diff options
Diffstat (limited to 'arch/arm/mach-msm/timer.c')
| -rw-r--r-- | arch/arm/mach-msm/timer.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/arch/arm/mach-msm/timer.c b/arch/arm/mach-msm/timer.c new file mode 100644 index 00000000000..bd4732d1ab3 --- /dev/null +++ b/arch/arm/mach-msm/timer.c @@ -0,0 +1,205 @@ +/* linux/arch/arm/mach-msm/timer.c + * + * Copyright (C) 2007 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/init.h> +#include <linux/time.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/delay.h> + +#include <asm/mach/time.h> +#include <asm/arch/msm_iomap.h> + +#include <asm/io.h> + +#define MSM_DGT_BASE (MSM_GPT_BASE + 0x10) +#define MSM_DGT_SHIFT (5) + +#define TIMER_MATCH_VAL 0x0000 +#define TIMER_COUNT_VAL 0x0004 +#define TIMER_ENABLE 0x0008 +#define TIMER_ENABLE_CLR_ON_MATCH_EN 2 +#define TIMER_ENABLE_EN 1 +#define TIMER_CLEAR 0x000C + +#define CSR_PROTECTION 0x0020 +#define CSR_PROTECTION_EN 1 + +#define GPT_HZ 32768 +#define DGT_HZ 19200000 /* 19.2 MHz or 600 KHz after shift */ + +struct msm_clock { + struct clock_event_device clockevent; + struct clocksource clocksource; + struct irqaction irq; + uint32_t regbase; + uint32_t freq; + uint32_t shift; +}; + +static irqreturn_t msm_timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *evt = dev_id; + evt->event_handler(evt); + return IRQ_HANDLED; +} + +static cycle_t msm_gpt_read(void) +{ + return readl(MSM_GPT_BASE + TIMER_COUNT_VAL); +} + +static cycle_t msm_dgt_read(void) +{ + return readl(MSM_DGT_BASE + TIMER_COUNT_VAL) >> MSM_DGT_SHIFT; +} + +static int msm_timer_set_next_event(unsigned long cycles, + struct clock_event_device *evt) +{ + struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent); + uint32_t now = readl(clock->regbase + TIMER_COUNT_VAL); + uint32_t alarm = now + (cycles << clock->shift); + int late; + + writel(alarm, clock->regbase + TIMER_MATCH_VAL); + now = readl(clock->regbase + TIMER_COUNT_VAL); + late = now - alarm; + if (late >= (-2 << clock->shift) && late < DGT_HZ*5) { + printk(KERN_NOTICE "msm_timer_set_next_event(%lu) clock %s, " + "alarm already expired, now %x, alarm %x, late %d\n", + cycles, clock->clockevent.name, now, alarm, late); + return -ETIME; + } + return 0; +} + +static void msm_timer_set_mode(enum clock_event_mode mode, + struct clock_event_device *evt) +{ + struct msm_clock *clock = container_of(evt, struct msm_clock, clockevent); + switch (mode) { + case CLOCK_EVT_MODE_RESUME: + case CLOCK_EVT_MODE_PERIODIC: + break; + case CLOCK_EVT_MODE_ONESHOT: + writel(TIMER_ENABLE_EN, clock->regbase + TIMER_ENABLE); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + writel(0, clock->regbase + TIMER_ENABLE); + break; + } +} + +static struct msm_clock msm_clocks[] = { + { + .clockevent = { + .name = "gp_timer", + .features = CLOCK_EVT_FEAT_ONESHOT, + .shift = 32, + .rating = 200, + .set_next_event = msm_timer_set_next_event, + .set_mode = msm_timer_set_mode, + }, + .clocksource = { + .name = "gp_timer", + .rating = 200, + .read = msm_gpt_read, + .mask = CLOCKSOURCE_MASK(32), + .shift = 24, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + }, + .irq = { + .name = "gp_timer", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING, + .handler = msm_timer_interrupt, + .dev_id = &msm_clocks[0].clockevent, + .irq = INT_GP_TIMER_EXP + }, + .regbase = MSM_GPT_BASE, + .freq = GPT_HZ + }, + { + .clockevent = { + .name = "dg_timer", + .features = CLOCK_EVT_FEAT_ONESHOT, + .shift = 32 + MSM_DGT_SHIFT, + .rating = 300, + .set_next_event = msm_timer_set_next_event, + .set_mode = msm_timer_set_mode, + }, + .clocksource = { + .name = "dg_timer", + .rating = 300, + .read = msm_dgt_read, + .mask = CLOCKSOURCE_MASK((32 - MSM_DGT_SHIFT)), + .shift = 24 - MSM_DGT_SHIFT, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + }, + .irq = { + .name = "dg_timer", + .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_TRIGGER_RISING, + .handler = msm_timer_interrupt, + .dev_id = &msm_clocks[1].clockevent, + .irq = INT_DEBUG_TIMER_EXP + }, + .regbase = MSM_DGT_BASE, + .freq = DGT_HZ >> MSM_DGT_SHIFT, + .shift = MSM_DGT_SHIFT + } +}; + +static void __init msm_timer_init(void) +{ + int i; + int res; + + for (i = 0; i < ARRAY_SIZE(msm_clocks); i++) { + struct msm_clock *clock = &msm_clocks[i]; + struct clock_event_device *ce = &clock->clockevent; + struct clocksource *cs = &clock->clocksource; + writel(0, clock->regbase + TIMER_ENABLE); + writel(0, clock->regbase + TIMER_CLEAR); + writel(~0, clock->regbase + TIMER_MATCH_VAL); + + ce->mult = div_sc(clock->freq, NSEC_PER_SEC, ce->shift); + /* allow at least 10 seconds to notice that the timer wrapped */ + ce->max_delta_ns = + clockevent_delta2ns(0xf0000000 >> clock->shift, ce); + /* 4 gets rounded down to 3 */ + ce->min_delta_ns = clockevent_delta2ns(4, ce); + ce->cpumask = cpumask_of_cpu(0); + + cs->mult = clocksource_hz2mult(clock->freq, cs->shift); + res = clocksource_register(cs); + if (res) + printk(KERN_ERR "msm_timer_init: clocksource_register " + "failed for %s\n", cs->name); + + res = setup_irq(clock->irq.irq, &clock->irq); + if (res) + printk(KERN_ERR "msm_timer_init: setup_irq " + "failed for %s\n", cs->name); + + clockevents_register_device(ce); + } +} + +struct sys_timer msm_timer = { + .init = msm_timer_init +}; |