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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/platform_device.h>
20#include <linux/delay.h>
21#include <linux/percpu.h>
22
23#include <mach/map.h>
24#include <mach/regs-mct.h>
25#include <asm/mach/time.h>
26
27static unsigned long clk_cnt_per_tick;
28static unsigned long clk_rate;
29
30struct mct_clock_event_device {
31 struct clock_event_device *evt;
32 void __iomem *base;
33};
34
35struct mct_clock_event_device mct_tick[2];
36
37static void exynos4_mct_write(unsigned int value, void *addr)
38{
39 void __iomem *stat_addr;
40 u32 mask;
41 u32 i;
42
43 __raw_writel(value, addr);
44
45 switch ((u32) addr) {
46 case (u32) EXYNOS4_MCT_G_TCON:
47 stat_addr = EXYNOS4_MCT_G_WSTAT;
48 mask = 1 << 16; /* G_TCON write status */
49 break;
50 case (u32) EXYNOS4_MCT_G_COMP0_L:
51 stat_addr = EXYNOS4_MCT_G_WSTAT;
52 mask = 1 << 0; /* G_COMP0_L write status */
53 break;
54 case (u32) EXYNOS4_MCT_G_COMP0_U:
55 stat_addr = EXYNOS4_MCT_G_WSTAT;
56 mask = 1 << 1; /* G_COMP0_U write status */
57 break;
58 case (u32) EXYNOS4_MCT_G_COMP0_ADD_INCR:
59 stat_addr = EXYNOS4_MCT_G_WSTAT;
60 mask = 1 << 2; /* G_COMP0_ADD_INCR write status */
61 break;
62 case (u32) EXYNOS4_MCT_G_CNT_L:
63 stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
64 mask = 1 << 0; /* G_CNT_L write status */
65 break;
66 case (u32) EXYNOS4_MCT_G_CNT_U:
67 stat_addr = EXYNOS4_MCT_G_CNT_WSTAT;
68 mask = 1 << 1; /* G_CNT_U write status */
69 break;
70 case (u32)(EXYNOS4_MCT_L0_BASE + MCT_L_TCON_OFFSET):
71 stat_addr = EXYNOS4_MCT_L0_BASE + MCT_L_WSTAT_OFFSET;
72 mask = 1 << 3; /* L0_TCON write status */
73 break;
74 case (u32)(EXYNOS4_MCT_L1_BASE + MCT_L_TCON_OFFSET):
75 stat_addr = EXYNOS4_MCT_L1_BASE + MCT_L_WSTAT_OFFSET;
76 mask = 1 << 3; /* L1_TCON write status */
77 break;
78 case (u32)(EXYNOS4_MCT_L0_BASE + MCT_L_TCNTB_OFFSET):
79 stat_addr = EXYNOS4_MCT_L0_BASE + MCT_L_WSTAT_OFFSET;
80 mask = 1 << 0; /* L0_TCNTB write status */
81 break;
82 case (u32)(EXYNOS4_MCT_L1_BASE + MCT_L_TCNTB_OFFSET):
83 stat_addr = EXYNOS4_MCT_L1_BASE + MCT_L_WSTAT_OFFSET;
84 mask = 1 << 0; /* L1_TCNTB write status */
85 break;
86 case (u32)(EXYNOS4_MCT_L0_BASE + MCT_L_ICNTB_OFFSET):
87 stat_addr = EXYNOS4_MCT_L0_BASE + MCT_L_WSTAT_OFFSET;
88 mask = 1 << 1; /* L0_ICNTB write status */
89 break;
90 case (u32)(EXYNOS4_MCT_L1_BASE + MCT_L_ICNTB_OFFSET):
91 stat_addr = EXYNOS4_MCT_L1_BASE + MCT_L_WSTAT_OFFSET;
92 mask = 1 << 1; /* L1_ICNTB write status */
93 break;
94 default:
95 return;
96 }
97
98 /* Wait maximum 1 ms until written values are applied */
99 for (i = 0; i < loops_per_jiffy / 1000 * HZ; i++)
100 if (__raw_readl(stat_addr) & mask) {
101 __raw_writel(mask, stat_addr);
102 return;
103 }
104
105 panic("MCT hangs after writing %d (addr:0x%08x)\n", value, (u32)addr);
106}
107
108/* Clocksource handling */
109static void exynos4_mct_frc_start(u32 hi, u32 lo)
110{
111 u32 reg;
112
113 exynos4_mct_write(lo, EXYNOS4_MCT_G_CNT_L);
114 exynos4_mct_write(hi, EXYNOS4_MCT_G_CNT_U);
115
116 reg = __raw_readl(EXYNOS4_MCT_G_TCON);
117 reg |= MCT_G_TCON_START;
118 exynos4_mct_write(reg, EXYNOS4_MCT_G_TCON);
119}
120
121static cycle_t exynos4_frc_read(struct clocksource *cs)
122{
123 unsigned int lo, hi;
124 u32 hi2 = __raw_readl(EXYNOS4_MCT_G_CNT_U);
125
126 do {
127 hi = hi2;
128 lo = __raw_readl(EXYNOS4_MCT_G_CNT_L);
129 hi2 = __raw_readl(EXYNOS4_MCT_G_CNT_U);
130 } while (hi != hi2);
131
132 return ((cycle_t)hi << 32) | lo;
133}
134
135static void exynos4_frc_resume(struct clocksource *cs)
136{
137 exynos4_mct_frc_start(0, 0);
138}
139
140struct clocksource mct_frc = {
141 .name = "mct-frc",
142 .rating = 400,
143 .read = exynos4_frc_read,
144 .mask = CLOCKSOURCE_MASK(64),
145 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
146 .resume = exynos4_frc_resume,
147};
148
149static void __init exynos4_clocksource_init(void)
150{
151 exynos4_mct_frc_start(0, 0);
152
153 if (clocksource_register_hz(&mct_frc, clk_rate))
154 panic("%s: can't register clocksource\n", mct_frc.name);
155}
156
157static void exynos4_mct_comp0_stop(void)
158{
159 unsigned int tcon;
160
161 tcon = __raw_readl(EXYNOS4_MCT_G_TCON);
162 tcon &= ~(MCT_G_TCON_COMP0_ENABLE | MCT_G_TCON_COMP0_AUTO_INC);
163
164 exynos4_mct_write(tcon, EXYNOS4_MCT_G_TCON);
165 exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
166}
167
168static void exynos4_mct_comp0_start(enum clock_event_mode mode,
169 unsigned long cycles)
170{
171 unsigned int tcon;
172 cycle_t comp_cycle;
173
174 tcon = __raw_readl(EXYNOS4_MCT_G_TCON);
175
176 if (mode == CLOCK_EVT_MODE_PERIODIC) {
177 tcon |= MCT_G_TCON_COMP0_AUTO_INC;
178 exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
179 }
180
181 comp_cycle = exynos4_frc_read(&mct_frc) + cycles;
182 exynos4_mct_write((u32)comp_cycle, EXYNOS4_MCT_G_COMP0_L);
183 exynos4_mct_write((u32)(comp_cycle >> 32), EXYNOS4_MCT_G_COMP0_U);
184
185 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_ENB);
186
187 tcon |= MCT_G_TCON_COMP0_ENABLE;
188 exynos4_mct_write(tcon , EXYNOS4_MCT_G_TCON);
189}
190
191static int exynos4_comp_set_next_event(unsigned long cycles,
192 struct clock_event_device *evt)
193{
194 exynos4_mct_comp0_start(evt->mode, cycles);
195
196 return 0;
197}
198
199static void exynos4_comp_set_mode(enum clock_event_mode mode,
200 struct clock_event_device *evt)
201{
202 exynos4_mct_comp0_stop();
203
204 switch (mode) {
205 case CLOCK_EVT_MODE_PERIODIC:
206 exynos4_mct_comp0_start(mode, clk_cnt_per_tick);
207 break;
208
209 case CLOCK_EVT_MODE_ONESHOT:
210 case CLOCK_EVT_MODE_UNUSED:
211 case CLOCK_EVT_MODE_SHUTDOWN:
212 case CLOCK_EVT_MODE_RESUME:
213 break;
214 }
215}
216
217static struct clock_event_device mct_comp_device = {
218 .name = "mct-comp",
219 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
220 .rating = 250,
221 .set_next_event = exynos4_comp_set_next_event,
222 .set_mode = exynos4_comp_set_mode,
223};
224
225static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
226{
227 struct clock_event_device *evt = dev_id;
228
229 exynos4_mct_write(0x1, EXYNOS4_MCT_G_INT_CSTAT);
230
231 evt->event_handler(evt);
232
233 return IRQ_HANDLED;
234}
235
236static struct irqaction mct_comp_event_irq = {
237 .name = "mct_comp_irq",
238 .flags = IRQF_TIMER | IRQF_IRQPOLL,
239 .handler = exynos4_mct_comp_isr,
240 .dev_id = &mct_comp_device,
241};
242
243static void exynos4_clockevent_init(void)
244{
245 clk_cnt_per_tick = clk_rate / 2 / HZ;
246
247 clockevents_calc_mult_shift(&mct_comp_device, clk_rate / 2, 5);
248 mct_comp_device.max_delta_ns =
249 clockevent_delta2ns(0xffffffff, &mct_comp_device);
250 mct_comp_device.min_delta_ns =
251 clockevent_delta2ns(0xf, &mct_comp_device);
252 mct_comp_device.cpumask = cpumask_of(0);
253 clockevents_register_device(&mct_comp_device);
254
255 setup_irq(IRQ_MCT_G0, &mct_comp_event_irq);
256}
257
258#ifdef CONFIG_LOCAL_TIMERS
259/* Clock event handling */
260static void exynos4_mct_tick_stop(struct mct_clock_event_device *mevt)
261{
262 unsigned long tmp;
263 unsigned long mask = MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START;
264 void __iomem *addr = mevt->base + MCT_L_TCON_OFFSET;
265
266 tmp = __raw_readl(addr);
267 if (tmp & mask) {
268 tmp &= ~mask;
269 exynos4_mct_write(tmp, addr);
270 }
271}
272
273static void exynos4_mct_tick_start(unsigned long cycles,
274 struct mct_clock_event_device *mevt)
275{
276 unsigned long tmp;
277
278 exynos4_mct_tick_stop(mevt);
279
280 tmp = (1 << 31) | cycles; /* MCT_L_UPDATE_ICNTB */
281
282 /* update interrupt count buffer */
283 exynos4_mct_write(tmp, mevt->base + MCT_L_ICNTB_OFFSET);
284
285 /* enable MCT tick interrupt */
286 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_ENB_OFFSET);
287
288 tmp = __raw_readl(mevt->base + MCT_L_TCON_OFFSET);
289 tmp |= MCT_L_TCON_INT_START | MCT_L_TCON_TIMER_START |
290 MCT_L_TCON_INTERVAL_MODE;
291 exynos4_mct_write(tmp, mevt->base + MCT_L_TCON_OFFSET);
292}
293
294static int exynos4_tick_set_next_event(unsigned long cycles,
295 struct clock_event_device *evt)
296{
297 struct mct_clock_event_device *mevt = &mct_tick[smp_processor_id()];
298
299 exynos4_mct_tick_start(cycles, mevt);
300
301 return 0;
302}
303
304static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
305 struct clock_event_device *evt)
306{
307 struct mct_clock_event_device *mevt = &mct_tick[smp_processor_id()];
308
309 exynos4_mct_tick_stop(mevt);
310
311 switch (mode) {
312 case CLOCK_EVT_MODE_PERIODIC:
313 exynos4_mct_tick_start(clk_cnt_per_tick, mevt);
314 break;
315
316 case CLOCK_EVT_MODE_ONESHOT:
317 case CLOCK_EVT_MODE_UNUSED:
318 case CLOCK_EVT_MODE_SHUTDOWN:
319 case CLOCK_EVT_MODE_RESUME:
320 break;
321 }
322}
323
324static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id)
325{
326 struct mct_clock_event_device *mevt = dev_id;
327 struct clock_event_device *evt = mevt->evt;
328
329 /*
330 * This is for supporting oneshot mode.
331 * Mct would generate interrupt periodically
332 * without explicit stopping.
333 */
334 if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
335 exynos4_mct_tick_stop(mevt);
336
337 /* Clear the MCT tick interrupt */
338 exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET);
339
340 evt->event_handler(evt);
341
342 return IRQ_HANDLED;
343}
344
345static struct irqaction mct_tick0_event_irq = {
346 .name = "mct_tick0_irq",
347 .flags = IRQF_TIMER | IRQF_NOBALANCING,
348 .handler = exynos4_mct_tick_isr,
349};
350
351static struct irqaction mct_tick1_event_irq = {
352 .name = "mct_tick1_irq",
353 .flags = IRQF_TIMER | IRQF_NOBALANCING,
354 .handler = exynos4_mct_tick_isr,
355};
356
357static void exynos4_mct_tick_init(struct clock_event_device *evt)
358{
359 unsigned int cpu = smp_processor_id();
360
361 mct_tick[cpu].evt = evt;
362
363 if (cpu == 0) {
364 mct_tick[cpu].base = EXYNOS4_MCT_L0_BASE;
365 evt->name = "mct_tick0";
366 } else {
367 mct_tick[cpu].base = EXYNOS4_MCT_L1_BASE;
368 evt->name = "mct_tick1";
369 }
370
371 evt->cpumask = cpumask_of(cpu);
372 evt->set_next_event = exynos4_tick_set_next_event;
373 evt->set_mode = exynos4_tick_set_mode;
374 evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
375 evt->rating = 450;
376
377 clockevents_calc_mult_shift(evt, clk_rate / 2, 5);
378 evt->max_delta_ns =
379 clockevent_delta2ns(0x7fffffff, evt);
380 evt->min_delta_ns =
381 clockevent_delta2ns(0xf, evt);
382
383 clockevents_register_device(evt);
384
385 exynos4_mct_write(0x1, mct_tick[cpu].base + MCT_L_TCNTB_OFFSET);
386
387 if (cpu == 0) {
388 mct_tick0_event_irq.dev_id = &mct_tick[cpu];
389 setup_irq(IRQ_MCT_L0, &mct_tick0_event_irq);
390 } else {
391 mct_tick1_event_irq.dev_id = &mct_tick[cpu];
392 setup_irq(IRQ_MCT_L1, &mct_tick1_event_irq);
393 irq_set_affinity(IRQ_MCT_L1, cpumask_of(1));
394 }
395}
396
397/* Setup the local clock events for a CPU */
398int __cpuinit local_timer_setup(struct clock_event_device *evt)
399{
400 exynos4_mct_tick_init(evt);
401
402 return 0;
403}
404
405int local_timer_ack(void)
406{
407 return 0;
408}
409
410#endif /* CONFIG_LOCAL_TIMERS */
411
412static void __init exynos4_timer_resources(void)
413{
414 struct clk *mct_clk;
415 mct_clk = clk_get(NULL, "xtal");
416
417 clk_rate = clk_get_rate(mct_clk);
418}
419
420static void __init exynos4_timer_init(void)
421{
422 exynos4_timer_resources();
423 exynos4_clocksource_init();
424 exynos4_clockevent_init();
425}
426
427struct sys_timer exynos4_timer = {
428 .init = exynos4_timer_init,
429};