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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/delay.h>
14#include <linux/device.h>
15#include <linux/smp.h>
16#include <linux/jiffies.h>
17#include <linux/clockchips.h>
18#include <linux/irq.h>
19#include <linux/io.h>
20
21#include <asm/smp_twd.h>
22#include <asm/hardware/gic.h>
23
24/* set up by the platform code */
25void __iomem *twd_base;
26
27static unsigned long twd_timer_rate;
28
29static void twd_set_mode(enum clock_event_mode mode,
30 struct clock_event_device *clk)
31{
32 unsigned long ctrl;
33
34 switch (mode) {
35 case CLOCK_EVT_MODE_PERIODIC:
36 /* timer load already set up */
37 ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
38 | TWD_TIMER_CONTROL_PERIODIC;
39 __raw_writel(twd_timer_rate / HZ, twd_base + TWD_TIMER_LOAD);
40 break;
41 case CLOCK_EVT_MODE_ONESHOT:
42 /* period set, and timer enabled in 'next_event' hook */
43 ctrl = TWD_TIMER_CONTROL_IT_ENABLE | TWD_TIMER_CONTROL_ONESHOT;
44 break;
45 case CLOCK_EVT_MODE_UNUSED:
46 case CLOCK_EVT_MODE_SHUTDOWN:
47 default:
48 ctrl = 0;
49 }
50
51 __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
52}
53
54static int twd_set_next_event(unsigned long evt,
55 struct clock_event_device *unused)
56{
57 unsigned long ctrl = __raw_readl(twd_base + TWD_TIMER_CONTROL);
58
59 ctrl |= TWD_TIMER_CONTROL_ENABLE;
60
61 __raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
62 __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
63
64 return 0;
65}
66
67/*
68 * local_timer_ack: checks for a local timer interrupt.
69 *
70 * If a local timer interrupt has occurred, acknowledge and return 1.
71 * Otherwise, return 0.
72 */
73int twd_timer_ack(void)
74{
75 if (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
76 __raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
77 return 1;
78 }
79
80 return 0;
81}
82
83static void __cpuinit twd_calibrate_rate(void)
84{
85 unsigned long count;
86 u64 waitjiffies;
87
88 /*
89 * If this is the first time round, we need to work out how fast
90 * the timer ticks
91 */
92 if (twd_timer_rate == 0) {
93 printk(KERN_INFO "Calibrating local timer... ");
94
95 /* Wait for a tick to start */
96 waitjiffies = get_jiffies_64() + 1;
97
98 while (get_jiffies_64() < waitjiffies)
99 udelay(10);
100
101 /* OK, now the tick has started, let's get the timer going */
102 waitjiffies += 5;
103
104 /* enable, no interrupt or reload */
105 __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
106
107 /* maximum value */
108 __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
109
110 while (get_jiffies_64() < waitjiffies)
111 udelay(10);
112
113 count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
114
115 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
116
117 printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
118 (twd_timer_rate / 10000) % 100);
119 }
120}
121
122/*
123 * Setup the local clock events for a CPU.
124 */
125void __cpuinit twd_timer_setup(struct clock_event_device *clk)
126{
127 twd_calibrate_rate();
128
129 clk->name = "local_timer";
130 clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
131 CLOCK_EVT_FEAT_C3STOP;
132 clk->rating = 350;
133 clk->set_mode = twd_set_mode;
134 clk->set_next_event = twd_set_next_event;
135 clk->shift = 20;
136 clk->mult = div_sc(twd_timer_rate, NSEC_PER_SEC, clk->shift);
137 clk->max_delta_ns = clockevent_delta2ns(0xffffffff, clk);
138 clk->min_delta_ns = clockevent_delta2ns(0xf, clk);
139
140 clockevents_register_device(clk);
141
142 /* Make sure our local interrupt controller has this enabled */
143 gic_enable_ppi(clk->irq);
144}
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_cpu_notify(struct notifier_block *self,
314 unsigned long action, void *hcpu)
315{
316 switch (action & ~CPU_TASKS_FROZEN) {
317 case CPU_STARTING:
318 twd_timer_setup();
319 break;
320 case CPU_DYING:
321 twd_timer_stop();
322 break;
323 }
324
325 return NOTIFY_OK;
326}
327
328static struct notifier_block twd_timer_cpu_nb = {
329 .notifier_call = twd_timer_cpu_notify,
330};
331
332static int __init twd_local_timer_common_register(struct device_node *np)
333{
334 int err;
335
336 twd_evt = alloc_percpu(struct clock_event_device);
337 if (!twd_evt) {
338 err = -ENOMEM;
339 goto out_free;
340 }
341
342 err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
343 if (err) {
344 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
345 goto out_free;
346 }
347
348 err = register_cpu_notifier(&twd_timer_cpu_nb);
349 if (err)
350 goto out_irq;
351
352 twd_get_clock(np);
353 if (!of_property_read_bool(np, "always-on"))
354 twd_features |= CLOCK_EVT_FEAT_C3STOP;
355
356 /*
357 * Immediately configure the timer on the boot CPU, unless we need
358 * jiffies to be incrementing to calibrate the rate in which case
359 * setup the timer in late_time_init.
360 */
361 if (twd_timer_rate)
362 twd_timer_setup();
363 else
364 late_time_init = twd_timer_setup;
365
366 return 0;
367
368out_irq:
369 free_percpu_irq(twd_ppi, twd_evt);
370out_free:
371 iounmap(twd_base);
372 twd_base = NULL;
373 free_percpu(twd_evt);
374
375 return err;
376}
377
378int __init twd_local_timer_register(struct twd_local_timer *tlt)
379{
380 if (twd_base || twd_evt)
381 return -EBUSY;
382
383 twd_ppi = tlt->res[1].start;
384
385 twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
386 if (!twd_base)
387 return -ENOMEM;
388
389 return twd_local_timer_common_register(NULL);
390}
391
392#ifdef CONFIG_OF
393static void __init twd_local_timer_of_register(struct device_node *np)
394{
395 int err;
396
397 twd_ppi = irq_of_parse_and_map(np, 0);
398 if (!twd_ppi) {
399 err = -EINVAL;
400 goto out;
401 }
402
403 twd_base = of_iomap(np, 0);
404 if (!twd_base) {
405 err = -ENOMEM;
406 goto out;
407 }
408
409 err = twd_local_timer_common_register(np);
410
411out:
412 WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
413}
414CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
415CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
416CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
417#endif