diff options
| -rw-r--r-- | arch/arm/cpu/arm1136/mx35/timer.c | 103 |
1 files changed, 64 insertions, 39 deletions
diff --git a/arch/arm/cpu/arm1136/mx35/timer.c b/arch/arm/cpu/arm1136/mx35/timer.c index 80c0675cfa..04937a1dfe 100644 --- a/arch/arm/cpu/arm1136/mx35/timer.c +++ b/arch/arm/cpu/arm1136/mx35/timer.c @@ -25,7 +25,14 @@ #include <common.h> #include <asm/io.h> +#include <div64.h> #include <asm/arch/imx-regs.h> +#include <asm/arch/clock.h> + +DECLARE_GLOBAL_DATA_PTR; + +#define timestamp (gd->tbl) +#define lastinc (gd->lastinc) /* General purpose timers bitfields */ #define GPTCR_SWR (1<<15) /* Software reset */ @@ -33,7 +40,24 @@ #define GPTCR_CLKSOURCE_32 (0x100<<6) /* Clock source */ #define GPTCR_CLKSOURCE_IPG (0x001<<6) /* Clock source */ #define GPTCR_TEN (1) /* Timer enable */ -#define GPTPR_VAL (66) + +#define TIMER_FREQ_HZ mxc_get_clock(MXC_IPG_CLK) + +static inline unsigned long long tick_to_time(unsigned long long tick) +{ + tick *= CONFIG_SYS_HZ; + do_div(tick, TIMER_FREQ_HZ); + + return tick; +} + +static inline unsigned long long us_to_tick(unsigned long long usec) +{ + usec *= TIMER_FREQ_HZ; + do_div(usec, 1000000); + + return usec; +} int timer_init(void) { @@ -45,7 +69,7 @@ int timer_init(void) for (i = 0; i < 100; i++) writel(0, &gpt->ctrl); /* We have no udelay by now */ - writel(GPTPR_VAL, &gpt->pre); + writel(0, &gpt->pre); /* Freerun Mode, PERCLK1 input */ writel(readl(&gpt->ctrl) | GPTCR_CLKSOURCE_IPG | GPTCR_TEN, @@ -54,58 +78,59 @@ int timer_init(void) return 0; } -void reset_timer_masked(void) +unsigned long long get_ticks(void) { struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; - - writel(0, &gpt->ctrl); - /* Freerun Mode, PERCLK1 input */ - writel(GPTCR_CLKSOURCE_IPG | GPTCR_TEN, - &gpt->ctrl); + ulong now = readl(&gpt->counter); /* current tick value */ + + if (now >= lastinc) { + /* + * normal mode (non roll) + * move stamp forward with absolut diff ticks + */ + timestamp += (now - lastinc); + } else { + /* we have rollover of incrementer */ + timestamp += (0xFFFFFFFF - lastinc) + now; + } + lastinc = now; + return timestamp; } -inline ulong get_timer_masked(void) +ulong get_timer_masked(void) { - - struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; - ulong val = readl(&gpt->counter); - - return val; + /* + * get_ticks() returns a long long (64 bit), it wraps in + * 2^64 / CONFIG_MX25_CLK32 = 2^64 / 2^15 = 2^49 ~ 5 * 10^14 (s) ~ + * 5 * 10^9 days... and get_ticks() * CONFIG_SYS_HZ wraps in + * 5 * 10^6 days - long enough. + */ + return tick_to_time(get_ticks()); } ulong get_timer(ulong base) { - ulong tmp; + return get_timer_masked() - base; +} - tmp = get_timer_masked(); +/* delay x useconds AND preserve advance timstamp value */ +void __udelay(unsigned long usec) +{ + unsigned long long tmp; + ulong tmo; - if (tmp <= (base * 1000)) { - /* Overflow */ - tmp += (0xffffffff - base); - } + tmo = us_to_tick(usec); + tmp = get_ticks() + tmo; /* get current timestamp */ - return (tmp / 1000) - base; + while (get_ticks() < tmp) /* loop till event */ + /*NOP*/; } /* - * delay x useconds AND preserve advance timstamp value - * GPTCNT is now supposed to tick 1 by 1 us. + * This function is derived from PowerPC code (timebase clock frequency). + * On ARM it returns the number of timer ticks per second. */ -void __udelay(unsigned long usec) +ulong get_tbclk(void) { - ulong tmp; - - tmp = get_timer_masked(); /* get current timestamp */ - - /* if setting this forward will roll time stamp */ - if ((usec + tmp + 1) < tmp) { - /* reset "advancing" timestamp to 0, set lastinc value */ - reset_timer_masked(); - } else { - /* else, set advancing stamp wake up time */ - tmp += usec; - } - - while (get_timer_masked() < tmp) /* loop till event */ - /*NOP*/; + return TIMER_FREQ_HZ; } |