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1/*
2 * Copyright (c) 2006 Dave Airlie <airlied@linux.ie>
3 * Copyright © 2006-2008,2010 Intel Corporation
4 * Jesse Barnes <jesse.barnes@intel.com>
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the next
14 * paragraph) shall be included in all copies or substantial portions of the
15 * Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
24 *
25 * Authors:
26 * Eric Anholt <eric@anholt.net>
27 * Chris Wilson <chris@chris-wilson.co.uk>
28 */
29
30#include <linux/export.h>
31#include <linux/i2c-algo-bit.h>
32#include <linux/i2c.h>
33
34#include <drm/drm_hdcp.h>
35
36#include "i915_drv.h"
37#include "intel_display_types.h"
38#include "intel_gmbus.h"
39
40struct gmbus_pin {
41 const char *name;
42 enum i915_gpio gpio;
43};
44
45/* Map gmbus pin pairs to names and registers. */
46static const struct gmbus_pin gmbus_pins[] = {
47 [GMBUS_PIN_SSC] = { "ssc", GPIOB },
48 [GMBUS_PIN_VGADDC] = { "vga", GPIOA },
49 [GMBUS_PIN_PANEL] = { "panel", GPIOC },
50 [GMBUS_PIN_DPC] = { "dpc", GPIOD },
51 [GMBUS_PIN_DPB] = { "dpb", GPIOE },
52 [GMBUS_PIN_DPD] = { "dpd", GPIOF },
53};
54
55static const struct gmbus_pin gmbus_pins_bdw[] = {
56 [GMBUS_PIN_VGADDC] = { "vga", GPIOA },
57 [GMBUS_PIN_DPC] = { "dpc", GPIOD },
58 [GMBUS_PIN_DPB] = { "dpb", GPIOE },
59 [GMBUS_PIN_DPD] = { "dpd", GPIOF },
60};
61
62static const struct gmbus_pin gmbus_pins_skl[] = {
63 [GMBUS_PIN_DPC] = { "dpc", GPIOD },
64 [GMBUS_PIN_DPB] = { "dpb", GPIOE },
65 [GMBUS_PIN_DPD] = { "dpd", GPIOF },
66};
67
68static const struct gmbus_pin gmbus_pins_bxt[] = {
69 [GMBUS_PIN_1_BXT] = { "dpb", GPIOB },
70 [GMBUS_PIN_2_BXT] = { "dpc", GPIOC },
71 [GMBUS_PIN_3_BXT] = { "misc", GPIOD },
72};
73
74static const struct gmbus_pin gmbus_pins_cnp[] = {
75 [GMBUS_PIN_1_BXT] = { "dpb", GPIOB },
76 [GMBUS_PIN_2_BXT] = { "dpc", GPIOC },
77 [GMBUS_PIN_3_BXT] = { "misc", GPIOD },
78 [GMBUS_PIN_4_CNP] = { "dpd", GPIOE },
79};
80
81static const struct gmbus_pin gmbus_pins_icp[] = {
82 [GMBUS_PIN_1_BXT] = { "dpa", GPIOB },
83 [GMBUS_PIN_2_BXT] = { "dpb", GPIOC },
84 [GMBUS_PIN_3_BXT] = { "dpc", GPIOD },
85 [GMBUS_PIN_9_TC1_ICP] = { "tc1", GPIOJ },
86 [GMBUS_PIN_10_TC2_ICP] = { "tc2", GPIOK },
87 [GMBUS_PIN_11_TC3_ICP] = { "tc3", GPIOL },
88 [GMBUS_PIN_12_TC4_ICP] = { "tc4", GPIOM },
89 [GMBUS_PIN_13_TC5_TGP] = { "tc5", GPION },
90 [GMBUS_PIN_14_TC6_TGP] = { "tc6", GPIOO },
91};
92
93/* pin is expected to be valid */
94static const struct gmbus_pin *get_gmbus_pin(struct drm_i915_private *dev_priv,
95 unsigned int pin)
96{
97 if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
98 return &gmbus_pins_icp[pin];
99 else if (HAS_PCH_CNP(dev_priv))
100 return &gmbus_pins_cnp[pin];
101 else if (IS_GEN9_LP(dev_priv))
102 return &gmbus_pins_bxt[pin];
103 else if (IS_GEN9_BC(dev_priv))
104 return &gmbus_pins_skl[pin];
105 else if (IS_BROADWELL(dev_priv))
106 return &gmbus_pins_bdw[pin];
107 else
108 return &gmbus_pins[pin];
109}
110
111bool intel_gmbus_is_valid_pin(struct drm_i915_private *dev_priv,
112 unsigned int pin)
113{
114 unsigned int size;
115
116 if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
117 size = ARRAY_SIZE(gmbus_pins_icp);
118 else if (HAS_PCH_CNP(dev_priv))
119 size = ARRAY_SIZE(gmbus_pins_cnp);
120 else if (IS_GEN9_LP(dev_priv))
121 size = ARRAY_SIZE(gmbus_pins_bxt);
122 else if (IS_GEN9_BC(dev_priv))
123 size = ARRAY_SIZE(gmbus_pins_skl);
124 else if (IS_BROADWELL(dev_priv))
125 size = ARRAY_SIZE(gmbus_pins_bdw);
126 else
127 size = ARRAY_SIZE(gmbus_pins);
128
129 return pin < size && get_gmbus_pin(dev_priv, pin)->name;
130}
131
132/* Intel GPIO access functions */
133
134#define I2C_RISEFALL_TIME 10
135
136static inline struct intel_gmbus *
137to_intel_gmbus(struct i2c_adapter *i2c)
138{
139 return container_of(i2c, struct intel_gmbus, adapter);
140}
141
142void
143intel_gmbus_reset(struct drm_i915_private *dev_priv)
144{
145 intel_de_write(dev_priv, GMBUS0, 0);
146 intel_de_write(dev_priv, GMBUS4, 0);
147}
148
149static void pnv_gmbus_clock_gating(struct drm_i915_private *dev_priv,
150 bool enable)
151{
152 u32 val;
153
154 /* When using bit bashing for I2C, this bit needs to be set to 1 */
155 val = intel_de_read(dev_priv, DSPCLK_GATE_D);
156 if (!enable)
157 val |= PNV_GMBUSUNIT_CLOCK_GATE_DISABLE;
158 else
159 val &= ~PNV_GMBUSUNIT_CLOCK_GATE_DISABLE;
160 intel_de_write(dev_priv, DSPCLK_GATE_D, val);
161}
162
163static void pch_gmbus_clock_gating(struct drm_i915_private *dev_priv,
164 bool enable)
165{
166 u32 val;
167
168 val = intel_de_read(dev_priv, SOUTH_DSPCLK_GATE_D);
169 if (!enable)
170 val |= PCH_GMBUSUNIT_CLOCK_GATE_DISABLE;
171 else
172 val &= ~PCH_GMBUSUNIT_CLOCK_GATE_DISABLE;
173 intel_de_write(dev_priv, SOUTH_DSPCLK_GATE_D, val);
174}
175
176static void bxt_gmbus_clock_gating(struct drm_i915_private *dev_priv,
177 bool enable)
178{
179 u32 val;
180
181 val = intel_de_read(dev_priv, GEN9_CLKGATE_DIS_4);
182 if (!enable)
183 val |= BXT_GMBUS_GATING_DIS;
184 else
185 val &= ~BXT_GMBUS_GATING_DIS;
186 intel_de_write(dev_priv, GEN9_CLKGATE_DIS_4, val);
187}
188
189static u32 get_reserved(struct intel_gmbus *bus)
190{
191 struct drm_i915_private *i915 = bus->dev_priv;
192 struct intel_uncore *uncore = &i915->uncore;
193 u32 reserved = 0;
194
195 /* On most chips, these bits must be preserved in software. */
196 if (!IS_I830(i915) && !IS_I845G(i915))
197 reserved = intel_uncore_read_notrace(uncore, bus->gpio_reg) &
198 (GPIO_DATA_PULLUP_DISABLE |
199 GPIO_CLOCK_PULLUP_DISABLE);
200
201 return reserved;
202}
203
204static int get_clock(void *data)
205{
206 struct intel_gmbus *bus = data;
207 struct intel_uncore *uncore = &bus->dev_priv->uncore;
208 u32 reserved = get_reserved(bus);
209
210 intel_uncore_write_notrace(uncore,
211 bus->gpio_reg,
212 reserved | GPIO_CLOCK_DIR_MASK);
213 intel_uncore_write_notrace(uncore, bus->gpio_reg, reserved);
214
215 return (intel_uncore_read_notrace(uncore, bus->gpio_reg) &
216 GPIO_CLOCK_VAL_IN) != 0;
217}
218
219static int get_data(void *data)
220{
221 struct intel_gmbus *bus = data;
222 struct intel_uncore *uncore = &bus->dev_priv->uncore;
223 u32 reserved = get_reserved(bus);
224
225 intel_uncore_write_notrace(uncore,
226 bus->gpio_reg,
227 reserved | GPIO_DATA_DIR_MASK);
228 intel_uncore_write_notrace(uncore, bus->gpio_reg, reserved);
229
230 return (intel_uncore_read_notrace(uncore, bus->gpio_reg) &
231 GPIO_DATA_VAL_IN) != 0;
232}
233
234static void set_clock(void *data, int state_high)
235{
236 struct intel_gmbus *bus = data;
237 struct intel_uncore *uncore = &bus->dev_priv->uncore;
238 u32 reserved = get_reserved(bus);
239 u32 clock_bits;
240
241 if (state_high)
242 clock_bits = GPIO_CLOCK_DIR_IN | GPIO_CLOCK_DIR_MASK;
243 else
244 clock_bits = GPIO_CLOCK_DIR_OUT | GPIO_CLOCK_DIR_MASK |
245 GPIO_CLOCK_VAL_MASK;
246
247 intel_uncore_write_notrace(uncore,
248 bus->gpio_reg,
249 reserved | clock_bits);
250 intel_uncore_posting_read(uncore, bus->gpio_reg);
251}
252
253static void set_data(void *data, int state_high)
254{
255 struct intel_gmbus *bus = data;
256 struct intel_uncore *uncore = &bus->dev_priv->uncore;
257 u32 reserved = get_reserved(bus);
258 u32 data_bits;
259
260 if (state_high)
261 data_bits = GPIO_DATA_DIR_IN | GPIO_DATA_DIR_MASK;
262 else
263 data_bits = GPIO_DATA_DIR_OUT | GPIO_DATA_DIR_MASK |
264 GPIO_DATA_VAL_MASK;
265
266 intel_uncore_write_notrace(uncore, bus->gpio_reg, reserved | data_bits);
267 intel_uncore_posting_read(uncore, bus->gpio_reg);
268}
269
270static int
271intel_gpio_pre_xfer(struct i2c_adapter *adapter)
272{
273 struct intel_gmbus *bus = container_of(adapter,
274 struct intel_gmbus,
275 adapter);
276 struct drm_i915_private *dev_priv = bus->dev_priv;
277
278 intel_gmbus_reset(dev_priv);
279
280 if (IS_PINEVIEW(dev_priv))
281 pnv_gmbus_clock_gating(dev_priv, false);
282
283 set_data(bus, 1);
284 set_clock(bus, 1);
285 udelay(I2C_RISEFALL_TIME);
286 return 0;
287}
288
289static void
290intel_gpio_post_xfer(struct i2c_adapter *adapter)
291{
292 struct intel_gmbus *bus = container_of(adapter,
293 struct intel_gmbus,
294 adapter);
295 struct drm_i915_private *dev_priv = bus->dev_priv;
296
297 set_data(bus, 1);
298 set_clock(bus, 1);
299
300 if (IS_PINEVIEW(dev_priv))
301 pnv_gmbus_clock_gating(dev_priv, true);
302}
303
304static void
305intel_gpio_setup(struct intel_gmbus *bus, unsigned int pin)
306{
307 struct drm_i915_private *dev_priv = bus->dev_priv;
308 struct i2c_algo_bit_data *algo;
309
310 algo = &bus->bit_algo;
311
312 bus->gpio_reg = GPIO(get_gmbus_pin(dev_priv, pin)->gpio);
313 bus->adapter.algo_data = algo;
314 algo->setsda = set_data;
315 algo->setscl = set_clock;
316 algo->getsda = get_data;
317 algo->getscl = get_clock;
318 algo->pre_xfer = intel_gpio_pre_xfer;
319 algo->post_xfer = intel_gpio_post_xfer;
320 algo->udelay = I2C_RISEFALL_TIME;
321 algo->timeout = usecs_to_jiffies(2200);
322 algo->data = bus;
323}
324
325static int gmbus_wait(struct drm_i915_private *dev_priv, u32 status, u32 irq_en)
326{
327 DEFINE_WAIT(wait);
328 u32 gmbus2;
329 int ret;
330
331 /* Important: The hw handles only the first bit, so set only one! Since
332 * we also need to check for NAKs besides the hw ready/idle signal, we
333 * need to wake up periodically and check that ourselves.
334 */
335 if (!HAS_GMBUS_IRQ(dev_priv))
336 irq_en = 0;
337
338 add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
339 intel_de_write_fw(dev_priv, GMBUS4, irq_en);
340
341 status |= GMBUS_SATOER;
342 ret = wait_for_us((gmbus2 = intel_de_read_fw(dev_priv, GMBUS2)) & status,
343 2);
344 if (ret)
345 ret = wait_for((gmbus2 = intel_de_read_fw(dev_priv, GMBUS2)) & status,
346 50);
347
348 intel_de_write_fw(dev_priv, GMBUS4, 0);
349 remove_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
350
351 if (gmbus2 & GMBUS_SATOER)
352 return -ENXIO;
353
354 return ret;
355}
356
357static int
358gmbus_wait_idle(struct drm_i915_private *dev_priv)
359{
360 DEFINE_WAIT(wait);
361 u32 irq_enable;
362 int ret;
363
364 /* Important: The hw handles only the first bit, so set only one! */
365 irq_enable = 0;
366 if (HAS_GMBUS_IRQ(dev_priv))
367 irq_enable = GMBUS_IDLE_EN;
368
369 add_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
370 intel_de_write_fw(dev_priv, GMBUS4, irq_enable);
371
372 ret = intel_wait_for_register_fw(&dev_priv->uncore,
373 GMBUS2, GMBUS_ACTIVE, 0,
374 10);
375
376 intel_de_write_fw(dev_priv, GMBUS4, 0);
377 remove_wait_queue(&dev_priv->gmbus_wait_queue, &wait);
378
379 return ret;
380}
381
382static unsigned int gmbus_max_xfer_size(struct drm_i915_private *dev_priv)
383{
384 return INTEL_GEN(dev_priv) >= 9 ? GEN9_GMBUS_BYTE_COUNT_MAX :
385 GMBUS_BYTE_COUNT_MAX;
386}
387
388static int
389gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv,
390 unsigned short addr, u8 *buf, unsigned int len,
391 u32 gmbus0_reg, u32 gmbus1_index)
392{
393 unsigned int size = len;
394 bool burst_read = len > gmbus_max_xfer_size(dev_priv);
395 bool extra_byte_added = false;
396
397 if (burst_read) {
398 /*
399 * As per HW Spec, for 512Bytes need to read extra Byte and
400 * Ignore the extra byte read.
401 */
402 if (len == 512) {
403 extra_byte_added = true;
404 len++;
405 }
406 size = len % 256 + 256;
407 intel_de_write_fw(dev_priv, GMBUS0,
408 gmbus0_reg | GMBUS_BYTE_CNT_OVERRIDE);
409 }
410
411 intel_de_write_fw(dev_priv, GMBUS1,
412 gmbus1_index | GMBUS_CYCLE_WAIT | (size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_READ | GMBUS_SW_RDY);
413 while (len) {
414 int ret;
415 u32 val, loop = 0;
416
417 ret = gmbus_wait(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN);
418 if (ret)
419 return ret;
420
421 val = intel_de_read_fw(dev_priv, GMBUS3);
422 do {
423 if (extra_byte_added && len == 1)
424 break;
425
426 *buf++ = val & 0xff;
427 val >>= 8;
428 } while (--len && ++loop < 4);
429
430 if (burst_read && len == size - 4)
431 /* Reset the override bit */
432 intel_de_write_fw(dev_priv, GMBUS0, gmbus0_reg);
433 }
434
435 return 0;
436}
437
438/*
439 * HW spec says that 512Bytes in Burst read need special treatment.
440 * But it doesn't talk about other multiple of 256Bytes. And couldn't locate
441 * an I2C slave, which supports such a lengthy burst read too for experiments.
442 *
443 * So until things get clarified on HW support, to avoid the burst read length
444 * in fold of 256Bytes except 512, max burst read length is fixed at 767Bytes.
445 */
446#define INTEL_GMBUS_BURST_READ_MAX_LEN 767U
447
448static int
449gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
450 u32 gmbus0_reg, u32 gmbus1_index)
451{
452 u8 *buf = msg->buf;
453 unsigned int rx_size = msg->len;
454 unsigned int len;
455 int ret;
456
457 do {
458 if (HAS_GMBUS_BURST_READ(dev_priv))
459 len = min(rx_size, INTEL_GMBUS_BURST_READ_MAX_LEN);
460 else
461 len = min(rx_size, gmbus_max_xfer_size(dev_priv));
462
463 ret = gmbus_xfer_read_chunk(dev_priv, msg->addr, buf, len,
464 gmbus0_reg, gmbus1_index);
465 if (ret)
466 return ret;
467
468 rx_size -= len;
469 buf += len;
470 } while (rx_size != 0);
471
472 return 0;
473}
474
475static int
476gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv,
477 unsigned short addr, u8 *buf, unsigned int len,
478 u32 gmbus1_index)
479{
480 unsigned int chunk_size = len;
481 u32 val, loop;
482
483 val = loop = 0;
484 while (len && loop < 4) {
485 val |= *buf++ << (8 * loop++);
486 len -= 1;
487 }
488
489 intel_de_write_fw(dev_priv, GMBUS3, val);
490 intel_de_write_fw(dev_priv, GMBUS1,
491 gmbus1_index | GMBUS_CYCLE_WAIT | (chunk_size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
492 while (len) {
493 int ret;
494
495 val = loop = 0;
496 do {
497 val |= *buf++ << (8 * loop);
498 } while (--len && ++loop < 4);
499
500 intel_de_write_fw(dev_priv, GMBUS3, val);
501
502 ret = gmbus_wait(dev_priv, GMBUS_HW_RDY, GMBUS_HW_RDY_EN);
503 if (ret)
504 return ret;
505 }
506
507 return 0;
508}
509
510static int
511gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
512 u32 gmbus1_index)
513{
514 u8 *buf = msg->buf;
515 unsigned int tx_size = msg->len;
516 unsigned int len;
517 int ret;
518
519 do {
520 len = min(tx_size, gmbus_max_xfer_size(dev_priv));
521
522 ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len,
523 gmbus1_index);
524 if (ret)
525 return ret;
526
527 buf += len;
528 tx_size -= len;
529 } while (tx_size != 0);
530
531 return 0;
532}
533
534/*
535 * The gmbus controller can combine a 1 or 2 byte write with another read/write
536 * that immediately follows it by using an "INDEX" cycle.
537 */
538static bool
539gmbus_is_index_xfer(struct i2c_msg *msgs, int i, int num)
540{
541 return (i + 1 < num &&
542 msgs[i].addr == msgs[i + 1].addr &&
543 !(msgs[i].flags & I2C_M_RD) &&
544 (msgs[i].len == 1 || msgs[i].len == 2) &&
545 msgs[i + 1].len > 0);
546}
547
548static int
549gmbus_index_xfer(struct drm_i915_private *dev_priv, struct i2c_msg *msgs,
550 u32 gmbus0_reg)
551{
552 u32 gmbus1_index = 0;
553 u32 gmbus5 = 0;
554 int ret;
555
556 if (msgs[0].len == 2)
557 gmbus5 = GMBUS_2BYTE_INDEX_EN |
558 msgs[0].buf[1] | (msgs[0].buf[0] << 8);
559 if (msgs[0].len == 1)
560 gmbus1_index = GMBUS_CYCLE_INDEX |
561 (msgs[0].buf[0] << GMBUS_SLAVE_INDEX_SHIFT);
562
563 /* GMBUS5 holds 16-bit index */
564 if (gmbus5)
565 intel_de_write_fw(dev_priv, GMBUS5, gmbus5);
566
567 if (msgs[1].flags & I2C_M_RD)
568 ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus0_reg,
569 gmbus1_index);
570 else
571 ret = gmbus_xfer_write(dev_priv, &msgs[1], gmbus1_index);
572
573 /* Clear GMBUS5 after each index transfer */
574 if (gmbus5)
575 intel_de_write_fw(dev_priv, GMBUS5, 0);
576
577 return ret;
578}
579
580static int
581do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num,
582 u32 gmbus0_source)
583{
584 struct intel_gmbus *bus = container_of(adapter,
585 struct intel_gmbus,
586 adapter);
587 struct drm_i915_private *dev_priv = bus->dev_priv;
588 int i = 0, inc, try = 0;
589 int ret = 0;
590
591 /* Display WA #0868: skl,bxt,kbl,cfl,glk,cnl */
592 if (IS_GEN9_LP(dev_priv))
593 bxt_gmbus_clock_gating(dev_priv, false);
594 else if (HAS_PCH_SPT(dev_priv) || HAS_PCH_CNP(dev_priv))
595 pch_gmbus_clock_gating(dev_priv, false);
596
597retry:
598 intel_de_write_fw(dev_priv, GMBUS0, gmbus0_source | bus->reg0);
599
600 for (; i < num; i += inc) {
601 inc = 1;
602 if (gmbus_is_index_xfer(msgs, i, num)) {
603 ret = gmbus_index_xfer(dev_priv, &msgs[i],
604 gmbus0_source | bus->reg0);
605 inc = 2; /* an index transmission is two msgs */
606 } else if (msgs[i].flags & I2C_M_RD) {
607 ret = gmbus_xfer_read(dev_priv, &msgs[i],
608 gmbus0_source | bus->reg0, 0);
609 } else {
610 ret = gmbus_xfer_write(dev_priv, &msgs[i], 0);
611 }
612
613 if (!ret)
614 ret = gmbus_wait(dev_priv,
615 GMBUS_HW_WAIT_PHASE, GMBUS_HW_WAIT_EN);
616 if (ret == -ETIMEDOUT)
617 goto timeout;
618 else if (ret)
619 goto clear_err;
620 }
621
622 /* Generate a STOP condition on the bus. Note that gmbus can't generata
623 * a STOP on the very first cycle. To simplify the code we
624 * unconditionally generate the STOP condition with an additional gmbus
625 * cycle. */
626 intel_de_write_fw(dev_priv, GMBUS1, GMBUS_CYCLE_STOP | GMBUS_SW_RDY);
627
628 /* Mark the GMBUS interface as disabled after waiting for idle.
629 * We will re-enable it at the start of the next xfer,
630 * till then let it sleep.
631 */
632 if (gmbus_wait_idle(dev_priv)) {
633 drm_dbg_kms(&dev_priv->drm,
634 "GMBUS [%s] timed out waiting for idle\n",
635 adapter->name);
636 ret = -ETIMEDOUT;
637 }
638 intel_de_write_fw(dev_priv, GMBUS0, 0);
639 ret = ret ?: i;
640 goto out;
641
642clear_err:
643 /*
644 * Wait for bus to IDLE before clearing NAK.
645 * If we clear the NAK while bus is still active, then it will stay
646 * active and the next transaction may fail.
647 *
648 * If no ACK is received during the address phase of a transaction, the
649 * adapter must report -ENXIO. It is not clear what to return if no ACK
650 * is received at other times. But we have to be careful to not return
651 * spurious -ENXIO because that will prevent i2c and drm edid functions
652 * from retrying. So return -ENXIO only when gmbus properly quiescents -
653 * timing out seems to happen when there _is_ a ddc chip present, but
654 * it's slow responding and only answers on the 2nd retry.
655 */
656 ret = -ENXIO;
657 if (gmbus_wait_idle(dev_priv)) {
658 drm_dbg_kms(&dev_priv->drm,
659 "GMBUS [%s] timed out after NAK\n",
660 adapter->name);
661 ret = -ETIMEDOUT;
662 }
663
664 /* Toggle the Software Clear Interrupt bit. This has the effect
665 * of resetting the GMBUS controller and so clearing the
666 * BUS_ERROR raised by the slave's NAK.
667 */
668 intel_de_write_fw(dev_priv, GMBUS1, GMBUS_SW_CLR_INT);
669 intel_de_write_fw(dev_priv, GMBUS1, 0);
670 intel_de_write_fw(dev_priv, GMBUS0, 0);
671
672 drm_dbg_kms(&dev_priv->drm, "GMBUS [%s] NAK for addr: %04x %c(%d)\n",
673 adapter->name, msgs[i].addr,
674 (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len);
675
676 /*
677 * Passive adapters sometimes NAK the first probe. Retry the first
678 * message once on -ENXIO for GMBUS transfers; the bit banging algorithm
679 * has retries internally. See also the retry loop in
680 * drm_do_probe_ddc_edid, which bails out on the first -ENXIO.
681 */
682 if (ret == -ENXIO && i == 0 && try++ == 0) {
683 drm_dbg_kms(&dev_priv->drm,
684 "GMBUS [%s] NAK on first message, retry\n",
685 adapter->name);
686 goto retry;
687 }
688
689 goto out;
690
691timeout:
692 drm_dbg_kms(&dev_priv->drm,
693 "GMBUS [%s] timed out, falling back to bit banging on pin %d\n",
694 bus->adapter.name, bus->reg0 & 0xff);
695 intel_de_write_fw(dev_priv, GMBUS0, 0);
696
697 /*
698 * Hardware may not support GMBUS over these pins? Try GPIO bitbanging
699 * instead. Use EAGAIN to have i2c core retry.
700 */
701 ret = -EAGAIN;
702
703out:
704 /* Display WA #0868: skl,bxt,kbl,cfl,glk,cnl */
705 if (IS_GEN9_LP(dev_priv))
706 bxt_gmbus_clock_gating(dev_priv, true);
707 else if (HAS_PCH_SPT(dev_priv) || HAS_PCH_CNP(dev_priv))
708 pch_gmbus_clock_gating(dev_priv, true);
709
710 return ret;
711}
712
713static int
714gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
715{
716 struct intel_gmbus *bus =
717 container_of(adapter, struct intel_gmbus, adapter);
718 struct drm_i915_private *dev_priv = bus->dev_priv;
719 intel_wakeref_t wakeref;
720 int ret;
721
722 wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
723
724 if (bus->force_bit) {
725 ret = i2c_bit_algo.master_xfer(adapter, msgs, num);
726 if (ret < 0)
727 bus->force_bit &= ~GMBUS_FORCE_BIT_RETRY;
728 } else {
729 ret = do_gmbus_xfer(adapter, msgs, num, 0);
730 if (ret == -EAGAIN)
731 bus->force_bit |= GMBUS_FORCE_BIT_RETRY;
732 }
733
734 intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS, wakeref);
735
736 return ret;
737}
738
739int intel_gmbus_output_aksv(struct i2c_adapter *adapter)
740{
741 struct intel_gmbus *bus =
742 container_of(adapter, struct intel_gmbus, adapter);
743 struct drm_i915_private *dev_priv = bus->dev_priv;
744 u8 cmd = DRM_HDCP_DDC_AKSV;
745 u8 buf[DRM_HDCP_KSV_LEN] = { 0 };
746 struct i2c_msg msgs[] = {
747 {
748 .addr = DRM_HDCP_DDC_ADDR,
749 .flags = 0,
750 .len = sizeof(cmd),
751 .buf = &cmd,
752 },
753 {
754 .addr = DRM_HDCP_DDC_ADDR,
755 .flags = 0,
756 .len = sizeof(buf),
757 .buf = buf,
758 }
759 };
760 intel_wakeref_t wakeref;
761 int ret;
762
763 wakeref = intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
764 mutex_lock(&dev_priv->gmbus_mutex);
765
766 /*
767 * In order to output Aksv to the receiver, use an indexed write to
768 * pass the i2c command, and tell GMBUS to use the HW-provided value
769 * instead of sourcing GMBUS3 for the data.
770 */
771 ret = do_gmbus_xfer(adapter, msgs, ARRAY_SIZE(msgs), GMBUS_AKSV_SELECT);
772
773 mutex_unlock(&dev_priv->gmbus_mutex);
774 intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS, wakeref);
775
776 return ret;
777}
778
779static u32 gmbus_func(struct i2c_adapter *adapter)
780{
781 return i2c_bit_algo.functionality(adapter) &
782 (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
783 /* I2C_FUNC_10BIT_ADDR | */
784 I2C_FUNC_SMBUS_READ_BLOCK_DATA |
785 I2C_FUNC_SMBUS_BLOCK_PROC_CALL);
786}
787
788static const struct i2c_algorithm gmbus_algorithm = {
789 .master_xfer = gmbus_xfer,
790 .functionality = gmbus_func
791};
792
793static void gmbus_lock_bus(struct i2c_adapter *adapter,
794 unsigned int flags)
795{
796 struct intel_gmbus *bus = to_intel_gmbus(adapter);
797 struct drm_i915_private *dev_priv = bus->dev_priv;
798
799 mutex_lock(&dev_priv->gmbus_mutex);
800}
801
802static int gmbus_trylock_bus(struct i2c_adapter *adapter,
803 unsigned int flags)
804{
805 struct intel_gmbus *bus = to_intel_gmbus(adapter);
806 struct drm_i915_private *dev_priv = bus->dev_priv;
807
808 return mutex_trylock(&dev_priv->gmbus_mutex);
809}
810
811static void gmbus_unlock_bus(struct i2c_adapter *adapter,
812 unsigned int flags)
813{
814 struct intel_gmbus *bus = to_intel_gmbus(adapter);
815 struct drm_i915_private *dev_priv = bus->dev_priv;
816
817 mutex_unlock(&dev_priv->gmbus_mutex);
818}
819
820static const struct i2c_lock_operations gmbus_lock_ops = {
821 .lock_bus = gmbus_lock_bus,
822 .trylock_bus = gmbus_trylock_bus,
823 .unlock_bus = gmbus_unlock_bus,
824};
825
826/**
827 * intel_gmbus_setup - instantiate all Intel i2c GMBuses
828 * @dev_priv: i915 device private
829 */
830int intel_gmbus_setup(struct drm_i915_private *dev_priv)
831{
832 struct pci_dev *pdev = dev_priv->drm.pdev;
833 struct intel_gmbus *bus;
834 unsigned int pin;
835 int ret;
836
837 if (!HAS_DISPLAY(dev_priv) || !INTEL_DISPLAY_ENABLED(dev_priv))
838 return 0;
839
840 if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
841 dev_priv->gpio_mmio_base = VLV_DISPLAY_BASE;
842 else if (!HAS_GMCH(dev_priv))
843 /*
844 * Broxton uses the same PCH offsets for South Display Engine,
845 * even though it doesn't have a PCH.
846 */
847 dev_priv->gpio_mmio_base = PCH_DISPLAY_BASE;
848
849 mutex_init(&dev_priv->gmbus_mutex);
850 init_waitqueue_head(&dev_priv->gmbus_wait_queue);
851
852 for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
853 if (!intel_gmbus_is_valid_pin(dev_priv, pin))
854 continue;
855
856 bus = &dev_priv->gmbus[pin];
857
858 bus->adapter.owner = THIS_MODULE;
859 bus->adapter.class = I2C_CLASS_DDC;
860 snprintf(bus->adapter.name,
861 sizeof(bus->adapter.name),
862 "i915 gmbus %s",
863 get_gmbus_pin(dev_priv, pin)->name);
864
865 bus->adapter.dev.parent = &pdev->dev;
866 bus->dev_priv = dev_priv;
867
868 bus->adapter.algo = &gmbus_algorithm;
869 bus->adapter.lock_ops = &gmbus_lock_ops;
870
871 /*
872 * We wish to retry with bit banging
873 * after a timed out GMBUS attempt.
874 */
875 bus->adapter.retries = 1;
876
877 /* By default use a conservative clock rate */
878 bus->reg0 = pin | GMBUS_RATE_100KHZ;
879
880 /* gmbus seems to be broken on i830 */
881 if (IS_I830(dev_priv))
882 bus->force_bit = 1;
883
884 intel_gpio_setup(bus, pin);
885
886 ret = i2c_add_adapter(&bus->adapter);
887 if (ret)
888 goto err;
889 }
890
891 intel_gmbus_reset(dev_priv);
892
893 return 0;
894
895err:
896 while (pin--) {
897 if (!intel_gmbus_is_valid_pin(dev_priv, pin))
898 continue;
899
900 bus = &dev_priv->gmbus[pin];
901 i2c_del_adapter(&bus->adapter);
902 }
903 return ret;
904}
905
906struct i2c_adapter *intel_gmbus_get_adapter(struct drm_i915_private *dev_priv,
907 unsigned int pin)
908{
909 if (drm_WARN_ON(&dev_priv->drm,
910 !intel_gmbus_is_valid_pin(dev_priv, pin)))
911 return NULL;
912
913 return &dev_priv->gmbus[pin].adapter;
914}
915
916void intel_gmbus_set_speed(struct i2c_adapter *adapter, int speed)
917{
918 struct intel_gmbus *bus = to_intel_gmbus(adapter);
919
920 bus->reg0 = (bus->reg0 & ~(0x3 << 8)) | speed;
921}
922
923void intel_gmbus_force_bit(struct i2c_adapter *adapter, bool force_bit)
924{
925 struct intel_gmbus *bus = to_intel_gmbus(adapter);
926 struct drm_i915_private *dev_priv = bus->dev_priv;
927
928 mutex_lock(&dev_priv->gmbus_mutex);
929
930 bus->force_bit += force_bit ? 1 : -1;
931 drm_dbg_kms(&dev_priv->drm,
932 "%sabling bit-banging on %s. force bit now %d\n",
933 force_bit ? "en" : "dis", adapter->name,
934 bus->force_bit);
935
936 mutex_unlock(&dev_priv->gmbus_mutex);
937}
938
939bool intel_gmbus_is_forced_bit(struct i2c_adapter *adapter)
940{
941 struct intel_gmbus *bus = to_intel_gmbus(adapter);
942
943 return bus->force_bit;
944}
945
946void intel_gmbus_teardown(struct drm_i915_private *dev_priv)
947{
948 struct intel_gmbus *bus;
949 unsigned int pin;
950
951 for (pin = 0; pin < ARRAY_SIZE(dev_priv->gmbus); pin++) {
952 if (!intel_gmbus_is_valid_pin(dev_priv, pin))
953 continue;
954
955 bus = &dev_priv->gmbus[pin];
956 i2c_del_adapter(&bus->adapter);
957 }
958}