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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/arch/arm/kernel/smp_twd.c
4 *
5 * Copyright (C) 2002 ARM Ltd.
6 * All Rights Reserved
7 */
8#include <linux/init.h>
9#include <linux/kernel.h>
10#include <linux/clk.h>
11#include <linux/cpu.h>
12#include <linux/delay.h>
13#include <linux/device.h>
14#include <linux/err.h>
15#include <linux/smp.h>
16#include <linux/jiffies.h>
17#include <linux/clockchips.h>
18#include <linux/interrupt.h>
19#include <linux/io.h>
20#include <linux/of_irq.h>
21#include <linux/of_address.h>
22
23#include <asm/smp_twd.h>
24
25/* set up by the platform code */
26static void __iomem *twd_base;
27
28static struct clk *twd_clk;
29static unsigned long twd_timer_rate;
30static DEFINE_PER_CPU(bool, percpu_setup_called);
31
32static struct clock_event_device __percpu *twd_evt;
33static unsigned int twd_features =
34 CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
35static int twd_ppi;
36
37static int twd_shutdown(struct clock_event_device *clk)
38{
39 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
40 return 0;
41}
42
43static int twd_set_oneshot(struct clock_event_device *clk)
44{
45 /* period set, and timer enabled in 'next_event' hook */
46 writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT,
47 twd_base + TWD_TIMER_CONTROL);
48 return 0;
49}
50
51static int twd_set_periodic(struct clock_event_device *clk)
52{
53 unsigned long ctrl = TWD_TIMER_CONTROL_ENABLE |
54 TWD_TIMER_CONTROL_IT_ENABLE |
55 TWD_TIMER_CONTROL_PERIODIC;
56
57 writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
58 twd_base + TWD_TIMER_LOAD);
59 writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);
60 return 0;
61}
62
63static int twd_set_next_event(unsigned long evt,
64 struct clock_event_device *unused)
65{
66 unsigned long ctrl = readl_relaxed(twd_base + TWD_TIMER_CONTROL);
67
68 ctrl |= TWD_TIMER_CONTROL_ENABLE;
69
70 writel_relaxed(evt, twd_base + TWD_TIMER_COUNTER);
71 writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);
72
73 return 0;
74}
75
76/*
77 * local_timer_ack: checks for a local timer interrupt.
78 *
79 * If a local timer interrupt has occurred, acknowledge and return 1.
80 * Otherwise, return 0.
81 */
82static int twd_timer_ack(void)
83{
84 if (readl_relaxed(twd_base + TWD_TIMER_INTSTAT)) {
85 writel_relaxed(1, twd_base + TWD_TIMER_INTSTAT);
86 return 1;
87 }
88
89 return 0;
90}
91
92static void twd_timer_stop(void)
93{
94 struct clock_event_device *clk = raw_cpu_ptr(twd_evt);
95
96 disable_percpu_irq(clk->irq);
97}
98
99/*
100 * Updates clockevent frequency when the cpu frequency changes.
101 * Called on the cpu that is changing frequency with interrupts disabled.
102 */
103static void twd_update_frequency(void *new_rate)
104{
105 twd_timer_rate = *((unsigned long *) new_rate);
106
107 clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate);
108}
109
110static int twd_rate_change(struct notifier_block *nb,
111 unsigned long flags, void *data)
112{
113 struct clk_notifier_data *cnd = data;
114
115 /*
116 * The twd clock events must be reprogrammed to account for the new
117 * frequency. The timer is local to a cpu, so cross-call to the
118 * changing cpu.
119 */
120 if (flags == POST_RATE_CHANGE)
121 on_each_cpu(twd_update_frequency,
122 (void *)&cnd->new_rate, 1);
123
124 return NOTIFY_OK;
125}
126
127static struct notifier_block twd_clk_nb = {
128 .notifier_call = twd_rate_change,
129};
130
131static int twd_clk_init(void)
132{
133 if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
134 return clk_notifier_register(twd_clk, &twd_clk_nb);
135
136 return 0;
137}
138core_initcall(twd_clk_init);
139
140static void twd_calibrate_rate(void)
141{
142 unsigned long count;
143 u64 waitjiffies;
144
145 /*
146 * If this is the first time round, we need to work out how fast
147 * the timer ticks
148 */
149 if (twd_timer_rate == 0) {
150 pr_info("Calibrating local timer... ");
151
152 /* Wait for a tick to start */
153 waitjiffies = get_jiffies_64() + 1;
154
155 while (get_jiffies_64() < waitjiffies)
156 udelay(10);
157
158 /* OK, now the tick has started, let's get the timer going */
159 waitjiffies += 5;
160
161 /* enable, no interrupt or reload */
162 writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL);
163
164 /* maximum value */
165 writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
166
167 while (get_jiffies_64() < waitjiffies)
168 udelay(10);
169
170 count = readl_relaxed(twd_base + TWD_TIMER_COUNTER);
171
172 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
173
174 pr_cont("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
175 (twd_timer_rate / 10000) % 100);
176 }
177}
178
179static irqreturn_t twd_handler(int irq, void *dev_id)
180{
181 struct clock_event_device *evt = dev_id;
182
183 if (twd_timer_ack()) {
184 evt->event_handler(evt);
185 return IRQ_HANDLED;
186 }
187
188 return IRQ_NONE;
189}
190
191static void twd_get_clock(struct device_node *np)
192{
193 int err;
194
195 if (np)
196 twd_clk = of_clk_get(np, 0);
197 else
198 twd_clk = clk_get_sys("smp_twd", NULL);
199
200 if (IS_ERR(twd_clk)) {
201 pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
202 return;
203 }
204
205 err = clk_prepare_enable(twd_clk);
206 if (err) {
207 pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
208 clk_put(twd_clk);
209 return;
210 }
211
212 twd_timer_rate = clk_get_rate(twd_clk);
213}
214
215/*
216 * Setup the local clock events for a CPU.
217 */
218static void twd_timer_setup(void)
219{
220 struct clock_event_device *clk = raw_cpu_ptr(twd_evt);
221 int cpu = smp_processor_id();
222
223 /*
224 * If the basic setup for this CPU has been done before don't
225 * bother with the below.
226 */
227 if (per_cpu(percpu_setup_called, cpu)) {
228 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
229 clockevents_register_device(clk);
230 enable_percpu_irq(clk->irq, 0);
231 return;
232 }
233 per_cpu(percpu_setup_called, cpu) = true;
234
235 twd_calibrate_rate();
236
237 /*
238 * The following is done once per CPU the first time .setup() is
239 * called.
240 */
241 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
242
243 clk->name = "local_timer";
244 clk->features = twd_features;
245 clk->rating = 350;
246 clk->set_state_shutdown = twd_shutdown;
247 clk->set_state_periodic = twd_set_periodic;
248 clk->set_state_oneshot = twd_set_oneshot;
249 clk->tick_resume = twd_shutdown;
250 clk->set_next_event = twd_set_next_event;
251 clk->irq = twd_ppi;
252 clk->cpumask = cpumask_of(cpu);
253
254 clockevents_config_and_register(clk, twd_timer_rate,
255 0xf, 0xffffffff);
256 enable_percpu_irq(clk->irq, 0);
257}
258
259static int twd_timer_starting_cpu(unsigned int cpu)
260{
261 twd_timer_setup();
262 return 0;
263}
264
265static int twd_timer_dying_cpu(unsigned int cpu)
266{
267 twd_timer_stop();
268 return 0;
269}
270
271static int __init twd_local_timer_common_register(struct device_node *np)
272{
273 int err;
274
275 twd_evt = alloc_percpu(struct clock_event_device);
276 if (!twd_evt) {
277 err = -ENOMEM;
278 goto out_free;
279 }
280
281 err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
282 if (err) {
283 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
284 goto out_free;
285 }
286
287 cpuhp_setup_state_nocalls(CPUHP_AP_ARM_TWD_STARTING,
288 "arm/timer/twd:starting",
289 twd_timer_starting_cpu, twd_timer_dying_cpu);
290
291 twd_get_clock(np);
292 if (!of_property_read_bool(np, "always-on"))
293 twd_features |= CLOCK_EVT_FEAT_C3STOP;
294
295 /*
296 * Immediately configure the timer on the boot CPU, unless we need
297 * jiffies to be incrementing to calibrate the rate in which case
298 * setup the timer in late_time_init.
299 */
300 if (twd_timer_rate)
301 twd_timer_setup();
302 else
303 late_time_init = twd_timer_setup;
304
305 return 0;
306
307out_free:
308 iounmap(twd_base);
309 twd_base = NULL;
310 free_percpu(twd_evt);
311
312 return err;
313}
314
315static int __init twd_local_timer_of_register(struct device_node *np)
316{
317 int err;
318
319 twd_ppi = irq_of_parse_and_map(np, 0);
320 if (!twd_ppi) {
321 err = -EINVAL;
322 goto out;
323 }
324
325 twd_base = of_iomap(np, 0);
326 if (!twd_base) {
327 err = -ENOMEM;
328 goto out;
329 }
330
331 err = twd_local_timer_common_register(np);
332
333out:
334 WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
335 return err;
336}
337TIMER_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
338TIMER_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
339TIMER_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
1/*
2 * linux/arch/arm/kernel/smp_twd.c
3 *
4 * Copyright (C) 2002 ARM Ltd.
5 * All Rights Reserved
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11#include <linux/init.h>
12#include <linux/kernel.h>
13#include <linux/clk.h>
14#include <linux/cpu.h>
15#include <linux/delay.h>
16#include <linux/device.h>
17#include <linux/err.h>
18#include <linux/smp.h>
19#include <linux/jiffies.h>
20#include <linux/clockchips.h>
21#include <linux/interrupt.h>
22#include <linux/io.h>
23#include <linux/of_irq.h>
24#include <linux/of_address.h>
25
26#include <asm/smp_twd.h>
27
28/* set up by the platform code */
29static void __iomem *twd_base;
30
31static struct clk *twd_clk;
32static unsigned long twd_timer_rate;
33static DEFINE_PER_CPU(bool, percpu_setup_called);
34
35static struct clock_event_device __percpu *twd_evt;
36static unsigned int twd_features =
37 CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
38static int twd_ppi;
39
40static int twd_shutdown(struct clock_event_device *clk)
41{
42 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
43 return 0;
44}
45
46static int twd_set_oneshot(struct clock_event_device *clk)
47{
48 /* period set, and timer enabled in 'next_event' hook */
49 writel_relaxed(TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT,
50 twd_base + TWD_TIMER_CONTROL);
51 return 0;
52}
53
54static int twd_set_periodic(struct clock_event_device *clk)
55{
56 unsigned long ctrl = TWD_TIMER_CONTROL_ENABLE |
57 TWD_TIMER_CONTROL_IT_ENABLE |
58 TWD_TIMER_CONTROL_PERIODIC;
59
60 writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
61 twd_base + TWD_TIMER_LOAD);
62 writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);
63 return 0;
64}
65
66static int twd_set_next_event(unsigned long evt,
67 struct clock_event_device *unused)
68{
69 unsigned long ctrl = readl_relaxed(twd_base + TWD_TIMER_CONTROL);
70
71 ctrl |= TWD_TIMER_CONTROL_ENABLE;
72
73 writel_relaxed(evt, twd_base + TWD_TIMER_COUNTER);
74 writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);
75
76 return 0;
77}
78
79/*
80 * local_timer_ack: checks for a local timer interrupt.
81 *
82 * If a local timer interrupt has occurred, acknowledge and return 1.
83 * Otherwise, return 0.
84 */
85static int twd_timer_ack(void)
86{
87 if (readl_relaxed(twd_base + TWD_TIMER_INTSTAT)) {
88 writel_relaxed(1, twd_base + TWD_TIMER_INTSTAT);
89 return 1;
90 }
91
92 return 0;
93}
94
95static void twd_timer_stop(void)
96{
97 struct clock_event_device *clk = raw_cpu_ptr(twd_evt);
98
99 twd_shutdown(clk);
100 disable_percpu_irq(clk->irq);
101}
102
103#ifdef CONFIG_COMMON_CLK
104
105/*
106 * Updates clockevent frequency when the cpu frequency changes.
107 * Called on the cpu that is changing frequency with interrupts disabled.
108 */
109static void twd_update_frequency(void *new_rate)
110{
111 twd_timer_rate = *((unsigned long *) new_rate);
112
113 clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate);
114}
115
116static int twd_rate_change(struct notifier_block *nb,
117 unsigned long flags, void *data)
118{
119 struct clk_notifier_data *cnd = data;
120
121 /*
122 * The twd clock events must be reprogrammed to account for the new
123 * frequency. The timer is local to a cpu, so cross-call to the
124 * changing cpu.
125 */
126 if (flags == POST_RATE_CHANGE)
127 on_each_cpu(twd_update_frequency,
128 (void *)&cnd->new_rate, 1);
129
130 return NOTIFY_OK;
131}
132
133static struct notifier_block twd_clk_nb = {
134 .notifier_call = twd_rate_change,
135};
136
137static int twd_clk_init(void)
138{
139 if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
140 return clk_notifier_register(twd_clk, &twd_clk_nb);
141
142 return 0;
143}
144core_initcall(twd_clk_init);
145
146#elif defined (CONFIG_CPU_FREQ)
147
148#include <linux/cpufreq.h>
149
150/*
151 * Updates clockevent frequency when the cpu frequency changes.
152 * Called on the cpu that is changing frequency with interrupts disabled.
153 */
154static void twd_update_frequency(void *data)
155{
156 twd_timer_rate = clk_get_rate(twd_clk);
157
158 clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate);
159}
160
161static int twd_cpufreq_transition(struct notifier_block *nb,
162 unsigned long state, void *data)
163{
164 struct cpufreq_freqs *freqs = data;
165
166 /*
167 * The twd clock events must be reprogrammed to account for the new
168 * frequency. The timer is local to a cpu, so cross-call to the
169 * changing cpu.
170 */
171 if (state == CPUFREQ_POSTCHANGE)
172 smp_call_function_single(freqs->cpu, twd_update_frequency,
173 NULL, 1);
174
175 return NOTIFY_OK;
176}
177
178static struct notifier_block twd_cpufreq_nb = {
179 .notifier_call = twd_cpufreq_transition,
180};
181
182static int twd_cpufreq_init(void)
183{
184 if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
185 return cpufreq_register_notifier(&twd_cpufreq_nb,
186 CPUFREQ_TRANSITION_NOTIFIER);
187
188 return 0;
189}
190core_initcall(twd_cpufreq_init);
191
192#endif
193
194static void twd_calibrate_rate(void)
195{
196 unsigned long count;
197 u64 waitjiffies;
198
199 /*
200 * If this is the first time round, we need to work out how fast
201 * the timer ticks
202 */
203 if (twd_timer_rate == 0) {
204 pr_info("Calibrating local timer... ");
205
206 /* Wait for a tick to start */
207 waitjiffies = get_jiffies_64() + 1;
208
209 while (get_jiffies_64() < waitjiffies)
210 udelay(10);
211
212 /* OK, now the tick has started, let's get the timer going */
213 waitjiffies += 5;
214
215 /* enable, no interrupt or reload */
216 writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL);
217
218 /* maximum value */
219 writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
220
221 while (get_jiffies_64() < waitjiffies)
222 udelay(10);
223
224 count = readl_relaxed(twd_base + TWD_TIMER_COUNTER);
225
226 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
227
228 pr_cont("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
229 (twd_timer_rate / 10000) % 100);
230 }
231}
232
233static irqreturn_t twd_handler(int irq, void *dev_id)
234{
235 struct clock_event_device *evt = dev_id;
236
237 if (twd_timer_ack()) {
238 evt->event_handler(evt);
239 return IRQ_HANDLED;
240 }
241
242 return IRQ_NONE;
243}
244
245static void twd_get_clock(struct device_node *np)
246{
247 int err;
248
249 if (np)
250 twd_clk = of_clk_get(np, 0);
251 else
252 twd_clk = clk_get_sys("smp_twd", NULL);
253
254 if (IS_ERR(twd_clk)) {
255 pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
256 return;
257 }
258
259 err = clk_prepare_enable(twd_clk);
260 if (err) {
261 pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
262 clk_put(twd_clk);
263 return;
264 }
265
266 twd_timer_rate = clk_get_rate(twd_clk);
267}
268
269/*
270 * Setup the local clock events for a CPU.
271 */
272static void twd_timer_setup(void)
273{
274 struct clock_event_device *clk = raw_cpu_ptr(twd_evt);
275 int cpu = smp_processor_id();
276
277 /*
278 * If the basic setup for this CPU has been done before don't
279 * bother with the below.
280 */
281 if (per_cpu(percpu_setup_called, cpu)) {
282 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
283 clockevents_register_device(clk);
284 enable_percpu_irq(clk->irq, 0);
285 return;
286 }
287 per_cpu(percpu_setup_called, cpu) = true;
288
289 twd_calibrate_rate();
290
291 /*
292 * The following is done once per CPU the first time .setup() is
293 * called.
294 */
295 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
296
297 clk->name = "local_timer";
298 clk->features = twd_features;
299 clk->rating = 350;
300 clk->set_state_shutdown = twd_shutdown;
301 clk->set_state_periodic = twd_set_periodic;
302 clk->set_state_oneshot = twd_set_oneshot;
303 clk->tick_resume = twd_shutdown;
304 clk->set_next_event = twd_set_next_event;
305 clk->irq = twd_ppi;
306 clk->cpumask = cpumask_of(cpu);
307
308 clockevents_config_and_register(clk, twd_timer_rate,
309 0xf, 0xffffffff);
310 enable_percpu_irq(clk->irq, 0);
311}
312
313static int twd_timer_starting_cpu(unsigned int cpu)
314{
315 twd_timer_setup();
316 return 0;
317}
318
319static int twd_timer_dying_cpu(unsigned int cpu)
320{
321 twd_timer_stop();
322 return 0;
323}
324
325static int __init twd_local_timer_common_register(struct device_node *np)
326{
327 int err;
328
329 twd_evt = alloc_percpu(struct clock_event_device);
330 if (!twd_evt) {
331 err = -ENOMEM;
332 goto out_free;
333 }
334
335 err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
336 if (err) {
337 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
338 goto out_free;
339 }
340
341 cpuhp_setup_state_nocalls(CPUHP_AP_ARM_TWD_STARTING,
342 "arm/timer/twd:starting",
343 twd_timer_starting_cpu, twd_timer_dying_cpu);
344
345 twd_get_clock(np);
346 if (!of_property_read_bool(np, "always-on"))
347 twd_features |= CLOCK_EVT_FEAT_C3STOP;
348
349 /*
350 * Immediately configure the timer on the boot CPU, unless we need
351 * jiffies to be incrementing to calibrate the rate in which case
352 * setup the timer in late_time_init.
353 */
354 if (twd_timer_rate)
355 twd_timer_setup();
356 else
357 late_time_init = twd_timer_setup;
358
359 return 0;
360
361out_free:
362 iounmap(twd_base);
363 twd_base = NULL;
364 free_percpu(twd_evt);
365
366 return err;
367}
368
369int __init twd_local_timer_register(struct twd_local_timer *tlt)
370{
371 if (twd_base || twd_evt)
372 return -EBUSY;
373
374 twd_ppi = tlt->res[1].start;
375
376 twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
377 if (!twd_base)
378 return -ENOMEM;
379
380 return twd_local_timer_common_register(NULL);
381}
382
383#ifdef CONFIG_OF
384static int __init twd_local_timer_of_register(struct device_node *np)
385{
386 int err;
387
388 twd_ppi = irq_of_parse_and_map(np, 0);
389 if (!twd_ppi) {
390 err = -EINVAL;
391 goto out;
392 }
393
394 twd_base = of_iomap(np, 0);
395 if (!twd_base) {
396 err = -ENOMEM;
397 goto out;
398 }
399
400 err = twd_local_timer_common_register(np);
401
402out:
403 WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
404 return err;
405}
406TIMER_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
407TIMER_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
408TIMER_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
409#endif