diff options
Diffstat (limited to 'arch/arm/mach-omap1/time.c')
-rw-r--r-- | arch/arm/mach-omap1/time.c | 40 |
1 files changed, 19 insertions, 21 deletions
diff --git a/arch/arm/mach-omap1/time.c b/arch/arm/mach-omap1/time.c index d540539c9bbb..191a9b1ee9b7 100644 --- a/arch/arm/mach-omap1/time.c +++ b/arch/arm/mach-omap1/time.c | |||
@@ -247,13 +247,6 @@ unsigned long long sched_clock(void) | |||
247 | #define OMAP_32K_TIMER_TCR 0x04 | 247 | #define OMAP_32K_TIMER_TCR 0x04 |
248 | 248 | ||
249 | #define OMAP_32K_TICKS_PER_HZ (32768 / HZ) | 249 | #define OMAP_32K_TICKS_PER_HZ (32768 / HZ) |
250 | #if (32768 % HZ) != 0 | ||
251 | /* We cannot ignore modulo. | ||
252 | * Potential error can be as high as several percent. | ||
253 | */ | ||
254 | #define OMAP_32K_TICK_MODULO (32768 % HZ) | ||
255 | static unsigned modulo_count = 0; /* Counts 1/HZ units */ | ||
256 | #endif | ||
257 | 250 | ||
258 | /* | 251 | /* |
259 | * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 | 252 | * TRM says 1 / HZ = ( TVR + 1) / 32768, so TRV = (32768 / HZ) - 1 |
@@ -296,13 +289,22 @@ static inline void omap_32k_timer_stop(void) | |||
296 | } | 289 | } |
297 | 290 | ||
298 | /* | 291 | /* |
299 | * Rounds down to nearest usec | 292 | * Rounds down to nearest usec. Note that this will overflow for larger values. |
300 | */ | 293 | */ |
301 | static inline unsigned long omap_32k_ticks_to_usecs(unsigned long ticks_32k) | 294 | static inline unsigned long omap_32k_ticks_to_usecs(unsigned long ticks_32k) |
302 | { | 295 | { |
303 | return (ticks_32k * 5*5*5*5*5*5) >> 9; | 296 | return (ticks_32k * 5*5*5*5*5*5) >> 9; |
304 | } | 297 | } |
305 | 298 | ||
299 | /* | ||
300 | * Rounds down to nearest nsec. | ||
301 | */ | ||
302 | static inline unsigned long long | ||
303 | omap_32k_ticks_to_nsecs(unsigned long ticks_32k) | ||
304 | { | ||
305 | return (unsigned long long) ticks_32k * 1000 * 5*5*5*5*5*5 >> 9; | ||
306 | } | ||
307 | |||
306 | static unsigned long omap_32k_last_tick = 0; | 308 | static unsigned long omap_32k_last_tick = 0; |
307 | 309 | ||
308 | /* | 310 | /* |
@@ -315,6 +317,15 @@ static unsigned long omap_32k_timer_gettimeoffset(void) | |||
315 | } | 317 | } |
316 | 318 | ||
317 | /* | 319 | /* |
320 | * Returns current time from boot in nsecs. It's OK for this to wrap | ||
321 | * around for now, as it's just a relative time stamp. | ||
322 | */ | ||
323 | unsigned long long sched_clock(void) | ||
324 | { | ||
325 | return omap_32k_ticks_to_nsecs(omap_32k_sync_timer_read()); | ||
326 | } | ||
327 | |||
328 | /* | ||
318 | * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this | 329 | * Timer interrupt for 32KHz timer. When dynamic tick is enabled, this |
319 | * function is also called from other interrupts to remove latency | 330 | * function is also called from other interrupts to remove latency |
320 | * issues with dynamic tick. In the dynamic tick case, we need to lock | 331 | * issues with dynamic tick. In the dynamic tick case, we need to lock |
@@ -330,19 +341,6 @@ static irqreturn_t omap_32k_timer_interrupt(int irq, void *dev_id, | |||
330 | now = omap_32k_sync_timer_read(); | 341 | now = omap_32k_sync_timer_read(); |
331 | 342 | ||
332 | while (now - omap_32k_last_tick >= OMAP_32K_TICKS_PER_HZ) { | 343 | while (now - omap_32k_last_tick >= OMAP_32K_TICKS_PER_HZ) { |
333 | #ifdef OMAP_32K_TICK_MODULO | ||
334 | /* Modulo addition may put omap_32k_last_tick ahead of now | ||
335 | * and cause unwanted repetition of the while loop. | ||
336 | */ | ||
337 | if (unlikely(now - omap_32k_last_tick == ~0)) | ||
338 | break; | ||
339 | |||
340 | modulo_count += OMAP_32K_TICK_MODULO; | ||
341 | if (modulo_count > HZ) { | ||
342 | ++omap_32k_last_tick; | ||
343 | modulo_count -= HZ; | ||
344 | } | ||
345 | #endif | ||
346 | omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; | 344 | omap_32k_last_tick += OMAP_32K_TICKS_PER_HZ; |
347 | timer_tick(regs); | 345 | timer_tick(regs); |
348 | } | 346 | } |