ce07d90aa8
Move __io_address to arch-realview/hardware.h, drop core.h from platsmp.c and localtimer.c, and include asm/io.h where required. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
129 lines
3.3 KiB
C
129 lines
3.3 KiB
C
/*
|
|
* linux/arch/arm/mach-realview/localtimer.c
|
|
*
|
|
* Copyright (C) 2002 ARM Ltd.
|
|
* All Rights Reserved
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/delay.h>
|
|
#include <linux/device.h>
|
|
#include <linux/smp.h>
|
|
|
|
#include <asm/mach/time.h>
|
|
#include <asm/hardware/arm_twd.h>
|
|
#include <asm/hardware/gic.h>
|
|
#include <asm/hardware.h>
|
|
#include <asm/io.h>
|
|
#include <asm/irq.h>
|
|
|
|
#define TWD_BASE(cpu) (__io_address(REALVIEW_TWD_BASE) + \
|
|
((cpu) * REALVIEW_TWD_SIZE))
|
|
|
|
static unsigned long mpcore_timer_rate;
|
|
|
|
/*
|
|
* local_timer_ack: checks for a local timer interrupt.
|
|
*
|
|
* If a local timer interrupt has occured, acknowledge and return 1.
|
|
* Otherwise, return 0.
|
|
*/
|
|
int local_timer_ack(void)
|
|
{
|
|
void __iomem *base = TWD_BASE(smp_processor_id());
|
|
|
|
if (__raw_readl(base + TWD_TIMER_INTSTAT)) {
|
|
__raw_writel(1, base + TWD_TIMER_INTSTAT);
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
void __cpuinit local_timer_setup(unsigned int cpu)
|
|
{
|
|
void __iomem *base = TWD_BASE(cpu);
|
|
unsigned int load, offset;
|
|
u64 waitjiffies;
|
|
unsigned int count;
|
|
|
|
/*
|
|
* If this is the first time round, we need to work out how fast
|
|
* the timer ticks
|
|
*/
|
|
if (mpcore_timer_rate == 0) {
|
|
printk("Calibrating local timer... ");
|
|
|
|
/* Wait for a tick to start */
|
|
waitjiffies = get_jiffies_64() + 1;
|
|
|
|
while (get_jiffies_64() < waitjiffies)
|
|
udelay(10);
|
|
|
|
/* OK, now the tick has started, let's get the timer going */
|
|
waitjiffies += 5;
|
|
|
|
/* enable, no interrupt or reload */
|
|
__raw_writel(0x1, base + TWD_TIMER_CONTROL);
|
|
|
|
/* maximum value */
|
|
__raw_writel(0xFFFFFFFFU, base + TWD_TIMER_COUNTER);
|
|
|
|
while (get_jiffies_64() < waitjiffies)
|
|
udelay(10);
|
|
|
|
count = __raw_readl(base + TWD_TIMER_COUNTER);
|
|
|
|
mpcore_timer_rate = (0xFFFFFFFFU - count) * (HZ / 5);
|
|
|
|
printk("%lu.%02luMHz.\n", mpcore_timer_rate / 1000000,
|
|
(mpcore_timer_rate / 100000) % 100);
|
|
}
|
|
|
|
load = mpcore_timer_rate / HZ;
|
|
|
|
__raw_writel(load, base + TWD_TIMER_LOAD);
|
|
__raw_writel(0x7, base + TWD_TIMER_CONTROL);
|
|
|
|
/*
|
|
* Now maneuver our local tick into the right part of the jiffy.
|
|
* Start by working out where within the tick our local timer
|
|
* interrupt should go.
|
|
*/
|
|
offset = ((mpcore_timer_rate / HZ) / (NR_CPUS + 1)) * (cpu + 1);
|
|
|
|
/*
|
|
* gettimeoffset() will return a number of us since the last tick.
|
|
* Convert this number of us to a local timer tick count.
|
|
* Be careful of integer overflow whilst keeping maximum precision.
|
|
*
|
|
* with HZ=100 and 1MHz (fpga) ~ 1GHz processor:
|
|
* load = 1 ~ 10,000
|
|
* mpcore_timer_rate/10000 = 100 ~ 100,000
|
|
*
|
|
* so the multiply value will be less than 10^9 always.
|
|
*/
|
|
load = (system_timer->offset() * (mpcore_timer_rate / 10000)) / 100;
|
|
|
|
/* Add on our offset to get the load value */
|
|
load = (load + offset) % (mpcore_timer_rate / HZ);
|
|
|
|
__raw_writel(load, base + TWD_TIMER_COUNTER);
|
|
|
|
/* Make sure our local interrupt controller has this enabled */
|
|
__raw_writel(1 << IRQ_LOCALTIMER,
|
|
__io_address(REALVIEW_GIC_DIST_BASE) + GIC_DIST_ENABLE_SET);
|
|
}
|
|
|
|
/*
|
|
* take a local timer down
|
|
*/
|
|
void __cpuexit local_timer_stop(unsigned int cpu)
|
|
{
|
|
__raw_writel(0, TWD_BASE(cpu) + TWD_TIMER_CONTROL);
|
|
}
|