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1 | // SPDX-License-Identifier: GPL-2.0-only | |
2 | /* | |
3 | * Generic Exynos Bus frequency driver with DEVFREQ Framework | |
4 | * | |
5 | * Copyright (c) 2016 Samsung Electronics Co., Ltd. | |
6 | * Author : Chanwoo Choi <cw00.choi@samsung.com> | |
7 | * | |
8 | * This driver support Exynos Bus frequency feature by using | |
9 | * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c. | |
10 | */ | |
11 | ||
12 | #include <linux/clk.h> | |
13 | #include <linux/devfreq.h> | |
14 | #include <linux/devfreq-event.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/export.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/of.h> | |
19 | #include <linux/pm_opp.h> | |
20 | #include <linux/platform_device.h> | |
21 | #include <linux/regulator/consumer.h> | |
22 | ||
23 | #define DEFAULT_SATURATION_RATIO 40 | |
24 | ||
25 | struct exynos_bus { | |
26 | struct device *dev; | |
27 | struct platform_device *icc_pdev; | |
28 | ||
29 | struct devfreq *devfreq; | |
30 | struct devfreq_event_dev **edev; | |
31 | unsigned int edev_count; | |
32 | struct mutex lock; | |
33 | ||
34 | unsigned long curr_freq; | |
35 | ||
36 | struct opp_table *opp_table; | |
37 | struct clk *clk; | |
38 | unsigned int ratio; | |
39 | }; | |
40 | ||
41 | /* | |
42 | * Control the devfreq-event device to get the current state of bus | |
43 | */ | |
44 | #define exynos_bus_ops_edev(ops) \ | |
45 | static int exynos_bus_##ops(struct exynos_bus *bus) \ | |
46 | { \ | |
47 | int i, ret; \ | |
48 | \ | |
49 | for (i = 0; i < bus->edev_count; i++) { \ | |
50 | if (!bus->edev[i]) \ | |
51 | continue; \ | |
52 | ret = devfreq_event_##ops(bus->edev[i]); \ | |
53 | if (ret < 0) \ | |
54 | return ret; \ | |
55 | } \ | |
56 | \ | |
57 | return 0; \ | |
58 | } | |
59 | exynos_bus_ops_edev(enable_edev); | |
60 | exynos_bus_ops_edev(disable_edev); | |
61 | exynos_bus_ops_edev(set_event); | |
62 | ||
63 | static int exynos_bus_get_event(struct exynos_bus *bus, | |
64 | struct devfreq_event_data *edata) | |
65 | { | |
66 | struct devfreq_event_data event_data; | |
67 | unsigned long load_count = 0, total_count = 0; | |
68 | int i, ret = 0; | |
69 | ||
70 | for (i = 0; i < bus->edev_count; i++) { | |
71 | if (!bus->edev[i]) | |
72 | continue; | |
73 | ||
74 | ret = devfreq_event_get_event(bus->edev[i], &event_data); | |
75 | if (ret < 0) | |
76 | return ret; | |
77 | ||
78 | if (i == 0 || event_data.load_count > load_count) { | |
79 | load_count = event_data.load_count; | |
80 | total_count = event_data.total_count; | |
81 | } | |
82 | } | |
83 | ||
84 | edata->load_count = load_count; | |
85 | edata->total_count = total_count; | |
86 | ||
87 | return ret; | |
88 | } | |
89 | ||
90 | /* | |
91 | * devfreq function for both simple-ondemand and passive governor | |
92 | */ | |
93 | static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags) | |
94 | { | |
95 | struct exynos_bus *bus = dev_get_drvdata(dev); | |
96 | struct dev_pm_opp *new_opp; | |
97 | int ret = 0; | |
98 | ||
99 | /* Get correct frequency for bus. */ | |
100 | new_opp = devfreq_recommended_opp(dev, freq, flags); | |
101 | if (IS_ERR(new_opp)) { | |
102 | dev_err(dev, "failed to get recommended opp instance\n"); | |
103 | return PTR_ERR(new_opp); | |
104 | } | |
105 | ||
106 | dev_pm_opp_put(new_opp); | |
107 | ||
108 | /* Change voltage and frequency according to new OPP level */ | |
109 | mutex_lock(&bus->lock); | |
110 | ret = dev_pm_opp_set_rate(dev, *freq); | |
111 | if (!ret) | |
112 | bus->curr_freq = *freq; | |
113 | ||
114 | mutex_unlock(&bus->lock); | |
115 | ||
116 | return ret; | |
117 | } | |
118 | ||
119 | static int exynos_bus_get_dev_status(struct device *dev, | |
120 | struct devfreq_dev_status *stat) | |
121 | { | |
122 | struct exynos_bus *bus = dev_get_drvdata(dev); | |
123 | struct devfreq_event_data edata; | |
124 | int ret; | |
125 | ||
126 | stat->current_frequency = bus->curr_freq; | |
127 | ||
128 | ret = exynos_bus_get_event(bus, &edata); | |
129 | if (ret < 0) { | |
130 | dev_err(dev, "failed to get event from devfreq-event devices\n"); | |
131 | stat->total_time = stat->busy_time = 0; | |
132 | goto err; | |
133 | } | |
134 | ||
135 | stat->busy_time = (edata.load_count * 100) / bus->ratio; | |
136 | stat->total_time = edata.total_count; | |
137 | ||
138 | dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time, | |
139 | stat->total_time); | |
140 | ||
141 | err: | |
142 | ret = exynos_bus_set_event(bus); | |
143 | if (ret < 0) { | |
144 | dev_err(dev, "failed to set event to devfreq-event devices\n"); | |
145 | return ret; | |
146 | } | |
147 | ||
148 | return ret; | |
149 | } | |
150 | ||
151 | static void exynos_bus_exit(struct device *dev) | |
152 | { | |
153 | struct exynos_bus *bus = dev_get_drvdata(dev); | |
154 | int ret; | |
155 | ||
156 | ret = exynos_bus_disable_edev(bus); | |
157 | if (ret < 0) | |
158 | dev_warn(dev, "failed to disable the devfreq-event devices\n"); | |
159 | ||
160 | platform_device_unregister(bus->icc_pdev); | |
161 | ||
162 | dev_pm_opp_of_remove_table(dev); | |
163 | clk_disable_unprepare(bus->clk); | |
164 | dev_pm_opp_put_regulators(bus->opp_table); | |
165 | bus->opp_table = NULL; | |
166 | } | |
167 | ||
168 | static void exynos_bus_passive_exit(struct device *dev) | |
169 | { | |
170 | struct exynos_bus *bus = dev_get_drvdata(dev); | |
171 | ||
172 | platform_device_unregister(bus->icc_pdev); | |
173 | ||
174 | dev_pm_opp_of_remove_table(dev); | |
175 | clk_disable_unprepare(bus->clk); | |
176 | } | |
177 | ||
178 | static int exynos_bus_parent_parse_of(struct device_node *np, | |
179 | struct exynos_bus *bus) | |
180 | { | |
181 | struct device *dev = bus->dev; | |
182 | struct opp_table *opp_table; | |
183 | const char *vdd = "vdd"; | |
184 | int i, ret, count, size; | |
185 | ||
186 | opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1); | |
187 | if (IS_ERR(opp_table)) { | |
188 | ret = PTR_ERR(opp_table); | |
189 | dev_err(dev, "failed to set regulators %d\n", ret); | |
190 | return ret; | |
191 | } | |
192 | ||
193 | bus->opp_table = opp_table; | |
194 | ||
195 | /* | |
196 | * Get the devfreq-event devices to get the current utilization of | |
197 | * buses. This raw data will be used in devfreq ondemand governor. | |
198 | */ | |
199 | count = devfreq_event_get_edev_count(dev, "devfreq-events"); | |
200 | if (count < 0) { | |
201 | dev_err(dev, "failed to get the count of devfreq-event dev\n"); | |
202 | ret = count; | |
203 | goto err_regulator; | |
204 | } | |
205 | bus->edev_count = count; | |
206 | ||
207 | size = sizeof(*bus->edev) * count; | |
208 | bus->edev = devm_kzalloc(dev, size, GFP_KERNEL); | |
209 | if (!bus->edev) { | |
210 | ret = -ENOMEM; | |
211 | goto err_regulator; | |
212 | } | |
213 | ||
214 | for (i = 0; i < count; i++) { | |
215 | bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, | |
216 | "devfreq-events", i); | |
217 | if (IS_ERR(bus->edev[i])) { | |
218 | ret = -EPROBE_DEFER; | |
219 | goto err_regulator; | |
220 | } | |
221 | } | |
222 | ||
223 | /* | |
224 | * Optionally, Get the saturation ratio according to Exynos SoC | |
225 | * When measuring the utilization of each AXI bus with devfreq-event | |
226 | * devices, the measured real cycle might be much lower than the | |
227 | * total cycle of bus during sampling rate. In result, the devfreq | |
228 | * simple-ondemand governor might not decide to change the current | |
229 | * frequency due to too utilization (= real cycle/total cycle). | |
230 | * So, this property is used to adjust the utilization when calculating | |
231 | * the busy_time in exynos_bus_get_dev_status(). | |
232 | */ | |
233 | if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio)) | |
234 | bus->ratio = DEFAULT_SATURATION_RATIO; | |
235 | ||
236 | return 0; | |
237 | ||
238 | err_regulator: | |
239 | dev_pm_opp_put_regulators(bus->opp_table); | |
240 | bus->opp_table = NULL; | |
241 | ||
242 | return ret; | |
243 | } | |
244 | ||
245 | static int exynos_bus_parse_of(struct device_node *np, | |
246 | struct exynos_bus *bus) | |
247 | { | |
248 | struct device *dev = bus->dev; | |
249 | struct dev_pm_opp *opp; | |
250 | unsigned long rate; | |
251 | int ret; | |
252 | ||
253 | /* Get the clock to provide each bus with source clock */ | |
254 | bus->clk = devm_clk_get(dev, "bus"); | |
255 | if (IS_ERR(bus->clk)) { | |
256 | dev_err(dev, "failed to get bus clock\n"); | |
257 | return PTR_ERR(bus->clk); | |
258 | } | |
259 | ||
260 | ret = clk_prepare_enable(bus->clk); | |
261 | if (ret < 0) { | |
262 | dev_err(dev, "failed to get enable clock\n"); | |
263 | return ret; | |
264 | } | |
265 | ||
266 | /* Get the freq and voltage from OPP table to scale the bus freq */ | |
267 | ret = dev_pm_opp_of_add_table(dev); | |
268 | if (ret < 0) { | |
269 | dev_err(dev, "failed to get OPP table\n"); | |
270 | goto err_clk; | |
271 | } | |
272 | ||
273 | rate = clk_get_rate(bus->clk); | |
274 | ||
275 | opp = devfreq_recommended_opp(dev, &rate, 0); | |
276 | if (IS_ERR(opp)) { | |
277 | dev_err(dev, "failed to find dev_pm_opp\n"); | |
278 | ret = PTR_ERR(opp); | |
279 | goto err_opp; | |
280 | } | |
281 | bus->curr_freq = dev_pm_opp_get_freq(opp); | |
282 | dev_pm_opp_put(opp); | |
283 | ||
284 | return 0; | |
285 | ||
286 | err_opp: | |
287 | dev_pm_opp_of_remove_table(dev); | |
288 | err_clk: | |
289 | clk_disable_unprepare(bus->clk); | |
290 | ||
291 | return ret; | |
292 | } | |
293 | ||
294 | static int exynos_bus_profile_init(struct exynos_bus *bus, | |
295 | struct devfreq_dev_profile *profile) | |
296 | { | |
297 | struct device *dev = bus->dev; | |
298 | struct devfreq_simple_ondemand_data *ondemand_data; | |
299 | int ret; | |
300 | ||
301 | /* Initialize the struct profile and governor data for parent device */ | |
302 | profile->polling_ms = 50; | |
303 | profile->target = exynos_bus_target; | |
304 | profile->get_dev_status = exynos_bus_get_dev_status; | |
305 | profile->exit = exynos_bus_exit; | |
306 | ||
307 | ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL); | |
308 | if (!ondemand_data) | |
309 | return -ENOMEM; | |
310 | ||
311 | ondemand_data->upthreshold = 40; | |
312 | ondemand_data->downdifferential = 5; | |
313 | ||
314 | /* Add devfreq device to monitor and handle the exynos bus */ | |
315 | bus->devfreq = devm_devfreq_add_device(dev, profile, | |
316 | DEVFREQ_GOV_SIMPLE_ONDEMAND, | |
317 | ondemand_data); | |
318 | if (IS_ERR(bus->devfreq)) { | |
319 | dev_err(dev, "failed to add devfreq device\n"); | |
320 | return PTR_ERR(bus->devfreq); | |
321 | } | |
322 | ||
323 | /* Register opp_notifier to catch the change of OPP */ | |
324 | ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq); | |
325 | if (ret < 0) { | |
326 | dev_err(dev, "failed to register opp notifier\n"); | |
327 | return ret; | |
328 | } | |
329 | ||
330 | /* | |
331 | * Enable devfreq-event to get raw data which is used to determine | |
332 | * current bus load. | |
333 | */ | |
334 | ret = exynos_bus_enable_edev(bus); | |
335 | if (ret < 0) { | |
336 | dev_err(dev, "failed to enable devfreq-event devices\n"); | |
337 | return ret; | |
338 | } | |
339 | ||
340 | ret = exynos_bus_set_event(bus); | |
341 | if (ret < 0) { | |
342 | dev_err(dev, "failed to set event to devfreq-event devices\n"); | |
343 | goto err_edev; | |
344 | } | |
345 | ||
346 | return 0; | |
347 | ||
348 | err_edev: | |
349 | if (exynos_bus_disable_edev(bus)) | |
350 | dev_warn(dev, "failed to disable the devfreq-event devices\n"); | |
351 | ||
352 | return ret; | |
353 | } | |
354 | ||
355 | static int exynos_bus_profile_init_passive(struct exynos_bus *bus, | |
356 | struct devfreq_dev_profile *profile) | |
357 | { | |
358 | struct device *dev = bus->dev; | |
359 | struct devfreq_passive_data *passive_data; | |
360 | struct devfreq *parent_devfreq; | |
361 | ||
362 | /* Initialize the struct profile and governor data for passive device */ | |
363 | profile->target = exynos_bus_target; | |
364 | profile->exit = exynos_bus_passive_exit; | |
365 | ||
366 | /* Get the instance of parent devfreq device */ | |
367 | parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0); | |
368 | if (IS_ERR(parent_devfreq)) | |
369 | return -EPROBE_DEFER; | |
370 | ||
371 | passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL); | |
372 | if (!passive_data) | |
373 | return -ENOMEM; | |
374 | ||
375 | passive_data->parent = parent_devfreq; | |
376 | ||
377 | /* Add devfreq device for exynos bus with passive governor */ | |
378 | bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE, | |
379 | passive_data); | |
380 | if (IS_ERR(bus->devfreq)) { | |
381 | dev_err(dev, | |
382 | "failed to add devfreq dev with passive governor\n"); | |
383 | return PTR_ERR(bus->devfreq); | |
384 | } | |
385 | ||
386 | return 0; | |
387 | } | |
388 | ||
389 | static int exynos_bus_probe(struct platform_device *pdev) | |
390 | { | |
391 | struct device *dev = &pdev->dev; | |
392 | struct device_node *np = dev->of_node, *node; | |
393 | struct devfreq_dev_profile *profile; | |
394 | struct exynos_bus *bus; | |
395 | int ret, max_state; | |
396 | unsigned long min_freq, max_freq; | |
397 | bool passive = false; | |
398 | ||
399 | if (!np) { | |
400 | dev_err(dev, "failed to find devicetree node\n"); | |
401 | return -EINVAL; | |
402 | } | |
403 | ||
404 | bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL); | |
405 | if (!bus) | |
406 | return -ENOMEM; | |
407 | mutex_init(&bus->lock); | |
408 | bus->dev = &pdev->dev; | |
409 | platform_set_drvdata(pdev, bus); | |
410 | ||
411 | profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL); | |
412 | if (!profile) | |
413 | return -ENOMEM; | |
414 | ||
415 | node = of_parse_phandle(dev->of_node, "devfreq", 0); | |
416 | if (node) { | |
417 | of_node_put(node); | |
418 | passive = true; | |
419 | } else { | |
420 | ret = exynos_bus_parent_parse_of(np, bus); | |
421 | if (ret < 0) | |
422 | return ret; | |
423 | } | |
424 | ||
425 | /* Parse the device-tree to get the resource information */ | |
426 | ret = exynos_bus_parse_of(np, bus); | |
427 | if (ret < 0) | |
428 | goto err_reg; | |
429 | ||
430 | if (passive) | |
431 | ret = exynos_bus_profile_init_passive(bus, profile); | |
432 | else | |
433 | ret = exynos_bus_profile_init(bus, profile); | |
434 | ||
435 | if (ret < 0) | |
436 | goto err; | |
437 | ||
438 | /* Create child platform device for the interconnect provider */ | |
439 | if (of_get_property(dev->of_node, "#interconnect-cells", NULL)) { | |
440 | bus->icc_pdev = platform_device_register_data( | |
441 | dev, "exynos-generic-icc", | |
442 | PLATFORM_DEVID_AUTO, NULL, 0); | |
443 | ||
444 | if (IS_ERR(bus->icc_pdev)) { | |
445 | ret = PTR_ERR(bus->icc_pdev); | |
446 | goto err; | |
447 | } | |
448 | } | |
449 | ||
450 | max_state = bus->devfreq->profile->max_state; | |
451 | min_freq = (bus->devfreq->profile->freq_table[0] / 1000); | |
452 | max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000); | |
453 | pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n", | |
454 | dev_name(dev), min_freq, max_freq); | |
455 | ||
456 | return 0; | |
457 | ||
458 | err: | |
459 | dev_pm_opp_of_remove_table(dev); | |
460 | clk_disable_unprepare(bus->clk); | |
461 | err_reg: | |
462 | dev_pm_opp_put_regulators(bus->opp_table); | |
463 | bus->opp_table = NULL; | |
464 | ||
465 | return ret; | |
466 | } | |
467 | ||
468 | static void exynos_bus_shutdown(struct platform_device *pdev) | |
469 | { | |
470 | struct exynos_bus *bus = dev_get_drvdata(&pdev->dev); | |
471 | ||
472 | devfreq_suspend_device(bus->devfreq); | |
473 | } | |
474 | ||
475 | #ifdef CONFIG_PM_SLEEP | |
476 | static int exynos_bus_resume(struct device *dev) | |
477 | { | |
478 | struct exynos_bus *bus = dev_get_drvdata(dev); | |
479 | int ret; | |
480 | ||
481 | ret = exynos_bus_enable_edev(bus); | |
482 | if (ret < 0) { | |
483 | dev_err(dev, "failed to enable the devfreq-event devices\n"); | |
484 | return ret; | |
485 | } | |
486 | ||
487 | return 0; | |
488 | } | |
489 | ||
490 | static int exynos_bus_suspend(struct device *dev) | |
491 | { | |
492 | struct exynos_bus *bus = dev_get_drvdata(dev); | |
493 | int ret; | |
494 | ||
495 | ret = exynos_bus_disable_edev(bus); | |
496 | if (ret < 0) { | |
497 | dev_err(dev, "failed to disable the devfreq-event devices\n"); | |
498 | return ret; | |
499 | } | |
500 | ||
501 | return 0; | |
502 | } | |
503 | #endif | |
504 | ||
505 | static const struct dev_pm_ops exynos_bus_pm = { | |
506 | SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume) | |
507 | }; | |
508 | ||
509 | static const struct of_device_id exynos_bus_of_match[] = { | |
510 | { .compatible = "samsung,exynos-bus", }, | |
511 | { /* sentinel */ }, | |
512 | }; | |
513 | MODULE_DEVICE_TABLE(of, exynos_bus_of_match); | |
514 | ||
515 | static struct platform_driver exynos_bus_platdrv = { | |
516 | .probe = exynos_bus_probe, | |
517 | .shutdown = exynos_bus_shutdown, | |
518 | .driver = { | |
519 | .name = "exynos-bus", | |
520 | .pm = &exynos_bus_pm, | |
521 | .of_match_table = of_match_ptr(exynos_bus_of_match), | |
522 | }, | |
523 | }; | |
524 | module_platform_driver(exynos_bus_platdrv); | |
525 | ||
526 | MODULE_DESCRIPTION("Generic Exynos Bus frequency driver"); | |
527 | MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>"); | |
528 | MODULE_LICENSE("GPL v2"); |