diff options
Diffstat (limited to 'arch/arm/plat-nomadik/timer.c')
| -rw-r--r-- | arch/arm/plat-nomadik/timer.c | 76 |
1 files changed, 54 insertions, 22 deletions
diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index 0ff3798769ab..41723402006b 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -1,8 +1,9 @@ /* - * linux/arch/arm/mach-nomadik/timer.c + * linux/arch/arm/plat-nomadik/timer.c * * Copyright (C) 2008 STMicroelectronics * Copyright (C) 2010 Alessandro Rubini + * Copyright (C) 2010 Linus Walleij for ST-Ericsson * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2, as @@ -13,12 +14,16 @@ #include <linux/irq.h> #include <linux/io.h> #include <linux/clockchips.h> +#include <linux/clk.h> #include <linux/jiffies.h> +#include <linux/err.h> +#include <linux/sched.h> #include <asm/mach/time.h> +#include <asm/sched_clock.h> #include <plat/mtu.h> -void __iomem *mtu_base; /* ssigned by machine code */ +void __iomem *mtu_base; /* Assigned by machine code */ /* * Kernel assumes that sched_clock can be called early @@ -40,23 +45,31 @@ static struct clocksource nmdk_clksrc = { .rating = 200, .read = nmdk_read_timer_dummy, .mask = CLOCKSOURCE_MASK(32), - .shift = 20, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; /* * Override the global weak sched_clock symbol with this * local implementation which uses the clocksource to get some - * better resolution when scheduling the kernel. We accept that - * this wraps around for now, since it is just a relative time - * stamp. (Inspired by OMAP implementation.) + * better resolution when scheduling the kernel. */ +static DEFINE_CLOCK_DATA(cd); + unsigned long long notrace sched_clock(void) { - return clocksource_cyc2ns(nmdk_clksrc.read( - &nmdk_clksrc), - nmdk_clksrc.mult, - nmdk_clksrc.shift); + u32 cyc; + + if (unlikely(!mtu_base)) + return 0; + + cyc = -readl(mtu_base + MTU_VAL(0)); + return cyc_to_sched_clock(&cd, cyc, (u32)~0); +} + +static void notrace nomadik_update_sched_clock(void) +{ + u32 cyc = -readl(mtu_base + MTU_VAL(0)); + update_sched_clock(&cd, cyc, (u32)~0); } /* Clockevent device: use one-shot mode */ @@ -74,12 +87,18 @@ static void nmdk_clkevt_mode(enum clock_event_mode mode, cr = readl(mtu_base + MTU_CR(1)); writel(0, mtu_base + MTU_LR(1)); writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(1)); - writel(0x2, mtu_base + MTU_IMSC); + writel(1 << 1, mtu_base + MTU_IMSC); break; case CLOCK_EVT_MODE_SHUTDOWN: case CLOCK_EVT_MODE_UNUSED: /* disable irq */ writel(0, mtu_base + MTU_IMSC); + /* disable timer */ + cr = readl(mtu_base + MTU_CR(1)); + cr &= ~MTU_CRn_ENA; + writel(cr, mtu_base + MTU_CR(1)); + /* load some high default value */ + writel(0xffffffff, mtu_base + MTU_LR(1)); break; case CLOCK_EVT_MODE_RESUME: break; @@ -96,7 +115,6 @@ static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev) static struct clock_event_device nmdk_clkevt = { .name = "mtu_1", .features = CLOCK_EVT_FEAT_ONESHOT, - .shift = 32, .rating = 200, .set_mode = nmdk_clkevt_mode, .set_next_event = nmdk_clkevt_next, @@ -124,14 +142,24 @@ static struct irqaction nmdk_timer_irq = { void __init nmdk_timer_init(void) { unsigned long rate; - u32 cr = MTU_CRn_32BITS;; + struct clk *clk0; + u32 cr = MTU_CRn_32BITS; + + clk0 = clk_get_sys("mtu0", NULL); + BUG_ON(IS_ERR(clk0)); + + clk_enable(clk0); /* - * Tick rate is 2.4MHz for Nomadik and 110MHz for ux500: - * use a divide-by-16 counter if it's more than 16MHz + * Tick rate is 2.4MHz for Nomadik and 2.4Mhz, 100MHz or 133 MHz + * for ux500. + * Use a divide-by-16 counter if the tick rate is more than 32MHz. + * At 32 MHz, the timer (with 32 bit counter) can be programmed + * to wake-up at a max 127s a head in time. Dividing a 2.4 MHz timer + * with 16 gives too low timer resolution. */ - rate = CLOCK_TICK_RATE; - if (rate > 16 << 20) { + rate = clk_get_rate(clk0); + if (rate > 32000000) { rate /= 16; cr |= MTU_CRn_PRESCALE_16; } else { @@ -144,17 +172,21 @@ void __init nmdk_timer_init(void) writel(0, mtu_base + MTU_BGLR(0)); writel(cr | MTU_CRn_ENA, mtu_base + MTU_CR(0)); - nmdk_clksrc.mult = clocksource_hz2mult(rate, nmdk_clksrc.shift); - /* Now the scheduling clock is ready */ + /* Now the clock source is ready */ nmdk_clksrc.read = nmdk_read_timer; - if (clocksource_register(&nmdk_clksrc)) + if (clocksource_register_hz(&nmdk_clksrc, rate)) pr_err("timer: failed to initialize clock source %s\n", nmdk_clksrc.name); - /* Timer 1 is used for events, fix according to rate */ + init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate); + + /* Timer 1 is used for events */ + + clockevents_calc_mult_shift(&nmdk_clkevt, rate, MTU_MIN_RANGE); + writel(cr | MTU_CRn_ONESHOT, mtu_base + MTU_CR(1)); /* off, currently */ - nmdk_clkevt.mult = div_sc(rate, NSEC_PER_SEC, nmdk_clkevt.shift); + nmdk_clkevt.max_delta_ns = clockevent_delta2ns(0xffffffff, &nmdk_clkevt); nmdk_clkevt.min_delta_ns = |