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/*
* Copyright (C) 2000, 2001 Broadcom Corporation
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
* These are routines to set up and handle interrupts from the
* sb1250 general purpose timer 0. We're using the timer as a
* system clock, so we set it up to run at 100 Hz. On every
* interrupt, we update our idea of what the time of day is,
* then call do_timer() in the architecture-independent kernel
* code to do general bookkeeping (e.g. update jiffies, run
* bottom halves, etc.)
*/
#include <linux/clockchips.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/kernel_stat.h>
#include <asm/irq.h>
#include <asm/addrspace.h>
#include <asm/time.h>
#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_int.h>
#include <asm/sibyte/sb1250_scd.h>
#define IMR_IP2_VAL K_INT_MAP_I0
#define IMR_IP3_VAL K_INT_MAP_I1
#define IMR_IP4_VAL K_INT_MAP_I2
#define SB1250_HPT_NUM 3
#define SB1250_HPT_VALUE M_SCD_TIMER_CNT /* max value */
extern int sb1250_steal_irq(int irq);
static cycle_t sb1250_hpt_read(void);
void __init sb1250_hpt_setup(void)
{
int cpu = smp_processor_id();
if (!cpu) {
/* Setup hpt using timer #3 but do not enable irq for it */
__raw_writeq(0, IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
__raw_writeq(SB1250_HPT_VALUE,
IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_INIT)));
__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG)));
mips_hpt_frequency = V_SCD_TIMER_FREQ;
clocksource_mips.read = sb1250_hpt_read;
clocksource_mips.mask = M_SCD_TIMER_INIT;
}
}
/*
* The general purpose timer ticks at 1 Mhz independent if
* the rest of the system
*/
static void sibyte_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
unsigned int cpu = smp_processor_id();
void __iomem *timer_cfg, *timer_init;
timer_cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
timer_init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
switch(mode) {
case CLOCK_EVT_MODE_PERIODIC:
__raw_writeq(0, timer_cfg);
__raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, timer_init);
__raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
timer_cfg);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* Stop the timer until we actually program a shot */
case CLOCK_EVT_MODE_SHUTDOWN:
__raw_writeq(0, timer_cfg);
break;
case CLOCK_EVT_MODE_UNUSED: /* shuddup gcc */
case CLOCK_EVT_MODE_RESUME:
;
}
}
static int
sibyte_next_event(unsigned long delta, struct clock_event_device *evt)
{
unsigned int cpu = smp_processor_id();
void __iomem *timer_cfg, *timer_init;
timer_cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
timer_init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
__raw_writeq(0, timer_cfg);
__raw_writeq(delta, timer_init);
__raw_writeq(M_SCD_TIMER_ENABLE, timer_cfg);
return 0;
}
struct clock_event_device sibyte_hpt_clockevent = {
.name = "sb1250-counter",
.features = CLOCK_EVT_FEAT_PERIODIC,
.set_mode = sibyte_set_mode,
.set_next_event = sibyte_next_event,
.shift = 32,
.irq = 0,
};
static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
{
struct clock_event_device *cd = &sibyte_hpt_clockevent;
cd->event_handler(cd);
return IRQ_HANDLED;
}
static struct irqaction sibyte_irqaction = {
.handler = sibyte_counter_handler,
.flags = IRQF_DISABLED | IRQF_PERCPU,
.name = "timer",
};
void __cpuinit sb1250_clockevent_init(void)
{
struct clock_event_device *cd = &sibyte_hpt_clockevent;
unsigned int cpu = smp_processor_id();
int irq = K_INT_TIMER_0 + cpu;
/* Only have 4 general purpose timers, and we use last one as hpt */
BUG_ON(cpu > 2);
sb1250_mask_irq(cpu, irq);
/* Map the timer interrupt to ip[4] of this cpu */
__raw_writeq(IMR_IP4_VAL,
IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
(irq << 3)));
cd->cpumask = cpumask_of_cpu(0);
sb1250_unmask_irq(cpu, irq);
sb1250_steal_irq(irq);
/*
* This interrupt is "special" in that it doesn't use the request_irq
* way to hook the irq line. The timer interrupt is initialized early
* enough to make this a major pain, and it's also firing enough to
* warrant a bit of special case code. sb1250_timer_interrupt is
* called directly from irq_handler.S when IP[4] is set during an
* interrupt
*/
setup_irq(irq, &sibyte_irqaction);
clockevents_register_device(cd);
}
/*
* The HPT is free running from SB1250_HPT_VALUE down to 0 then starts over
* again.
*/
static cycle_t sb1250_hpt_read(void)
{
unsigned int count;
count = G_SCD_TIMER_CNT(__raw_readq(IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CNT))));
return SB1250_HPT_VALUE - count;
}
struct clocksource bcm1250_clocksource = {
.name = "MIPS",
.rating = 200,
.read = sb1250_hpt_read,
.mask = CLOCKSOURCE_MASK(32),
.shift = 32,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
void __init sb1250_clocksource_init(void)
{
struct clocksource *cs = &bcm1250_clocksource;
clocksource_set_clock(cs, V_SCD_TIMER_FREQ);
clocksource_register(cs);
}
void __init plat_time_init(void)
{
sb1250_clocksource_init();
sb1250_clockevent_init();
}
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