux)
566 {
567 struct dp_aux_private *aux;
568
569 if (!dp_aux)
570 return;
571
572 aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
573
574 mutex_destroy(&aux->mutex);
575
576 devm_kfree(aux->dev, aux);
577 }
578