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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_plat.h>
27#include <asm/smp_twd.h>
28
29/* set up by the platform code */
30static void __iomem *twd_base;
31
32static struct clk *twd_clk;
33static unsigned long twd_timer_rate;
34static DEFINE_PER_CPU(bool, percpu_setup_called);
35
36static struct clock_event_device __percpu *twd_evt;
37static int twd_ppi;
38
39static void twd_set_mode(enum clock_event_mode mode,
40 struct clock_event_device *clk)
41{
42 unsigned long ctrl;
43
44 switch (mode) {
45 case CLOCK_EVT_MODE_PERIODIC:
46 ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
47 | TWD_TIMER_CONTROL_PERIODIC;
48 writel_relaxed(DIV_ROUND_CLOSEST(twd_timer_rate, HZ),
49 twd_base + TWD_TIMER_LOAD);
50 break;
51 case CLOCK_EVT_MODE_ONESHOT:
52 /* period set, and timer enabled in 'next_event' hook */
53 ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT;
54 break;
55 case CLOCK_EVT_MODE_UNUSED:
56 case CLOCK_EVT_MODE_SHUTDOWN:
57 default:
58 ctrl = 0;
59 }
60
61 writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);
62}
63
64static int twd_set_next_event(unsigned long evt,
65 struct clock_event_device *unused)
66{
67 unsigned long ctrl = readl_relaxed(twd_base + TWD_TIMER_CONTROL);
68
69 ctrl |= TWD_TIMER_CONTROL_ENABLE;
70
71 writel_relaxed(evt, twd_base + TWD_TIMER_COUNTER);
72 writel_relaxed(ctrl, twd_base + TWD_TIMER_CONTROL);
73
74 return 0;
75}
76
77/*
78 * local_timer_ack: checks for a local timer interrupt.
79 *
80 * If a local timer interrupt has occurred, acknowledge and return 1.
81 * Otherwise, return 0.
82 */
83static int twd_timer_ack(void)
84{
85 if (readl_relaxed(twd_base + TWD_TIMER_INTSTAT)) {
86 writel_relaxed(1, twd_base + TWD_TIMER_INTSTAT);
87 return 1;
88 }
89
90 return 0;
91}
92
93static void twd_timer_stop(void)
94{
95 struct clock_event_device *clk = __this_cpu_ptr(twd_evt);
96
97 twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
98 disable_percpu_irq(clk->irq);
99}
100
101#ifdef CONFIG_COMMON_CLK
102
103/*
104 * Updates clockevent frequency when the cpu frequency changes.
105 * Called on the cpu that is changing frequency with interrupts disabled.
106 */
107static void twd_update_frequency(void *new_rate)
108{
109 twd_timer_rate = *((unsigned long *) new_rate);
110
111 clockevents_update_freq(__this_cpu_ptr(twd_evt), twd_timer_rate);
112}
113
114static int twd_rate_change(struct notifier_block *nb,
115 unsigned long flags, void *data)
116{
117 struct clk_notifier_data *cnd = data;
118
119 /*
120 * The twd clock events must be reprogrammed to account for the new
121 * frequency. The timer is local to a cpu, so cross-call to the
122 * changing cpu.
123 */
124 if (flags == POST_RATE_CHANGE)
125 on_each_cpu(twd_update_frequency,
126 (void *)&cnd->new_rate, 1);
127
128 return NOTIFY_OK;
129}
130
131static struct notifier_block twd_clk_nb = {
132 .notifier_call = twd_rate_change,
133};
134
135static int twd_clk_init(void)
136{
137 if (twd_evt && __this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
138 return clk_notifier_register(twd_clk, &twd_clk_nb);
139
140 return 0;
141}
142core_initcall(twd_clk_init);
143
144#elif defined (CONFIG_CPU_FREQ)
145
146#include <linux/cpufreq.h>
147
148/*
149 * Updates clockevent frequency when the cpu frequency changes.
150 * Called on the cpu that is changing frequency with interrupts disabled.
151 */
152static void twd_update_frequency(void *data)
153{
154 twd_timer_rate = clk_get_rate(twd_clk);
155
156 clockevents_update_freq(__this_cpu_ptr(twd_evt), twd_timer_rate);
157}
158
159static int twd_cpufreq_transition(struct notifier_block *nb,
160 unsigned long state, void *data)
161{
162 struct cpufreq_freqs *freqs = data;
163
164 /*
165 * The twd clock events must be reprogrammed to account for the new
166 * frequency. The timer is local to a cpu, so cross-call to the
167 * changing cpu.
168 */
169 if (state == CPUFREQ_POSTCHANGE)
170 smp_call_function_single(freqs->cpu, twd_update_frequency,
171 NULL, 1);
172
173 return NOTIFY_OK;
174}
175
176static struct notifier_block twd_cpufreq_nb = {
177 .notifier_call = twd_cpufreq_transition,
178};
179
180static int twd_cpufreq_init(void)
181{
182 if (twd_evt && __this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
183 return cpufreq_register_notifier(&twd_cpufreq_nb,
184 CPUFREQ_TRANSITION_NOTIFIER);
185
186 return 0;
187}
188core_initcall(twd_cpufreq_init);
189
190#endif
191
192static void twd_calibrate_rate(void)
193{
194 unsigned long count;
195 u64 waitjiffies;
196
197 /*
198 * If this is the first time round, we need to work out how fast
199 * the timer ticks
200 */
201 if (twd_timer_rate == 0) {
202 printk(KERN_INFO "Calibrating local timer... ");
203
204 /* Wait for a tick to start */
205 waitjiffies = get_jiffies_64() + 1;
206
207 while (get_jiffies_64() < waitjiffies)
208 udelay(10);
209
210 /* OK, now the tick has started, let's get the timer going */
211 waitjiffies += 5;
212
213 /* enable, no interrupt or reload */
214 writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL);
215
216 /* maximum value */
217 writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
218
219 while (get_jiffies_64() < waitjiffies)
220 udelay(10);
221
222 count = readl_relaxed(twd_base + TWD_TIMER_COUNTER);
223
224 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
225
226 printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
227 (twd_timer_rate / 10000) % 100);
228 }
229}
230
231static irqreturn_t twd_handler(int irq, void *dev_id)
232{
233 struct clock_event_device *evt = dev_id;
234
235 if (twd_timer_ack()) {
236 evt->event_handler(evt);
237 return IRQ_HANDLED;
238 }
239
240 return IRQ_NONE;
241}
242
243static void twd_get_clock(struct device_node *np)
244{
245 int err;
246
247 if (np)
248 twd_clk = of_clk_get(np, 0);
249 else
250 twd_clk = clk_get_sys("smp_twd", NULL);
251
252 if (IS_ERR(twd_clk)) {
253 pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
254 return;
255 }
256
257 err = clk_prepare_enable(twd_clk);
258 if (err) {
259 pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
260 clk_put(twd_clk);
261 return;
262 }
263
264 twd_timer_rate = clk_get_rate(twd_clk);
265}
266
267/*
268 * Setup the local clock events for a CPU.
269 */
270static void twd_timer_setup(void)
271{
272 struct clock_event_device *clk = __this_cpu_ptr(twd_evt);
273 int cpu = smp_processor_id();
274
275 /*
276 * If the basic setup for this CPU has been done before don't
277 * bother with the below.
278 */
279 if (per_cpu(percpu_setup_called, cpu)) {
280 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
281 clockevents_register_device(clk);
282 enable_percpu_irq(clk->irq, 0);
283 return;
284 }
285 per_cpu(percpu_setup_called, cpu) = true;
286
287 twd_calibrate_rate();
288
289 /*
290 * The following is done once per CPU the first time .setup() is
291 * called.
292 */
293 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
294
295 clk->name = "local_timer";
296 clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
297 CLOCK_EVT_FEAT_C3STOP;
298 clk->rating = 350;
299 clk->set_mode = twd_set_mode;
300 clk->set_next_event = twd_set_next_event;
301 clk->irq = twd_ppi;
302 clk->cpumask = cpumask_of(cpu);
303
304 clockevents_config_and_register(clk, twd_timer_rate,
305 0xf, 0xffffffff);
306 enable_percpu_irq(clk->irq, 0);
307}
308
309static int twd_timer_cpu_notify(struct notifier_block *self,
310 unsigned long action, void *hcpu)
311{
312 switch (action & ~CPU_TASKS_FROZEN) {
313 case CPU_STARTING:
314 twd_timer_setup();
315 break;
316 case CPU_DYING:
317 twd_timer_stop();
318 break;
319 }
320
321 return NOTIFY_OK;
322}
323
324static struct notifier_block twd_timer_cpu_nb = {
325 .notifier_call = twd_timer_cpu_notify,
326};
327
328static int __init twd_local_timer_common_register(struct device_node *np)
329{
330 int err;
331
332 twd_evt = alloc_percpu(struct clock_event_device);
333 if (!twd_evt) {
334 err = -ENOMEM;
335 goto out_free;
336 }
337
338 err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
339 if (err) {
340 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
341 goto out_free;
342 }
343
344 err = register_cpu_notifier(&twd_timer_cpu_nb);
345 if (err)
346 goto out_irq;
347
348 twd_get_clock(np);
349
350 /*
351 * Immediately configure the timer on the boot CPU, unless we need
352 * jiffies to be incrementing to calibrate the rate in which case
353 * setup the timer in late_time_init.
354 */
355 if (twd_timer_rate)
356 twd_timer_setup();
357 else
358 late_time_init = twd_timer_setup;
359
360 return 0;
361
362out_irq:
363 free_percpu_irq(twd_ppi, twd_evt);
364out_free:
365 iounmap(twd_base);
366 twd_base = NULL;
367 free_percpu(twd_evt);
368
369 return err;
370}
371
372int __init twd_local_timer_register(struct twd_local_timer *tlt)
373{
374 if (twd_base || twd_evt)
375 return -EBUSY;
376
377 twd_ppi = tlt->res[1].start;
378
379 twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
380 if (!twd_base)
381 return -ENOMEM;
382
383 return twd_local_timer_common_register(NULL);
384}
385
386#ifdef CONFIG_OF
387static void __init twd_local_timer_of_register(struct device_node *np)
388{
389 int err;
390
391 if (!is_smp() || !setup_max_cpus)
392 return;
393
394 twd_ppi = irq_of_parse_and_map(np, 0);
395 if (!twd_ppi) {
396 err = -EINVAL;
397 goto out;
398 }
399
400 twd_base = of_iomap(np, 0);
401 if (!twd_base) {
402 err = -ENOMEM;
403 goto out;
404 }
405
406 err = twd_local_timer_common_register(np);
407
408out:
409 WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
410}
411CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
412CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
413CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
414#endif
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 twd_shutdown(clk);
97 disable_percpu_irq(clk->irq);
98}
99
100/*
101 * Updates clockevent frequency when the cpu frequency changes.
102 * Called on the cpu that is changing frequency with interrupts disabled.
103 */
104static void twd_update_frequency(void *new_rate)
105{
106 twd_timer_rate = *((unsigned long *) new_rate);
107
108 clockevents_update_freq(raw_cpu_ptr(twd_evt), twd_timer_rate);
109}
110
111static int twd_rate_change(struct notifier_block *nb,
112 unsigned long flags, void *data)
113{
114 struct clk_notifier_data *cnd = data;
115
116 /*
117 * The twd clock events must be reprogrammed to account for the new
118 * frequency. The timer is local to a cpu, so cross-call to the
119 * changing cpu.
120 */
121 if (flags == POST_RATE_CHANGE)
122 on_each_cpu(twd_update_frequency,
123 (void *)&cnd->new_rate, 1);
124
125 return NOTIFY_OK;
126}
127
128static struct notifier_block twd_clk_nb = {
129 .notifier_call = twd_rate_change,
130};
131
132static int twd_clk_init(void)
133{
134 if (twd_evt && raw_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
135 return clk_notifier_register(twd_clk, &twd_clk_nb);
136
137 return 0;
138}
139core_initcall(twd_clk_init);
140
141static void twd_calibrate_rate(void)
142{
143 unsigned long count;
144 u64 waitjiffies;
145
146 /*
147 * If this is the first time round, we need to work out how fast
148 * the timer ticks
149 */
150 if (twd_timer_rate == 0) {
151 pr_info("Calibrating local timer... ");
152
153 /* Wait for a tick to start */
154 waitjiffies = get_jiffies_64() + 1;
155
156 while (get_jiffies_64() < waitjiffies)
157 udelay(10);
158
159 /* OK, now the tick has started, let's get the timer going */
160 waitjiffies += 5;
161
162 /* enable, no interrupt or reload */
163 writel_relaxed(0x1, twd_base + TWD_TIMER_CONTROL);
164
165 /* maximum value */
166 writel_relaxed(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
167
168 while (get_jiffies_64() < waitjiffies)
169 udelay(10);
170
171 count = readl_relaxed(twd_base + TWD_TIMER_COUNTER);
172
173 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
174
175 pr_cont("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
176 (twd_timer_rate / 10000) % 100);
177 }
178}
179
180static irqreturn_t twd_handler(int irq, void *dev_id)
181{
182 struct clock_event_device *evt = dev_id;
183
184 if (twd_timer_ack()) {
185 evt->event_handler(evt);
186 return IRQ_HANDLED;
187 }
188
189 return IRQ_NONE;
190}
191
192static void twd_get_clock(struct device_node *np)
193{
194 int err;
195
196 if (np)
197 twd_clk = of_clk_get(np, 0);
198 else
199 twd_clk = clk_get_sys("smp_twd", NULL);
200
201 if (IS_ERR(twd_clk)) {
202 pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
203 return;
204 }
205
206 err = clk_prepare_enable(twd_clk);
207 if (err) {
208 pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
209 clk_put(twd_clk);
210 return;
211 }
212
213 twd_timer_rate = clk_get_rate(twd_clk);
214}
215
216/*
217 * Setup the local clock events for a CPU.
218 */
219static void twd_timer_setup(void)
220{
221 struct clock_event_device *clk = raw_cpu_ptr(twd_evt);
222 int cpu = smp_processor_id();
223
224 /*
225 * If the basic setup for this CPU has been done before don't
226 * bother with the below.
227 */
228 if (per_cpu(percpu_setup_called, cpu)) {
229 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
230 clockevents_register_device(clk);
231 enable_percpu_irq(clk->irq, 0);
232 return;
233 }
234 per_cpu(percpu_setup_called, cpu) = true;
235
236 twd_calibrate_rate();
237
238 /*
239 * The following is done once per CPU the first time .setup() is
240 * called.
241 */
242 writel_relaxed(0, twd_base + TWD_TIMER_CONTROL);
243
244 clk->name = "local_timer";
245 clk->features = twd_features;
246 clk->rating = 350;
247 clk->set_state_shutdown = twd_shutdown;
248 clk->set_state_periodic = twd_set_periodic;
249 clk->set_state_oneshot = twd_set_oneshot;
250 clk->tick_resume = twd_shutdown;
251 clk->set_next_event = twd_set_next_event;
252 clk->irq = twd_ppi;
253 clk->cpumask = cpumask_of(cpu);
254
255 clockevents_config_and_register(clk, twd_timer_rate,
256 0xf, 0xffffffff);
257 enable_percpu_irq(clk->irq, 0);
258}
259
260static int twd_timer_starting_cpu(unsigned int cpu)
261{
262 twd_timer_setup();
263 return 0;
264}
265
266static int twd_timer_dying_cpu(unsigned int cpu)
267{
268 twd_timer_stop();
269 return 0;
270}
271
272static int __init twd_local_timer_common_register(struct device_node *np)
273{
274 int err;
275
276 twd_evt = alloc_percpu(struct clock_event_device);
277 if (!twd_evt) {
278 err = -ENOMEM;
279 goto out_free;
280 }
281
282 err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
283 if (err) {
284 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
285 goto out_free;
286 }
287
288 cpuhp_setup_state_nocalls(CPUHP_AP_ARM_TWD_STARTING,
289 "arm/timer/twd:starting",
290 twd_timer_starting_cpu, twd_timer_dying_cpu);
291
292 twd_get_clock(np);
293 if (!of_property_read_bool(np, "always-on"))
294 twd_features |= CLOCK_EVT_FEAT_C3STOP;
295
296 /*
297 * Immediately configure the timer on the boot CPU, unless we need
298 * jiffies to be incrementing to calibrate the rate in which case
299 * setup the timer in late_time_init.
300 */
301 if (twd_timer_rate)
302 twd_timer_setup();
303 else
304 late_time_init = twd_timer_setup;
305
306 return 0;
307
308out_free:
309 iounmap(twd_base);
310 twd_base = NULL;
311 free_percpu(twd_evt);
312
313 return err;
314}
315
316static int __init twd_local_timer_of_register(struct device_node *np)
317{
318 int err;
319
320 twd_ppi = irq_of_parse_and_map(np, 0);
321 if (!twd_ppi) {
322 err = -EINVAL;
323 goto out;
324 }
325
326 twd_base = of_iomap(np, 0);
327 if (!twd_base) {
328 err = -ENOMEM;
329 goto out;
330 }
331
332 err = twd_local_timer_common_register(np);
333
334out:
335 WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
336 return err;
337}
338TIMER_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
339TIMER_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
340TIMER_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);