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1/*
2 * Copyright (C) 2007-2009 ST-Ericsson AB
3 * License terms: GNU General Public License (GPL) version 2
4 * Timer COH 901 328, runs the OS timer interrupt.
5 * Author: Linus Walleij <linus.walleij@stericsson.com>
6 */
7#include <linux/interrupt.h>
8#include <linux/time.h>
9#include <linux/timex.h>
10#include <linux/clockchips.h>
11#include <linux/clocksource.h>
12#include <linux/types.h>
13#include <linux/io.h>
14#include <linux/clk.h>
15#include <linux/err.h>
16#include <linux/irq.h>
17#include <linux/delay.h>
18#include <linux/of_address.h>
19#include <linux/of_irq.h>
20#include <linux/sched_clock.h>
21
22/* Generic stuff */
23#include <asm/mach/map.h>
24#include <asm/mach/time.h>
25
26/*
27 * APP side special timer registers
28 * This timer contains four timers which can fire an interrupt each.
29 * OS (operating system) timer @ 32768 Hz
30 * DD (device driver) timer @ 1 kHz
31 * GP1 (general purpose 1) timer @ 1MHz
32 * GP2 (general purpose 2) timer @ 1MHz
33 */
34
35/* Reset OS Timer 32bit (-/W) */
36#define U300_TIMER_APP_ROST (0x0000)
37#define U300_TIMER_APP_ROST_TIMER_RESET (0x00000000)
38/* Enable OS Timer 32bit (-/W) */
39#define U300_TIMER_APP_EOST (0x0004)
40#define U300_TIMER_APP_EOST_TIMER_ENABLE (0x00000000)
41/* Disable OS Timer 32bit (-/W) */
42#define U300_TIMER_APP_DOST (0x0008)
43#define U300_TIMER_APP_DOST_TIMER_DISABLE (0x00000000)
44/* OS Timer Mode Register 32bit (-/W) */
45#define U300_TIMER_APP_SOSTM (0x000c)
46#define U300_TIMER_APP_SOSTM_MODE_CONTINUOUS (0x00000000)
47#define U300_TIMER_APP_SOSTM_MODE_ONE_SHOT (0x00000001)
48/* OS Timer Status Register 32bit (R/-) */
49#define U300_TIMER_APP_OSTS (0x0010)
50#define U300_TIMER_APP_OSTS_TIMER_STATE_MASK (0x0000000F)
51#define U300_TIMER_APP_OSTS_TIMER_STATE_IDLE (0x00000001)
52#define U300_TIMER_APP_OSTS_TIMER_STATE_ACTIVE (0x00000002)
53#define U300_TIMER_APP_OSTS_ENABLE_IND (0x00000010)
54#define U300_TIMER_APP_OSTS_MODE_MASK (0x00000020)
55#define U300_TIMER_APP_OSTS_MODE_CONTINUOUS (0x00000000)
56#define U300_TIMER_APP_OSTS_MODE_ONE_SHOT (0x00000020)
57#define U300_TIMER_APP_OSTS_IRQ_ENABLED_IND (0x00000040)
58#define U300_TIMER_APP_OSTS_IRQ_PENDING_IND (0x00000080)
59/* OS Timer Current Count Register 32bit (R/-) */
60#define U300_TIMER_APP_OSTCC (0x0014)
61/* OS Timer Terminal Count Register 32bit (R/W) */
62#define U300_TIMER_APP_OSTTC (0x0018)
63/* OS Timer Interrupt Enable Register 32bit (-/W) */
64#define U300_TIMER_APP_OSTIE (0x001c)
65#define U300_TIMER_APP_OSTIE_IRQ_DISABLE (0x00000000)
66#define U300_TIMER_APP_OSTIE_IRQ_ENABLE (0x00000001)
67/* OS Timer Interrupt Acknowledge Register 32bit (-/W) */
68#define U300_TIMER_APP_OSTIA (0x0020)
69#define U300_TIMER_APP_OSTIA_IRQ_ACK (0x00000080)
70
71/* Reset DD Timer 32bit (-/W) */
72#define U300_TIMER_APP_RDDT (0x0040)
73#define U300_TIMER_APP_RDDT_TIMER_RESET (0x00000000)
74/* Enable DD Timer 32bit (-/W) */
75#define U300_TIMER_APP_EDDT (0x0044)
76#define U300_TIMER_APP_EDDT_TIMER_ENABLE (0x00000000)
77/* Disable DD Timer 32bit (-/W) */
78#define U300_TIMER_APP_DDDT (0x0048)
79#define U300_TIMER_APP_DDDT_TIMER_DISABLE (0x00000000)
80/* DD Timer Mode Register 32bit (-/W) */
81#define U300_TIMER_APP_SDDTM (0x004c)
82#define U300_TIMER_APP_SDDTM_MODE_CONTINUOUS (0x00000000)
83#define U300_TIMER_APP_SDDTM_MODE_ONE_SHOT (0x00000001)
84/* DD Timer Status Register 32bit (R/-) */
85#define U300_TIMER_APP_DDTS (0x0050)
86#define U300_TIMER_APP_DDTS_TIMER_STATE_MASK (0x0000000F)
87#define U300_TIMER_APP_DDTS_TIMER_STATE_IDLE (0x00000001)
88#define U300_TIMER_APP_DDTS_TIMER_STATE_ACTIVE (0x00000002)
89#define U300_TIMER_APP_DDTS_ENABLE_IND (0x00000010)
90#define U300_TIMER_APP_DDTS_MODE_MASK (0x00000020)
91#define U300_TIMER_APP_DDTS_MODE_CONTINUOUS (0x00000000)
92#define U300_TIMER_APP_DDTS_MODE_ONE_SHOT (0x00000020)
93#define U300_TIMER_APP_DDTS_IRQ_ENABLED_IND (0x00000040)
94#define U300_TIMER_APP_DDTS_IRQ_PENDING_IND (0x00000080)
95/* DD Timer Current Count Register 32bit (R/-) */
96#define U300_TIMER_APP_DDTCC (0x0054)
97/* DD Timer Terminal Count Register 32bit (R/W) */
98#define U300_TIMER_APP_DDTTC (0x0058)
99/* DD Timer Interrupt Enable Register 32bit (-/W) */
100#define U300_TIMER_APP_DDTIE (0x005c)
101#define U300_TIMER_APP_DDTIE_IRQ_DISABLE (0x00000000)
102#define U300_TIMER_APP_DDTIE_IRQ_ENABLE (0x00000001)
103/* DD Timer Interrupt Acknowledge Register 32bit (-/W) */
104#define U300_TIMER_APP_DDTIA (0x0060)
105#define U300_TIMER_APP_DDTIA_IRQ_ACK (0x00000080)
106
107/* Reset GP1 Timer 32bit (-/W) */
108#define U300_TIMER_APP_RGPT1 (0x0080)
109#define U300_TIMER_APP_RGPT1_TIMER_RESET (0x00000000)
110/* Enable GP1 Timer 32bit (-/W) */
111#define U300_TIMER_APP_EGPT1 (0x0084)
112#define U300_TIMER_APP_EGPT1_TIMER_ENABLE (0x00000000)
113/* Disable GP1 Timer 32bit (-/W) */
114#define U300_TIMER_APP_DGPT1 (0x0088)
115#define U300_TIMER_APP_DGPT1_TIMER_DISABLE (0x00000000)
116/* GP1 Timer Mode Register 32bit (-/W) */
117#define U300_TIMER_APP_SGPT1M (0x008c)
118#define U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS (0x00000000)
119#define U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT (0x00000001)
120/* GP1 Timer Status Register 32bit (R/-) */
121#define U300_TIMER_APP_GPT1S (0x0090)
122#define U300_TIMER_APP_GPT1S_TIMER_STATE_MASK (0x0000000F)
123#define U300_TIMER_APP_GPT1S_TIMER_STATE_IDLE (0x00000001)
124#define U300_TIMER_APP_GPT1S_TIMER_STATE_ACTIVE (0x00000002)
125#define U300_TIMER_APP_GPT1S_ENABLE_IND (0x00000010)
126#define U300_TIMER_APP_GPT1S_MODE_MASK (0x00000020)
127#define U300_TIMER_APP_GPT1S_MODE_CONTINUOUS (0x00000000)
128#define U300_TIMER_APP_GPT1S_MODE_ONE_SHOT (0x00000020)
129#define U300_TIMER_APP_GPT1S_IRQ_ENABLED_IND (0x00000040)
130#define U300_TIMER_APP_GPT1S_IRQ_PENDING_IND (0x00000080)
131/* GP1 Timer Current Count Register 32bit (R/-) */
132#define U300_TIMER_APP_GPT1CC (0x0094)
133/* GP1 Timer Terminal Count Register 32bit (R/W) */
134#define U300_TIMER_APP_GPT1TC (0x0098)
135/* GP1 Timer Interrupt Enable Register 32bit (-/W) */
136#define U300_TIMER_APP_GPT1IE (0x009c)
137#define U300_TIMER_APP_GPT1IE_IRQ_DISABLE (0x00000000)
138#define U300_TIMER_APP_GPT1IE_IRQ_ENABLE (0x00000001)
139/* GP1 Timer Interrupt Acknowledge Register 32bit (-/W) */
140#define U300_TIMER_APP_GPT1IA (0x00a0)
141#define U300_TIMER_APP_GPT1IA_IRQ_ACK (0x00000080)
142
143/* Reset GP2 Timer 32bit (-/W) */
144#define U300_TIMER_APP_RGPT2 (0x00c0)
145#define U300_TIMER_APP_RGPT2_TIMER_RESET (0x00000000)
146/* Enable GP2 Timer 32bit (-/W) */
147#define U300_TIMER_APP_EGPT2 (0x00c4)
148#define U300_TIMER_APP_EGPT2_TIMER_ENABLE (0x00000000)
149/* Disable GP2 Timer 32bit (-/W) */
150#define U300_TIMER_APP_DGPT2 (0x00c8)
151#define U300_TIMER_APP_DGPT2_TIMER_DISABLE (0x00000000)
152/* GP2 Timer Mode Register 32bit (-/W) */
153#define U300_TIMER_APP_SGPT2M (0x00cc)
154#define U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS (0x00000000)
155#define U300_TIMER_APP_SGPT2M_MODE_ONE_SHOT (0x00000001)
156/* GP2 Timer Status Register 32bit (R/-) */
157#define U300_TIMER_APP_GPT2S (0x00d0)
158#define U300_TIMER_APP_GPT2S_TIMER_STATE_MASK (0x0000000F)
159#define U300_TIMER_APP_GPT2S_TIMER_STATE_IDLE (0x00000001)
160#define U300_TIMER_APP_GPT2S_TIMER_STATE_ACTIVE (0x00000002)
161#define U300_TIMER_APP_GPT2S_ENABLE_IND (0x00000010)
162#define U300_TIMER_APP_GPT2S_MODE_MASK (0x00000020)
163#define U300_TIMER_APP_GPT2S_MODE_CONTINUOUS (0x00000000)
164#define U300_TIMER_APP_GPT2S_MODE_ONE_SHOT (0x00000020)
165#define U300_TIMER_APP_GPT2S_IRQ_ENABLED_IND (0x00000040)
166#define U300_TIMER_APP_GPT2S_IRQ_PENDING_IND (0x00000080)
167/* GP2 Timer Current Count Register 32bit (R/-) */
168#define U300_TIMER_APP_GPT2CC (0x00d4)
169/* GP2 Timer Terminal Count Register 32bit (R/W) */
170#define U300_TIMER_APP_GPT2TC (0x00d8)
171/* GP2 Timer Interrupt Enable Register 32bit (-/W) */
172#define U300_TIMER_APP_GPT2IE (0x00dc)
173#define U300_TIMER_APP_GPT2IE_IRQ_DISABLE (0x00000000)
174#define U300_TIMER_APP_GPT2IE_IRQ_ENABLE (0x00000001)
175/* GP2 Timer Interrupt Acknowledge Register 32bit (-/W) */
176#define U300_TIMER_APP_GPT2IA (0x00e0)
177#define U300_TIMER_APP_GPT2IA_IRQ_ACK (0x00000080)
178
179/* Clock request control register - all four timers */
180#define U300_TIMER_APP_CRC (0x100)
181#define U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE (0x00000001)
182
183static void __iomem *u300_timer_base;
184
185struct u300_clockevent_data {
186 struct clock_event_device cevd;
187 unsigned ticks_per_jiffy;
188};
189
190/*
191 * The u300_set_mode() function is always called first, if we
192 * have oneshot timer active, the oneshot scheduling function
193 * u300_set_next_event() is called immediately after.
194 */
195static void u300_set_mode(enum clock_event_mode mode,
196 struct clock_event_device *evt)
197{
198 struct u300_clockevent_data *cevdata =
199 container_of(evt, struct u300_clockevent_data, cevd);
200
201 switch (mode) {
202 case CLOCK_EVT_MODE_PERIODIC:
203 /* Disable interrupts on GPT1 */
204 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
205 u300_timer_base + U300_TIMER_APP_GPT1IE);
206 /* Disable GP1 while we're reprogramming it. */
207 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
208 u300_timer_base + U300_TIMER_APP_DGPT1);
209 /*
210 * Set the periodic mode to a certain number of ticks per
211 * jiffy.
212 */
213 writel(cevdata->ticks_per_jiffy,
214 u300_timer_base + U300_TIMER_APP_GPT1TC);
215 /*
216 * Set continuous mode, so the timer keeps triggering
217 * interrupts.
218 */
219 writel(U300_TIMER_APP_SGPT1M_MODE_CONTINUOUS,
220 u300_timer_base + U300_TIMER_APP_SGPT1M);
221 /* Enable timer interrupts */
222 writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
223 u300_timer_base + U300_TIMER_APP_GPT1IE);
224 /* Then enable the OS timer again */
225 writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
226 u300_timer_base + U300_TIMER_APP_EGPT1);
227 break;
228 case CLOCK_EVT_MODE_ONESHOT:
229 /* Just break; here? */
230 /*
231 * The actual event will be programmed by the next event hook,
232 * so we just set a dummy value somewhere at the end of the
233 * universe here.
234 */
235 /* Disable interrupts on GPT1 */
236 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
237 u300_timer_base + U300_TIMER_APP_GPT1IE);
238 /* Disable GP1 while we're reprogramming it. */
239 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
240 u300_timer_base + U300_TIMER_APP_DGPT1);
241 /*
242 * Expire far in the future, u300_set_next_event() will be
243 * called soon...
244 */
245 writel(0xFFFFFFFF, u300_timer_base + U300_TIMER_APP_GPT1TC);
246 /* We run one shot per tick here! */
247 writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
248 u300_timer_base + U300_TIMER_APP_SGPT1M);
249 /* Enable interrupts for this timer */
250 writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
251 u300_timer_base + U300_TIMER_APP_GPT1IE);
252 /* Enable timer */
253 writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
254 u300_timer_base + U300_TIMER_APP_EGPT1);
255 break;
256 case CLOCK_EVT_MODE_UNUSED:
257 case CLOCK_EVT_MODE_SHUTDOWN:
258 /* Disable interrupts on GP1 */
259 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
260 u300_timer_base + U300_TIMER_APP_GPT1IE);
261 /* Disable GP1 */
262 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
263 u300_timer_base + U300_TIMER_APP_DGPT1);
264 break;
265 case CLOCK_EVT_MODE_RESUME:
266 /* Ignore this call */
267 break;
268 }
269}
270
271/*
272 * The app timer in one shot mode obviously has to be reprogrammed
273 * in EXACTLY this sequence to work properly. Do NOT try to e.g. replace
274 * the interrupt disable + timer disable commands with a reset command,
275 * it will fail miserably. Apparently (and I found this the hard way)
276 * the timer is very sensitive to the instruction order, though you don't
277 * get that impression from the data sheet.
278 */
279static int u300_set_next_event(unsigned long cycles,
280 struct clock_event_device *evt)
281
282{
283 /* Disable interrupts on GPT1 */
284 writel(U300_TIMER_APP_GPT1IE_IRQ_DISABLE,
285 u300_timer_base + U300_TIMER_APP_GPT1IE);
286 /* Disable GP1 while we're reprogramming it. */
287 writel(U300_TIMER_APP_DGPT1_TIMER_DISABLE,
288 u300_timer_base + U300_TIMER_APP_DGPT1);
289 /* Reset the General Purpose timer 1. */
290 writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
291 u300_timer_base + U300_TIMER_APP_RGPT1);
292 /* IRQ in n * cycles */
293 writel(cycles, u300_timer_base + U300_TIMER_APP_GPT1TC);
294 /*
295 * We run one shot per tick here! (This is necessary to reconfigure,
296 * the timer will tilt if you don't!)
297 */
298 writel(U300_TIMER_APP_SGPT1M_MODE_ONE_SHOT,
299 u300_timer_base + U300_TIMER_APP_SGPT1M);
300 /* Enable timer interrupts */
301 writel(U300_TIMER_APP_GPT1IE_IRQ_ENABLE,
302 u300_timer_base + U300_TIMER_APP_GPT1IE);
303 /* Then enable the OS timer again */
304 writel(U300_TIMER_APP_EGPT1_TIMER_ENABLE,
305 u300_timer_base + U300_TIMER_APP_EGPT1);
306 return 0;
307}
308
309static struct u300_clockevent_data u300_clockevent_data = {
310 /* Use general purpose timer 1 as clock event */
311 .cevd = {
312 .name = "GPT1",
313 /* Reasonably fast and accurate clock event */
314 .rating = 300,
315 .features = CLOCK_EVT_FEAT_PERIODIC |
316 CLOCK_EVT_FEAT_ONESHOT,
317 .set_next_event = u300_set_next_event,
318 .set_mode = u300_set_mode,
319 },
320};
321
322/* Clock event timer interrupt handler */
323static irqreturn_t u300_timer_interrupt(int irq, void *dev_id)
324{
325 struct clock_event_device *evt = &u300_clockevent_data.cevd;
326 /* ACK/Clear timer IRQ for the APP GPT1 Timer */
327
328 writel(U300_TIMER_APP_GPT1IA_IRQ_ACK,
329 u300_timer_base + U300_TIMER_APP_GPT1IA);
330 evt->event_handler(evt);
331 return IRQ_HANDLED;
332}
333
334static struct irqaction u300_timer_irq = {
335 .name = "U300 Timer Tick",
336 .flags = IRQF_TIMER | IRQF_IRQPOLL,
337 .handler = u300_timer_interrupt,
338};
339
340/*
341 * Override the global weak sched_clock symbol with this
342 * local implementation which uses the clocksource to get some
343 * better resolution when scheduling the kernel. We accept that
344 * this wraps around for now, since it is just a relative time
345 * stamp. (Inspired by OMAP implementation.)
346 */
347
348static u64 notrace u300_read_sched_clock(void)
349{
350 return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
351}
352
353static unsigned long u300_read_current_timer(void)
354{
355 return readl(u300_timer_base + U300_TIMER_APP_GPT2CC);
356}
357
358static struct delay_timer u300_delay_timer;
359
360/*
361 * This sets up the system timers, clock source and clock event.
362 */
363static void __init u300_timer_init_of(struct device_node *np)
364{
365 unsigned int irq;
366 struct clk *clk;
367 unsigned long rate;
368
369 u300_timer_base = of_iomap(np, 0);
370 if (!u300_timer_base)
371 panic("could not ioremap system timer\n");
372
373 /* Get the IRQ for the GP1 timer */
374 irq = irq_of_parse_and_map(np, 2);
375 if (!irq)
376 panic("no IRQ for system timer\n");
377
378 pr_info("U300 GP1 timer @ base: %p, IRQ: %u\n", u300_timer_base, irq);
379
380 /* Clock the interrupt controller */
381 clk = of_clk_get(np, 0);
382 BUG_ON(IS_ERR(clk));
383 clk_prepare_enable(clk);
384 rate = clk_get_rate(clk);
385
386 u300_clockevent_data.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
387
388 sched_clock_register(u300_read_sched_clock, 32, rate);
389
390 u300_delay_timer.read_current_timer = &u300_read_current_timer;
391 u300_delay_timer.freq = rate;
392 register_current_timer_delay(&u300_delay_timer);
393
394 /*
395 * Disable the "OS" and "DD" timers - these are designed for Symbian!
396 * Example usage in cnh1601578 cpu subsystem pd_timer_app.c
397 */
398 writel(U300_TIMER_APP_CRC_CLOCK_REQUEST_ENABLE,
399 u300_timer_base + U300_TIMER_APP_CRC);
400 writel(U300_TIMER_APP_ROST_TIMER_RESET,
401 u300_timer_base + U300_TIMER_APP_ROST);
402 writel(U300_TIMER_APP_DOST_TIMER_DISABLE,
403 u300_timer_base + U300_TIMER_APP_DOST);
404 writel(U300_TIMER_APP_RDDT_TIMER_RESET,
405 u300_timer_base + U300_TIMER_APP_RDDT);
406 writel(U300_TIMER_APP_DDDT_TIMER_DISABLE,
407 u300_timer_base + U300_TIMER_APP_DDDT);
408
409 /* Reset the General Purpose timer 1. */
410 writel(U300_TIMER_APP_RGPT1_TIMER_RESET,
411 u300_timer_base + U300_TIMER_APP_RGPT1);
412
413 /* Set up the IRQ handler */
414 setup_irq(irq, &u300_timer_irq);
415
416 /* Reset the General Purpose timer 2 */
417 writel(U300_TIMER_APP_RGPT2_TIMER_RESET,
418 u300_timer_base + U300_TIMER_APP_RGPT2);
419 /* Set this timer to run around forever */
420 writel(0xFFFFFFFFU, u300_timer_base + U300_TIMER_APP_GPT2TC);
421 /* Set continuous mode so it wraps around */
422 writel(U300_TIMER_APP_SGPT2M_MODE_CONTINUOUS,
423 u300_timer_base + U300_TIMER_APP_SGPT2M);
424 /* Disable timer interrupts */
425 writel(U300_TIMER_APP_GPT2IE_IRQ_DISABLE,
426 u300_timer_base + U300_TIMER_APP_GPT2IE);
427 /* Then enable the GP2 timer to use as a free running us counter */
428 writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE,
429 u300_timer_base + U300_TIMER_APP_EGPT2);
430
431 /* Use general purpose timer 2 as clock source */
432 if (clocksource_mmio_init(u300_timer_base + U300_TIMER_APP_GPT2CC,
433 "GPT2", rate, 300, 32, clocksource_mmio_readl_up))
434 pr_err("timer: failed to initialize U300 clock source\n");
435
436 /* Configure and register the clockevent */
437 clockevents_config_and_register(&u300_clockevent_data.cevd, rate,
438 1, 0xffffffff);
439
440 /*
441 * TODO: init and register the rest of the timers too, they can be
442 * used by hrtimers!
443 */
444}
445
446CLOCKSOURCE_OF_DECLARE(u300_timer, "stericsson,u300-apptimer",
447 u300_timer_init_of);