diff options
Diffstat (limited to 'arch/arm/plat-omap/counter_32k.c')
| -rw-r--r-- | arch/arm/plat-omap/counter_32k.c | 135 |
1 files changed, 69 insertions, 66 deletions
diff --git a/arch/arm/plat-omap/counter_32k.c b/arch/arm/plat-omap/counter_32k.c index 5f0f2292b7f..61b4d705c26 100644 --- a/arch/arm/plat-omap/counter_32k.c +++ b/arch/arm/plat-omap/counter_32k.c @@ -18,13 +18,17 @@ #include <linux/err.h> #include <linux/io.h> #include <linux/clocksource.h> +#include <linux/sched_clock.h> -#include <asm/sched_clock.h> +#include <asm/mach/time.h> -#include <plat/common.h> -#include <plat/board.h> +#include <plat/counter-32k.h> -#include <plat/clock.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 @@ -32,89 +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 *timer_32k_base; +static void __iomem *sync32k_cnt_reg; -#define OMAP16XX_TIMER_32K_SYNCHRONIZED 0xfffbc410 - -static u32 notrace omap_32k_read_sched_clock(void) +static u64 notrace omap_32k_read_sched_clock(void) { - return timer_32k_base ? __raw_readl(timer_32k_base) : 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; +static cycles_t cycles; static unsigned int persistent_mult, persistent_shift; -void read_persistent_clock(struct timespec *ts) +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 = timer_32k_base ? __raw_readl(timer_32k_base) : 0; - delta = cycles - last_cycles; + cycles = sync32k_cnt_reg ? readl_relaxed(sync32k_cnt_reg) : 0; - nsecs = clocksource_cyc2ns(delta, persistent_mult, persistent_shift); + nsecs = clocksource_cyc2ns(cycles - last_cycles, + persistent_mult, persistent_shift); - timespec_add_ns(tsp, nsecs); - *ts = *tsp; + timespec_add_ns(&persistent_ts, nsecs); + + *ts = persistent_ts; + + 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()) { - u32 pbase; - unsigned long size = SZ_4K; - void __iomem *base; - struct clk *sync_32k_ick; - - if (cpu_is_omap16xx()) { - pbase = OMAP16XX_TIMER_32K_SYNCHRONIZED; - size = SZ_1K; - } else if (cpu_is_omap2420()) - pbase = OMAP2420_32KSYNCT_BASE + 0x10; - else if (cpu_is_omap2430()) - pbase = OMAP2430_32KSYNCT_BASE + 0x10; - else if (cpu_is_omap34xx()) - pbase = OMAP3430_32KSYNCT_BASE + 0x10; - else if (cpu_is_omap44xx()) - pbase = OMAP4430_32KSYNCT_BASE + 0x10; - else - return -ENODEV; - - /* For this to work we must have a static mapping in io.c for this area */ - base = ioremap(pbase, size); - if (!base) - return -ENODEV; - - sync_32k_ick = clk_get(NULL, "omap_32ksync_ick"); - if (!IS_ERR(sync_32k_ick)) - clk_enable(sync_32k_ick); - - timer_32k_base = base; - - /* - * 120000 rough estimate from the calculations in - * __clocksource_updatefreq_scale. - */ - clocks_calc_mult_shift(&persistent_mult, &persistent_shift, - 32768, NSEC_PER_SEC, 120000); - - if (clocksource_mmio_init(base, "32k_counter", 32768, 250, 32, - clocksource_mmio_readl_up)) - printk(err, "32k_counter"); - - setup_sched_clock(omap_32k_read_sched_clock, 32, 32768); + 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; } |