diff options
Diffstat (limited to 'arch/arm/plat-omap/counter_32k.c')
| -rw-r--r-- | arch/arm/plat-omap/counter_32k.c | 226 |
1 files changed, 71 insertions, 155 deletions
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c index 862dda95d61..61b4d705c26 100644 --- a/arch/arm/plat-omap/counter_32k.c +++ b/arch/arm/plat-omap/counter_32k.c @@ -17,15 +17,18 @@ #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> -#include <linux/sched.h> - -#include <asm/sched_clock.h> +#include <linux/clocksource.h> +#include <linux/sched_clock.h> -#include <plat/common.h> -#include <plat/board.h> +#include <asm/mach/time.h> -#include <plat/clock.h> +#include <plat/counter-32k.h> +/* OMAP2_32KSYNCNT_CR_OFF: offset of 32ksync counter register */ +#define OMAP2_32KSYNCNT_REV_OFF 0x0 +#define OMAP2_32KSYNCNT_REV_SCHEME (0x3 << 30) +#define OMAP2_32KSYNCNT_CR_OFF_LOW 0x10 +#define OMAP2_32KSYNCNT_CR_OFF_HIGH 0x30 /* * 32KHz clocksource ... always available, on pretty most chips except @@ -33,175 +36,88 @@ * higher resolution in free-running counter modes (e.g. 12 MHz xtal), * but systems won't necessarily want to spend resources that way. */ +static void __iomem *sync32k_cnt_reg; -#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410 - -#include <linux/clocksource.h> - -/* - * offset_32k holds the init time counter value. It is then subtracted - * from every counter read to achieve a counter that counts time from the - * kernel boot (needed for sched_clock()). - */ -static u32 offset_32k __read_mostly; - -#ifdef CONFIG_ARCH_OMAP16XX -static cycle_t notrace omap16xx_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP16XX_TIMER_32K_SYNCHRONIZED) - offset_32k; -} -#else -#define omap16xx_32k_read NULL -#endif - -#ifdef CONFIG_ARCH_OMAP2420 -static cycle_t notrace omap2420_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP2420_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap2420_32k_read NULL -#endif - -#ifdef CONFIG_ARCH_OMAP2430 -static cycle_t notrace omap2430_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP2430_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap2430_32k_read NULL -#endif - -#ifdef CONFIG_ARCH_OMAP3 -static cycle_t notrace omap34xx_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP3430_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap34xx_32k_read NULL -#endif - -#ifdef CONFIG_ARCH_OMAP4 -static cycle_t notrace omap44xx_32k_read(struct clocksource *cs) -{ - return omap_readl(OMAP4430_32KSYNCT_BASE + 0x10) - offset_32k; -} -#else -#define omap44xx_32k_read NULL -#endif - -/* - * Kernel assumes that sched_clock can be called early but may not have - * things ready yet. - */ -static cycle_t notrace omap_32k_read_dummy(struct clocksource *cs) -{ - return 0; -} - -static struct clocksource clocksource_32k = { - .name = "32k_counter", - .rating = 250, - .read = omap_32k_read_dummy, - .mask = CLOCKSOURCE_MASK(32), - .flags = CLOCK_SOURCE_IS_CONTINUOUS, -}; - -/* - * Returns current time from boot in nsecs. It's OK for this to wrap - * around for now, as it's just a relative time stamp. - */ -static DEFINE_CLOCK_DATA(cd); - -/* - * Constants generated by clocks_calc_mult_shift(m, s, 32768, NSEC_PER_SEC, 60). - * This gives a resolution of about 30us and a wrap period of about 36hrs. - */ -#define SC_MULT 4000000000u -#define SC_SHIFT 17 - -static inline unsigned long long notrace _omap_32k_sched_clock(void) -{ - u32 cyc = clocksource_32k.read(&clocksource_32k); - return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT); -} - -#ifndef CONFIG_OMAP_MPU_TIMER -unsigned long long notrace sched_clock(void) -{ - return _omap_32k_sched_clock(); -} -#else -unsigned long long notrace omap_32k_sched_clock(void) +static u64 notrace omap_32k_read_sched_clock(void) { - return _omap_32k_sched_clock(); -} -#endif - -static void notrace omap_update_sched_clock(void) -{ - u32 cyc = clocksource_32k.read(&clocksource_32k); - update_sched_clock(&cd, cyc, (u32)~0); + return sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; } /** - * read_persistent_clock - Return time from a persistent clock. + * omap_read_persistent_clock - Return time from a persistent clock. * * Reads the time from a source which isn't disabled during PM, the * 32k sync timer. Convert the cycles elapsed since last read into * nsecs and adds to a monotonically increasing timespec. */ static struct timespec persistent_ts; -static cycles_t cycles, last_cycles; -void read_persistent_clock(struct timespec *ts) +static cycles_t cycles; +static unsigned int persistent_mult, persistent_shift; +static DEFINE_SPINLOCK(read_persistent_clock_lock); + +static void omap_read_persistent_clock(struct timespec *ts) { unsigned long long nsecs; - cycles_t delta; - struct timespec *tsp = &persistent_ts; + cycles_t last_cycles; + unsigned long flags; + + spin_lock_irqsave(&read_persistent_clock_lock, flags); last_cycles = cycles; - cycles = clocksource_32k.read(&clocksource_32k); - delta = cycles - last_cycles; + cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; + + nsecs = clocksource_cyc2ns(cycles - last_cycles, + persistent_mult, persistent_shift); + + timespec_add_ns(&persistent_ts, nsecs); - nsecs = clocksource_cyc2ns(delta, - clocksource_32k.mult, clocksource_32k.shift); + *ts = persistent_ts; - timespec_add_ns(tsp, nsecs); - *ts = *tsp; + spin_unlock_irqrestore(&read_persistent_clock_lock, flags); } -int __init omap_init_clocksource_32k(void) +/** + * omap_init_clocksource_32k - setup and register counter 32k as a + * kernel clocksource + * @pbase: base addr of counter_32k module + * @size: size of counter_32k to map + * + * Returns 0 upon success or negative error code upon failure. + * + */ +int __init omap_init_clocksource_32k(void __iomem *vbase) { - static char err[] __initdata = KERN_ERR - "%s: can't register clocksource!\n"; - - if (cpu_is_omap16xx() || cpu_class_is_omap2()) { - struct clk *sync_32k_ick; - - if (cpu_is_omap16xx()) - clocksource_32k.read = omap16xx_32k_read; - else if (cpu_is_omap2420()) - clocksource_32k.read = omap2420_32k_read; - else if (cpu_is_omap2430()) - clocksource_32k.read = omap2430_32k_read; - else if (cpu_is_omap34xx()) - clocksource_32k.read = omap34xx_32k_read; - else if (cpu_is_omap44xx()) - clocksource_32k.read = omap44xx_32k_read; - else - return -ENODEV; - - sync_32k_ick = clk_get(NULL, "omap_32ksync_ick"); - if (!IS_ERR(sync_32k_ick)) - clk_enable(sync_32k_ick); - - offset_32k = clocksource_32k.read(&clocksource_32k); - - if (clocksource_register_hz(&clocksource_32k, 32768)) - printk(err, clocksource_32k.name); - - init_fixed_sched_clock(&cd, omap_update_sched_clock, 32, - 32768, SC_MULT, SC_SHIFT); + int ret; + + /* + * 32k sync Counter IP register offsets vary between the + * highlander version and the legacy ones. + * The 'SCHEME' bits(30-31) of the revision register is used + * to identify the version. + */ + if (readl_relaxed(vbase + OMAP2_32KSYNCNT_REV_OFF) & + OMAP2_32KSYNCNT_REV_SCHEME) + sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_HIGH; + else + sync32k_cnt_reg = vbase + OMAP2_32KSYNCNT_CR_OFF_LOW; + + /* + * 120000 rough estimate from the calculations in + * __clocksource_updatefreq_scale. + */ + clocks_calc_mult_shift(&persistent_mult, &persistent_shift, + 32768, NSEC_PER_SEC, 120000); + + ret = clocksource_mmio_init(sync32k_cnt_reg, "32k_counter", 32768, + 250, 32, clocksource_mmio_readl_up); + if (ret) { + pr_err("32k_counter: can't register clocksource\n"); + return ret; } + + sched_clock_register(omap_32k_read_sched_clock, 32, 32768); + register_persistent_clock(NULL, omap_read_persistent_clock); + pr_info("OMAP clocksource: 32k_counter at 32768 Hz\n"); + return 0; } |