diff options
Diffstat (limited to 'arch/arm/cpu/arm1136/mx35/timer.c')
| -rw-r--r-- | arch/arm/cpu/arm1136/mx35/timer.c | 46 |
1 files changed, 28 insertions, 18 deletions
diff --git a/arch/arm/cpu/arm1136/mx35/timer.c b/arch/arm/cpu/arm1136/mx35/timer.c index 04937a1df..9680b7fde 100644 --- a/arch/arm/cpu/arm1136/mx35/timer.c +++ b/arch/arm/cpu/arm1136/mx35/timer.c @@ -27,6 +27,7 @@ #include <asm/io.h> #include <div64.h> #include <asm/arch/imx-regs.h> +#include <asm/arch/crm_regs.h> #include <asm/arch/clock.h> DECLARE_GLOBAL_DATA_PTR; @@ -37,43 +38,52 @@ DECLARE_GLOBAL_DATA_PTR; /* General purpose timers bitfields */ #define GPTCR_SWR (1<<15) /* Software reset */ #define GPTCR_FRR (1<<9) /* Freerun / restart */ -#define GPTCR_CLKSOURCE_32 (0x100<<6) /* Clock source */ -#define GPTCR_CLKSOURCE_IPG (0x001<<6) /* Clock source */ +#define GPTCR_CLKSOURCE_32 (4<<6) /* Clock source */ #define GPTCR_TEN (1) /* Timer enable */ -#define TIMER_FREQ_HZ mxc_get_clock(MXC_IPG_CLK) - +/* + * "time" is measured in 1 / CONFIG_SYS_HZ seconds, + * "tick" is internal timer period + */ +/* ~0.4% error - measured with stop-watch on 100s boot-delay */ static inline unsigned long long tick_to_time(unsigned long long tick) { tick *= CONFIG_SYS_HZ; - do_div(tick, TIMER_FREQ_HZ); + do_div(tick, MXC_CLK32); return tick; } -static inline unsigned long long us_to_tick(unsigned long long usec) +static inline unsigned long long us_to_tick(unsigned long long us) { - usec *= TIMER_FREQ_HZ; - do_div(usec, 1000000); + us = us * MXC_CLK32 + 999999; + do_div(us, 1000000); - return usec; + return us; } +/* + * nothing really to do with interrupts, just starts up a counter. + * The 32KHz 32-bit timer overruns in 134217 seconds + */ int timer_init(void) { int i; struct gpt_regs *gpt = (struct gpt_regs *)GPT1_BASE_ADDR; + struct ccm_regs *ccm = (struct ccm_regs *)CCM_BASE_ADDR; /* setup GP Timer 1 */ writel(GPTCR_SWR, &gpt->ctrl); - for (i = 0; i < 100; i++) - writel(0, &gpt->ctrl); /* We have no udelay by now */ - writel(0, &gpt->pre); - /* Freerun Mode, PERCLK1 input */ - writel(readl(&gpt->ctrl) | - GPTCR_CLKSOURCE_IPG | GPTCR_TEN, - &gpt->ctrl); + writel(readl(&ccm->cgr1) | 3 << MXC_CCM_CGR1_GPT_OFFSET, &ccm->cgr1); + + for (i = 0; i < 100; i++) + writel(0, &gpt->ctrl); /* We have no udelay by now */ + writel(0, &gpt->pre); /* prescaler = 1 */ + /* Freerun Mode, 32KHz input */ + writel(readl(&gpt->ctrl) | GPTCR_CLKSOURCE_32 | GPTCR_FRR, + &gpt->ctrl); + writel(readl(&gpt->ctrl) | GPTCR_TEN, &gpt->ctrl); return 0; } @@ -101,7 +111,7 @@ ulong get_timer_masked(void) { /* * 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) ~ + * 2^64 / MXC_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. */ @@ -132,5 +142,5 @@ void __udelay(unsigned long usec) */ ulong get_tbclk(void) { - return TIMER_FREQ_HZ; + return MXC_CLK32; } |