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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/cpufreq.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#include <asm/localtimer.h>
28#include <asm/hardware/gic.h>
29
30/* set up by the platform code */
31static void __iomem *twd_base;
32
33static struct clk *twd_clk;
34static unsigned long twd_timer_rate;
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 /* timer load already set up */
47 ctrl = TWD_TIMER_CONTROL_ENABLE | TWD_TIMER_CONTROL_IT_ENABLE
48 | TWD_TIMER_CONTROL_PERIODIC;
49 __raw_writel(twd_timer_rate / HZ, 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 __raw_writel(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 = __raw_readl(twd_base + TWD_TIMER_CONTROL);
68
69 ctrl |= TWD_TIMER_CONTROL_ENABLE;
70
71 __raw_writel(evt, twd_base + TWD_TIMER_COUNTER);
72 __raw_writel(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 (__raw_readl(twd_base + TWD_TIMER_INTSTAT)) {
86 __raw_writel(1, twd_base + TWD_TIMER_INTSTAT);
87 return 1;
88 }
89
90 return 0;
91}
92
93static void twd_timer_stop(struct clock_event_device *clk)
94{
95 twd_set_mode(CLOCK_EVT_MODE_UNUSED, clk);
96 disable_percpu_irq(clk->irq);
97}
98
99#ifdef CONFIG_CPU_FREQ
100
101/*
102 * Updates clockevent frequency when the cpu frequency changes.
103 * Called on the cpu that is changing frequency with interrupts disabled.
104 */
105static void twd_update_frequency(void *data)
106{
107 twd_timer_rate = clk_get_rate(twd_clk);
108
109 clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
110}
111
112static int twd_cpufreq_transition(struct notifier_block *nb,
113 unsigned long state, void *data)
114{
115 struct cpufreq_freqs *freqs = data;
116
117 /*
118 * The twd clock events must be reprogrammed to account for the new
119 * frequency. The timer is local to a cpu, so cross-call to the
120 * changing cpu.
121 */
122 if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE)
123 smp_call_function_single(freqs->cpu, twd_update_frequency,
124 NULL, 1);
125
126 return NOTIFY_OK;
127}
128
129static struct notifier_block twd_cpufreq_nb = {
130 .notifier_call = twd_cpufreq_transition,
131};
132
133static int twd_cpufreq_init(void)
134{
135 if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
136 return cpufreq_register_notifier(&twd_cpufreq_nb,
137 CPUFREQ_TRANSITION_NOTIFIER);
138
139 return 0;
140}
141core_initcall(twd_cpufreq_init);
142
143#endif
144
145static void __cpuinit twd_calibrate_rate(void)
146{
147 unsigned long count;
148 u64 waitjiffies;
149
150 /*
151 * If this is the first time round, we need to work out how fast
152 * the timer ticks
153 */
154 if (twd_timer_rate == 0) {
155 printk(KERN_INFO "Calibrating local timer... ");
156
157 /* Wait for a tick to start */
158 waitjiffies = get_jiffies_64() + 1;
159
160 while (get_jiffies_64() < waitjiffies)
161 udelay(10);
162
163 /* OK, now the tick has started, let's get the timer going */
164 waitjiffies += 5;
165
166 /* enable, no interrupt or reload */
167 __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
168
169 /* maximum value */
170 __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
171
172 while (get_jiffies_64() < waitjiffies)
173 udelay(10);
174
175 count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
176
177 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
178
179 printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
180 (twd_timer_rate / 10000) % 100);
181 }
182}
183
184static irqreturn_t twd_handler(int irq, void *dev_id)
185{
186 struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
187
188 if (twd_timer_ack()) {
189 evt->event_handler(evt);
190 return IRQ_HANDLED;
191 }
192
193 return IRQ_NONE;
194}
195
196static struct clk *twd_get_clock(void)
197{
198 struct clk *clk;
199 int err;
200
201 clk = clk_get_sys("smp_twd", NULL);
202 if (IS_ERR(clk)) {
203 pr_err("smp_twd: clock not found: %d\n", (int)PTR_ERR(clk));
204 return clk;
205 }
206
207 err = clk_prepare(clk);
208 if (err) {
209 pr_err("smp_twd: clock failed to prepare: %d\n", err);
210 clk_put(clk);
211 return ERR_PTR(err);
212 }
213
214 err = clk_enable(clk);
215 if (err) {
216 pr_err("smp_twd: clock failed to enable: %d\n", err);
217 clk_unprepare(clk);
218 clk_put(clk);
219 return ERR_PTR(err);
220 }
221
222 return clk;
223}
224
225/*
226 * Setup the local clock events for a CPU.
227 */
228static int __cpuinit twd_timer_setup(struct clock_event_device *clk)
229{
230 struct clock_event_device **this_cpu_clk;
231
232 if (!twd_clk)
233 twd_clk = twd_get_clock();
234
235 if (!IS_ERR_OR_NULL(twd_clk))
236 twd_timer_rate = clk_get_rate(twd_clk);
237 else
238 twd_calibrate_rate();
239
240 __raw_writel(0, twd_base + TWD_TIMER_CONTROL);
241
242 clk->name = "local_timer";
243 clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
244 CLOCK_EVT_FEAT_C3STOP;
245 clk->rating = 350;
246 clk->set_mode = twd_set_mode;
247 clk->set_next_event = twd_set_next_event;
248 clk->irq = twd_ppi;
249
250 this_cpu_clk = __this_cpu_ptr(twd_evt);
251 *this_cpu_clk = clk;
252
253 clockevents_config_and_register(clk, twd_timer_rate,
254 0xf, 0xffffffff);
255 enable_percpu_irq(clk->irq, 0);
256
257 return 0;
258}
259
260static struct local_timer_ops twd_lt_ops __cpuinitdata = {
261 .setup = twd_timer_setup,
262 .stop = twd_timer_stop,
263};
264
265static int __init twd_local_timer_common_register(void)
266{
267 int err;
268
269 twd_evt = alloc_percpu(struct clock_event_device *);
270 if (!twd_evt) {
271 err = -ENOMEM;
272 goto out_free;
273 }
274
275 err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
276 if (err) {
277 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
278 goto out_free;
279 }
280
281 err = local_timer_register(&twd_lt_ops);
282 if (err)
283 goto out_irq;
284
285 return 0;
286
287out_irq:
288 free_percpu_irq(twd_ppi, twd_evt);
289out_free:
290 iounmap(twd_base);
291 twd_base = NULL;
292 free_percpu(twd_evt);
293
294 return err;
295}
296
297int __init twd_local_timer_register(struct twd_local_timer *tlt)
298{
299 if (twd_base || twd_evt)
300 return -EBUSY;
301
302 twd_ppi = tlt->res[1].start;
303
304 twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
305 if (!twd_base)
306 return -ENOMEM;
307
308 return twd_local_timer_common_register();
309}
310
311#ifdef CONFIG_OF
312const static struct of_device_id twd_of_match[] __initconst = {
313 { .compatible = "arm,cortex-a9-twd-timer", },
314 { .compatible = "arm,cortex-a5-twd-timer", },
315 { .compatible = "arm,arm11mp-twd-timer", },
316 { },
317};
318
319void __init twd_local_timer_of_register(void)
320{
321 struct device_node *np;
322 int err;
323
324 np = of_find_matching_node(NULL, twd_of_match);
325 if (!np) {
326 err = -ENODEV;
327 goto out;
328 }
329
330 twd_ppi = irq_of_parse_and_map(np, 0);
331 if (!twd_ppi) {
332 err = -EINVAL;
333 goto out;
334 }
335
336 twd_base = of_iomap(np, 0);
337 if (!twd_base) {
338 err = -ENOMEM;
339 goto out;
340 }
341
342 err = twd_local_timer_common_register();
343
344out:
345 WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
346}
347#endif
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}