/* * linux/arch/arm/mach-omap2/timer-gp.c * * OMAP2 GP timer support. * * Copyright (C) 2009 Nokia Corporation * * Update to use new clocksource/clockevent layers * Author: Kevin Hilman, MontaVista Software, Inc. <source@mvista.com> * Copyright (C) 2007 MontaVista Software, Inc. * * Original driver: * Copyright (C) 2005 Nokia Corporation * Author: Paul Mundt <paul.mundt@nokia.com> * Juha Yrjölä <juha.yrjola@nokia.com> * OMAP Dual-mode timer framework support by Timo Teras * * Some parts based off of TI's 24xx code: * * Copyright (C) 2004-2009 Texas Instruments, Inc. * * Roughly modelled after the OMAP1 MPU timer code. * Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com> * * This file is subject to the terms and conditions of the GNU General Public * License. See the file "COPYING" in the main directory of this archive * for more details. */ #include <linux/init.h> #include <linux/time.h> #include <linux/interrupt.h> #include <linux/err.h> #include <linux/clk.h> #include <linux/delay.h> #include <linux/irq.h> #include <linux/clocksource.h> #include <linux/clockchips.h> #include <asm/mach/time.h> #include <plat/dmtimer.h> #include <asm/localtimer.h> /* MAX_GPTIMER_ID: number of GPTIMERs on the chip */ #define MAX_GPTIMER_ID 12 static struct omap_dm_timer *gptimer; static struct clock_event_device clockevent_gpt; static u8 __initdata gptimer_id = 1; static u8 __initdata inited; struct omap_dm_timer *gptimer_wakeup; static irqreturn_t omap2_gp_timer_interrupt(int irq, void *dev_id) { struct omap_dm_timer *gpt = (struct omap_dm_timer *)dev_id; struct clock_event_device *evt = &clockevent_gpt; omap_dm_timer_write_status(gpt, OMAP_TIMER_INT_OVERFLOW); evt->event_handler(evt); return IRQ_HANDLED; } static struct irqaction omap2_gp_timer_irq = { .name = "gp timer", .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL, .handler = omap2_gp_timer_interrupt, }; static int omap2_gp_timer_set_next_event(unsigned long cycles, struct clock_event_device *evt) { omap_dm_timer_set_load_start(gptimer, 0, 0xffffffff - cycles); return 0; } static void omap2_gp_timer_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) { u32 period; omap_dm_timer_stop(gptimer); switch (mode) { case CLOCK_EVT_MODE_PERIODIC: period = clk_get_rate(omap_dm_timer_get_fclk(gptimer)) / HZ; period -= 1; if (cpu_is_omap44xx()) period = 0xff; /* FIXME: */ omap_dm_timer_set_load_start(gptimer, 1, 0xffffffff - period); 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 clockevent_gpt = { .name = "gp timer", .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, .shift = 32, .set_next_event = omap2_gp_timer_set_next_event, .set_mode = omap2_gp_timer_set_mode, }; /** * omap2_gp_clockevent_set_gptimer - set which GPTIMER is used for clockevents * @id: GPTIMER to use (1..MAX_GPTIMER_ID) * * Define the GPTIMER that the system should use for the tick timer. * Meant to be called from board-*.c files in the event that GPTIMER1, the * default, is unsuitable. Returns -EINVAL on error or 0 on success. */ int __init omap2_gp_clockevent_set_gptimer(u8 id) { if (id < 1 || id > MAX_GPTIMER_ID) return -EINVAL; BUG_ON(inited); gptimer_id = id; return 0; } static void __init omap2_gp_clockevent_init(void) { u32 tick_rate; int src; inited = 1; gptimer = omap_dm_timer_request_specific(gptimer_id); BUG_ON(gptimer == NULL); gptimer_wakeup = gptimer; #if defined(CONFIG_OMAP_32K_TIMER) src = OMAP_TIMER_SRC_32_KHZ; #else src = OMAP_TIMER_SRC_SYS_CLK; WARN(gptimer_id == 12, "WARNING: GPTIMER12 can only use the " "secure 32KiHz clock source\n"); #endif if (gptimer_id != 12) WARN(IS_ERR_VALUE(omap_dm_timer_set_source(gptimer, src)), "timer-gp: omap_dm_timer_set_source() failed\n"); tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gptimer)); if (cpu_is_omap44xx()) /* Assuming 32kHz clk is driving GPT1 */ tick_rate = 32768; /* FIXME: */ pr_info("OMAP clockevent source: GPTIMER%d at %u Hz\n", gptimer_id, tick_rate); omap2_gp_timer_irq.dev_id = (void *)gptimer; setup_irq(omap_dm_timer_get_irq(gptimer), &omap2_gp_timer_irq); omap_dm_timer_set_int_enable(gptimer, OMAP_TIMER_INT_OVERFLOW); clockevent_gpt.mult = div_sc(tick_rate, NSEC_PER_SEC, clockevent_gpt.shift); clockevent_gpt.max_delta_ns = clockevent_delta2ns(0xffffffff, &clockevent_gpt); clockevent_gpt.min_delta_ns = clockevent_delta2ns(3, &clockevent_gpt); /* Timer internal resynch latency. */ clockevent_gpt.cpumask = cpumask_of(0); clockevents_register_device(&clockevent_gpt); } /* Clocksource code */ #ifdef CONFIG_OMAP_32K_TIMER /* * When 32k-timer is enabled, don't use GPTimer for clocksource * instead, just leave default clocksource which uses the 32k * sync counter. See clocksource setup in see plat-omap/common.c. */ static inline void __init omap2_gp_clocksource_init(void) {} #else /* * clocksource */ static struct omap_dm_timer *gpt_clocksource; static cycle_t clocksource_read_cycles(struct clocksource *cs) { return (cycle_t)omap_dm_timer_read_counter(gpt_clocksource); } static struct clocksource clocksource_gpt = { .name = "gp timer", .rating = 300, .read = clocksource_read_cycles, .mask = CLOCKSOURCE_MASK(32), .shift = 24, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; /* Setup free-running counter for clocksource */ static void __init omap2_gp_clocksource_init(void) { static struct omap_dm_timer *gpt; u32 tick_rate, tick_period; static char err1[] __initdata = KERN_ERR "%s: failed to request dm-timer\n"; static char err2[] __initdata = KERN_ERR "%s: can't register clocksource!\n"; gpt = omap_dm_timer_request(); if (!gpt) printk(err1, clocksource_gpt.name); gpt_clocksource = gpt; omap_dm_timer_set_source(gpt, OMAP_TIMER_SRC_SYS_CLK); tick_rate = clk_get_rate(omap_dm_timer_get_fclk(gpt)); tick_period = (tick_rate / HZ) - 1; omap_dm_timer_set_load_start(gpt, 1, 0); clocksource_gpt.mult = clocksource_khz2mult(tick_rate/1000, clocksource_gpt.shift); if (clocksource_register(&clocksource_gpt)) printk(err2, clocksource_gpt.name); } #endif static void __init omap2_gp_timer_init(void) { #ifdef CONFIG_LOCAL_TIMERS twd_base = ioremap(OMAP44XX_LOCAL_TWD_BASE, SZ_256); BUG_ON(!twd_base); #endif omap_dm_timer_init(); omap2_gp_clockevent_init(); omap2_gp_clocksource_init(); } struct sys_timer omap_timer = { .init = omap2_gp_timer_init, };