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// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/m68k/hp300/time.c
*
* Copyright (C) 1998 Philip Blundell <philb@gnu.org>
*
* This file contains the HP300-specific time handling code.
*/
#include <asm/ptrace.h>
#include <linux/clocksource.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/traps.h>
#include <asm/blinken.h>
#include "time.h"
static u64 hp300_read_clk(struct clocksource *cs);
static struct clocksource hp300_clk = {
.name = "timer",
.rating = 250,
.read = hp300_read_clk,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static u32 clk_total, clk_offset;
/* Clock hardware definitions */
#define CLOCKBASE 0xf05f8000
#define CLKCR1 0x1
#define CLKCR2 0x3
#define CLKCR3 CLKCR1
#define CLKSR CLKCR2
#define CLKMSB1 0x5
#define CLKLSB1 0x7
#define CLKMSB2 0x9
#define CLKMSB3 0xD
#define CLKSR_INT1 BIT(0)
/* This is for machines which generate the exact clock. */
#define HP300_TIMER_CLOCK_FREQ 250000
#define HP300_TIMER_CYCLES (HP300_TIMER_CLOCK_FREQ / HZ)
#define INTVAL (HP300_TIMER_CYCLES - 1)
static irqreturn_t hp300_tick(int irq, void *dev_id)
{
unsigned long flags;
unsigned long tmp;
local_irq_save(flags);
in_8(CLOCKBASE + CLKSR);
asm volatile ("movpw %1@(5),%0" : "=d" (tmp) : "a" (CLOCKBASE));
clk_total += INTVAL;
clk_offset = 0;
legacy_timer_tick(1);
timer_heartbeat();
local_irq_restore(flags);
/* Turn off the network and SCSI leds */
blinken_leds(0, 0xe0);
return IRQ_HANDLED;
}
static u64 hp300_read_clk(struct clocksource *cs)
{
unsigned long flags;
unsigned char lsb, msb, msb_new;
u32 ticks;
local_irq_save(flags);
/* Read current timer 1 value */
msb = in_8(CLOCKBASE + CLKMSB1);
again:
if ((in_8(CLOCKBASE + CLKSR) & CLKSR_INT1) && msb > 0)
clk_offset = INTVAL;
lsb = in_8(CLOCKBASE + CLKLSB1);
msb_new = in_8(CLOCKBASE + CLKMSB1);
if (msb_new != msb) {
msb = msb_new;
goto again;
}
ticks = INTVAL - ((msb << 8) | lsb);
ticks += clk_offset + clk_total;
local_irq_restore(flags);
return ticks;
}
void __init hp300_sched_init(void)
{
out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
out_8(CLOCKBASE + CLKCR1, 0x1); /* reset */
asm volatile(" movpw %0,%1@(5)" : : "d" (INTVAL), "a" (CLOCKBASE));
if (request_irq(IRQ_AUTO_6, hp300_tick, IRQF_TIMER, "timer tick", NULL))
pr_err("Couldn't register timer interrupt\n");
out_8(CLOCKBASE + CLKCR2, 0x1); /* select CR1 */
out_8(CLOCKBASE + CLKCR1, 0x40); /* enable irq */
clocksource_register_hz(&hp300_clk, HP300_TIMER_CLOCK_FREQ);
}
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