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1 | /* |
2 | * linux/arch/arm/mach-omap/time.c | |
3 | * | |
4 | * OMAP Timers | |
5 | * | |
6 | * Copyright (C) 2004 Nokia Corporation | |
7 | * Partial timer rewrite and additional VST timer support by | |
8 | * Tony Lindgen <tony@atomide.com> and | |
9 | * Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com> | |
10 | * | |
11 | * MPU timer code based on the older MPU timer code for OMAP | |
12 | * Copyright (C) 2000 RidgeRun, Inc. | |
13 | * Author: Greg Lonnon <glonnon@ridgerun.com> | |
14 | * | |
15 | * This program is free software; you can redistribute it and/or modify it | |
16 | * under the terms of the GNU General Public License as published by the | |
17 | * Free Software Foundation; either version 2 of the License, or (at your | |
18 | * option) any later version. | |
19 | * | |
20 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED | |
21 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF | |
22 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN | |
23 | * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
24 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
25 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF | |
26 | * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON | |
27 | * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
28 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
29 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
30 | * | |
31 | * You should have received a copy of the GNU General Public License along | |
32 | * with this program; if not, write to the Free Software Foundation, Inc., | |
33 | * 675 Mass Ave, Cambridge, MA 02139, USA. | |
34 | */ | |
35 | ||
36 | #include <linux/config.h> | |
37 | #include <linux/kernel.h> | |
38 | #include <linux/init.h> | |
39 | #include <linux/delay.h> | |
40 | #include <linux/interrupt.h> | |
41 | #include <linux/sched.h> | |
42 | #include <linux/spinlock.h> | |
43 | ||
44 | #include <asm/system.h> | |
45 | #include <asm/hardware.h> | |
46 | #include <asm/io.h> | |
47 | #include <asm/leds.h> | |
48 | #include <asm/irq.h> | |
49 | #include <asm/mach/irq.h> | |
50 | #include <asm/mach/time.h> | |
51 | ||
52 | struct sys_timer omap_timer; | |
53 | ||
54 | #ifdef CONFIG_OMAP_MPU_TIMER | |
55 | ||
56 | /* | |
57 | * --------------------------------------------------------------------------- | |
58 | * MPU timer | |
59 | * --------------------------------------------------------------------------- | |
60 | */ | |
61 | #define OMAP_MPU_TIMER1_BASE (0xfffec500) | |
62 | #define OMAP_MPU_TIMER2_BASE (0xfffec600) | |
63 | #define OMAP_MPU_TIMER3_BASE (0xfffec700) | |
64 | #define OMAP_MPU_TIMER_BASE OMAP_MPU_TIMER1_BASE | |
65 | #define OMAP_MPU_TIMER_OFFSET 0x100 | |
66 | ||
67 | #define MPU_TIMER_FREE (1 << 6) | |
68 | #define MPU_TIMER_CLOCK_ENABLE (1 << 5) | |
69 | #define MPU_TIMER_AR (1 << 1) | |
70 | #define MPU_TIMER_ST (1 << 0) | |
71 | ||
72 | /* cycles to nsec conversions taken from arch/i386/kernel/timers/timer_tsc.c, | |
73 | * converted to use kHz by Kevin Hilman */ | |
74 | /* convert from cycles(64bits) => nanoseconds (64bits) | |
75 | * basic equation: | |
76 | * ns = cycles / (freq / ns_per_sec) | |
77 | * ns = cycles * (ns_per_sec / freq) | |
78 | * ns = cycles * (10^9 / (cpu_khz * 10^3)) | |
79 | * ns = cycles * (10^6 / cpu_khz) | |
80 | * | |
81 | * Then we use scaling math (suggested by george at mvista.com) to get: | |
82 | * ns = cycles * (10^6 * SC / cpu_khz / SC | |
83 | * ns = cycles * cyc2ns_scale / SC | |
84 | * | |
85 | * And since SC is a constant power of two, we can convert the div | |
86 | * into a shift. | |
87 | * -johnstul at us.ibm.com "math is hard, lets go shopping!" | |
88 | */ | |
89 | static unsigned long cyc2ns_scale; | |
90 | #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ | |
91 | ||
92 | static inline void set_cyc2ns_scale(unsigned long cpu_khz) | |
93 | { | |
94 | cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz; | |
95 | } | |
96 | ||
97 | static inline unsigned long long cycles_2_ns(unsigned long long cyc) | |
98 | { | |
99 | return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; | |
100 | } | |
101 | ||
102 | /* | |
103 | * MPU_TICKS_PER_SEC must be an even number, otherwise machinecycles_to_usecs | |
104 | * will break. On P2, the timer count rate is 6.5 MHz after programming PTV | |
105 | * with 0. This divides the 13MHz input by 2, and is undocumented. | |
106 | */ | |
107 | #ifdef CONFIG_MACH_OMAP_PERSEUS2 | |
108 | /* REVISIT: This ifdef construct should be replaced by a query to clock | |
109 | * framework to see if timer base frequency is 12.0, 13.0 or 19.2 MHz. | |
110 | */ | |
111 | #define MPU_TICKS_PER_SEC (13000000 / 2) | |
112 | #else | |
113 | #define MPU_TICKS_PER_SEC (12000000 / 2) | |
114 | #endif | |
115 | ||
116 | #define MPU_TIMER_TICK_PERIOD ((MPU_TICKS_PER_SEC / HZ) - 1) | |
117 | ||
118 | typedef struct { | |
119 | u32 cntl; /* CNTL_TIMER, R/W */ | |
120 | u32 load_tim; /* LOAD_TIM, W */ | |
121 | u32 read_tim; /* READ_TIM, R */ | |
122 | } omap_mpu_timer_regs_t; | |
123 | ||
124 | #define omap_mpu_timer_base(n) \ | |
125 | ((volatile omap_mpu_timer_regs_t*)IO_ADDRESS(OMAP_MPU_TIMER_BASE + \ | |
126 | (n)*OMAP_MPU_TIMER_OFFSET)) | |
127 | ||
128 | static inline unsigned long omap_mpu_timer_read(int nr) | |
129 | { | |
130 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); | |
131 | return timer->read_tim; | |
132 | } | |
133 | ||
134 | static inline void omap_mpu_timer_start(int nr, unsigned long load_val) | |
135 | { | |
136 | volatile omap_mpu_timer_regs_t* timer = omap_mpu_timer_base(nr); | |
137 | ||
138 | timer->cntl = MPU_TIMER_CLOCK_ENABLE; | |
139 | udelay(1); | |
140 | timer->load_tim = load_val; | |
141 | udelay(1); | |
142 | timer->cntl = (MPU_TIMER_CLOCK_ENABLE | MPU_TIMER_AR | MPU_TIMER_ST); | |
143 | } | |
144 | ||
145 | unsigned long omap_mpu_timer_ticks_to_usecs(unsigned long nr_ticks) | |
146 | { | |
147 | unsigned long long nsec; | |
148 | ||
149 | nsec = cycles_2_ns((unsigned long long)nr_ticks); | |
150 | return (unsigned long)nsec / 1000; | |
151 | } | |
152 | ||
153 | /* | |
154 | * Last processed system timer interrupt | |
155 | */ | |
156 | static unsigned long omap_mpu_timer_last = 0; | |
157 | ||
158 | /* | |
159 | * Returns elapsed usecs since last system timer interrupt | |
160 | */ | |
161 | static unsigned long omap_mpu_timer_gettimeoffset(void) | |
162 | { | |
163 | unsigned long now = 0 - omap_mpu_timer_read(0); | |
164 | unsigned long elapsed = now - omap_mpu_timer_last; | |
165 | ||
166 | return omap_mpu_timer_ticks_to_usecs(elapsed); | |
167 | } | |
168 | ||
169 | /* | |
170 | * Elapsed time between interrupts is calculated using timer0. | |
171 | * Latency during the interrupt is calculated using timer1. | |
172 | * Both timer0 and timer1 are counting at 6MHz (P2 6.5MHz). | |
173 | */ | |
174 | static irqreturn_t omap_mpu_timer_interrupt(int irq, void *dev_id, | |
175 | struct pt_regs *regs) | |
176 | { | |
177 | unsigned long now, latency; | |
178 | ||
179 | write_seqlock(&xtime_lock); | |
180 | now = 0 - omap_mpu_timer_read(0); | |
181 | latency = MPU_TICKS_PER_SEC / HZ - omap_mpu_timer_read(1); | |
182 | omap_mpu_timer_last = now - latency; | |
183 | timer_tick(regs); | |
184 | write_sequnlock(&xtime_lock); | |
185 | ||
186 | return IRQ_HANDLED; | |
187 | } | |
188 | ||
189 | static struct irqaction omap_mpu_timer_irq = { | |
190 | .name = "mpu timer", | |
09b8b5f8 RK |
191 | .flags = SA_INTERRUPT | SA_TIMER, |
192 | .handler = omap_mpu_timer_interrupt, | |
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193 | }; |
194 | ||
195 | static unsigned long omap_mpu_timer1_overflows; | |
196 | static irqreturn_t omap_mpu_timer1_interrupt(int irq, void *dev_id, | |
197 | struct pt_regs *regs) | |
198 | { | |
199 | omap_mpu_timer1_overflows++; | |
200 | return IRQ_HANDLED; | |
201 | } | |
202 | ||
203 | static struct irqaction omap_mpu_timer1_irq = { | |
204 | .name = "mpu timer1 overflow", | |
205 | .flags = SA_INTERRUPT, | |
09b8b5f8 | 206 | .handler = omap_mpu_timer1_interrupt, |
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207 | }; |
208 | ||
209 | static __init void omap_init_mpu_timer(void) | |
210 | { | |
211 | set_cyc2ns_scale(MPU_TICKS_PER_SEC / 1000); | |
212 | omap_timer.offset = omap_mpu_timer_gettimeoffset; | |
213 | setup_irq(INT_TIMER1, &omap_mpu_timer1_irq); | |
214 | setup_irq(INT_TIMER2, &omap_mpu_timer_irq); | |
215 | omap_mpu_timer_start(0, 0xffffffff); | |
216 | omap_mpu_timer_start(1, MPU_TIMER_TICK_PERIOD); | |
217 | } | |
218 | ||
219 | /* | |
220 | * Scheduler clock - returns current time in nanosec units. | |
221 | */ | |
222 | unsigned long long sched_clock(void) | |
223 | { | |
224 | unsigned long ticks = 0 - omap_mpu_timer_read(0); | |
225 | unsigned long long ticks64; | |
226 | ||
227 | ticks64 = omap_mpu_timer1_overflows; | |
228 | ticks64 <<= 32; | |
229 | ticks64 |= ticks; | |
230 | ||
231 | return cycles_2_ns(ticks64); | |
232 | } | |
233 | #endif /* CONFIG_OMAP_MPU_TIMER */ | |
234 | ||
235 | #ifdef CONFIG_OMAP_32K_TIMER | |
236 | ||
237 | #ifdef CONFIG_ARCH_OMAP1510 | |
238 | #error OMAP 32KHz timer does not currently work on 1510! | |
239 | #endif | |
240 | ||
241 | /* | |
242 | * --------------------------------------------------------------------------- | |
243 | * 32KHz OS timer | |
244 | * | |
245 | * This currently works only on 16xx, as 1510 does not have the continuous | |
246 | * 32KHz synchronous timer. The 32KHz synchronous timer is used to keep track | |
247 | * of time in addition to the 32KHz OS timer. Using only the 32KHz OS timer | |
248 | * on 1510 would be possible, but the timer would not be as accurate as | |
249 | * with the 32KHz synchronized timer. | |
250 | * --------------------------------------------------------------------------- | |
251 | */ | |
252 | #define OMAP_32K_TIMER_BASE 0xfffb9000 | |
253 | #define OMAP_32K_TIMER_CR 0x08 | |
254 | #define OMAP_32K_TIMER_TVR 0x00 | |
255 | #define OMAP_32K_TIMER_TCR 0x04 | |
256 | ||
257 | #define OMAP_32K_TICKS_PER_HZ (32768 / HZ) | |
258 | ||
259 | /* | |
260 | * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 | |
261 | * so with HZ = 100, TVR = 327.68. | |
262 | */ | |
263 | #define OMAP_32K_TIMER_TICK_PERIOD ((32768 / HZ) - 1) | |
264 | #define MAX_SKIP_JIFFIES 25 | |
265 | #define TIMER_32K_SYNCHRONIZED 0xfffbc410 | |
266 | ||
267 | #define JIFFIES_TO_HW_TICKS(nr_jiffies, clock_rate) \ | |
268 | (((nr_jiffies) * (clock_rate)) / HZ) | |
269 | ||
270 | static inline void omap_32k_timer_write(int val, int reg) | |
271 | { | |
272 | omap_writew(val, reg + OMAP_32K_TIMER_BASE); | |
273 | } | |
274 | ||
275 | static inline unsigned long omap_32k_timer_read(int reg) | |
276 | { | |
277 | return omap_readl(reg + OMAP_32K_TIMER_BASE) & 0xffffff; | |
278 | } | |
279 | ||
280 | /* | |
281 | * The 32KHz synchronized timer is an additional timer on 16xx. | |
282 | * It is always running. | |
283 | */ | |
284 | static inline unsigned long omap_32k_sync_timer_read(void) | |
285 | { | |
286 | return omap_readl(TIMER_32K_SYNCHRONIZED); | |
287 | } | |
288 | ||
289 | static inline void omap_32k_timer_start(unsigned long load_val) | |
290 | { | |
291 | omap_32k_timer_write(load_val, OMAP_32K_TIMER_TVR); | |
292 | omap_32k_timer_write(0x0f, OMAP_32K_TIMER_CR); | |
293 | } | |
294 | ||
295 | static inline void omap_32k_timer_stop(void) | |
296 | { | |
297 | omap_32k_timer_write(0x0, OMAP_32K_TIMER_CR); | |
298 | } | |
299 | ||
300 | /* | |
301 | * Rounds down to nearest usec | |
302 | */ | |
303 | static inline unsigned long omap_32k_ticks_to_usecs(unsigned long ticks_32k) | |
304 | { | |
305 | return (ticks_32k * 5*5*5*5*5*5) >> 9; | |
306 | } | |
307 | ||
308 | static unsigned long omap_32k_last_tick = 0; | |
309 | ||
310 | /* | |
311 | * Returns elapsed usecs since last 32k timer interrupt | |
312 | */ | |
313 | static unsigned long omap_32k_timer_gettimeoffset(void) | |
314 | { | |
315 | unsigned long now = omap_32k_sync_timer_read(); | |
316 | return omap_32k_ticks_to_usecs(now - omap_32k_last_tick); | |
317 | } | |
318 | ||
319 | /* | |
320 | * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this | |
321 | * function is also called from other interrupts to remove latency | |
322 | * issues with dynamic tick. In the dynamic tick case, we need to lock | |
323 | * with irqsave. | |
324 | */ | |
325 | static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id, | |
326 | struct pt_regs *regs) | |
327 | { | |
328 | unsigned long flags; | |
329 | unsigned long now; | |
330 | ||
331 | write_seqlock_irqsave(&xtime_lock, flags); | |
332 | now = omap_32k_sync_timer_read(); | |
333 | ||
334 | while (now - omap_32k_last_tick >= OMAP_32K_TICKS_PER_HZ) { | |
335 | omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; | |
336 | timer_tick(regs); | |
337 | } | |
338 | ||
339 | /* Restart timer so we don't drift off due to modulo or dynamic tick. | |
340 | * By default we program the next timer to be continuous to avoid | |
341 | * latencies during high system load. During dynamic tick operation the | |
342 | * continuous timer can be overridden from pm_idle to be longer. | |
343 | */ | |
344 | omap_32k_timer_start(omap_32k_last_tick + OMAP_32K_TICKS_PER_HZ - now); | |
345 | write_sequnlock_irqrestore(&xtime_lock, flags); | |
346 | ||
347 | return IRQ_HANDLED; | |
348 | } | |
349 | ||
350 | static struct irqaction omap_32k_timer_irq = { | |
351 | .name = "32KHz timer", | |
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352 | .flags = SA_INTERRUPT | SA_TIMER, |
353 | .handler = omap_32k_timer_interrupt, | |
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354 | }; |
355 | ||
356 | static __init void omap_init_32k_timer(void) | |
357 | { | |
358 | setup_irq(INT_OS_TIMER, &omap_32k_timer_irq); | |
359 | omap_timer.offset = omap_32k_timer_gettimeoffset; | |
360 | omap_32k_last_tick = omap_32k_sync_timer_read(); | |
361 | omap_32k_timer_start(OMAP_32K_TIMER_TICK_PERIOD); | |
362 | } | |
363 | #endif /* CONFIG_OMAP_32K_TIMER */ | |
364 | ||
365 | /* | |
366 | * --------------------------------------------------------------------------- | |
367 | * Timer initialization | |
368 | * --------------------------------------------------------------------------- | |
369 | */ | |
370 | void __init omap_timer_init(void) | |
371 | { | |
372 | #if defined(CONFIG_OMAP_MPU_TIMER) | |
373 | omap_init_mpu_timer(); | |
374 | #elif defined(CONFIG_OMAP_32K_TIMER) | |
375 | omap_init_32k_timer(); | |
376 | #else | |
377 | #error No system timer selected in Kconfig! | |
378 | #endif | |
379 | } | |
380 | ||
381 | struct sys_timer omap_timer = { | |
382 | .init = omap_timer_init, | |
383 | .offset = NULL, /* Initialized later */ | |
384 | }; |