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/*
* arch/arm/mach-pnx4008/time.c
*
* PNX4008 Timers
*
* Authors: Vitaly Wool, Dmitry Chigirev, Grigory Tolstolytkin <source@mvista.com>
*
* 2005 (c) MontaVista Software, Inc. This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/kallsyms.h>
#include <asm/system.h>
#include <asm/hardware.h>
#include <asm/io.h>
#include <asm/leds.h>
#include <asm/irq.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <asm/errno.h>
/*! Note: all timers are UPCOUNTING */
/*!
* Returns number of us since last clock interrupt. Note that interrupts
* will have been disabled by do_gettimeoffset()
*/
static unsigned long pnx4008_gettimeoffset(void)
{
u32 ticks_to_match =
__raw_readl(HSTIM_MATCH0) - __raw_readl(HSTIM_COUNTER);
u32 elapsed = LATCH - ticks_to_match;
return (elapsed * (tick_nsec / 1000)) / LATCH;
}
/*!
* IRQ handler for the timer
*/
static irqreturn_t pnx4008_timer_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
if (__raw_readl(HSTIM_INT) & MATCH0_INT) {
write_seqlock(&xtime_lock);
do {
timer_tick(regs);
/*
* this algorithm takes care of possible delay
* for this interrupt handling longer than a normal
* timer period
*/
__raw_writel(__raw_readl(HSTIM_MATCH0) + LATCH,
HSTIM_MATCH0);
__raw_writel(MATCH0_INT, HSTIM_INT); /* clear interrupt */
/*
* The goal is to keep incrementing HSTIM_MATCH0
* register until HSTIM_MATCH0 indicates time after
* what HSTIM_COUNTER indicates.
*/
} while ((signed)
(__raw_readl(HSTIM_MATCH0) -
__raw_readl(HSTIM_COUNTER)) < 0);
write_sequnlock(&xtime_lock);
}
return IRQ_HANDLED;
}
static struct irqaction pnx4008_timer_irq = {
.name = "PNX4008 Tick Timer",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = pnx4008_timer_interrupt
};
/*!
* Set up timer and timer interrupt.
*/
static __init void pnx4008_setup_timer(void)
{
__raw_writel(RESET_COUNT, MSTIM_CTRL);
while (__raw_readl(MSTIM_COUNTER)) ; /* wait for reset to complete. 100% guarantee event */
__raw_writel(0, MSTIM_CTRL); /* stop the timer */
__raw_writel(0, MSTIM_MCTRL);
__raw_writel(RESET_COUNT, HSTIM_CTRL);
while (__raw_readl(HSTIM_COUNTER)) ; /* wait for reset to complete. 100% guarantee event */
__raw_writel(0, HSTIM_CTRL);
__raw_writel(0, HSTIM_MCTRL);
__raw_writel(0, HSTIM_CCR);
__raw_writel(12, HSTIM_PMATCH); /* scale down to 1 MHZ */
__raw_writel(LATCH, HSTIM_MATCH0);
__raw_writel(MR0_INT, HSTIM_MCTRL);
setup_irq(HSTIMER_INT, &pnx4008_timer_irq);
__raw_writel(COUNT_ENAB | DEBUG_EN, HSTIM_CTRL); /*start timer, stop when JTAG active */
}
/* Timer Clock Control in PM register */
#define TIMCLK_CTRL_REG IO_ADDRESS((PNX4008_PWRMAN_BASE + 0xBC))
#define WATCHDOG_CLK_EN 1
#define TIMER_CLK_EN 2 /* HS and MS timers? */
static u32 timclk_ctrl_reg_save;
void pnx4008_timer_suspend(void)
{
timclk_ctrl_reg_save = __raw_readl(TIMCLK_CTRL_REG);
__raw_writel(0, TIMCLK_CTRL_REG); /* disable timers */
}
void pnx4008_timer_resume(void)
{
__raw_writel(timclk_ctrl_reg_save, TIMCLK_CTRL_REG); /* enable timers */
}
struct sys_timer pnx4008_timer = {
.init = pnx4008_setup_timer,
.offset = pnx4008_gettimeoffset,
.suspend = pnx4008_timer_suspend,
.resume = pnx4008_timer_resume,
};
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