Merge tag 'for-linus-v3.10-rc1-2' of git://oss.sgi.com/xfs/xfs
[pandora-kernel.git] / arch / arm / kernel / smp_twd.c
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/delay.h>
15 #include <linux/device.h>
16 #include <linux/err.h>
17 #include <linux/smp.h>
18 #include <linux/jiffies.h>
19 #include <linux/clockchips.h>
20 #include <linux/interrupt.h>
21 #include <linux/io.h>
22 #include <linux/of_irq.h>
23 #include <linux/of_address.h>
24
25 #include <asm/smp_plat.h>
26 #include <asm/smp_twd.h>
27 #include <asm/localtimer.h>
28
29 /* set up by the platform code */
30 static void __iomem *twd_base;
31
32 static struct clk *twd_clk;
33 static unsigned long twd_timer_rate;
34 static DEFINE_PER_CPU(bool, percpu_setup_called);
35
36 static struct clock_event_device __percpu **twd_evt;
37 static int twd_ppi;
38
39 static 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                 __raw_writel(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         __raw_writel(ctrl, twd_base + TWD_TIMER_CONTROL);
62 }
63
64 static 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  */
83 static 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
93 static 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_COMMON_CLK
100
101 /*
102  * Updates clockevent frequency when the cpu frequency changes.
103  * Called on the cpu that is changing frequency with interrupts disabled.
104  */
105 static void twd_update_frequency(void *new_rate)
106 {
107         twd_timer_rate = *((unsigned long *) new_rate);
108
109         clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
110 }
111
112 static int twd_rate_change(struct notifier_block *nb,
113         unsigned long flags, void *data)
114 {
115         struct clk_notifier_data *cnd = 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 (flags == POST_RATE_CHANGE)
123                 smp_call_function(twd_update_frequency,
124                                   (void *)&cnd->new_rate, 1);
125
126         return NOTIFY_OK;
127 }
128
129 static struct notifier_block twd_clk_nb = {
130         .notifier_call = twd_rate_change,
131 };
132
133 static int twd_clk_init(void)
134 {
135         if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
136                 return clk_notifier_register(twd_clk, &twd_clk_nb);
137
138         return 0;
139 }
140 core_initcall(twd_clk_init);
141
142 #elif defined (CONFIG_CPU_FREQ)
143
144 #include <linux/cpufreq.h>
145
146 /*
147  * Updates clockevent frequency when the cpu frequency changes.
148  * Called on the cpu that is changing frequency with interrupts disabled.
149  */
150 static void twd_update_frequency(void *data)
151 {
152         twd_timer_rate = clk_get_rate(twd_clk);
153
154         clockevents_update_freq(*__this_cpu_ptr(twd_evt), twd_timer_rate);
155 }
156
157 static int twd_cpufreq_transition(struct notifier_block *nb,
158         unsigned long state, void *data)
159 {
160         struct cpufreq_freqs *freqs = data;
161
162         /*
163          * The twd clock events must be reprogrammed to account for the new
164          * frequency.  The timer is local to a cpu, so cross-call to the
165          * changing cpu.
166          */
167         if (state == CPUFREQ_POSTCHANGE || state == CPUFREQ_RESUMECHANGE)
168                 smp_call_function_single(freqs->cpu, twd_update_frequency,
169                         NULL, 1);
170
171         return NOTIFY_OK;
172 }
173
174 static struct notifier_block twd_cpufreq_nb = {
175         .notifier_call = twd_cpufreq_transition,
176 };
177
178 static int twd_cpufreq_init(void)
179 {
180         if (twd_evt && *__this_cpu_ptr(twd_evt) && !IS_ERR(twd_clk))
181                 return cpufreq_register_notifier(&twd_cpufreq_nb,
182                         CPUFREQ_TRANSITION_NOTIFIER);
183
184         return 0;
185 }
186 core_initcall(twd_cpufreq_init);
187
188 #endif
189
190 static void __cpuinit twd_calibrate_rate(void)
191 {
192         unsigned long count;
193         u64 waitjiffies;
194
195         /*
196          * If this is the first time round, we need to work out how fast
197          * the timer ticks
198          */
199         if (twd_timer_rate == 0) {
200                 printk(KERN_INFO "Calibrating local timer... ");
201
202                 /* Wait for a tick to start */
203                 waitjiffies = get_jiffies_64() + 1;
204
205                 while (get_jiffies_64() < waitjiffies)
206                         udelay(10);
207
208                 /* OK, now the tick has started, let's get the timer going */
209                 waitjiffies += 5;
210
211                                  /* enable, no interrupt or reload */
212                 __raw_writel(0x1, twd_base + TWD_TIMER_CONTROL);
213
214                                  /* maximum value */
215                 __raw_writel(0xFFFFFFFFU, twd_base + TWD_TIMER_COUNTER);
216
217                 while (get_jiffies_64() < waitjiffies)
218                         udelay(10);
219
220                 count = __raw_readl(twd_base + TWD_TIMER_COUNTER);
221
222                 twd_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
223
224                 printk("%lu.%02luMHz.\n", twd_timer_rate / 1000000,
225                         (twd_timer_rate / 10000) % 100);
226         }
227 }
228
229 static irqreturn_t twd_handler(int irq, void *dev_id)
230 {
231         struct clock_event_device *evt = *(struct clock_event_device **)dev_id;
232
233         if (twd_timer_ack()) {
234                 evt->event_handler(evt);
235                 return IRQ_HANDLED;
236         }
237
238         return IRQ_NONE;
239 }
240
241 static void twd_get_clock(struct device_node *np)
242 {
243         int err;
244
245         if (np)
246                 twd_clk = of_clk_get(np, 0);
247         else
248                 twd_clk = clk_get_sys("smp_twd", NULL);
249
250         if (IS_ERR(twd_clk)) {
251                 pr_err("smp_twd: clock not found %d\n", (int) PTR_ERR(twd_clk));
252                 return;
253         }
254
255         err = clk_prepare_enable(twd_clk);
256         if (err) {
257                 pr_err("smp_twd: clock failed to prepare+enable: %d\n", err);
258                 clk_put(twd_clk);
259                 return;
260         }
261
262         twd_timer_rate = clk_get_rate(twd_clk);
263 }
264
265 /*
266  * Setup the local clock events for a CPU.
267  */
268 static int __cpuinit twd_timer_setup(struct clock_event_device *clk)
269 {
270         struct clock_event_device **this_cpu_clk;
271         int cpu = smp_processor_id();
272
273         /*
274          * If the basic setup for this CPU has been done before don't
275          * bother with the below.
276          */
277         if (per_cpu(percpu_setup_called, cpu)) {
278                 __raw_writel(0, twd_base + TWD_TIMER_CONTROL);
279                 clockevents_register_device(*__this_cpu_ptr(twd_evt));
280                 enable_percpu_irq(clk->irq, 0);
281                 return 0;
282         }
283         per_cpu(percpu_setup_called, cpu) = true;
284
285         twd_calibrate_rate();
286
287         /*
288          * The following is done once per CPU the first time .setup() is
289          * called.
290          */
291         __raw_writel(0, twd_base + TWD_TIMER_CONTROL);
292
293         clk->name = "local_timer";
294         clk->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT |
295                         CLOCK_EVT_FEAT_C3STOP;
296         clk->rating = 350;
297         clk->set_mode = twd_set_mode;
298         clk->set_next_event = twd_set_next_event;
299         clk->irq = twd_ppi;
300
301         this_cpu_clk = __this_cpu_ptr(twd_evt);
302         *this_cpu_clk = clk;
303
304         clockevents_config_and_register(clk, twd_timer_rate,
305                                         0xf, 0xffffffff);
306         enable_percpu_irq(clk->irq, 0);
307
308         return 0;
309 }
310
311 static struct local_timer_ops twd_lt_ops __cpuinitdata = {
312         .setup  = twd_timer_setup,
313         .stop   = twd_timer_stop,
314 };
315
316 static int __init twd_local_timer_common_register(struct device_node *np)
317 {
318         int err;
319
320         twd_evt = alloc_percpu(struct clock_event_device *);
321         if (!twd_evt) {
322                 err = -ENOMEM;
323                 goto out_free;
324         }
325
326         err = request_percpu_irq(twd_ppi, twd_handler, "twd", twd_evt);
327         if (err) {
328                 pr_err("twd: can't register interrupt %d (%d)\n", twd_ppi, err);
329                 goto out_free;
330         }
331
332         err = local_timer_register(&twd_lt_ops);
333         if (err)
334                 goto out_irq;
335
336         twd_get_clock(np);
337
338         return 0;
339
340 out_irq:
341         free_percpu_irq(twd_ppi, twd_evt);
342 out_free:
343         iounmap(twd_base);
344         twd_base = NULL;
345         free_percpu(twd_evt);
346
347         return err;
348 }
349
350 int __init twd_local_timer_register(struct twd_local_timer *tlt)
351 {
352         if (twd_base || twd_evt)
353                 return -EBUSY;
354
355         twd_ppi = tlt->res[1].start;
356
357         twd_base = ioremap(tlt->res[0].start, resource_size(&tlt->res[0]));
358         if (!twd_base)
359                 return -ENOMEM;
360
361         return twd_local_timer_common_register(NULL);
362 }
363
364 #ifdef CONFIG_OF
365 static void __init twd_local_timer_of_register(struct device_node *np)
366 {
367         int err;
368
369         if (!is_smp() || !setup_max_cpus)
370                 return;
371
372         twd_ppi = irq_of_parse_and_map(np, 0);
373         if (!twd_ppi) {
374                 err = -EINVAL;
375                 goto out;
376         }
377
378         twd_base = of_iomap(np, 0);
379         if (!twd_base) {
380                 err = -ENOMEM;
381                 goto out;
382         }
383
384         err = twd_local_timer_common_register(np);
385
386 out:
387         WARN(err, "twd_local_timer_of_register failed (%d)\n", err);
388 }
389 CLOCKSOURCE_OF_DECLARE(arm_twd_a9, "arm,cortex-a9-twd-timer", twd_local_timer_of_register);
390 CLOCKSOURCE_OF_DECLARE(arm_twd_a5, "arm,cortex-a5-twd-timer", twd_local_timer_of_register);
391 CLOCKSOURCE_OF_DECLARE(arm_twd_11mp, "arm,arm11mp-twd-timer", twd_local_timer_of_register);
392 #endif