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[~andy/linux] / drivers / clocksource / exynos_mct.c
1 /* linux/arch/arm/mach-exynos4/mct.c
2  *
3  * Copyright (c) 2011 Samsung Electronics Co., Ltd.
4  *              http://www.samsung.com
5  *
6  * EXYNOS4 MCT(Multi-Core Timer) support
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License version 2 as
10  * published by the Free Software Foundation.
11 */
12
13 #include <linux/sched.h>
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/err.h>
17 #include <linux/clk.h>
18 #include <linux/clockchips.h>
19 #include <linux/cpu.h>
20 #include <linux/platform_device.h>
21 #include <linux/delay.h>
22 #include <linux/percpu.h>
23 #include <linux/of.h>
24 #include <linux/of_irq.h>
25 #include <linux/of_address.h>
26 #include <linux/clocksource.h>
27
28 #include <asm/mach/time.h>
29
30 #define EXYNOS4_MCTREG(x)               (x)
31 #define EXYNOS4_MCT_G_CNT_L             EXYNOS4_MCTREG(0x100)
32 #define EXYNOS4_MCT_G_CNT_U             EXYNOS4_MCTREG(0x104)
33 #define EXYNOS4_MCT_G_CNT_WSTAT         EXYNOS4_MCTREG(0x110)
34 #define EXYNOS4_MCT_G_COMP0_L           EXYNOS4_MCTREG(0x200)
35 #define EXYNOS4_MCT_G_COMP0_U           EXYNOS4_MCTREG(0x204)
36 #define EXYNOS4_MCT_G_COMP0_ADD_INCR    EXYNOS4_MCTREG(0x208)
37 #define EXYNOS4_MCT_G_TCON              EXYNOS4_MCTREG(0x240)
38 #define EXYNOS4_MCT_G_INT_CSTAT         EXYNOS4_MCTREG(0x244)
39 #define EXYNOS4_MCT_G_INT_ENB           EXYNOS4_MCTREG(0x248)
40 #define EXYNOS4_MCT_G_WSTAT             EXYNOS4_MCTREG(0x24C)
41 #define _EXYNOS4_MCT_L_BASE             EXYNOS4_MCTREG(0x300)
42 #define EXYNOS4_MCT_L_BASE(x)           (_EXYNOS4_MCT_L_BASE + (0x100 * x))
43 #define EXYNOS4_MCT_L_MASK              (0xffffff00)
44
45 #define MCT_L_TCNTB_OFFSET              (0x00)
46 #define MCT_L_ICNTB_OFFSET              (0x08)
47 #define MCT_L_TCON_OFFSET               (0x20)
48 #define MCT_L_INT_CSTAT_OFFSET          (0x30)
49 #define MCT_L_INT_ENB_OFFSET            (0x34)
50 #define MCT_L_WSTAT_OFFSET              (0x40)
51 #define MCT_G_TCON_START                (1 << 8)
52 #define MCT_G_TCON_COMP0_AUTO_INC       (1 << 1)
53 #define MCT_G_TCON_COMP0_ENABLE         (1 << 0)
54 #define MCT_L_TCON_INTERVAL_MODE        (1 << 2)
55 #define MCT_L_TCON_INT_START            (1 << 1)
56 #define MCT_L_TCON_TIMER_START          (1 << 0)
57
58 #define TICK_BASE_CNT   1
59
60 enum {
61         MCT_INT_SPI,
62         MCT_INT_PPI
63 };
64
65 enum {
66         MCT_G0_IRQ,
67         MCT_G1_IRQ,
68         MCT_G2_IRQ,
69         MCT_G3_IRQ,
70         MCT_L0_IRQ,
71         MCT_L1_IRQ,
72         MCT_L2_IRQ,
73         MCT_L3_IRQ,
74         MCT_L4_IRQ,
75         MCT_L5_IRQ,
76         MCT_L6_IRQ,
77         MCT_L7_IRQ,
78         MCT_NR_IRQS,
79 };
80
81 static void __iomem *reg_base;
82 static unsigned long clk_rate;
83 static unsigned int mct_int_type;
84 static int mct_irqs[MCT_NR_IRQS];
85
86 struct mct_clock_event_device {
87         struct clock_event_device evt;
88         unsigned long base;
89         char name[10];
90 };
91
92 static void exynos4_mct_write(unsigned int value, unsigned long offset)
93 {
94         unsigned long stat_addr;
95         u32 mask;
96         u32 i;
97
98         __raw_writel(value, reg_base + offset);
99
100         if (likely(offset >= EXYNOS4_MCT_L_BASE(0))) {
101                 stat_addr = (offset & ~EXYNOS4_MCT_L_MASK) + MCT_L_WSTAT_OFFSET;
102                 switch (offset & EXYNOS4_MCT_L_MASK) {
103                 case MCT_L_TCON_OFFSET:
104                         mask = 1 << 3;          /* L_TCON write status */
105                         break;
106                 case MCT_L_ICNTB_OFFSET:
107                         mask = 1 << 1;          /* L_ICNTB write status */
108                         break;
109                 case MCT_L_TCNTB_OFFSET:
110                         mask = 1 << 0;          /* L_TCNTB write status */
111                         break;
112                 default:
113                         return;
114                 }
115         } else {
116                 switch (offset) {
117                 case EXYNOS4_MCT_G_TCON:
118                         stat_addr = EXYNOS4_MCT_G_WSTAT;
119                         mask = 1 << 16;         /* G_TCON write status */
120                         break;
121                 case EXYNOS4_MCT_G_COMP0_L:
122                         stat_addr = EXYNOS4_MCT_G_WSTAT;
123                         mask = 1 << 0;          /* G_COMP0_L write status */
124                         break;
125                 case EXYNOS4_MCT_G_COMP0_U:
126                         stat_addr = EXYNOS4_MCT_G_WSTAT;
127                         mask = 1 << 1;          /* G_COMP0_U write status */
128                         break;
129                 case EXYNOS4_MCT_G_COMP0_ADD_INCR:
130                         stat_addr = EXYNOS4_MCT_G_WSTAT;
131                         mask = 1 << 2;          /* G_COMP0_ADD_INCR w status */
132                         break;
133                 case EXYNOS4_MCT_G_CNT_L:
134                         stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
135                         mask = 1 << 0;          /* G_CNT_L write status */
136                         break;
137                 case EXYNOS4_MCT_G_CNT_U:
138                         stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
139                         mask = 1 << 1;          /* G_CNT_U write status */
140                         break;
141                 default:
142                         return;
143                 }
144         }
145
146         /* Wait maximum 1 ms until written values are applied */
147         for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
148                 if (__raw_readl(reg_base + stat_addr) & mask) {
149                         __raw_writel(mask, reg_base + stat_addr);
150                         return;
151                 }
152
153         panic("MCT hangs after writing %d (offset:0x%lx)\n", value, offset);
154 }
155
156 /* Clocksource handling */
157 static void exynos4_mct_frc_start(u32 hi, u32 lo)
158 {
159         u32 reg;
160
161         exynos4_mct_write(lo, EXYNOS4_MCT_G_CNT_L);
162         exynos4_mct_write(hi, EXYNOS4_MCT_G_CNT_U);
163
164         reg = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
165         reg |= MCT_G_TCON_START;
166         exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
167 }
168
169 static cycle_t exynos4_frc_read(struct clocksource *cs)
170 {
171         unsigned int lo, hi;
172         u32 hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U);
173
174         do {
175                 hi = hi2;
176                 lo = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_L);
177                 hi2 = __raw_readl(reg_base + EXYNOS4_MCT_G_CNT_U);
178         } while (hi != hi2);
179
180         return ((cycle_t)hi << 32) | lo;
181 }
182
183 static void exynos4_frc_resume(struct clocksource *cs)
184 {
185         exynos4_mct_frc_start(0, 0);
186 }
187
188 struct clocksource mct_frc = {
189         .name           = "mct-frc",
190         .rating         = 400,
191         .read           = exynos4_frc_read,
192         .mask           = CLOCKSOURCE_MASK(64),
193         .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
194         .resume         = exynos4_frc_resume,
195 };
196
197 static void __init exynos4_clocksource_init(void)
198 {
199         exynos4_mct_frc_start(0, 0);
200
201         if (clocksource_register_hz(&mct_frc, clk_rate))
202                 panic("%s: can't register clocksource\n", mct_frc.name);
203 }
204
205 static void exynos4_mct_comp0_stop(void)
206 {
207         unsigned int tcon;
208
209         tcon = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
210         tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
211
212         exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
213         exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
214 }
215
216 static void exynos4_mct_comp0_start(enum clock_event_mode mode,
217                                     unsigned long cycles)
218 {
219         unsigned int tcon;
220         cycle_t comp_cycle;
221
222         tcon = __raw_readl(reg_base + EXYNOS4_MCT_G_TCON);
223
224         if (mode == CLOCK_EVT_MODE_PERIODIC) {
225                 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
226                 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
227         }
228
229         comp_cycle = exynos4_frc_read(&mct_frc) + cycles;
230         exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
231         exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
232
233         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
234
235         tcon |= MCT_G_TCON_COMP0_ENABLE;
236         exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
237 }
238
239 static int exynos4_comp_set_next_event(unsigned long cycles,
240                                        struct clock_event_device *evt)
241 {
242         exynos4_mct_comp0_start(evt->mode, cycles);
243
244         return 0;
245 }
246
247 static void exynos4_comp_set_mode(enum clock_event_mode mode,
248                                   struct clock_event_device *evt)
249 {
250         unsigned long cycles_per_jiffy;
251         exynos4_mct_comp0_stop();
252
253         switch (mode) {
254         case CLOCK_EVT_MODE_PERIODIC:
255                 cycles_per_jiffy =
256                         (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
257                 exynos4_mct_comp0_start(mode, cycles_per_jiffy);
258                 break;
259
260         case CLOCK_EVT_MODE_ONESHOT:
261         case CLOCK_EVT_MODE_UNUSED:
262         case CLOCK_EVT_MODE_SHUTDOWN:
263         case CLOCK_EVT_MODE_RESUME:
264                 break;
265         }
266 }
267
268 static struct clock_event_device mct_comp_device = {
269         .name           = "mct-comp",
270         .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
271         .rating         = 250,
272         .set_next_event = exynos4_comp_set_next_event,
273         .set_mode       = exynos4_comp_set_mode,
274 };
275
276 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
277 {
278         struct clock_event_device *evt = dev_id;
279
280         exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
281
282         evt->event_handler(evt);
283
284         return IRQ_HANDLED;
285 }
286
287 static struct irqaction mct_comp_event_irq = {
288         .name           = "mct_comp_irq",
289         .flags          = IRQF_TIMER | IRQF_IRQPOLL,
290         .handler        = exynos4_mct_comp_isr,
291         .dev_id         = &mct_comp_device,
292 };
293
294 static void exynos4_clockevent_init(void)
295 {
296         mct_comp_device.cpumask = cpumask_of(0);
297         clockevents_config_and_register(&mct_comp_device, clk_rate,
298                                         0xf, 0xffffffff);
299         setup_irq(mct_irqs[MCT_G0_IRQ], &mct_comp_event_irq);
300 }
301
302 static DEFINE_PER_CPU(struct mct_clock_event_device, percpu_mct_tick);
303
304 /* Clock event handling */
305 static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
306 {
307         unsigned long tmp;
308         unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
309         unsigned long offset = mevt->base + MCT_L_TCON_OFFSET;
310
311         tmp = __raw_readl(reg_base + offset);
312         if (tmp & mask) {
313                 tmp &= ~mask;
314                 exynos4_mct_write(tmp, offset);
315         }
316 }
317
318 static void exynos4_mct_tick_start(unsigned long cycles,
319                                    struct mct_clock_event_device *mevt)
320 {
321         unsigned long tmp;
322
323         exynos4_mct_tick_stop(mevt);
324
325         tmp = (1 << 31) | cycles;       /* MCT_L_UPDATE_ICNTB */
326
327         /* update interrupt count buffer */
328         exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
329
330         /* enable MCT tick interrupt */
331         exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
332
333         tmp = __raw_readl(reg_base + mevt->base + MCT_L_TCON_OFFSET);
334         tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
335                MCT_L_TCON_INTERVAL_MODE;
336         exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
337 }
338
339 static int exynos4_tick_set_next_event(unsigned long cycles,
340                                        struct clock_event_device *evt)
341 {
342         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
343
344         exynos4_mct_tick_start(cycles, mevt);
345
346         return 0;
347 }
348
349 static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
350                                          struct clock_event_device *evt)
351 {
352         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
353         unsigned long cycles_per_jiffy;
354
355         exynos4_mct_tick_stop(mevt);
356
357         switch (mode) {
358         case CLOCK_EVT_MODE_PERIODIC:
359                 cycles_per_jiffy =
360                         (((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
361                 exynos4_mct_tick_start(cycles_per_jiffy, mevt);
362                 break;
363
364         case CLOCK_EVT_MODE_ONESHOT:
365         case CLOCK_EVT_MODE_UNUSED:
366         case CLOCK_EVT_MODE_SHUTDOWN:
367         case CLOCK_EVT_MODE_RESUME:
368                 break;
369         }
370 }
371
372 static int exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
373 {
374         struct clock_event_device *evt = &mevt->evt;
375
376         /*
377          * This is for supporting oneshot mode.
378          * Mct would generate interrupt periodically
379          * without explicit stopping.
380          */
381         if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
382                 exynos4_mct_tick_stop(mevt);
383
384         /* Clear the MCT tick interrupt */
385         if (__raw_readl(reg_base + mevt->base + MCT_L_INT_CSTAT_OFFSET) & 1) {
386                 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
387                 return 1;
388         } else {
389                 return 0;
390         }
391 }
392
393 static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
394 {
395         struct mct_clock_event_device *mevt = dev_id;
396         struct clock_event_device *evt = &mevt->evt;
397
398         exynos4_mct_tick_clear(mevt);
399
400         evt->event_handler(evt);
401
402         return IRQ_HANDLED;
403 }
404
405 static int exynos4_local_timer_setup(struct clock_event_device *evt)
406 {
407         struct mct_clock_event_device *mevt;
408         unsigned int cpu = smp_processor_id();
409
410         mevt = container_of(evt, struct mct_clock_event_device, evt);
411
412         mevt->base = EXYNOS4_MCT_L_BASE(cpu);
413         sprintf(mevt->name, "mct_tick%d", cpu);
414
415         evt->name = mevt->name;
416         evt->cpumask = cpumask_of(cpu);
417         evt->set_next_event = exynos4_tick_set_next_event;
418         evt->set_mode = exynos4_tick_set_mode;
419         evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
420         evt->rating = 450;
421         clockevents_config_and_register(evt, clk_rate / (TICK_BASE_CNT + 1),
422                                         0xf, 0x7fffffff);
423
424         exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET);
425
426         if (mct_int_type == MCT_INT_SPI) {
427                 evt->irq = mct_irqs[MCT_L0_IRQ + cpu];
428                 if (request_irq(evt->irq, exynos4_mct_tick_isr,
429                                 IRQF_TIMER | IRQF_NOBALANCING,
430                                 evt->name, mevt)) {
431                         pr_err("exynos-mct: cannot register IRQ %d\n",
432                                 evt->irq);
433                         return -EIO;
434                 }
435         } else {
436                 enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0);
437         }
438
439         return 0;
440 }
441
442 static void exynos4_local_timer_stop(struct clock_event_device *evt)
443 {
444         evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
445         if (mct_int_type == MCT_INT_SPI)
446                 free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick));
447         else
448                 disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);
449 }
450
451 static int exynos4_mct_cpu_notify(struct notifier_block *self,
452                                            unsigned long action, void *hcpu)
453 {
454         struct mct_clock_event_device *mevt;
455         unsigned int cpu;
456
457         /*
458          * Grab cpu pointer in each case to avoid spurious
459          * preemptible warnings
460          */
461         switch (action & ~CPU_TASKS_FROZEN) {
462         case CPU_STARTING:
463                 mevt = this_cpu_ptr(&percpu_mct_tick);
464                 exynos4_local_timer_setup(&mevt->evt);
465                 break;
466         case CPU_ONLINE:
467                 cpu = (unsigned long)hcpu;
468                 if (mct_int_type == MCT_INT_SPI)
469                         irq_set_affinity(mct_irqs[MCT_L0_IRQ + cpu],
470                                                 cpumask_of(cpu));
471                 break;
472         case CPU_DYING:
473                 mevt = this_cpu_ptr(&percpu_mct_tick);
474                 exynos4_local_timer_stop(&mevt->evt);
475                 break;
476         }
477
478         return NOTIFY_OK;
479 }
480
481 static struct notifier_block exynos4_mct_cpu_nb = {
482         .notifier_call = exynos4_mct_cpu_notify,
483 };
484
485 static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base)
486 {
487         int err;
488         struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
489         struct clk *mct_clk, *tick_clk;
490
491         tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
492                                 clk_get(NULL, "fin_pll");
493         if (IS_ERR(tick_clk))
494                 panic("%s: unable to determine tick clock rate\n", __func__);
495         clk_rate = clk_get_rate(tick_clk);
496
497         mct_clk = np ? of_clk_get_by_name(np, "mct") : clk_get(NULL, "mct");
498         if (IS_ERR(mct_clk))
499                 panic("%s: unable to retrieve mct clock instance\n", __func__);
500         clk_prepare_enable(mct_clk);
501
502         reg_base = base;
503         if (!reg_base)
504                 panic("%s: unable to ioremap mct address space\n", __func__);
505
506         if (mct_int_type == MCT_INT_PPI) {
507
508                 err = request_percpu_irq(mct_irqs[MCT_L0_IRQ],
509                                          exynos4_mct_tick_isr, "MCT",
510                                          &percpu_mct_tick);
511                 WARN(err, "MCT: can't request IRQ %d (%d)\n",
512                      mct_irqs[MCT_L0_IRQ], err);
513         } else {
514                 irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0));
515         }
516
517         err = register_cpu_notifier(&exynos4_mct_cpu_nb);
518         if (err)
519                 goto out_irq;
520
521         /* Immediately configure the timer on the boot CPU */
522         exynos4_local_timer_setup(&mevt->evt);
523         return;
524
525 out_irq:
526         free_percpu_irq(mct_irqs[MCT_L0_IRQ], &percpu_mct_tick);
527 }
528
529 void __init mct_init(void __iomem *base, int irq_g0, int irq_l0, int irq_l1)
530 {
531         mct_irqs[MCT_G0_IRQ] = irq_g0;
532         mct_irqs[MCT_L0_IRQ] = irq_l0;
533         mct_irqs[MCT_L1_IRQ] = irq_l1;
534         mct_int_type = MCT_INT_SPI;
535
536         exynos4_timer_resources(NULL, base);
537         exynos4_clocksource_init();
538         exynos4_clockevent_init();
539 }
540
541 static void __init mct_init_dt(struct device_node *np, unsigned int int_type)
542 {
543         u32 nr_irqs, i;
544
545         mct_int_type = int_type;
546
547         /* This driver uses only one global timer interrupt */
548         mct_irqs[MCT_G0_IRQ] = irq_of_parse_and_map(np, MCT_G0_IRQ);
549
550         /*
551          * Find out the number of local irqs specified. The local
552          * timer irqs are specified after the four global timer
553          * irqs are specified.
554          */
555 #ifdef CONFIG_OF
556         nr_irqs = of_irq_count(np);
557 #else
558         nr_irqs = 0;
559 #endif
560         for (i = MCT_L0_IRQ; i < nr_irqs; i++)
561                 mct_irqs[i] = irq_of_parse_and_map(np, i);
562
563         exynos4_timer_resources(np, of_iomap(np, 0));
564         exynos4_clocksource_init();
565         exynos4_clockevent_init();
566 }
567
568
569 static void __init mct_init_spi(struct device_node *np)
570 {
571         return mct_init_dt(np, MCT_INT_SPI);
572 }
573
574 static void __init mct_init_ppi(struct device_node *np)
575 {
576         return mct_init_dt(np, MCT_INT_PPI);
577 }
578 CLOCKSOURCE_OF_DECLARE(exynos4210, "samsung,exynos4210-mct", mct_init_spi);
579 CLOCKSOURCE_OF_DECLARE(exynos4412, "samsung,exynos4412-mct", mct_init_ppi);