1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * A devfreq driver for NVIDIA Tegra SoCs
4  *
5  * Copyright (c) 2014 NVIDIA CORPORATION. All rights reserved.
6  * Copyright (C) 2014 Google, Inc
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/cpufreq.h>
11 #include <linux/devfreq.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/irq.h>
15 #include <linux/module.h>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/pm_opp.h>
19 #include <linux/reset.h>
20 #include <linux/workqueue.h>
21 
22 #include <soc/tegra/fuse.h>
23 
24 #include "governor.h"
25 
26 #define ACTMON_GLB_STATUS					0x0
27 #define ACTMON_GLB_PERIOD_CTRL					0x4
28 
29 #define ACTMON_DEV_CTRL						0x0
30 #define ACTMON_DEV_CTRL_K_VAL_SHIFT				10
31 #define ACTMON_DEV_CTRL_ENB_PERIODIC				BIT(18)
32 #define ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN			BIT(20)
33 #define ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN			BIT(21)
34 #define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT	23
35 #define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT	26
36 #define ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN		BIT(29)
37 #define ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN		BIT(30)
38 #define ACTMON_DEV_CTRL_ENB					BIT(31)
39 
40 #define ACTMON_DEV_CTRL_STOP					0x00000000
41 
42 #define ACTMON_DEV_UPPER_WMARK					0x4
43 #define ACTMON_DEV_LOWER_WMARK					0x8
44 #define ACTMON_DEV_INIT_AVG					0xc
45 #define ACTMON_DEV_AVG_UPPER_WMARK				0x10
46 #define ACTMON_DEV_AVG_LOWER_WMARK				0x14
47 #define ACTMON_DEV_COUNT_WEIGHT					0x18
48 #define ACTMON_DEV_AVG_COUNT					0x20
49 #define ACTMON_DEV_INTR_STATUS					0x24
50 
51 #define ACTMON_INTR_STATUS_CLEAR				0xffffffff
52 
53 #define ACTMON_DEV_INTR_CONSECUTIVE_UPPER			BIT(31)
54 #define ACTMON_DEV_INTR_CONSECUTIVE_LOWER			BIT(30)
55 
56 #define ACTMON_ABOVE_WMARK_WINDOW				1
57 #define ACTMON_BELOW_WMARK_WINDOW				3
58 #define ACTMON_BOOST_FREQ_STEP					16000
59 
60 /*
61  * ACTMON_AVERAGE_WINDOW_LOG2: default value for @DEV_CTRL_K_VAL, which
62  * translates to 2 ^ (K_VAL + 1). ex: 2 ^ (6 + 1) = 128
63  */
64 #define ACTMON_AVERAGE_WINDOW_LOG2			6
65 #define ACTMON_SAMPLING_PERIOD				12 /* ms */
66 #define ACTMON_DEFAULT_AVG_BAND				6  /* 1/10 of % */
67 
68 #define KHZ							1000
69 
70 #define KHZ_MAX						(ULONG_MAX / KHZ)
71 
72 /* Assume that the bus is saturated if the utilization is 25% */
73 #define BUS_SATURATION_RATIO					25
74 
75 /**
76  * struct tegra_devfreq_device_config - configuration specific to an ACTMON
77  * device
78  *
79  * Coefficients and thresholds are percentages unless otherwise noted
80  */
81 struct tegra_devfreq_device_config {
82 	u32		offset;
83 	u32		irq_mask;
84 
85 	/* Factors applied to boost_freq every consecutive watermark breach */
86 	unsigned int	boost_up_coeff;
87 	unsigned int	boost_down_coeff;
88 
89 	/* Define the watermark bounds when applied to the current avg */
90 	unsigned int	boost_up_threshold;
91 	unsigned int	boost_down_threshold;
92 
93 	/*
94 	 * Threshold of activity (cycles translated to kHz) below which the
95 	 * CPU frequency isn't to be taken into account. This is to avoid
96 	 * increasing the EMC frequency when the CPU is very busy but not
97 	 * accessing the bus often.
98 	 */
99 	u32		avg_dependency_threshold;
100 };
101 
102 enum tegra_actmon_device {
103 	MCALL = 0,
104 	MCCPU,
105 };
106 
107 static const struct tegra_devfreq_device_config tegra124_device_configs[] = {
108 	{
109 		/* MCALL: All memory accesses (including from the CPUs) */
110 		.offset = 0x1c0,
111 		.irq_mask = 1 << 26,
112 		.boost_up_coeff = 200,
113 		.boost_down_coeff = 50,
114 		.boost_up_threshold = 60,
115 		.boost_down_threshold = 40,
116 	},
117 	{
118 		/* MCCPU: memory accesses from the CPUs */
119 		.offset = 0x200,
120 		.irq_mask = 1 << 25,
121 		.boost_up_coeff = 800,
122 		.boost_down_coeff = 40,
123 		.boost_up_threshold = 27,
124 		.boost_down_threshold = 10,
125 		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
126 	},
127 };
128 
129 static const struct tegra_devfreq_device_config tegra30_device_configs[] = {
130 	{
131 		/* MCALL: All memory accesses (including from the CPUs) */
132 		.offset = 0x1c0,
133 		.irq_mask = 1 << 26,
134 		.boost_up_coeff = 200,
135 		.boost_down_coeff = 50,
136 		.boost_up_threshold = 20,
137 		.boost_down_threshold = 10,
138 	},
139 	{
140 		/* MCCPU: memory accesses from the CPUs */
141 		.offset = 0x200,
142 		.irq_mask = 1 << 25,
143 		.boost_up_coeff = 800,
144 		.boost_down_coeff = 40,
145 		.boost_up_threshold = 27,
146 		.boost_down_threshold = 10,
147 		.avg_dependency_threshold = 16000, /* 16MHz in kHz units */
148 	},
149 };
150 
151 /**
152  * struct tegra_devfreq_device - state specific to an ACTMON device
153  *
154  * Frequencies are in kHz.
155  */
156 struct tegra_devfreq_device {
157 	const struct tegra_devfreq_device_config *config;
158 	void __iomem *regs;
159 
160 	/* Average event count sampled in the last interrupt */
161 	u32 avg_count;
162 
163 	/*
164 	 * Extra frequency to increase the target by due to consecutive
165 	 * watermark breaches.
166 	 */
167 	unsigned long boost_freq;
168 
169 	/* Optimal frequency calculated from the stats for this device */
170 	unsigned long target_freq;
171 };
172 
173 struct tegra_devfreq_soc_data {
174 	const struct tegra_devfreq_device_config *configs;
175 	/* Weight value for count measurements */
176 	unsigned int count_weight;
177 };
178 
179 struct tegra_devfreq {
180 	struct devfreq		*devfreq;
181 	struct opp_table	*opp_table;
182 
183 	struct reset_control	*reset;
184 	struct clk		*clock;
185 	void __iomem		*regs;
186 
187 	struct clk		*emc_clock;
188 	unsigned long		max_freq;
189 	unsigned long		cur_freq;
190 	struct notifier_block	clk_rate_change_nb;
191 
192 	struct delayed_work	cpufreq_update_work;
193 	struct notifier_block	cpu_rate_change_nb;
194 
195 	struct tegra_devfreq_device devices[2];
196 
197 	unsigned int		irq;
198 
199 	bool			started;
200 
201 	const struct tegra_devfreq_soc_data *soc;
202 };
203 
204 struct tegra_actmon_emc_ratio {
205 	unsigned long cpu_freq;
206 	unsigned long emc_freq;
207 };
208 
209 static const struct tegra_actmon_emc_ratio actmon_emc_ratios[] = {
210 	{ 1400000,    KHZ_MAX },
211 	{ 1200000,    750000 },
212 	{ 1100000,    600000 },
213 	{ 1000000,    500000 },
214 	{  800000,    375000 },
215 	{  500000,    200000 },
216 	{  250000,    100000 },
217 };
218 
219 static u32 actmon_readl(struct tegra_devfreq *tegra, u32 offset)
220 {
221 	return readl_relaxed(tegra->regs + offset);
222 }
223 
224 static void actmon_writel(struct tegra_devfreq *tegra, u32 val, u32 offset)
225 {
226 	writel_relaxed(val, tegra->regs + offset);
227 }
228 
229 static u32 device_readl(struct tegra_devfreq_device *dev, u32 offset)
230 {
231 	return readl_relaxed(dev->regs + offset);
232 }
233 
234 static void device_writel(struct tegra_devfreq_device *dev, u32 val,
235 			  u32 offset)
236 {
237 	writel_relaxed(val, dev->regs + offset);
238 }
239 
240 static unsigned long do_percent(unsigned long long val, unsigned int pct)
241 {
242 	val = val * pct;
243 	do_div(val, 100);
244 
245 	/*
246 	 * High freq + high boosting percent + large polling interval are
247 	 * resulting in integer overflow when watermarks are calculated.
248 	 */
249 	return min_t(u64, val, U32_MAX);
250 }
251 
252 static void tegra_devfreq_update_avg_wmark(struct tegra_devfreq *tegra,
253 					   struct tegra_devfreq_device *dev)
254 {
255 	u32 avg_band_freq = tegra->max_freq * ACTMON_DEFAULT_AVG_BAND / KHZ;
256 	u32 band = avg_band_freq * tegra->devfreq->profile->polling_ms;
257 	u32 avg;
258 
259 	avg = min(dev->avg_count, U32_MAX - band);
260 	device_writel(dev, avg + band, ACTMON_DEV_AVG_UPPER_WMARK);
261 
262 	avg = max(dev->avg_count, band);
263 	device_writel(dev, avg - band, ACTMON_DEV_AVG_LOWER_WMARK);
264 }
265 
266 static void tegra_devfreq_update_wmark(struct tegra_devfreq *tegra,
267 				       struct tegra_devfreq_device *dev)
268 {
269 	u32 val = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
270 
271 	device_writel(dev, do_percent(val, dev->config->boost_up_threshold),
272 		      ACTMON_DEV_UPPER_WMARK);
273 
274 	device_writel(dev, do_percent(val, dev->config->boost_down_threshold),
275 		      ACTMON_DEV_LOWER_WMARK);
276 }
277 
278 static void actmon_isr_device(struct tegra_devfreq *tegra,
279 			      struct tegra_devfreq_device *dev)
280 {
281 	u32 intr_status, dev_ctrl;
282 
283 	dev->avg_count = device_readl(dev, ACTMON_DEV_AVG_COUNT);
284 	tegra_devfreq_update_avg_wmark(tegra, dev);
285 
286 	intr_status = device_readl(dev, ACTMON_DEV_INTR_STATUS);
287 	dev_ctrl = device_readl(dev, ACTMON_DEV_CTRL);
288 
289 	if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_UPPER) {
290 		/*
291 		 * new_boost = min(old_boost * up_coef + step, max_freq)
292 		 */
293 		dev->boost_freq = do_percent(dev->boost_freq,
294 					     dev->config->boost_up_coeff);
295 		dev->boost_freq += ACTMON_BOOST_FREQ_STEP;
296 
297 		dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
298 
299 		if (dev->boost_freq >= tegra->max_freq) {
300 			dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
301 			dev->boost_freq = tegra->max_freq;
302 		}
303 	} else if (intr_status & ACTMON_DEV_INTR_CONSECUTIVE_LOWER) {
304 		/*
305 		 * new_boost = old_boost * down_coef
306 		 * or 0 if (old_boost * down_coef < step / 2)
307 		 */
308 		dev->boost_freq = do_percent(dev->boost_freq,
309 					     dev->config->boost_down_coeff);
310 
311 		dev_ctrl |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
312 
313 		if (dev->boost_freq < (ACTMON_BOOST_FREQ_STEP >> 1)) {
314 			dev_ctrl &= ~ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_EN;
315 			dev->boost_freq = 0;
316 		}
317 	}
318 
319 	device_writel(dev, dev_ctrl, ACTMON_DEV_CTRL);
320 
321 	device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
322 }
323 
324 static unsigned long actmon_cpu_to_emc_rate(struct tegra_devfreq *tegra,
325 					    unsigned long cpu_freq)
326 {
327 	unsigned int i;
328 	const struct tegra_actmon_emc_ratio *ratio = actmon_emc_ratios;
329 
330 	for (i = 0; i < ARRAY_SIZE(actmon_emc_ratios); i++, ratio++) {
331 		if (cpu_freq >= ratio->cpu_freq) {
332 			if (ratio->emc_freq >= tegra->max_freq)
333 				return tegra->max_freq;
334 			else
335 				return ratio->emc_freq;
336 		}
337 	}
338 
339 	return 0;
340 }
341 
342 static unsigned long actmon_device_target_freq(struct tegra_devfreq *tegra,
343 					       struct tegra_devfreq_device *dev)
344 {
345 	unsigned int avg_sustain_coef;
346 	unsigned long target_freq;
347 
348 	target_freq = dev->avg_count / tegra->devfreq->profile->polling_ms;
349 	avg_sustain_coef = 100 * 100 / dev->config->boost_up_threshold;
350 	target_freq = do_percent(target_freq, avg_sustain_coef);
351 
352 	return target_freq;
353 }
354 
355 static void actmon_update_target(struct tegra_devfreq *tegra,
356 				 struct tegra_devfreq_device *dev)
357 {
358 	unsigned long cpu_freq = 0;
359 	unsigned long static_cpu_emc_freq = 0;
360 
361 	dev->target_freq = actmon_device_target_freq(tegra, dev);
362 
363 	if (dev->config->avg_dependency_threshold &&
364 	    dev->config->avg_dependency_threshold <= dev->target_freq) {
365 		cpu_freq = cpufreq_quick_get(0);
366 		static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
367 
368 		dev->target_freq += dev->boost_freq;
369 		dev->target_freq = max(dev->target_freq, static_cpu_emc_freq);
370 	} else {
371 		dev->target_freq += dev->boost_freq;
372 	}
373 }
374 
375 static irqreturn_t actmon_thread_isr(int irq, void *data)
376 {
377 	struct tegra_devfreq *tegra = data;
378 	bool handled = false;
379 	unsigned int i;
380 	u32 val;
381 
382 	mutex_lock(&tegra->devfreq->lock);
383 
384 	val = actmon_readl(tegra, ACTMON_GLB_STATUS);
385 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
386 		if (val & tegra->devices[i].config->irq_mask) {
387 			actmon_isr_device(tegra, tegra->devices + i);
388 			handled = true;
389 		}
390 	}
391 
392 	if (handled)
393 		update_devfreq(tegra->devfreq);
394 
395 	mutex_unlock(&tegra->devfreq->lock);
396 
397 	return handled ? IRQ_HANDLED : IRQ_NONE;
398 }
399 
400 static int tegra_actmon_clk_notify_cb(struct notifier_block *nb,
401 				      unsigned long action, void *ptr)
402 {
403 	struct clk_notifier_data *data = ptr;
404 	struct tegra_devfreq *tegra;
405 	struct tegra_devfreq_device *dev;
406 	unsigned int i;
407 
408 	if (action != POST_RATE_CHANGE)
409 		return NOTIFY_OK;
410 
411 	tegra = container_of(nb, struct tegra_devfreq, clk_rate_change_nb);
412 
413 	tegra->cur_freq = data->new_rate / KHZ;
414 
415 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
416 		dev = &tegra->devices[i];
417 
418 		tegra_devfreq_update_wmark(tegra, dev);
419 	}
420 
421 	return NOTIFY_OK;
422 }
423 
424 static void tegra_actmon_delayed_update(struct work_struct *work)
425 {
426 	struct tegra_devfreq *tegra = container_of(work, struct tegra_devfreq,
427 						   cpufreq_update_work.work);
428 
429 	mutex_lock(&tegra->devfreq->lock);
430 	update_devfreq(tegra->devfreq);
431 	mutex_unlock(&tegra->devfreq->lock);
432 }
433 
434 static unsigned long
435 tegra_actmon_cpufreq_contribution(struct tegra_devfreq *tegra,
436 				  unsigned int cpu_freq)
437 {
438 	struct tegra_devfreq_device *actmon_dev = &tegra->devices[MCCPU];
439 	unsigned long static_cpu_emc_freq, dev_freq;
440 
441 	dev_freq = actmon_device_target_freq(tegra, actmon_dev);
442 
443 	/* check whether CPU's freq is taken into account at all */
444 	if (dev_freq < actmon_dev->config->avg_dependency_threshold)
445 		return 0;
446 
447 	static_cpu_emc_freq = actmon_cpu_to_emc_rate(tegra, cpu_freq);
448 
449 	if (dev_freq + actmon_dev->boost_freq >= static_cpu_emc_freq)
450 		return 0;
451 
452 	return static_cpu_emc_freq;
453 }
454 
455 static int tegra_actmon_cpu_notify_cb(struct notifier_block *nb,
456 				      unsigned long action, void *ptr)
457 {
458 	struct cpufreq_freqs *freqs = ptr;
459 	struct tegra_devfreq *tegra;
460 	unsigned long old, new, delay;
461 
462 	if (action != CPUFREQ_POSTCHANGE)
463 		return NOTIFY_OK;
464 
465 	tegra = container_of(nb, struct tegra_devfreq, cpu_rate_change_nb);
466 
467 	/*
468 	 * Quickly check whether CPU frequency should be taken into account
469 	 * at all, without blocking CPUFreq's core.
470 	 */
471 	if (mutex_trylock(&tegra->devfreq->lock)) {
472 		old = tegra_actmon_cpufreq_contribution(tegra, freqs->old);
473 		new = tegra_actmon_cpufreq_contribution(tegra, freqs->new);
474 		mutex_unlock(&tegra->devfreq->lock);
475 
476 		/*
477 		 * If CPU's frequency shouldn't be taken into account at
478 		 * the moment, then there is no need to update the devfreq's
479 		 * state because ISR will re-check CPU's frequency on the
480 		 * next interrupt.
481 		 */
482 		if (old == new)
483 			return NOTIFY_OK;
484 	}
485 
486 	/*
487 	 * CPUFreq driver should support CPUFREQ_ASYNC_NOTIFICATION in order
488 	 * to allow asynchronous notifications. This means we can't block
489 	 * here for too long, otherwise CPUFreq's core will complain with a
490 	 * warning splat.
491 	 */
492 	delay = msecs_to_jiffies(ACTMON_SAMPLING_PERIOD);
493 	schedule_delayed_work(&tegra->cpufreq_update_work, delay);
494 
495 	return NOTIFY_OK;
496 }
497 
498 static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
499 					  struct tegra_devfreq_device *dev)
500 {
501 	u32 val = 0;
502 
503 	/* reset boosting on governor's restart */
504 	dev->boost_freq = 0;
505 
506 	dev->target_freq = tegra->cur_freq;
507 
508 	dev->avg_count = tegra->cur_freq * tegra->devfreq->profile->polling_ms;
509 	device_writel(dev, dev->avg_count, ACTMON_DEV_INIT_AVG);
510 
511 	tegra_devfreq_update_avg_wmark(tegra, dev);
512 	tegra_devfreq_update_wmark(tegra, dev);
513 
514 	device_writel(dev, tegra->soc->count_weight, ACTMON_DEV_COUNT_WEIGHT);
515 	device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
516 
517 	val |= ACTMON_DEV_CTRL_ENB_PERIODIC;
518 	val |= (ACTMON_AVERAGE_WINDOW_LOG2 - 1)
519 		<< ACTMON_DEV_CTRL_K_VAL_SHIFT;
520 	val |= (ACTMON_BELOW_WMARK_WINDOW - 1)
521 		<< ACTMON_DEV_CTRL_CONSECUTIVE_BELOW_WMARK_NUM_SHIFT;
522 	val |= (ACTMON_ABOVE_WMARK_WINDOW - 1)
523 		<< ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_NUM_SHIFT;
524 	val |= ACTMON_DEV_CTRL_AVG_ABOVE_WMARK_EN;
525 	val |= ACTMON_DEV_CTRL_AVG_BELOW_WMARK_EN;
526 	val |= ACTMON_DEV_CTRL_CONSECUTIVE_ABOVE_WMARK_EN;
527 	val |= ACTMON_DEV_CTRL_ENB;
528 
529 	device_writel(dev, val, ACTMON_DEV_CTRL);
530 }
531 
532 static void tegra_actmon_stop_devices(struct tegra_devfreq *tegra)
533 {
534 	struct tegra_devfreq_device *dev = tegra->devices;
535 	unsigned int i;
536 
537 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++, dev++) {
538 		device_writel(dev, ACTMON_DEV_CTRL_STOP, ACTMON_DEV_CTRL);
539 		device_writel(dev, ACTMON_INTR_STATUS_CLEAR,
540 			      ACTMON_DEV_INTR_STATUS);
541 	}
542 }
543 
544 static int tegra_actmon_resume(struct tegra_devfreq *tegra)
545 {
546 	unsigned int i;
547 	int err;
548 
549 	if (!tegra->devfreq->profile->polling_ms || !tegra->started)
550 		return 0;
551 
552 	actmon_writel(tegra, tegra->devfreq->profile->polling_ms - 1,
553 		      ACTMON_GLB_PERIOD_CTRL);
554 
555 	/*
556 	 * CLK notifications are needed in order to reconfigure the upper
557 	 * consecutive watermark in accordance to the actual clock rate
558 	 * to avoid unnecessary upper interrupts.
559 	 */
560 	err = clk_notifier_register(tegra->emc_clock,
561 				    &tegra->clk_rate_change_nb);
562 	if (err) {
563 		dev_err(tegra->devfreq->dev.parent,
564 			"Failed to register rate change notifier\n");
565 		return err;
566 	}
567 
568 	tegra->cur_freq = clk_get_rate(tegra->emc_clock) / KHZ;
569 
570 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
571 		tegra_actmon_configure_device(tegra, &tegra->devices[i]);
572 
573 	/*
574 	 * We are estimating CPU's memory bandwidth requirement based on
575 	 * amount of memory accesses and system's load, judging by CPU's
576 	 * frequency. We also don't want to receive events about CPU's
577 	 * frequency transaction when governor is stopped, hence notifier
578 	 * is registered dynamically.
579 	 */
580 	err = cpufreq_register_notifier(&tegra->cpu_rate_change_nb,
581 					CPUFREQ_TRANSITION_NOTIFIER);
582 	if (err) {
583 		dev_err(tegra->devfreq->dev.parent,
584 			"Failed to register rate change notifier: %d\n", err);
585 		goto err_stop;
586 	}
587 
588 	enable_irq(tegra->irq);
589 
590 	return 0;
591 
592 err_stop:
593 	tegra_actmon_stop_devices(tegra);
594 
595 	clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
596 
597 	return err;
598 }
599 
600 static int tegra_actmon_start(struct tegra_devfreq *tegra)
601 {
602 	int ret = 0;
603 
604 	if (!tegra->started) {
605 		tegra->started = true;
606 
607 		ret = tegra_actmon_resume(tegra);
608 		if (ret)
609 			tegra->started = false;
610 	}
611 
612 	return ret;
613 }
614 
615 static void tegra_actmon_pause(struct tegra_devfreq *tegra)
616 {
617 	if (!tegra->devfreq->profile->polling_ms || !tegra->started)
618 		return;
619 
620 	disable_irq(tegra->irq);
621 
622 	cpufreq_unregister_notifier(&tegra->cpu_rate_change_nb,
623 				    CPUFREQ_TRANSITION_NOTIFIER);
624 
625 	cancel_delayed_work_sync(&tegra->cpufreq_update_work);
626 
627 	tegra_actmon_stop_devices(tegra);
628 
629 	clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
630 }
631 
632 static void tegra_actmon_stop(struct tegra_devfreq *tegra)
633 {
634 	tegra_actmon_pause(tegra);
635 	tegra->started = false;
636 }
637 
638 static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
639 				u32 flags)
640 {
641 	struct dev_pm_opp *opp;
642 	int ret;
643 
644 	opp = devfreq_recommended_opp(dev, freq, flags);
645 	if (IS_ERR(opp)) {
646 		dev_err(dev, "Failed to find opp for %lu Hz\n", *freq);
647 		return PTR_ERR(opp);
648 	}
649 
650 	ret = dev_pm_opp_set_opp(dev, opp);
651 	dev_pm_opp_put(opp);
652 
653 	return ret;
654 }
655 
656 static int tegra_devfreq_get_dev_status(struct device *dev,
657 					struct devfreq_dev_status *stat)
658 {
659 	struct tegra_devfreq *tegra = dev_get_drvdata(dev);
660 	struct tegra_devfreq_device *actmon_dev;
661 	unsigned long cur_freq;
662 
663 	cur_freq = READ_ONCE(tegra->cur_freq);
664 
665 	/* To be used by the tegra governor */
666 	stat->private_data = tegra;
667 
668 	/* The below are to be used by the other governors */
669 	stat->current_frequency = cur_freq * KHZ;
670 
671 	actmon_dev = &tegra->devices[MCALL];
672 
673 	/* Number of cycles spent on memory access */
674 	stat->busy_time = device_readl(actmon_dev, ACTMON_DEV_AVG_COUNT);
675 
676 	/* The bus can be considered to be saturated way before 100% */
677 	stat->busy_time *= 100 / BUS_SATURATION_RATIO;
678 
679 	/* Number of cycles in a sampling period */
680 	stat->total_time = tegra->devfreq->profile->polling_ms * cur_freq;
681 
682 	stat->busy_time = min(stat->busy_time, stat->total_time);
683 
684 	return 0;
685 }
686 
687 static struct devfreq_dev_profile tegra_devfreq_profile = {
688 	.polling_ms	= ACTMON_SAMPLING_PERIOD,
689 	.target		= tegra_devfreq_target,
690 	.get_dev_status	= tegra_devfreq_get_dev_status,
691 };
692 
693 static int tegra_governor_get_target(struct devfreq *devfreq,
694 				     unsigned long *freq)
695 {
696 	struct devfreq_dev_status *stat;
697 	struct tegra_devfreq *tegra;
698 	struct tegra_devfreq_device *dev;
699 	unsigned long target_freq = 0;
700 	unsigned int i;
701 	int err;
702 
703 	err = devfreq_update_stats(devfreq);
704 	if (err)
705 		return err;
706 
707 	stat = &devfreq->last_status;
708 
709 	tegra = stat->private_data;
710 
711 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
712 		dev = &tegra->devices[i];
713 
714 		actmon_update_target(tegra, dev);
715 
716 		target_freq = max(target_freq, dev->target_freq);
717 	}
718 
719 	/*
720 	 * tegra-devfreq driver operates with KHz units, while OPP table
721 	 * entries use Hz units. Hence we need to convert the units for the
722 	 * devfreq core.
723 	 */
724 	*freq = target_freq * KHZ;
725 
726 	return 0;
727 }
728 
729 static int tegra_governor_event_handler(struct devfreq *devfreq,
730 					unsigned int event, void *data)
731 {
732 	struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
733 	unsigned int *new_delay = data;
734 	int ret = 0;
735 
736 	/*
737 	 * Couple devfreq-device with the governor early because it is
738 	 * needed at the moment of governor's start (used by ISR).
739 	 */
740 	tegra->devfreq = devfreq;
741 
742 	switch (event) {
743 	case DEVFREQ_GOV_START:
744 		devfreq_monitor_start(devfreq);
745 		ret = tegra_actmon_start(tegra);
746 		break;
747 
748 	case DEVFREQ_GOV_STOP:
749 		tegra_actmon_stop(tegra);
750 		devfreq_monitor_stop(devfreq);
751 		break;
752 
753 	case DEVFREQ_GOV_UPDATE_INTERVAL:
754 		/*
755 		 * ACTMON hardware supports up to 256 milliseconds for the
756 		 * sampling period.
757 		 */
758 		if (*new_delay > 256) {
759 			ret = -EINVAL;
760 			break;
761 		}
762 
763 		tegra_actmon_pause(tegra);
764 		devfreq_update_interval(devfreq, new_delay);
765 		ret = tegra_actmon_resume(tegra);
766 		break;
767 
768 	case DEVFREQ_GOV_SUSPEND:
769 		tegra_actmon_stop(tegra);
770 		devfreq_monitor_suspend(devfreq);
771 		break;
772 
773 	case DEVFREQ_GOV_RESUME:
774 		devfreq_monitor_resume(devfreq);
775 		ret = tegra_actmon_start(tegra);
776 		break;
777 	}
778 
779 	return ret;
780 }
781 
782 static struct devfreq_governor tegra_devfreq_governor = {
783 	.name = "tegra_actmon",
784 	.attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL,
785 	.flags = DEVFREQ_GOV_FLAG_IMMUTABLE
786 		| DEVFREQ_GOV_FLAG_IRQ_DRIVEN,
787 	.get_target_freq = tegra_governor_get_target,
788 	.event_handler = tegra_governor_event_handler,
789 };
790 
791 static int tegra_devfreq_probe(struct platform_device *pdev)
792 {
793 	u32 hw_version = BIT(tegra_sku_info.soc_speedo_id);
794 	struct tegra_devfreq_device *dev;
795 	struct tegra_devfreq *tegra;
796 	struct devfreq *devfreq;
797 	unsigned int i;
798 	long rate;
799 	int err;
800 
801 	tegra = devm_kzalloc(&pdev->dev, sizeof(*tegra), GFP_KERNEL);
802 	if (!tegra)
803 		return -ENOMEM;
804 
805 	tegra->soc = of_device_get_match_data(&pdev->dev);
806 
807 	tegra->regs = devm_platform_ioremap_resource(pdev, 0);
808 	if (IS_ERR(tegra->regs))
809 		return PTR_ERR(tegra->regs);
810 
811 	tegra->reset = devm_reset_control_get(&pdev->dev, "actmon");
812 	if (IS_ERR(tegra->reset)) {
813 		dev_err(&pdev->dev, "Failed to get reset\n");
814 		return PTR_ERR(tegra->reset);
815 	}
816 
817 	tegra->clock = devm_clk_get(&pdev->dev, "actmon");
818 	if (IS_ERR(tegra->clock)) {
819 		dev_err(&pdev->dev, "Failed to get actmon clock\n");
820 		return PTR_ERR(tegra->clock);
821 	}
822 
823 	tegra->emc_clock = devm_clk_get(&pdev->dev, "emc");
824 	if (IS_ERR(tegra->emc_clock))
825 		return dev_err_probe(&pdev->dev, PTR_ERR(tegra->emc_clock),
826 				     "Failed to get emc clock\n");
827 
828 	err = platform_get_irq(pdev, 0);
829 	if (err < 0)
830 		return err;
831 
832 	tegra->irq = err;
833 
834 	irq_set_status_flags(tegra->irq, IRQ_NOAUTOEN);
835 
836 	err = devm_request_threaded_irq(&pdev->dev, tegra->irq, NULL,
837 					actmon_thread_isr, IRQF_ONESHOT,
838 					"tegra-devfreq", tegra);
839 	if (err) {
840 		dev_err(&pdev->dev, "Interrupt request failed: %d\n", err);
841 		return err;
842 	}
843 
844 	tegra->opp_table = dev_pm_opp_set_supported_hw(&pdev->dev,
845 						       &hw_version, 1);
846 	err = PTR_ERR_OR_ZERO(tegra->opp_table);
847 	if (err) {
848 		dev_err(&pdev->dev, "Failed to set supported HW: %d\n", err);
849 		return err;
850 	}
851 
852 	err = dev_pm_opp_of_add_table_noclk(&pdev->dev, 0);
853 	if (err) {
854 		dev_err(&pdev->dev, "Failed to add OPP table: %d\n", err);
855 		goto put_hw;
856 	}
857 
858 	err = clk_prepare_enable(tegra->clock);
859 	if (err) {
860 		dev_err(&pdev->dev,
861 			"Failed to prepare and enable ACTMON clock\n");
862 		goto remove_table;
863 	}
864 
865 	err = reset_control_reset(tegra->reset);
866 	if (err) {
867 		dev_err(&pdev->dev, "Failed to reset hardware: %d\n", err);
868 		goto disable_clk;
869 	}
870 
871 	rate = clk_round_rate(tegra->emc_clock, ULONG_MAX);
872 	if (rate < 0) {
873 		dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate);
874 		err = rate;
875 		goto disable_clk;
876 	}
877 
878 	tegra->max_freq = rate / KHZ;
879 
880 	for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
881 		dev = tegra->devices + i;
882 		dev->config = tegra->soc->configs + i;
883 		dev->regs = tegra->regs + dev->config->offset;
884 	}
885 
886 	platform_set_drvdata(pdev, tegra);
887 
888 	tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb;
889 	tegra->cpu_rate_change_nb.notifier_call = tegra_actmon_cpu_notify_cb;
890 
891 	INIT_DELAYED_WORK(&tegra->cpufreq_update_work,
892 			  tegra_actmon_delayed_update);
893 
894 	err = devfreq_add_governor(&tegra_devfreq_governor);
895 	if (err) {
896 		dev_err(&pdev->dev, "Failed to add governor: %d\n", err);
897 		goto remove_opps;
898 	}
899 
900 	tegra_devfreq_profile.initial_freq = clk_get_rate(tegra->emc_clock);
901 
902 	devfreq = devfreq_add_device(&pdev->dev, &tegra_devfreq_profile,
903 				     "tegra_actmon", NULL);
904 	if (IS_ERR(devfreq)) {
905 		err = PTR_ERR(devfreq);
906 		goto remove_governor;
907 	}
908 
909 	return 0;
910 
911 remove_governor:
912 	devfreq_remove_governor(&tegra_devfreq_governor);
913 
914 remove_opps:
915 	dev_pm_opp_remove_all_dynamic(&pdev->dev);
916 
917 	reset_control_reset(tegra->reset);
918 disable_clk:
919 	clk_disable_unprepare(tegra->clock);
920 remove_table:
921 	dev_pm_opp_of_remove_table(&pdev->dev);
922 put_hw:
923 	dev_pm_opp_put_supported_hw(tegra->opp_table);
924 
925 	return err;
926 }
927 
928 static int tegra_devfreq_remove(struct platform_device *pdev)
929 {
930 	struct tegra_devfreq *tegra = platform_get_drvdata(pdev);
931 
932 	devfreq_remove_device(tegra->devfreq);
933 	devfreq_remove_governor(&tegra_devfreq_governor);
934 
935 	reset_control_reset(tegra->reset);
936 	clk_disable_unprepare(tegra->clock);
937 
938 	dev_pm_opp_of_remove_table(&pdev->dev);
939 	dev_pm_opp_put_supported_hw(tegra->opp_table);
940 
941 	return 0;
942 }
943 
944 static const struct tegra_devfreq_soc_data tegra124_soc = {
945 	.configs = tegra124_device_configs,
946 
947 	/*
948 	 * Activity counter is incremented every 256 memory transactions,
949 	 * and each transaction takes 4 EMC clocks.
950 	 */
951 	.count_weight = 4 * 256,
952 };
953 
954 static const struct tegra_devfreq_soc_data tegra30_soc = {
955 	.configs = tegra30_device_configs,
956 	.count_weight = 2 * 256,
957 };
958 
959 static const struct of_device_id tegra_devfreq_of_match[] = {
960 	{ .compatible = "nvidia,tegra30-actmon",  .data = &tegra30_soc, },
961 	{ .compatible = "nvidia,tegra124-actmon", .data = &tegra124_soc, },
962 	{ },
963 };
964 
965 MODULE_DEVICE_TABLE(of, tegra_devfreq_of_match);
966 
967 static struct platform_driver tegra_devfreq_driver = {
968 	.probe	= tegra_devfreq_probe,
969 	.remove	= tegra_devfreq_remove,
970 	.driver = {
971 		.name = "tegra-devfreq",
972 		.of_match_table = tegra_devfreq_of_match,
973 	},
974 };
975 module_platform_driver(tegra_devfreq_driver);
976 
977 MODULE_LICENSE("GPL v2");
978 MODULE_DESCRIPTION("Tegra devfreq driver");
979 MODULE_AUTHOR("Tomeu Vizoso <tomeu.vizoso@collabora.com>");
980