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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 <[email protected]>
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
25struct 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) \
45static 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}
59exynos_bus_ops_edev(enable_edev);
60exynos_bus_ops_edev(disable_edev);
61exynos_bus_ops_edev(set_event);
62
63static 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 */
93static 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
119static 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
141err:
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
151static 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
166static 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
175static 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
233err_regulator:
234 dev_pm_opp_put_regulators(bus->opp_token);
235
236 return ret;
237}
238
239static int exynos_bus_parse_of(struct exynos_bus *bus)
240{
241 struct device *dev = bus->dev;
242 struct dev_pm_opp *opp;
243 unsigned long rate;
244 int ret;
245
246 /* Get the clock to provide each bus with source clock */
247 bus->clk = devm_clk_get_enabled(dev, "bus");
248 if (IS_ERR(bus->clk))
249 return dev_err_probe(dev, PTR_ERR(bus->clk),
250 "failed to get bus clock\n");
251
252 /* Get the freq and voltage from OPP table to scale the bus freq */
253 ret = dev_pm_opp_of_add_table(dev);
254 if (ret < 0) {
255 dev_err(dev, "failed to get OPP table\n");
256 return ret;
257 }
258
259 rate = clk_get_rate(bus->clk);
260
261 opp = devfreq_recommended_opp(dev, &rate, 0);
262 if (IS_ERR(opp)) {
263 dev_err(dev, "failed to find dev_pm_opp\n");
264 ret = PTR_ERR(opp);
265 goto err_opp;
266 }
267 bus->curr_freq = dev_pm_opp_get_freq(opp);
268 dev_pm_opp_put(opp);
269
270 return 0;
271
272err_opp:
273 dev_pm_opp_of_remove_table(dev);
274
275 return ret;
276}
277
278static int exynos_bus_profile_init(struct exynos_bus *bus,
279 struct devfreq_dev_profile *profile)
280{
281 struct device *dev = bus->dev;
282 struct devfreq_simple_ondemand_data *ondemand_data;
283 int ret;
284
285 /* Initialize the struct profile and governor data for parent device */
286 profile->polling_ms = 50;
287 profile->target = exynos_bus_target;
288 profile->get_dev_status = exynos_bus_get_dev_status;
289 profile->exit = exynos_bus_exit;
290
291 ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
292 if (!ondemand_data)
293 return -ENOMEM;
294
295 ondemand_data->upthreshold = 40;
296 ondemand_data->downdifferential = 5;
297
298 /* Add devfreq device to monitor and handle the exynos bus */
299 bus->devfreq = devm_devfreq_add_device(dev, profile,
300 DEVFREQ_GOV_SIMPLE_ONDEMAND,
301 ondemand_data);
302 if (IS_ERR(bus->devfreq)) {
303 dev_err(dev, "failed to add devfreq device\n");
304 return PTR_ERR(bus->devfreq);
305 }
306
307 /* Register opp_notifier to catch the change of OPP */
308 ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
309 if (ret < 0) {
310 dev_err(dev, "failed to register opp notifier\n");
311 return ret;
312 }
313
314 /*
315 * Enable devfreq-event to get raw data which is used to determine
316 * current bus load.
317 */
318 ret = exynos_bus_enable_edev(bus);
319 if (ret < 0) {
320 dev_err(dev, "failed to enable devfreq-event devices\n");
321 return ret;
322 }
323
324 ret = exynos_bus_set_event(bus);
325 if (ret < 0) {
326 dev_err(dev, "failed to set event to devfreq-event devices\n");
327 goto err_edev;
328 }
329
330 return 0;
331
332err_edev:
333 if (exynos_bus_disable_edev(bus))
334 dev_warn(dev, "failed to disable the devfreq-event devices\n");
335
336 return ret;
337}
338
339static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
340 struct devfreq_dev_profile *profile)
341{
342 struct device *dev = bus->dev;
343 struct devfreq_passive_data *passive_data;
344 struct devfreq *parent_devfreq;
345
346 /* Initialize the struct profile and governor data for passive device */
347 profile->target = exynos_bus_target;
348 profile->exit = exynos_bus_passive_exit;
349
350 /* Get the instance of parent devfreq device */
351 parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0);
352 if (IS_ERR(parent_devfreq))
353 return -EPROBE_DEFER;
354
355 passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
356 if (!passive_data)
357 return -ENOMEM;
358
359 passive_data->parent = parent_devfreq;
360
361 /* Add devfreq device for exynos bus with passive governor */
362 bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
363 passive_data);
364 if (IS_ERR(bus->devfreq)) {
365 dev_err(dev,
366 "failed to add devfreq dev with passive governor\n");
367 return PTR_ERR(bus->devfreq);
368 }
369
370 return 0;
371}
372
373static int exynos_bus_probe(struct platform_device *pdev)
374{
375 struct device *dev = &pdev->dev;
376 struct device_node *np = dev->of_node, *node;
377 struct devfreq_dev_profile *profile;
378 struct exynos_bus *bus;
379 int ret, max_state;
380 unsigned long min_freq, max_freq;
381 bool passive = false;
382
383 if (!np) {
384 dev_err(dev, "failed to find devicetree node\n");
385 return -EINVAL;
386 }
387
388 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
389 if (!bus)
390 return -ENOMEM;
391 mutex_init(&bus->lock);
392 bus->dev = &pdev->dev;
393 platform_set_drvdata(pdev, bus);
394
395 profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
396 if (!profile)
397 return -ENOMEM;
398
399 node = of_parse_phandle(dev->of_node, "devfreq", 0);
400 if (node) {
401 of_node_put(node);
402 passive = true;
403 } else {
404 ret = exynos_bus_parent_parse_of(np, bus);
405 if (ret < 0)
406 return ret;
407 }
408
409 /* Parse the device-tree to get the resource information */
410 ret = exynos_bus_parse_of(bus);
411 if (ret < 0)
412 goto err_reg;
413
414 if (passive)
415 ret = exynos_bus_profile_init_passive(bus, profile);
416 else
417 ret = exynos_bus_profile_init(bus, profile);
418
419 if (ret < 0)
420 goto err;
421
422 /* Create child platform device for the interconnect provider */
423 if (of_property_present(dev->of_node, "#interconnect-cells")) {
424 bus->icc_pdev = platform_device_register_data(
425 dev, "exynos-generic-icc",
426 PLATFORM_DEVID_AUTO, NULL, 0);
427
428 if (IS_ERR(bus->icc_pdev)) {
429 ret = PTR_ERR(bus->icc_pdev);
430 goto err;
431 }
432 }
433
434 max_state = bus->devfreq->max_state;
435 min_freq = (bus->devfreq->freq_table[0] / 1000);
436 max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
437 pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
438 dev_name(dev), min_freq, max_freq);
439
440 return 0;
441
442err:
443 dev_pm_opp_of_remove_table(dev);
444err_reg:
445 dev_pm_opp_put_regulators(bus->opp_token);
446
447 return ret;
448}
449
450static void exynos_bus_shutdown(struct platform_device *pdev)
451{
452 struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
453
454 devfreq_suspend_device(bus->devfreq);
455}
456
457static int exynos_bus_resume(struct device *dev)
458{
459 struct exynos_bus *bus = dev_get_drvdata(dev);
460 int ret;
461
462 ret = exynos_bus_enable_edev(bus);
463 if (ret < 0) {
464 dev_err(dev, "failed to enable the devfreq-event devices\n");
465 return ret;
466 }
467
468 return 0;
469}
470
471static int exynos_bus_suspend(struct device *dev)
472{
473 struct exynos_bus *bus = dev_get_drvdata(dev);
474 int ret;
475
476 ret = exynos_bus_disable_edev(bus);
477 if (ret < 0) {
478 dev_err(dev, "failed to disable the devfreq-event devices\n");
479 return ret;
480 }
481
482 return 0;
483}
484
485static DEFINE_SIMPLE_DEV_PM_OPS(exynos_bus_pm,
486 exynos_bus_suspend, exynos_bus_resume);
487
488static const struct of_device_id exynos_bus_of_match[] = {
489 { .compatible = "samsung,exynos-bus", },
490 { /* sentinel */ },
491};
492MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
493
494static struct platform_driver exynos_bus_platdrv = {
495 .probe = exynos_bus_probe,
496 .shutdown = exynos_bus_shutdown,
497 .driver = {
498 .name = "exynos-bus",
499 .pm = pm_sleep_ptr(&exynos_bus_pm),
500 .of_match_table = exynos_bus_of_match,
501 },
502};
503module_platform_driver(exynos_bus_platdrv);
504
505MODULE_SOFTDEP("pre: exynos_ppmu");
506MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
507MODULE_AUTHOR("Chanwoo Choi <[email protected]>");
508MODULE_LICENSE("GPL v2");