mirror of
https://github.com/torvalds/linux.git
synced 2024-12-15 15:41:58 +00:00
193c3cc125
Move the xtime write mode seqlock into timer_tick(), so it only surrounds the call to do_timer(). This avoids a deadlock in update_process_times() ... hrtimer_get_softirq_time() which tries to get a read mode seqlock on xtime, thereby preventing booting. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
/*
|
|
* 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/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 <linux/time.h>
|
|
#include <linux/timex.h>
|
|
#include <linux/irq.h>
|
|
|
|
#include <asm/system.h>
|
|
#include <asm/hardware.h>
|
|
#include <asm/io.h>
|
|
#include <asm/leds.h>
|
|
#include <asm/mach/time.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)
|
|
{
|
|
if (__raw_readl(HSTIM_INT) & MATCH0_INT) {
|
|
|
|
do {
|
|
timer_tick();
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static struct irqaction pnx4008_timer_irq = {
|
|
.name = "PNX4008 Tick Timer",
|
|
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
|
|
.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,
|
|
};
|
|
|