1 /*
2 * DaVinci timer subsystem
3 *
4 * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com>
5 *
6 * 2007 (c) MontaVista Software, Inc. This file is licensed under
7 * the terms of the GNU General Public License version 2. This program
8 * is licensed "as is" without any warranty of any kind, whether express
9 * or implied.
10 */
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/interrupt.h>
15 #include <linux/clocksource.h>
16 #include <linux/clockchips.h>
17 #include <linux/io.h>
18 #include <linux/clk.h>
19 #include <linux/err.h>
20 #include <linux/platform_device.h>
21 #include <linux/sched_clock.h>
22
23 #include <asm/mach/irq.h>
24 #include <asm/mach/time.h>
25
26 #include <mach/cputype.h>
27 #include <mach/hardware.h>
28 #include <mach/time.h>
29
30 #include "clock.h"
31
32 static struct clock_event_device clockevent_davinci;
33 static unsigned int davinci_clock_tick_rate;
34
35 /*
36 * This driver configures the 2 64-bit count-up timers as 4 independent
37 * 32-bit count-up timers used as follows:
38 */
39
40 enum {
41 TID_CLOCKEVENT,
42 TID_CLOCKSOURCE,
43 };
44
45 /* Timer register offsets */
46 #define PID12 0x0
47 #define TIM12 0x10
48 #define TIM34 0x14
49 #define PRD12 0x18
50 #define PRD34 0x1c
51 #define TCR 0x20
52 #define TGCR 0x24
53 #define WDTCR 0x28
54
55 /* Offsets of the 8 compare registers */
56 #define CMP12_0 0x60
57 #define CMP12_1 0x64
58 #define CMP12_2 0x68
59 #define CMP12_3 0x6c
60 #define CMP12_4 0x70
61 #define CMP12_5 0x74
62 #define CMP12_6 0x78
63 #define CMP12_7 0x7c
64
65 /* Timer register bitfields */
66 #define TCR_ENAMODE_DISABLE 0x0
67 #define TCR_ENAMODE_ONESHOT 0x1
68 #define TCR_ENAMODE_PERIODIC 0x2
69 #define TCR_ENAMODE_MASK 0x3
70
71 #define TGCR_TIMMODE_SHIFT 2
72 #define TGCR_TIMMODE_64BIT_GP 0x0
73 #define TGCR_TIMMODE_32BIT_UNCHAINED 0x1
74 #define TGCR_TIMMODE_64BIT_WDOG 0x2
75 #define TGCR_TIMMODE_32BIT_CHAINED 0x3
76
77 #define TGCR_TIM12RS_SHIFT 0
78 #define TGCR_TIM34RS_SHIFT 1
79 #define TGCR_RESET 0x0
80 #define TGCR_UNRESET 0x1
81 #define TGCR_RESET_MASK 0x3
82
83 #define WDTCR_WDEN_SHIFT 14
84 #define WDTCR_WDEN_DISABLE 0x0
85 #define WDTCR_WDEN_ENABLE 0x1
86 #define WDTCR_WDKEY_SHIFT 16
87 #define WDTCR_WDKEY_SEQ0 0xa5c6
88 #define WDTCR_WDKEY_SEQ1 0xda7e
89
90 struct timer_s {
91 char *name;
92 unsigned int id;
93 unsigned long period;
94 unsigned long opts;
95 unsigned long flags;
96 void __iomem *base;
97 unsigned long tim_off;
98 unsigned long prd_off;
99 unsigned long enamode_shift;
100 struct irqaction irqaction;
101 };
102 static struct timer_s timers[];
103
104 /* values for 'opts' field of struct timer_s */
105 #define TIMER_OPTS_DISABLED 0x01
106 #define TIMER_OPTS_ONESHOT 0x02
107 #define TIMER_OPTS_PERIODIC 0x04
108 #define TIMER_OPTS_STATE_MASK 0x07
109
110 #define TIMER_OPTS_USE_COMPARE 0x80000000
111 #define USING_COMPARE(t) ((t)->opts & TIMER_OPTS_USE_COMPARE)
112
113 static char *id_to_name[] = {
114 [T0_BOT] = "timer0_0",
115 [T0_TOP] = "timer0_1",
116 [T1_BOT] = "timer1_0",
117 [T1_TOP] = "timer1_1",
118 };
119
timer32_config(struct timer_s * t)120 static int timer32_config(struct timer_s *t)
121 {
122 u32 tcr;
123 struct davinci_soc_info *soc_info = &davinci_soc_info;
124
125 if (USING_COMPARE(t)) {
126 struct davinci_timer_instance *dtip =
127 soc_info->timer_info->timers;
128 int event_timer = ID_TO_TIMER(timers[TID_CLOCKEVENT].id);
129
130 /*
131 * Next interrupt should be the current time reg value plus
132 * the new period (using 32-bit unsigned addition/wrapping
133 * to 0 on overflow). This assumes that the clocksource
134 * is setup to count to 2^32-1 before wrapping around to 0.
135 */
136 __raw_writel(__raw_readl(t->base + t->tim_off) + t->period,
137 t->base + dtip[event_timer].cmp_off);
138 } else {
139 tcr = __raw_readl(t->base + TCR);
140
141 /* disable timer */
142 tcr &= ~(TCR_ENAMODE_MASK << t->enamode_shift);
143 __raw_writel(tcr, t->base + TCR);
144
145 /* reset counter to zero, set new period */
146 __raw_writel(0, t->base + t->tim_off);
147 __raw_writel(t->period, t->base + t->prd_off);
148
149 /* Set enable mode */
150 if (t->opts & TIMER_OPTS_ONESHOT)
151 tcr |= TCR_ENAMODE_ONESHOT << t->enamode_shift;
152 else if (t->opts & TIMER_OPTS_PERIODIC)
153 tcr |= TCR_ENAMODE_PERIODIC << t->enamode_shift;
154
155 __raw_writel(tcr, t->base + TCR);
156 }
157 return 0;
158 }
159
timer32_read(struct timer_s * t)160 static inline u32 timer32_read(struct timer_s *t)
161 {
162 return __raw_readl(t->base + t->tim_off);
163 }
164
timer_interrupt(int irq,void * dev_id)165 static irqreturn_t timer_interrupt(int irq, void *dev_id)
166 {
167 struct clock_event_device *evt = &clockevent_davinci;
168
169 evt->event_handler(evt);
170 return IRQ_HANDLED;
171 }
172
173 /* called when 32-bit counter wraps */
freerun_interrupt(int irq,void * dev_id)174 static irqreturn_t freerun_interrupt(int irq, void *dev_id)
175 {
176 return IRQ_HANDLED;
177 }
178
179 static struct timer_s timers[] = {
180 [TID_CLOCKEVENT] = {
181 .name = "clockevent",
182 .opts = TIMER_OPTS_DISABLED,
183 .irqaction = {
184 .flags = IRQF_TIMER,
185 .handler = timer_interrupt,
186 }
187 },
188 [TID_CLOCKSOURCE] = {
189 .name = "free-run counter",
190 .period = ~0,
191 .opts = TIMER_OPTS_PERIODIC,
192 .irqaction = {
193 .flags = IRQF_TIMER,
194 .handler = freerun_interrupt,
195 }
196 },
197 };
198
timer_init(void)199 static void __init timer_init(void)
200 {
201 struct davinci_soc_info *soc_info = &davinci_soc_info;
202 struct davinci_timer_instance *dtip = soc_info->timer_info->timers;
203 void __iomem *base[2];
204 int i;
205
206 /* Global init of each 64-bit timer as a whole */
207 for(i=0; i<2; i++) {
208 u32 tgcr;
209
210 base[i] = ioremap(dtip[i].base, SZ_4K);
211 if (WARN_ON(!base[i]))
212 continue;
213
214 /* Disabled, Internal clock source */
215 __raw_writel(0, base[i] + TCR);
216
217 /* reset both timers, no pre-scaler for timer34 */
218 tgcr = 0;
219 __raw_writel(tgcr, base[i] + TGCR);
220
221 /* Set both timers to unchained 32-bit */
222 tgcr = TGCR_TIMMODE_32BIT_UNCHAINED << TGCR_TIMMODE_SHIFT;
223 __raw_writel(tgcr, base[i] + TGCR);
224
225 /* Unreset timers */
226 tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
227 (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
228 __raw_writel(tgcr, base[i] + TGCR);
229
230 /* Init both counters to zero */
231 __raw_writel(0, base[i] + TIM12);
232 __raw_writel(0, base[i] + TIM34);
233 }
234
235 /* Init of each timer as a 32-bit timer */
236 for (i=0; i< ARRAY_SIZE(timers); i++) {
237 struct timer_s *t = &timers[i];
238 int timer = ID_TO_TIMER(t->id);
239 u32 irq;
240
241 t->base = base[timer];
242 if (!t->base)
243 continue;
244
245 if (IS_TIMER_BOT(t->id)) {
246 t->enamode_shift = 6;
247 t->tim_off = TIM12;
248 t->prd_off = PRD12;
249 irq = dtip[timer].bottom_irq;
250 } else {
251 t->enamode_shift = 22;
252 t->tim_off = TIM34;
253 t->prd_off = PRD34;
254 irq = dtip[timer].top_irq;
255 }
256
257 /* Register interrupt */
258 t->irqaction.name = t->name;
259 t->irqaction.dev_id = (void *)t;
260
261 if (t->irqaction.handler != NULL) {
262 irq = USING_COMPARE(t) ? dtip[i].cmp_irq : irq;
263 setup_irq(irq, &t->irqaction);
264 }
265 }
266 }
267
268 /*
269 * clocksource
270 */
read_cycles(struct clocksource * cs)271 static cycle_t read_cycles(struct clocksource *cs)
272 {
273 struct timer_s *t = &timers[TID_CLOCKSOURCE];
274
275 return (cycles_t)timer32_read(t);
276 }
277
278 static struct clocksource clocksource_davinci = {
279 .rating = 300,
280 .read = read_cycles,
281 .mask = CLOCKSOURCE_MASK(32),
282 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
283 };
284
285 /*
286 * Overwrite weak default sched_clock with something more precise
287 */
davinci_read_sched_clock(void)288 static u64 notrace davinci_read_sched_clock(void)
289 {
290 return timer32_read(&timers[TID_CLOCKSOURCE]);
291 }
292
293 /*
294 * clockevent
295 */
davinci_set_next_event(unsigned long cycles,struct clock_event_device * evt)296 static int davinci_set_next_event(unsigned long cycles,
297 struct clock_event_device *evt)
298 {
299 struct timer_s *t = &timers[TID_CLOCKEVENT];
300
301 t->period = cycles;
302 timer32_config(t);
303 return 0;
304 }
305
davinci_shutdown(struct clock_event_device * evt)306 static int davinci_shutdown(struct clock_event_device *evt)
307 {
308 struct timer_s *t = &timers[TID_CLOCKEVENT];
309
310 t->opts &= ~TIMER_OPTS_STATE_MASK;
311 t->opts |= TIMER_OPTS_DISABLED;
312 return 0;
313 }
314
davinci_set_oneshot(struct clock_event_device * evt)315 static int davinci_set_oneshot(struct clock_event_device *evt)
316 {
317 struct timer_s *t = &timers[TID_CLOCKEVENT];
318
319 t->opts &= ~TIMER_OPTS_STATE_MASK;
320 t->opts |= TIMER_OPTS_ONESHOT;
321 return 0;
322 }
323
davinci_set_periodic(struct clock_event_device * evt)324 static int davinci_set_periodic(struct clock_event_device *evt)
325 {
326 struct timer_s *t = &timers[TID_CLOCKEVENT];
327
328 t->period = davinci_clock_tick_rate / (HZ);
329 t->opts &= ~TIMER_OPTS_STATE_MASK;
330 t->opts |= TIMER_OPTS_PERIODIC;
331 timer32_config(t);
332 return 0;
333 }
334
335 static struct clock_event_device clockevent_davinci = {
336 .features = CLOCK_EVT_FEAT_PERIODIC |
337 CLOCK_EVT_FEAT_ONESHOT,
338 .set_next_event = davinci_set_next_event,
339 .set_state_shutdown = davinci_shutdown,
340 .set_state_periodic = davinci_set_periodic,
341 .set_state_oneshot = davinci_set_oneshot,
342 };
343
344
davinci_timer_init(void)345 void __init davinci_timer_init(void)
346 {
347 struct clk *timer_clk;
348 struct davinci_soc_info *soc_info = &davinci_soc_info;
349 unsigned int clockevent_id;
350 unsigned int clocksource_id;
351 int i;
352
353 clockevent_id = soc_info->timer_info->clockevent_id;
354 clocksource_id = soc_info->timer_info->clocksource_id;
355
356 timers[TID_CLOCKEVENT].id = clockevent_id;
357 timers[TID_CLOCKSOURCE].id = clocksource_id;
358
359 /*
360 * If using same timer for both clock events & clocksource,
361 * a compare register must be used to generate an event interrupt.
362 * This is equivalent to a oneshot timer only (not periodic).
363 */
364 if (clockevent_id == clocksource_id) {
365 struct davinci_timer_instance *dtip =
366 soc_info->timer_info->timers;
367 int event_timer = ID_TO_TIMER(clockevent_id);
368
369 /* Only bottom timers can use compare regs */
370 if (IS_TIMER_TOP(clockevent_id))
371 pr_warn("%s: Invalid use of system timers. Results unpredictable.\n",
372 __func__);
373 else if ((dtip[event_timer].cmp_off == 0)
374 || (dtip[event_timer].cmp_irq == 0))
375 pr_warn("%s: Invalid timer instance setup. Results unpredictable.\n",
376 __func__);
377 else {
378 timers[TID_CLOCKEVENT].opts |= TIMER_OPTS_USE_COMPARE;
379 clockevent_davinci.features = CLOCK_EVT_FEAT_ONESHOT;
380 }
381 }
382
383 timer_clk = clk_get(NULL, "timer0");
384 BUG_ON(IS_ERR(timer_clk));
385 clk_prepare_enable(timer_clk);
386
387 /* init timer hw */
388 timer_init();
389
390 davinci_clock_tick_rate = clk_get_rate(timer_clk);
391
392 /* setup clocksource */
393 clocksource_davinci.name = id_to_name[clocksource_id];
394 if (clocksource_register_hz(&clocksource_davinci,
395 davinci_clock_tick_rate))
396 pr_err("%s: can't register clocksource!\n",
397 clocksource_davinci.name);
398
399 sched_clock_register(davinci_read_sched_clock, 32,
400 davinci_clock_tick_rate);
401
402 /* setup clockevent */
403 clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id];
404
405 clockevent_davinci.cpumask = cpumask_of(0);
406 clockevents_config_and_register(&clockevent_davinci,
407 davinci_clock_tick_rate, 1, 0xfffffffe);
408
409 for (i=0; i< ARRAY_SIZE(timers); i++)
410 timer32_config(&timers[i]);
411 }
412
413 /* reset board using watchdog timer */
davinci_watchdog_reset(struct platform_device * pdev)414 void davinci_watchdog_reset(struct platform_device *pdev)
415 {
416 u32 tgcr, wdtcr;
417 void __iomem *base;
418 struct clk *wd_clk;
419
420 base = ioremap(pdev->resource[0].start, SZ_4K);
421 if (WARN_ON(!base))
422 return;
423
424 wd_clk = clk_get(&pdev->dev, NULL);
425 if (WARN_ON(IS_ERR(wd_clk)))
426 return;
427 clk_prepare_enable(wd_clk);
428
429 /* disable, internal clock source */
430 __raw_writel(0, base + TCR);
431
432 /* reset timer, set mode to 64-bit watchdog, and unreset */
433 tgcr = 0;
434 __raw_writel(tgcr, base + TGCR);
435 tgcr = TGCR_TIMMODE_64BIT_WDOG << TGCR_TIMMODE_SHIFT;
436 tgcr |= (TGCR_UNRESET << TGCR_TIM12RS_SHIFT) |
437 (TGCR_UNRESET << TGCR_TIM34RS_SHIFT);
438 __raw_writel(tgcr, base + TGCR);
439
440 /* clear counter and period regs */
441 __raw_writel(0, base + TIM12);
442 __raw_writel(0, base + TIM34);
443 __raw_writel(0, base + PRD12);
444 __raw_writel(0, base + PRD34);
445
446 /* put watchdog in pre-active state */
447 wdtcr = __raw_readl(base + WDTCR);
448 wdtcr = (WDTCR_WDKEY_SEQ0 << WDTCR_WDKEY_SHIFT) |
449 (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
450 __raw_writel(wdtcr, base + WDTCR);
451
452 /* put watchdog in active state */
453 wdtcr = (WDTCR_WDKEY_SEQ1 << WDTCR_WDKEY_SHIFT) |
454 (WDTCR_WDEN_ENABLE << WDTCR_WDEN_SHIFT);
455 __raw_writel(wdtcr, base + WDTCR);
456
457 /* write an invalid value to the WDKEY field to trigger
458 * a watchdog reset */
459 wdtcr = 0x00004000;
460 __raw_writel(wdtcr, base + WDTCR);
461 }
462