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 int opp_token;
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
exynos_bus_get_event(struct exynos_bus * bus,struct devfreq_event_data * edata)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 */
exynos_bus_target(struct device * dev,unsigned long * freq,u32 flags)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
exynos_bus_get_dev_status(struct device * dev,struct devfreq_dev_status * stat)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
exynos_bus_exit(struct device * dev)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 dev_pm_opp_put_regulators(bus->opp_token);
164 }
165
exynos_bus_passive_exit(struct device * dev)166 static void exynos_bus_passive_exit(struct device *dev)
167 {
168 struct exynos_bus *bus = dev_get_drvdata(dev);
169
170 platform_device_unregister(bus->icc_pdev);
171
172 dev_pm_opp_of_remove_table(dev);
173 }
174
exynos_bus_parent_parse_of(struct device_node * np,struct exynos_bus * bus)175 static int exynos_bus_parent_parse_of(struct device_node *np,
176 struct exynos_bus *bus)
177 {
178 struct device *dev = bus->dev;
179 const char *supplies[] = { "vdd", NULL };
180 int i, ret, count, size;
181
182 ret = dev_pm_opp_set_regulators(dev, supplies);
183 if (ret < 0) {
184 dev_err(dev, "failed to set regulators %d\n", ret);
185 return ret;
186 }
187
188 bus->opp_token = ret;
189
190 /*
191 * Get the devfreq-event devices to get the current utilization of
192 * buses. This raw data will be used in devfreq ondemand governor.
193 */
194 count = devfreq_event_get_edev_count(dev, "devfreq-events");
195 if (count < 0) {
196 dev_err(dev, "failed to get the count of devfreq-event dev\n");
197 ret = count;
198 goto err_regulator;
199 }
200 bus->edev_count = count;
201
202 size = sizeof(*bus->edev) * count;
203 bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
204 if (!bus->edev) {
205 ret = -ENOMEM;
206 goto err_regulator;
207 }
208
209 for (i = 0; i < count; i++) {
210 bus->edev[i] = devfreq_event_get_edev_by_phandle(dev,
211 "devfreq-events", i);
212 if (IS_ERR(bus->edev[i])) {
213 ret = -EPROBE_DEFER;
214 goto err_regulator;
215 }
216 }
217
218 /*
219 * Optionally, Get the saturation ratio according to Exynos SoC
220 * When measuring the utilization of each AXI bus with devfreq-event
221 * devices, the measured real cycle might be much lower than the
222 * total cycle of bus during sampling rate. In result, the devfreq
223 * simple-ondemand governor might not decide to change the current
224 * frequency due to too utilization (= real cycle/total cycle).
225 * So, this property is used to adjust the utilization when calculating
226 * the busy_time in exynos_bus_get_dev_status().
227 */
228 if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
229 bus->ratio = DEFAULT_SATURATION_RATIO;
230
231 return 0;
232
233 err_regulator:
234 dev_pm_opp_put_regulators(bus->opp_token);
235
236 return ret;
237 }
238
exynos_bus_parse_of(struct device_node * np,struct exynos_bus * bus)239 static int exynos_bus_parse_of(struct device_node *np,
240 struct exynos_bus *bus)
241 {
242 struct device *dev = bus->dev;
243 struct dev_pm_opp *opp;
244 unsigned long rate;
245 int ret;
246
247 /* Get the clock to provide each bus with source clock */
248 bus->clk = devm_clk_get_enabled(dev, "bus");
249 if (IS_ERR(bus->clk))
250 return dev_err_probe(dev, PTR_ERR(bus->clk),
251 "failed to get bus clock\n");
252
253 /* Get the freq and voltage from OPP table to scale the bus freq */
254 ret = dev_pm_opp_of_add_table(dev);
255 if (ret < 0) {
256 dev_err(dev, "failed to get OPP table\n");
257 return ret;
258 }
259
260 rate = clk_get_rate(bus->clk);
261
262 opp = devfreq_recommended_opp(dev, &rate, 0);
263 if (IS_ERR(opp)) {
264 dev_err(dev, "failed to find dev_pm_opp\n");
265 ret = PTR_ERR(opp);
266 goto err_opp;
267 }
268 bus->curr_freq = dev_pm_opp_get_freq(opp);
269 dev_pm_opp_put(opp);
270
271 return 0;
272
273 err_opp:
274 dev_pm_opp_of_remove_table(dev);
275
276 return ret;
277 }
278
exynos_bus_profile_init(struct exynos_bus * bus,struct devfreq_dev_profile * profile)279 static int exynos_bus_profile_init(struct exynos_bus *bus,
280 struct devfreq_dev_profile *profile)
281 {
282 struct device *dev = bus->dev;
283 struct devfreq_simple_ondemand_data *ondemand_data;
284 int ret;
285
286 /* Initialize the struct profile and governor data for parent device */
287 profile->polling_ms = 50;
288 profile->target = exynos_bus_target;
289 profile->get_dev_status = exynos_bus_get_dev_status;
290 profile->exit = exynos_bus_exit;
291
292 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
293 if (!ondemand_data)
294 return -ENOMEM;
295
296 ondemand_data->upthreshold = 40;
297 ondemand_data->downdifferential = 5;
298
299 /* Add devfreq device to monitor and handle the exynos bus */
300 bus->devfreq = devm_devfreq_add_device(dev, profile,
301 DEVFREQ_GOV_SIMPLE_ONDEMAND,
302 ondemand_data);
303 if (IS_ERR(bus->devfreq)) {
304 dev_err(dev, "failed to add devfreq device\n");
305 return PTR_ERR(bus->devfreq);
306 }
307
308 /* Register opp_notifier to catch the change of OPP */
309 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
310 if (ret < 0) {
311 dev_err(dev, "failed to register opp notifier\n");
312 return ret;
313 }
314
315 /*
316 * Enable devfreq-event to get raw data which is used to determine
317 * current bus load.
318 */
319 ret = exynos_bus_enable_edev(bus);
320 if (ret < 0) {
321 dev_err(dev, "failed to enable devfreq-event devices\n");
322 return ret;
323 }
324
325 ret = exynos_bus_set_event(bus);
326 if (ret < 0) {
327 dev_err(dev, "failed to set event to devfreq-event devices\n");
328 goto err_edev;
329 }
330
331 return 0;
332
333 err_edev:
334 if (exynos_bus_disable_edev(bus))
335 dev_warn(dev, "failed to disable the devfreq-event devices\n");
336
337 return ret;
338 }
339
exynos_bus_profile_init_passive(struct exynos_bus * bus,struct devfreq_dev_profile * profile)340 static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
341 struct devfreq_dev_profile *profile)
342 {
343 struct device *dev = bus->dev;
344 struct devfreq_passive_data *passive_data;
345 struct devfreq *parent_devfreq;
346
347 /* Initialize the struct profile and governor data for passive device */
348 profile->target = exynos_bus_target;
349 profile->exit = exynos_bus_passive_exit;
350
351 /* Get the instance of parent devfreq device */
352 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0);
353 if (IS_ERR(parent_devfreq))
354 return -EPROBE_DEFER;
355
356 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
357 if (!passive_data)
358 return -ENOMEM;
359
360 passive_data->parent = parent_devfreq;
361
362 /* Add devfreq device for exynos bus with passive governor */
363 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
364 passive_data);
365 if (IS_ERR(bus->devfreq)) {
366 dev_err(dev,
367 "failed to add devfreq dev with passive governor\n");
368 return PTR_ERR(bus->devfreq);
369 }
370
371 return 0;
372 }
373
exynos_bus_probe(struct platform_device * pdev)374 static int exynos_bus_probe(struct platform_device *pdev)
375 {
376 struct device *dev = &pdev->dev;
377 struct device_node *np = dev->of_node, *node;
378 struct devfreq_dev_profile *profile;
379 struct exynos_bus *bus;
380 int ret, max_state;
381 unsigned long min_freq, max_freq;
382 bool passive = false;
383
384 if (!np) {
385 dev_err(dev, "failed to find devicetree node\n");
386 return -EINVAL;
387 }
388
389 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
390 if (!bus)
391 return -ENOMEM;
392 mutex_init(&bus->lock);
393 bus->dev = &pdev->dev;
394 platform_set_drvdata(pdev, bus);
395
396 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
397 if (!profile)
398 return -ENOMEM;
399
400 node = of_parse_phandle(dev->of_node, "devfreq", 0);
401 if (node) {
402 of_node_put(node);
403 passive = true;
404 } else {
405 ret = exynos_bus_parent_parse_of(np, bus);
406 if (ret < 0)
407 return ret;
408 }
409
410 /* Parse the device-tree to get the resource information */
411 ret = exynos_bus_parse_of(np, bus);
412 if (ret < 0)
413 goto err_reg;
414
415 if (passive)
416 ret = exynos_bus_profile_init_passive(bus, profile);
417 else
418 ret = exynos_bus_profile_init(bus, profile);
419
420 if (ret < 0)
421 goto err;
422
423 /* Create child platform device for the interconnect provider */
424 if (of_property_present(dev->of_node, "#interconnect-cells")) {
425 bus->icc_pdev = platform_device_register_data(
426 dev, "exynos-generic-icc",
427 PLATFORM_DEVID_AUTO, NULL, 0);
428
429 if (IS_ERR(bus->icc_pdev)) {
430 ret = PTR_ERR(bus->icc_pdev);
431 goto err;
432 }
433 }
434
435 max_state = bus->devfreq->max_state;
436 min_freq = (bus->devfreq->freq_table[0] / 1000);
437 max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
438 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
439 dev_name(dev), min_freq, max_freq);
440
441 return 0;
442
443 err:
444 dev_pm_opp_of_remove_table(dev);
445 err_reg:
446 dev_pm_opp_put_regulators(bus->opp_token);
447
448 return ret;
449 }
450
exynos_bus_shutdown(struct platform_device * pdev)451 static void exynos_bus_shutdown(struct platform_device *pdev)
452 {
453 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
454
455 devfreq_suspend_device(bus->devfreq);
456 }
457
exynos_bus_resume(struct device * dev)458 static int exynos_bus_resume(struct device *dev)
459 {
460 struct exynos_bus *bus = dev_get_drvdata(dev);
461 int ret;
462
463 ret = exynos_bus_enable_edev(bus);
464 if (ret < 0) {
465 dev_err(dev, "failed to enable the devfreq-event devices\n");
466 return ret;
467 }
468
469 return 0;
470 }
471
exynos_bus_suspend(struct device * dev)472 static int exynos_bus_suspend(struct device *dev)
473 {
474 struct exynos_bus *bus = dev_get_drvdata(dev);
475 int ret;
476
477 ret = exynos_bus_disable_edev(bus);
478 if (ret < 0) {
479 dev_err(dev, "failed to disable the devfreq-event devices\n");
480 return ret;
481 }
482
483 return 0;
484 }
485
486 static DEFINE_SIMPLE_DEV_PM_OPS(exynos_bus_pm,
487 exynos_bus_suspend, exynos_bus_resume);
488
489 static const struct of_device_id exynos_bus_of_match[] = {
490 { .compatible = "samsung,exynos-bus", },
491 { /* sentinel */ },
492 };
493 MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
494
495 static struct platform_driver exynos_bus_platdrv = {
496 .probe = exynos_bus_probe,
497 .shutdown = exynos_bus_shutdown,
498 .driver = {
499 .name = "exynos-bus",
500 .pm = pm_sleep_ptr(&exynos_bus_pm),
501 .of_match_table = exynos_bus_of_match,
502 },
503 };
504 module_platform_driver(exynos_bus_platdrv);
505
506 MODULE_SOFTDEP("pre: exynos_ppmu");
507 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
508 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
509 MODULE_LICENSE("GPL v2");
510