265 lines
6.7 KiB
C
265 lines
6.7 KiB
C
/*
|
|
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
|
|
*
|
|
* 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.
|
|
*
|
|
* vineetg: Jan 1011
|
|
* -sched_clock( ) no longer jiffies based. Uses the same clocksource
|
|
* as gtod
|
|
*
|
|
* Rajeshwarr/Vineetg: Mar 2008
|
|
* -Implemented CONFIG_GENERIC_TIME (rather deleted arch specific code)
|
|
* for arch independent gettimeofday()
|
|
* -Implemented CONFIG_GENERIC_CLOCKEVENTS as base for hrtimers
|
|
*
|
|
* Vineetg: Mar 2008: Forked off from time.c which now is time-jiff.c
|
|
*/
|
|
|
|
/* ARC700 has two 32bit independent prog Timers: TIMER0 and TIMER1
|
|
* Each can programmed to go from @count to @limit and optionally
|
|
* interrupt when that happens.
|
|
* A write to Control Register clears the Interrupt
|
|
*
|
|
* We've designated TIMER0 for events (clockevents)
|
|
* while TIMER1 for free running (clocksource)
|
|
*
|
|
* Newer ARC700 cores have 64bit clk fetching RTSC insn, preferred over TIMER1
|
|
*/
|
|
|
|
#include <linux/spinlock.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/module.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/time.h>
|
|
#include <linux/init.h>
|
|
#include <linux/timex.h>
|
|
#include <linux/profile.h>
|
|
#include <linux/clocksource.h>
|
|
#include <linux/clockchips.h>
|
|
#include <asm/irq.h>
|
|
#include <asm/arcregs.h>
|
|
#include <asm/clk.h>
|
|
#include <asm/mach_desc.h>
|
|
|
|
#define ARC_TIMER_MAX 0xFFFFFFFF
|
|
|
|
/********** Clock Source Device *********/
|
|
|
|
#ifdef CONFIG_ARC_HAS_RTSC
|
|
|
|
int __cpuinit arc_counter_setup(void)
|
|
{
|
|
/* RTSC insn taps into cpu clk, needs no setup */
|
|
|
|
/* For SMP, only allowed if cross-core-sync, hence usable as cs */
|
|
return 1;
|
|
}
|
|
|
|
static cycle_t arc_counter_read(struct clocksource *cs)
|
|
{
|
|
unsigned long flags;
|
|
union {
|
|
#ifdef CONFIG_CPU_BIG_ENDIAN
|
|
struct { u32 high, low; };
|
|
#else
|
|
struct { u32 low, high; };
|
|
#endif
|
|
cycle_t full;
|
|
} stamp;
|
|
|
|
flags = arch_local_irq_save();
|
|
|
|
__asm__ __volatile(
|
|
" .extCoreRegister tsch, 58, r, cannot_shortcut \n"
|
|
" rtsc %0, 0 \n"
|
|
" mov %1, 0 \n"
|
|
: "=r" (stamp.low), "=r" (stamp.high));
|
|
|
|
arch_local_irq_restore(flags);
|
|
|
|
return stamp.full;
|
|
}
|
|
|
|
static struct clocksource arc_counter = {
|
|
.name = "ARC RTSC",
|
|
.rating = 300,
|
|
.read = arc_counter_read,
|
|
.mask = CLOCKSOURCE_MASK(32),
|
|
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
|
|
};
|
|
|
|
#else /* !CONFIG_ARC_HAS_RTSC */
|
|
|
|
static bool is_usable_as_clocksource(void)
|
|
{
|
|
#ifdef CONFIG_SMP
|
|
return 0;
|
|
#else
|
|
return 1;
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* set 32bit TIMER1 to keep counting monotonically and wraparound
|
|
*/
|
|
int __cpuinit arc_counter_setup(void)
|
|
{
|
|
write_aux_reg(ARC_REG_TIMER1_LIMIT, ARC_TIMER_MAX);
|
|
write_aux_reg(ARC_REG_TIMER1_CNT, 0);
|
|
write_aux_reg(ARC_REG_TIMER1_CTRL, TIMER_CTRL_NH);
|
|
|
|
return is_usable_as_clocksource();
|
|
}
|
|
|
|
static cycle_t arc_counter_read(struct clocksource *cs)
|
|
{
|
|
return (cycle_t) read_aux_reg(ARC_REG_TIMER1_CNT);
|
|
}
|
|
|
|
static struct clocksource arc_counter = {
|
|
.name = "ARC Timer1",
|
|
.rating = 300,
|
|
.read = arc_counter_read,
|
|
.mask = CLOCKSOURCE_MASK(32),
|
|
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
|
|
};
|
|
|
|
#endif
|
|
|
|
/********** Clock Event Device *********/
|
|
|
|
/*
|
|
* Arm the timer to interrupt after @limit cycles
|
|
* The distinction for oneshot/periodic is done in arc_event_timer_ack() below
|
|
*/
|
|
static void arc_timer_event_setup(unsigned int limit)
|
|
{
|
|
write_aux_reg(ARC_REG_TIMER0_LIMIT, limit);
|
|
write_aux_reg(ARC_REG_TIMER0_CNT, 0); /* start from 0 */
|
|
|
|
write_aux_reg(ARC_REG_TIMER0_CTRL, TIMER_CTRL_IE | TIMER_CTRL_NH);
|
|
}
|
|
|
|
/*
|
|
* Acknowledge the interrupt (oneshot) and optionally re-arm it (periodic)
|
|
* -Any write to CTRL Reg will ack the intr (NH bit: Count when not halted)
|
|
* -Rearming is done by setting the IE bit
|
|
*
|
|
* Small optimisation: Normal code would have been
|
|
* if (irq_reenable)
|
|
* CTRL_REG = (IE | NH);
|
|
* else
|
|
* CTRL_REG = NH;
|
|
* However since IE is BIT0 we can fold the branch
|
|
*/
|
|
static void arc_timer_event_ack(unsigned int irq_reenable)
|
|
{
|
|
write_aux_reg(ARC_REG_TIMER0_CTRL, irq_reenable | TIMER_CTRL_NH);
|
|
}
|
|
|
|
static int arc_clkevent_set_next_event(unsigned long delta,
|
|
struct clock_event_device *dev)
|
|
{
|
|
arc_timer_event_setup(delta);
|
|
return 0;
|
|
}
|
|
|
|
static void arc_clkevent_set_mode(enum clock_event_mode mode,
|
|
struct clock_event_device *dev)
|
|
{
|
|
switch (mode) {
|
|
case CLOCK_EVT_MODE_PERIODIC:
|
|
arc_timer_event_setup(arc_get_core_freq() / HZ);
|
|
break;
|
|
case CLOCK_EVT_MODE_ONESHOT:
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
|
|
return;
|
|
}
|
|
|
|
static DEFINE_PER_CPU(struct clock_event_device, arc_clockevent_device) = {
|
|
.name = "ARC Timer0",
|
|
.features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC,
|
|
.mode = CLOCK_EVT_MODE_UNUSED,
|
|
.rating = 300,
|
|
.irq = TIMER0_IRQ, /* hardwired, no need for resources */
|
|
.set_next_event = arc_clkevent_set_next_event,
|
|
.set_mode = arc_clkevent_set_mode,
|
|
};
|
|
|
|
static irqreturn_t timer_irq_handler(int irq, void *dev_id)
|
|
{
|
|
struct clock_event_device *clk = &__get_cpu_var(arc_clockevent_device);
|
|
|
|
arc_timer_event_ack(clk->mode == CLOCK_EVT_MODE_PERIODIC);
|
|
clk->event_handler(clk);
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static struct irqaction arc_timer_irq = {
|
|
.name = "Timer0 (clock-evt-dev)",
|
|
.flags = IRQF_TIMER | IRQF_PERCPU,
|
|
.handler = timer_irq_handler,
|
|
};
|
|
|
|
/*
|
|
* Setup the local event timer for @cpu
|
|
* N.B. weak so that some exotic ARC SoCs can completely override it
|
|
*/
|
|
void __attribute__((weak)) __cpuinit arc_local_timer_setup(unsigned int cpu)
|
|
{
|
|
struct clock_event_device *clk = &per_cpu(arc_clockevent_device, cpu);
|
|
|
|
clockevents_calc_mult_shift(clk, arc_get_core_freq(), 5);
|
|
|
|
clk->max_delta_ns = clockevent_delta2ns(ARC_TIMER_MAX, clk);
|
|
clk->cpumask = cpumask_of(cpu);
|
|
|
|
clockevents_register_device(clk);
|
|
|
|
/*
|
|
* setup the per-cpu timer IRQ handler - for all cpus
|
|
* For non boot CPU explicitly unmask at intc
|
|
* setup_irq() -> .. -> irq_startup() already does this on boot-cpu
|
|
*/
|
|
if (!cpu)
|
|
setup_irq(TIMER0_IRQ, &arc_timer_irq);
|
|
else
|
|
arch_unmask_irq(TIMER0_IRQ);
|
|
}
|
|
|
|
/*
|
|
* Called from start_kernel() - boot CPU only
|
|
*
|
|
* -Sets up h/w timers as applicable on boot cpu
|
|
* -Also sets up any global state needed for timer subsystem:
|
|
* - for "counting" timer, registers a clocksource, usable across CPUs
|
|
* (provided that underlying counter h/w is synchronized across cores)
|
|
* - for "event" timer, sets up TIMER0 IRQ (as that is platform agnostic)
|
|
*/
|
|
void __init time_init(void)
|
|
{
|
|
/*
|
|
* sets up the timekeeping free-flowing counter which also returns
|
|
* whether the counter is usable as clocksource
|
|
*/
|
|
if (arc_counter_setup())
|
|
/*
|
|
* CLK upto 4.29 GHz can be safely represented in 32 bits
|
|
* because Max 32 bit number is 4,294,967,295
|
|
*/
|
|
clocksource_register_hz(&arc_counter, arc_get_core_freq());
|
|
|
|
/* sets up the periodic event timer */
|
|
arc_local_timer_setup(smp_processor_id());
|
|
|
|
if (machine_desc->init_time)
|
|
machine_desc->init_time();
|
|
}
|