xref: /openbmc/linux/drivers/devfreq/exynos-bus.c (revision ccb69e22)
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 	clk_disable_unprepare(bus->clk);
164 	dev_pm_opp_put_regulators(bus->opp_token);
165 }
166 
exynos_bus_passive_exit(struct device * dev)167 static void exynos_bus_passive_exit(struct device *dev)
168 {
169 	struct exynos_bus *bus = dev_get_drvdata(dev);
170 
171 	platform_device_unregister(bus->icc_pdev);
172 
173 	dev_pm_opp_of_remove_table(dev);
174 	clk_disable_unprepare(bus->clk);
175 }
176 
exynos_bus_parent_parse_of(struct device_node * np,struct exynos_bus * bus)177 static int exynos_bus_parent_parse_of(struct device_node *np,
178 					struct exynos_bus *bus)
179 {
180 	struct device *dev = bus->dev;
181 	const char *supplies[] = { "vdd", NULL };
182 	int i, ret, count, size;
183 
184 	ret = dev_pm_opp_set_regulators(dev, supplies);
185 	if (ret < 0) {
186 		dev_err(dev, "failed to set regulators %d\n", ret);
187 		return ret;
188 	}
189 
190 	bus->opp_token = ret;
191 
192 	/*
193 	 * Get the devfreq-event devices to get the current utilization of
194 	 * buses. This raw data will be used in devfreq ondemand governor.
195 	 */
196 	count = devfreq_event_get_edev_count(dev, "devfreq-events");
197 	if (count < 0) {
198 		dev_err(dev, "failed to get the count of devfreq-event dev\n");
199 		ret = count;
200 		goto err_regulator;
201 	}
202 	bus->edev_count = count;
203 
204 	size = sizeof(*bus->edev) * count;
205 	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
206 	if (!bus->edev) {
207 		ret = -ENOMEM;
208 		goto err_regulator;
209 	}
210 
211 	for (i = 0; i < count; i++) {
212 		bus->edev[i] = devfreq_event_get_edev_by_phandle(dev,
213 							"devfreq-events", i);
214 		if (IS_ERR(bus->edev[i])) {
215 			ret = -EPROBE_DEFER;
216 			goto err_regulator;
217 		}
218 	}
219 
220 	/*
221 	 * Optionally, Get the saturation ratio according to Exynos SoC
222 	 * When measuring the utilization of each AXI bus with devfreq-event
223 	 * devices, the measured real cycle might be much lower than the
224 	 * total cycle of bus during sampling rate. In result, the devfreq
225 	 * simple-ondemand governor might not decide to change the current
226 	 * frequency due to too utilization (= real cycle/total cycle).
227 	 * So, this property is used to adjust the utilization when calculating
228 	 * the busy_time in exynos_bus_get_dev_status().
229 	 */
230 	if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
231 		bus->ratio = DEFAULT_SATURATION_RATIO;
232 
233 	return 0;
234 
235 err_regulator:
236 	dev_pm_opp_put_regulators(bus->opp_token);
237 
238 	return ret;
239 }
240 
exynos_bus_parse_of(struct device_node * np,struct exynos_bus * bus)241 static int exynos_bus_parse_of(struct device_node *np,
242 			      struct exynos_bus *bus)
243 {
244 	struct device *dev = bus->dev;
245 	struct dev_pm_opp *opp;
246 	unsigned long rate;
247 	int ret;
248 
249 	/* Get the clock to provide each bus with source clock */
250 	bus->clk = devm_clk_get(dev, "bus");
251 	if (IS_ERR(bus->clk)) {
252 		dev_err(dev, "failed to get bus clock\n");
253 		return PTR_ERR(bus->clk);
254 	}
255 
256 	ret = clk_prepare_enable(bus->clk);
257 	if (ret < 0) {
258 		dev_err(dev, "failed to get enable clock\n");
259 		return ret;
260 	}
261 
262 	/* Get the freq and voltage from OPP table to scale the bus freq */
263 	ret = dev_pm_opp_of_add_table(dev);
264 	if (ret < 0) {
265 		dev_err(dev, "failed to get OPP table\n");
266 		goto err_clk;
267 	}
268 
269 	rate = clk_get_rate(bus->clk);
270 
271 	opp = devfreq_recommended_opp(dev, &rate, 0);
272 	if (IS_ERR(opp)) {
273 		dev_err(dev, "failed to find dev_pm_opp\n");
274 		ret = PTR_ERR(opp);
275 		goto err_opp;
276 	}
277 	bus->curr_freq = dev_pm_opp_get_freq(opp);
278 	dev_pm_opp_put(opp);
279 
280 	return 0;
281 
282 err_opp:
283 	dev_pm_opp_of_remove_table(dev);
284 err_clk:
285 	clk_disable_unprepare(bus->clk);
286 
287 	return ret;
288 }
289 
exynos_bus_profile_init(struct exynos_bus * bus,struct devfreq_dev_profile * profile)290 static int exynos_bus_profile_init(struct exynos_bus *bus,
291 				   struct devfreq_dev_profile *profile)
292 {
293 	struct device *dev = bus->dev;
294 	struct devfreq_simple_ondemand_data *ondemand_data;
295 	int ret;
296 
297 	/* Initialize the struct profile and governor data for parent device */
298 	profile->polling_ms = 50;
299 	profile->target = exynos_bus_target;
300 	profile->get_dev_status = exynos_bus_get_dev_status;
301 	profile->exit = exynos_bus_exit;
302 
303 	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
304 	if (!ondemand_data)
305 		return -ENOMEM;
306 
307 	ondemand_data->upthreshold = 40;
308 	ondemand_data->downdifferential = 5;
309 
310 	/* Add devfreq device to monitor and handle the exynos bus */
311 	bus->devfreq = devm_devfreq_add_device(dev, profile,
312 						DEVFREQ_GOV_SIMPLE_ONDEMAND,
313 						ondemand_data);
314 	if (IS_ERR(bus->devfreq)) {
315 		dev_err(dev, "failed to add devfreq device\n");
316 		return PTR_ERR(bus->devfreq);
317 	}
318 
319 	/* Register opp_notifier to catch the change of OPP  */
320 	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
321 	if (ret < 0) {
322 		dev_err(dev, "failed to register opp notifier\n");
323 		return ret;
324 	}
325 
326 	/*
327 	 * Enable devfreq-event to get raw data which is used to determine
328 	 * current bus load.
329 	 */
330 	ret = exynos_bus_enable_edev(bus);
331 	if (ret < 0) {
332 		dev_err(dev, "failed to enable devfreq-event devices\n");
333 		return ret;
334 	}
335 
336 	ret = exynos_bus_set_event(bus);
337 	if (ret < 0) {
338 		dev_err(dev, "failed to set event to devfreq-event devices\n");
339 		goto err_edev;
340 	}
341 
342 	return 0;
343 
344 err_edev:
345 	if (exynos_bus_disable_edev(bus))
346 		dev_warn(dev, "failed to disable the devfreq-event devices\n");
347 
348 	return ret;
349 }
350 
exynos_bus_profile_init_passive(struct exynos_bus * bus,struct devfreq_dev_profile * profile)351 static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
352 					   struct devfreq_dev_profile *profile)
353 {
354 	struct device *dev = bus->dev;
355 	struct devfreq_passive_data *passive_data;
356 	struct devfreq *parent_devfreq;
357 
358 	/* Initialize the struct profile and governor data for passive device */
359 	profile->target = exynos_bus_target;
360 	profile->exit = exynos_bus_passive_exit;
361 
362 	/* Get the instance of parent devfreq device */
363 	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, "devfreq", 0);
364 	if (IS_ERR(parent_devfreq))
365 		return -EPROBE_DEFER;
366 
367 	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
368 	if (!passive_data)
369 		return -ENOMEM;
370 
371 	passive_data->parent = parent_devfreq;
372 
373 	/* Add devfreq device for exynos bus with passive governor */
374 	bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
375 						passive_data);
376 	if (IS_ERR(bus->devfreq)) {
377 		dev_err(dev,
378 			"failed to add devfreq dev with passive governor\n");
379 		return PTR_ERR(bus->devfreq);
380 	}
381 
382 	return 0;
383 }
384 
exynos_bus_probe(struct platform_device * pdev)385 static int exynos_bus_probe(struct platform_device *pdev)
386 {
387 	struct device *dev = &pdev->dev;
388 	struct device_node *np = dev->of_node, *node;
389 	struct devfreq_dev_profile *profile;
390 	struct exynos_bus *bus;
391 	int ret, max_state;
392 	unsigned long min_freq, max_freq;
393 	bool passive = false;
394 
395 	if (!np) {
396 		dev_err(dev, "failed to find devicetree node\n");
397 		return -EINVAL;
398 	}
399 
400 	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
401 	if (!bus)
402 		return -ENOMEM;
403 	mutex_init(&bus->lock);
404 	bus->dev = &pdev->dev;
405 	platform_set_drvdata(pdev, bus);
406 
407 	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
408 	if (!profile)
409 		return -ENOMEM;
410 
411 	node = of_parse_phandle(dev->of_node, "devfreq", 0);
412 	if (node) {
413 		of_node_put(node);
414 		passive = true;
415 	} else {
416 		ret = exynos_bus_parent_parse_of(np, bus);
417 		if (ret < 0)
418 			return ret;
419 	}
420 
421 	/* Parse the device-tree to get the resource information */
422 	ret = exynos_bus_parse_of(np, bus);
423 	if (ret < 0)
424 		goto err_reg;
425 
426 	if (passive)
427 		ret = exynos_bus_profile_init_passive(bus, profile);
428 	else
429 		ret = exynos_bus_profile_init(bus, profile);
430 
431 	if (ret < 0)
432 		goto err;
433 
434 	/* Create child platform device for the interconnect provider */
435 	if (of_property_present(dev->of_node, "#interconnect-cells")) {
436 		bus->icc_pdev = platform_device_register_data(
437 						dev, "exynos-generic-icc",
438 						PLATFORM_DEVID_AUTO, NULL, 0);
439 
440 		if (IS_ERR(bus->icc_pdev)) {
441 			ret = PTR_ERR(bus->icc_pdev);
442 			goto err;
443 		}
444 	}
445 
446 	max_state = bus->devfreq->max_state;
447 	min_freq = (bus->devfreq->freq_table[0] / 1000);
448 	max_freq = (bus->devfreq->freq_table[max_state - 1] / 1000);
449 	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
450 			dev_name(dev), min_freq, max_freq);
451 
452 	return 0;
453 
454 err:
455 	dev_pm_opp_of_remove_table(dev);
456 	clk_disable_unprepare(bus->clk);
457 err_reg:
458 	dev_pm_opp_put_regulators(bus->opp_token);
459 
460 	return ret;
461 }
462 
exynos_bus_shutdown(struct platform_device * pdev)463 static void exynos_bus_shutdown(struct platform_device *pdev)
464 {
465 	struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
466 
467 	devfreq_suspend_device(bus->devfreq);
468 }
469 
470 #ifdef CONFIG_PM_SLEEP
exynos_bus_resume(struct device * dev)471 static int exynos_bus_resume(struct device *dev)
472 {
473 	struct exynos_bus *bus = dev_get_drvdata(dev);
474 	int ret;
475 
476 	ret = exynos_bus_enable_edev(bus);
477 	if (ret < 0) {
478 		dev_err(dev, "failed to enable the devfreq-event devices\n");
479 		return ret;
480 	}
481 
482 	return 0;
483 }
484 
exynos_bus_suspend(struct device * dev)485 static int exynos_bus_suspend(struct device *dev)
486 {
487 	struct exynos_bus *bus = dev_get_drvdata(dev);
488 	int ret;
489 
490 	ret = exynos_bus_disable_edev(bus);
491 	if (ret < 0) {
492 		dev_err(dev, "failed to disable the devfreq-event devices\n");
493 		return ret;
494 	}
495 
496 	return 0;
497 }
498 #endif
499 
500 static const struct dev_pm_ops exynos_bus_pm = {
501 	SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
502 };
503 
504 static const struct of_device_id exynos_bus_of_match[] = {
505 	{ .compatible = "samsung,exynos-bus", },
506 	{ /* sentinel */ },
507 };
508 MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
509 
510 static struct platform_driver exynos_bus_platdrv = {
511 	.probe		= exynos_bus_probe,
512 	.shutdown	= exynos_bus_shutdown,
513 	.driver = {
514 		.name	= "exynos-bus",
515 		.pm	= &exynos_bus_pm,
516 		.of_match_table = exynos_bus_of_match,
517 	},
518 };
519 module_platform_driver(exynos_bus_platdrv);
520 
521 MODULE_SOFTDEP("pre: exynos_ppmu");
522 MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
523 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
524 MODULE_LICENSE("GPL v2");
525