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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015, 2017-2018, 2022, The Linux Foundation. All rights reserved.
4 */
5
6#include <linux/bitops.h>
7#include <linux/delay.h>
8#include <linux/err.h>
9#include <linux/export.h>
10#include <linux/jiffies.h>
11#include <linux/kernel.h>
12#include <linux/ktime.h>
13#include <linux/pm_domain.h>
14#include <linux/regmap.h>
15#include <linux/regulator/consumer.h>
16#include <linux/reset-controller.h>
17#include <linux/slab.h>
18#include "gdsc.h"
19
20#define PWR_ON_MASK BIT(31)
21#define EN_REST_WAIT_MASK GENMASK_ULL(23, 20)
22#define EN_FEW_WAIT_MASK GENMASK_ULL(19, 16)
23#define CLK_DIS_WAIT_MASK GENMASK_ULL(15, 12)
24#define SW_OVERRIDE_MASK BIT(2)
25#define HW_CONTROL_MASK BIT(1)
26#define SW_COLLAPSE_MASK BIT(0)
27#define GMEM_CLAMP_IO_MASK BIT(0)
28#define GMEM_RESET_MASK BIT(4)
29
30/* CFG_GDSCR */
31#define GDSC_POWER_UP_COMPLETE BIT(16)
32#define GDSC_POWER_DOWN_COMPLETE BIT(15)
33#define GDSC_RETAIN_FF_ENABLE BIT(11)
34#define CFG_GDSCR_OFFSET 0x4
35
36/* Wait 2^n CXO cycles between all states. Here, n=2 (4 cycles). */
37#define EN_REST_WAIT_VAL 0x2
38#define EN_FEW_WAIT_VAL 0x8
39#define CLK_DIS_WAIT_VAL 0x2
40
41/* Transition delay shifts */
42#define EN_REST_WAIT_SHIFT 20
43#define EN_FEW_WAIT_SHIFT 16
44#define CLK_DIS_WAIT_SHIFT 12
45
46#define RETAIN_MEM BIT(14)
47#define RETAIN_PERIPH BIT(13)
48
49#define STATUS_POLL_TIMEOUT_US 1500
50#define TIMEOUT_US 500
51
52#define domain_to_gdsc(domain) container_of(domain, struct gdsc, pd)
53
54enum gdsc_status {
55 GDSC_OFF,
56 GDSC_ON
57};
58
59/* Returns 1 if GDSC status is status, 0 if not, and < 0 on error */
60static int gdsc_check_status(struct gdsc *sc, enum gdsc_status status)
61{
62 unsigned int reg;
63 u32 val;
64 int ret;
65
66 if (sc->flags & POLL_CFG_GDSCR)
67 reg = sc->gdscr + CFG_GDSCR_OFFSET;
68 else if (sc->gds_hw_ctrl)
69 reg = sc->gds_hw_ctrl;
70 else
71 reg = sc->gdscr;
72
73 ret = regmap_read(sc->regmap, reg, &val);
74 if (ret)
75 return ret;
76
77 if (sc->flags & POLL_CFG_GDSCR) {
78 switch (status) {
79 case GDSC_ON:
80 return !!(val & GDSC_POWER_UP_COMPLETE);
81 case GDSC_OFF:
82 return !!(val & GDSC_POWER_DOWN_COMPLETE);
83 }
84 }
85
86 switch (status) {
87 case GDSC_ON:
88 return !!(val & PWR_ON_MASK);
89 case GDSC_OFF:
90 return !(val & PWR_ON_MASK);
91 }
92
93 return -EINVAL;
94}
95
96static int gdsc_hwctrl(struct gdsc *sc, bool en)
97{
98 u32 val = en ? HW_CONTROL_MASK : 0;
99
100 return regmap_update_bits(sc->regmap, sc->gdscr, HW_CONTROL_MASK, val);
101}
102
103static int gdsc_poll_status(struct gdsc *sc, enum gdsc_status status)
104{
105 ktime_t start;
106
107 start = ktime_get();
108 do {
109 if (gdsc_check_status(sc, status))
110 return 0;
111 } while (ktime_us_delta(ktime_get(), start) < STATUS_POLL_TIMEOUT_US);
112
113 if (gdsc_check_status(sc, status))
114 return 0;
115
116 return -ETIMEDOUT;
117}
118
119static int gdsc_update_collapse_bit(struct gdsc *sc, bool val)
120{
121 u32 reg, mask;
122 int ret;
123
124 if (sc->collapse_mask) {
125 reg = sc->collapse_ctrl;
126 mask = sc->collapse_mask;
127 } else {
128 reg = sc->gdscr;
129 mask = SW_COLLAPSE_MASK;
130 }
131
132 ret = regmap_update_bits(sc->regmap, reg, mask, val ? mask : 0);
133 if (ret)
134 return ret;
135
136 return 0;
137}
138
139static int gdsc_toggle_logic(struct gdsc *sc, enum gdsc_status status,
140 bool wait)
141{
142 int ret;
143
144 if (status == GDSC_ON && sc->rsupply) {
145 ret = regulator_enable(sc->rsupply);
146 if (ret < 0)
147 return ret;
148 }
149
150 ret = gdsc_update_collapse_bit(sc, status == GDSC_OFF);
151
152 /* If disabling votable gdscs, don't poll on status */
153 if ((sc->flags & VOTABLE) && status == GDSC_OFF && !wait) {
154 /*
155 * Add a short delay here to ensure that an enable
156 * right after it was disabled does not put it in an
157 * unknown state
158 */
159 udelay(TIMEOUT_US);
160 return 0;
161 }
162
163 if (sc->gds_hw_ctrl) {
164 /*
165 * The gds hw controller asserts/de-asserts the status bit soon
166 * after it receives a power on/off request from a master.
167 * The controller then takes around 8 xo cycles to start its
168 * internal state machine and update the status bit. During
169 * this time, the status bit does not reflect the true status
170 * of the core.
171 * Add a delay of 1 us between writing to the SW_COLLAPSE bit
172 * and polling the status bit.
173 */
174 udelay(1);
175 }
176
177 ret = gdsc_poll_status(sc, status);
178 WARN(ret, "%s status stuck at 'o%s'", sc->pd.name, status ? "ff" : "n");
179
180 if (!ret && status == GDSC_OFF && sc->rsupply) {
181 ret = regulator_disable(sc->rsupply);
182 if (ret < 0)
183 return ret;
184 }
185
186 return ret;
187}
188
189static inline int gdsc_deassert_reset(struct gdsc *sc)
190{
191 int i;
192
193 for (i = 0; i < sc->reset_count; i++)
194 sc->rcdev->ops->deassert(sc->rcdev, sc->resets[i]);
195 return 0;
196}
197
198static inline int gdsc_assert_reset(struct gdsc *sc)
199{
200 int i;
201
202 for (i = 0; i < sc->reset_count; i++)
203 sc->rcdev->ops->assert(sc->rcdev, sc->resets[i]);
204 return 0;
205}
206
207static inline void gdsc_force_mem_on(struct gdsc *sc)
208{
209 int i;
210 u32 mask = RETAIN_MEM;
211
212 if (!(sc->flags & NO_RET_PERIPH))
213 mask |= RETAIN_PERIPH;
214
215 for (i = 0; i < sc->cxc_count; i++)
216 regmap_update_bits(sc->regmap, sc->cxcs[i], mask, mask);
217}
218
219static inline void gdsc_clear_mem_on(struct gdsc *sc)
220{
221 int i;
222 u32 mask = RETAIN_MEM;
223
224 if (!(sc->flags & NO_RET_PERIPH))
225 mask |= RETAIN_PERIPH;
226
227 for (i = 0; i < sc->cxc_count; i++)
228 regmap_update_bits(sc->regmap, sc->cxcs[i], mask, 0);
229}
230
231static inline void gdsc_deassert_clamp_io(struct gdsc *sc)
232{
233 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
234 GMEM_CLAMP_IO_MASK, 0);
235}
236
237static inline void gdsc_assert_clamp_io(struct gdsc *sc)
238{
239 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
240 GMEM_CLAMP_IO_MASK, 1);
241}
242
243static inline void gdsc_assert_reset_aon(struct gdsc *sc)
244{
245 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
246 GMEM_RESET_MASK, 1);
247 udelay(1);
248 regmap_update_bits(sc->regmap, sc->clamp_io_ctrl,
249 GMEM_RESET_MASK, 0);
250}
251
252static void gdsc_retain_ff_on(struct gdsc *sc)
253{
254 u32 mask = GDSC_RETAIN_FF_ENABLE;
255
256 regmap_update_bits(sc->regmap, sc->gdscr, mask, mask);
257}
258
259static int gdsc_enable(struct generic_pm_domain *domain)
260{
261 struct gdsc *sc = domain_to_gdsc(domain);
262 int ret;
263
264 if (sc->pwrsts == PWRSTS_ON)
265 return gdsc_deassert_reset(sc);
266
267 if (sc->flags & SW_RESET) {
268 gdsc_assert_reset(sc);
269 udelay(1);
270 gdsc_deassert_reset(sc);
271 }
272
273 if (sc->flags & CLAMP_IO) {
274 if (sc->flags & AON_RESET)
275 gdsc_assert_reset_aon(sc);
276 gdsc_deassert_clamp_io(sc);
277 }
278
279 ret = gdsc_toggle_logic(sc, GDSC_ON, false);
280 if (ret)
281 return ret;
282
283 if (sc->pwrsts & PWRSTS_OFF)
284 gdsc_force_mem_on(sc);
285
286 /*
287 * If clocks to this power domain were already on, they will take an
288 * additional 4 clock cycles to re-enable after the power domain is
289 * enabled. Delay to account for this. A delay is also needed to ensure
290 * clocks are not enabled within 400ns of enabling power to the
291 * memories.
292 */
293 udelay(1);
294
295 /* Turn on HW trigger mode if supported */
296 if (sc->flags & HW_CTRL) {
297 ret = gdsc_hwctrl(sc, true);
298 if (ret)
299 return ret;
300 /*
301 * Wait for the GDSC to go through a power down and
302 * up cycle. In case a firmware ends up polling status
303 * bits for the gdsc, it might read an 'on' status before
304 * the GDSC can finish the power cycle.
305 * We wait 1us before returning to ensure the firmware
306 * can't immediately poll the status bits.
307 */
308 udelay(1);
309 }
310
311 if (sc->flags & RETAIN_FF_ENABLE)
312 gdsc_retain_ff_on(sc);
313
314 return 0;
315}
316
317static int gdsc_disable(struct generic_pm_domain *domain)
318{
319 struct gdsc *sc = domain_to_gdsc(domain);
320 int ret;
321
322 if (sc->pwrsts == PWRSTS_ON)
323 return gdsc_assert_reset(sc);
324
325 /* Turn off HW trigger mode if supported */
326 if (sc->flags & HW_CTRL) {
327 ret = gdsc_hwctrl(sc, false);
328 if (ret < 0)
329 return ret;
330 /*
331 * Wait for the GDSC to go through a power down and
332 * up cycle. In case we end up polling status
333 * bits for the gdsc before the power cycle is completed
334 * it might read an 'on' status wrongly.
335 */
336 udelay(1);
337
338 ret = gdsc_poll_status(sc, GDSC_ON);
339 if (ret)
340 return ret;
341 }
342
343 if (sc->pwrsts & PWRSTS_OFF)
344 gdsc_clear_mem_on(sc);
345
346 /*
347 * If the GDSC supports only a Retention state, apart from ON,
348 * leave it in ON state.
349 * There is no SW control to transition the GDSC into
350 * Retention state. This happens in HW when the parent
351 * domain goes down to a Low power state
352 */
353 if (sc->pwrsts == PWRSTS_RET_ON)
354 return 0;
355
356 ret = gdsc_toggle_logic(sc, GDSC_OFF, domain->synced_poweroff);
357 if (ret)
358 return ret;
359
360 if (sc->flags & CLAMP_IO)
361 gdsc_assert_clamp_io(sc);
362
363 return 0;
364}
365
366static int gdsc_init(struct gdsc *sc)
367{
368 u32 mask, val;
369 int on, ret;
370
371 /*
372 * Disable HW trigger: collapse/restore occur based on registers writes.
373 * Disable SW override: Use hardware state-machine for sequencing.
374 * Configure wait time between states.
375 */
376 mask = HW_CONTROL_MASK | SW_OVERRIDE_MASK |
377 EN_REST_WAIT_MASK | EN_FEW_WAIT_MASK | CLK_DIS_WAIT_MASK;
378
379 if (!sc->en_rest_wait_val)
380 sc->en_rest_wait_val = EN_REST_WAIT_VAL;
381 if (!sc->en_few_wait_val)
382 sc->en_few_wait_val = EN_FEW_WAIT_VAL;
383 if (!sc->clk_dis_wait_val)
384 sc->clk_dis_wait_val = CLK_DIS_WAIT_VAL;
385
386 val = sc->en_rest_wait_val << EN_REST_WAIT_SHIFT |
387 sc->en_few_wait_val << EN_FEW_WAIT_SHIFT |
388 sc->clk_dis_wait_val << CLK_DIS_WAIT_SHIFT;
389
390 ret = regmap_update_bits(sc->regmap, sc->gdscr, mask, val);
391 if (ret)
392 return ret;
393
394 /* Force gdsc ON if only ON state is supported */
395 if (sc->pwrsts == PWRSTS_ON) {
396 ret = gdsc_toggle_logic(sc, GDSC_ON, false);
397 if (ret)
398 return ret;
399 }
400
401 on = gdsc_check_status(sc, GDSC_ON);
402 if (on < 0)
403 return on;
404
405 if (on) {
406 /* The regulator must be on, sync the kernel state */
407 if (sc->rsupply) {
408 ret = regulator_enable(sc->rsupply);
409 if (ret < 0)
410 return ret;
411 }
412
413 /*
414 * Votable GDSCs can be ON due to Vote from other masters.
415 * If a Votable GDSC is ON, make sure we have a Vote.
416 */
417 if (sc->flags & VOTABLE) {
418 ret = gdsc_update_collapse_bit(sc, false);
419 if (ret)
420 goto err_disable_supply;
421 }
422
423 /* Turn on HW trigger mode if supported */
424 if (sc->flags & HW_CTRL) {
425 ret = gdsc_hwctrl(sc, true);
426 if (ret < 0)
427 goto err_disable_supply;
428 }
429
430 /*
431 * Make sure the retain bit is set if the GDSC is already on,
432 * otherwise we end up turning off the GDSC and destroying all
433 * the register contents that we thought we were saving.
434 */
435 if (sc->flags & RETAIN_FF_ENABLE)
436 gdsc_retain_ff_on(sc);
437 } else if (sc->flags & ALWAYS_ON) {
438 /* If ALWAYS_ON GDSCs are not ON, turn them ON */
439 gdsc_enable(&sc->pd);
440 on = true;
441 }
442
443 if (on || (sc->pwrsts & PWRSTS_RET))
444 gdsc_force_mem_on(sc);
445 else
446 gdsc_clear_mem_on(sc);
447
448 if (sc->flags & ALWAYS_ON)
449 sc->pd.flags |= GENPD_FLAG_ALWAYS_ON;
450 if (!sc->pd.power_off)
451 sc->pd.power_off = gdsc_disable;
452 if (!sc->pd.power_on)
453 sc->pd.power_on = gdsc_enable;
454
455 ret = pm_genpd_init(&sc->pd, NULL, !on);
456 if (ret)
457 goto err_disable_supply;
458
459 return 0;
460
461err_disable_supply:
462 if (on && sc->rsupply)
463 regulator_disable(sc->rsupply);
464
465 return ret;
466}
467
468int gdsc_register(struct gdsc_desc *desc,
469 struct reset_controller_dev *rcdev, struct regmap *regmap)
470{
471 int i, ret;
472 struct genpd_onecell_data *data;
473 struct device *dev = desc->dev;
474 struct gdsc **scs = desc->scs;
475 size_t num = desc->num;
476
477 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
478 if (!data)
479 return -ENOMEM;
480
481 data->domains = devm_kcalloc(dev, num, sizeof(*data->domains),
482 GFP_KERNEL);
483 if (!data->domains)
484 return -ENOMEM;
485
486 for (i = 0; i < num; i++) {
487 if (!scs[i] || !scs[i]->supply)
488 continue;
489
490 scs[i]->rsupply = devm_regulator_get(dev, scs[i]->supply);
491 if (IS_ERR(scs[i]->rsupply))
492 return PTR_ERR(scs[i]->rsupply);
493 }
494
495 data->num_domains = num;
496 for (i = 0; i < num; i++) {
497 if (!scs[i])
498 continue;
499 scs[i]->regmap = regmap;
500 scs[i]->rcdev = rcdev;
501 ret = gdsc_init(scs[i]);
502 if (ret)
503 return ret;
504 data->domains[i] = &scs[i]->pd;
505 }
506
507 /* Add subdomains */
508 for (i = 0; i < num; i++) {
509 if (!scs[i])
510 continue;
511 if (scs[i]->parent)
512 pm_genpd_add_subdomain(scs[i]->parent, &scs[i]->pd);
513 else if (!IS_ERR_OR_NULL(dev->pm_domain))
514 pm_genpd_add_subdomain(pd_to_genpd(dev->pm_domain), &scs[i]->pd);
515 }
516
517 return of_genpd_add_provider_onecell(dev->of_node, data);
518}
519
520void gdsc_unregister(struct gdsc_desc *desc)
521{
522 int i;
523 struct device *dev = desc->dev;
524 struct gdsc **scs = desc->scs;
525 size_t num = desc->num;
526
527 /* Remove subdomains */
528 for (i = 0; i < num; i++) {
529 if (!scs[i])
530 continue;
531 if (scs[i]->parent)
532 pm_genpd_remove_subdomain(scs[i]->parent, &scs[i]->pd);
533 else if (!IS_ERR_OR_NULL(dev->pm_domain))
534 pm_genpd_remove_subdomain(pd_to_genpd(dev->pm_domain), &scs[i]->pd);
535 }
536 of_genpd_del_provider(dev->of_node);
537}
538
539/*
540 * On SDM845+ the GPU GX domain is *almost* entirely controlled by the GMU
541 * running in the CX domain so the CPU doesn't need to know anything about the
542 * GX domain EXCEPT....
543 *
544 * Hardware constraints dictate that the GX be powered down before the CX. If
545 * the GMU crashes it could leave the GX on. In order to successfully bring back
546 * the device the CPU needs to disable the GX headswitch. There being no sane
547 * way to reach in and touch that register from deep inside the GPU driver we
548 * need to set up the infrastructure to be able to ensure that the GPU can
549 * ensure that the GX is off during this super special case. We do this by
550 * defining a GX gdsc with a dummy enable function and a "default" disable
551 * function.
552 *
553 * This allows us to attach with genpd_dev_pm_attach_by_name() in the GPU
554 * driver. During power up, nothing will happen from the CPU (and the GMU will
555 * power up normally but during power down this will ensure that the GX domain
556 * is *really* off - this gives us a semi standard way of doing what we need.
557 */
558int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain)
559{
560 /* Do nothing but give genpd the impression that we were successful */
561 return 0;
562}
563EXPORT_SYMBOL_GPL(gdsc_gx_do_nothing_enable);