diff options
Diffstat (limited to 'arch/arm/mach-exynos4/time.c')
| -rw-r--r-- | arch/arm/mach-exynos4/time.c | 299 |
1 files changed, 299 insertions, 0 deletions
diff --git a/arch/arm/mach-exynos4/time.c b/arch/arm/mach-exynos4/time.c new file mode 100644 index 000000000000..86b9fa0d3639 --- /dev/null +++ b/arch/arm/mach-exynos4/time.c @@ -0,0 +1,299 @@ +/* linux/arch/arm/mach-exynos4/time.c + * + * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd. + * http://www.samsung.com + * + * EXYNOS4 (and compatible) HRT support + * PWM 2/4 is used for this feature + * + * 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 + * published by the Free Software Foundation. +*/ + +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/err.h> +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/platform_device.h> + +#include <asm/smp_twd.h> + +#include <mach/map.h> +#include <plat/regs-timer.h> +#include <asm/mach/time.h> + +static unsigned long clock_count_per_tick; + +static struct clk *tin2; +static struct clk *tin4; +static struct clk *tdiv2; +static struct clk *tdiv4; +static struct clk *timerclk; + +static void exynos4_pwm_stop(unsigned int pwm_id) +{ + unsigned long tcon; + + tcon = __raw_readl(S3C2410_TCON); + + switch (pwm_id) { + case 2: + tcon &= ~S3C2410_TCON_T2START; + break; + case 4: + tcon &= ~S3C2410_TCON_T4START; + break; + default: + break; + } + __raw_writel(tcon, S3C2410_TCON); +} + +static void exynos4_pwm_init(unsigned int pwm_id, unsigned long tcnt) +{ + unsigned long tcon; + + tcon = __raw_readl(S3C2410_TCON); + + /* timers reload after counting zero, so reduce the count by 1 */ + tcnt--; + + /* ensure timer is stopped... */ + switch (pwm_id) { + case 2: + tcon &= ~(0xf<<12); + tcon |= S3C2410_TCON_T2MANUALUPD; + + __raw_writel(tcnt, S3C2410_TCNTB(2)); + __raw_writel(tcnt, S3C2410_TCMPB(2)); + __raw_writel(tcon, S3C2410_TCON); + + break; + case 4: + tcon &= ~(7<<20); + tcon |= S3C2410_TCON_T4MANUALUPD; + + __raw_writel(tcnt, S3C2410_TCNTB(4)); + __raw_writel(tcnt, S3C2410_TCMPB(4)); + __raw_writel(tcon, S3C2410_TCON); + + break; + default: + break; + } +} + +static inline void exynos4_pwm_start(unsigned int pwm_id, bool periodic) +{ + unsigned long tcon; + + tcon = __raw_readl(S3C2410_TCON); + + switch (pwm_id) { + case 2: + tcon |= S3C2410_TCON_T2START; + tcon &= ~S3C2410_TCON_T2MANUALUPD; + + if (periodic) + tcon |= S3C2410_TCON_T2RELOAD; + else + tcon &= ~S3C2410_TCON_T2RELOAD; + break; + case 4: + tcon |= S3C2410_TCON_T4START; + tcon &= ~S3C2410_TCON_T4MANUALUPD; + + if (periodic) + tcon |= S3C2410_TCON_T4RELOAD; + else + tcon &= ~S3C2410_TCON_T4RELOAD; + break; + default: + break; + } + __raw_writel(tcon, S3C2410_TCON); +} + +static int exynos4_pwm_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + exynos4_pwm_init(2, cycles); + exynos4_pwm_start(2, 0); + return 0; +} + +static void exynos4_pwm_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + exynos4_pwm_stop(2); + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + exynos4_pwm_init(2, clock_count_per_tick); + exynos4_pwm_start(2, 1); + break; + case CLOCK_EVT_MODE_ONESHOT: + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_RESUME: + break; + } +} + +static struct clock_event_device pwm_event_device = { + .name = "pwm_timer2", + .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, + .rating = 200, + .shift = 32, + .set_next_event = exynos4_pwm_set_next_event, + .set_mode = exynos4_pwm_set_mode, +}; + +irqreturn_t exynos4_clock_event_isr(int irq, void *dev_id) +{ + struct clock_event_device *evt = &pwm_event_device; + + evt->event_handler(evt); + + return IRQ_HANDLED; +} + +static struct irqaction exynos4_clock_event_irq = { + .name = "pwm_timer2_irq", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, + .handler = exynos4_clock_event_isr, +}; + +static void __init exynos4_clockevent_init(void) +{ + unsigned long pclk; + unsigned long clock_rate; + struct clk *tscaler; + + pclk = clk_get_rate(timerclk); + + /* configure clock tick */ + + tscaler = clk_get_parent(tdiv2); + + clk_set_rate(tscaler, pclk / 2); + clk_set_rate(tdiv2, pclk / 2); + clk_set_parent(tin2, tdiv2); + + clock_rate = clk_get_rate(tin2); + + clock_count_per_tick = clock_rate / HZ; + + pwm_event_device.mult = + div_sc(clock_rate, NSEC_PER_SEC, pwm_event_device.shift); + pwm_event_device.max_delta_ns = + clockevent_delta2ns(-1, &pwm_event_device); + pwm_event_device.min_delta_ns = + clockevent_delta2ns(1, &pwm_event_device); + + pwm_event_device.cpumask = cpumask_of(0); + clockevents_register_device(&pwm_event_device); + + setup_irq(IRQ_TIMER2, &exynos4_clock_event_irq); +} + +static cycle_t exynos4_pwm4_read(struct clocksource *cs) +{ + return (cycle_t) ~__raw_readl(S3C_TIMERREG(0x40)); +} + +static void exynos4_pwm4_resume(struct clocksource *cs) +{ + unsigned long pclk; + + pclk = clk_get_rate(timerclk); + + clk_set_rate(tdiv4, pclk / 2); + clk_set_parent(tin4, tdiv4); + + exynos4_pwm_init(4, ~0); + exynos4_pwm_start(4, 1); +} + +struct clocksource pwm_clocksource = { + .name = "pwm_timer4", + .rating = 250, + .read = exynos4_pwm4_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS , +#ifdef CONFIG_PM + .resume = exynos4_pwm4_resume, +#endif +}; + +static void __init exynos4_clocksource_init(void) +{ + unsigned long pclk; + unsigned long clock_rate; + + pclk = clk_get_rate(timerclk); + + clk_set_rate(tdiv4, pclk / 2); + clk_set_parent(tin4, tdiv4); + + clock_rate = clk_get_rate(tin4); + + exynos4_pwm_init(4, ~0); + exynos4_pwm_start(4, 1); + + if (clocksource_register_hz(&pwm_clocksource, clock_rate)) + panic("%s: can't register clocksource\n", pwm_clocksource.name); +} + +static void __init exynos4_timer_resources(void) +{ + struct platform_device tmpdev; + + tmpdev.dev.bus = &platform_bus_type; + + timerclk = clk_get(NULL, "timers"); + if (IS_ERR(timerclk)) + panic("failed to get timers clock for system timer"); + + clk_enable(timerclk); + + tmpdev.id = 2; + tin2 = clk_get(&tmpdev.dev, "pwm-tin"); + if (IS_ERR(tin2)) + panic("failed to get pwm-tin2 clock for system timer"); + + tdiv2 = clk_get(&tmpdev.dev, "pwm-tdiv"); + if (IS_ERR(tdiv2)) + panic("failed to get pwm-tdiv2 clock for system timer"); + clk_enable(tin2); + + tmpdev.id = 4; + tin4 = clk_get(&tmpdev.dev, "pwm-tin"); + if (IS_ERR(tin4)) + panic("failed to get pwm-tin4 clock for system timer"); + + tdiv4 = clk_get(&tmpdev.dev, "pwm-tdiv"); + if (IS_ERR(tdiv4)) + panic("failed to get pwm-tdiv4 clock for system timer"); + + clk_enable(tin4); +} + +static void __init exynos4_timer_init(void) +{ +#ifdef CONFIG_LOCAL_TIMERS + twd_base = S5P_VA_TWD; +#endif + + exynos4_timer_resources(); + exynos4_clockevent_init(); + exynos4_clocksource_init(); +} + +struct sys_timer exynos4_timer = { + .init = exynos4_timer_init, +}; |