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/*
* 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 Texas Instruments, Inc.
*
* Roughly modelled after the OMAP1 MPU timer code.
*
* 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 <mach/dmtimer.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;
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;
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);
#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));
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)
{
omap_dm_timer_init();
omap2_gp_clockevent_init();
omap2_gp_clocksource_init();
}
struct sys_timer omap_timer = {
.init = omap2_gp_timer_init,
};
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