Commit 2a98beb6 authored by Russell King's avatar Russell King Committed by Russell King

[ARM SMP] Add local timer support for Realview MPcore

Add platform specific parts for local timer support for the
Realview board.
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 37ee16ae
......@@ -358,7 +358,7 @@ config HOTPLUG_CPU
config LOCAL_TIMERS
bool "Use local timer interrupts"
depends on SMP && n
depends on SMP && REALVIEW_MPCORE
default y
help
Enable support for local timers on SMP platforms, rather then the
......
......@@ -5,3 +5,4 @@
obj-y := core.o clock.o
obj-$(CONFIG_MACH_REALVIEW_EB) += realview_eb.o
obj-$(CONFIG_SMP) += platsmp.o headsmp.o
obj-$(CONFIG_LOCAL_TIMERS) += localtimer.o
......@@ -550,7 +550,7 @@ static irqreturn_t realview_timer_interrupt(int irq, void *dev_id, struct pt_reg
timer_tick(regs);
#ifdef CONFIG_SMP
#if defined(CONFIG_SMP) && !defined(CONFIG_LOCAL_TIMERS)
smp_send_timer();
update_process_times(user_mode(regs));
#endif
......
/*
* 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>
#include "core.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);
}
......@@ -174,6 +174,11 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
if (max_cpus > ncores)
max_cpus = ncores;
/*
* Enable the local timer for primary CPU
*/
local_timer_setup(cpu);
/*
* Initialise the possible/present maps.
* cpu_possible_map describes the set of CPUs which may be present
......
......@@ -61,3 +61,14 @@
strcc \irqstat, [\base, #GIC_CPU_EOI]
cmpcs \irqnr, \irqnr
.endm
/* As above, this assumes that irqstat and base are preserved.. */
.macro test_for_ltirq, irqnr, irqstat, base, tmp
bic \irqnr, \irqstat, #0x1c00
mov \tmp, #0
cmp \irqnr, #29
moveq \tmp, #1
streq \irqstat, [\base, #GIC_CPU_EOI]
cmp \tmp, #0
.endm
......@@ -21,6 +21,9 @@
#include <asm/arch/platform.h>
#define IRQ_LOCALTIMER 29
#define IRQ_LOCALWDOG 30
/*
* IRQ interrupts definitions are the same the INT definitions
* held within platform.h
......
......@@ -209,6 +209,8 @@
#else
#define REALVIEW_MPCORE_SCU_BASE 0x10100000 /* SCU registers */
#define REALVIEW_GIC_CPU_BASE 0x10100100 /* Generic interrupt controller CPU interface */
#define REALVIEW_TWD_BASE 0x10100700
#define REALVIEW_TWD_SIZE 0x00000100
#define REALVIEW_GIC_DIST_BASE 0x10101000 /* Generic interrupt controller distributor */
#endif
#define REALVIEW_SMC_BASE 0x10080000 /* SMC */
......@@ -305,9 +307,6 @@
#define INT_TSPENINT 30 /* Touchscreen pen */
#define INT_TSKPADINT 31 /* Touchscreen keypad */
#else
#define INT_LOCALTIMER 29
#define INT_LOCALWDOG 30
#define INT_AACI 0
#define INT_TIMERINT0_1 1
#define INT_TIMERINT2_3 2
......
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