linux/arch/m68k/sun3x/time.c
Finn Thain 1efdd4bd25 m68k: Call timer_interrupt() with interrupts disabled
Some platforms execute their timer handler with the interrupt priority
level set below 6. That means the handler could be interrupted by another
driver and this could lead to re-entry of the timer core.

Avoid this by use of local_irq_save/restore for timer interrupt dispatch.
This provides mutual exclusion around the timer interrupt flag access
which is needed later in this series for the clocksource conversion.

Reported-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1811131407120.2697@nanos.tec.linutronix.de
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2019-03-25 10:22:24 +01:00

110 lines
2.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/m68k/sun3x/time.c
*
* Sun3x-specific time handling
*/
#include <linux/types.h>
#include <linux/kd.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <linux/rtc.h>
#include <linux/bcd.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/machdep.h>
#include <asm/traps.h>
#include <asm/sun3x.h>
#include <asm/sun3ints.h>
#include "time.h"
#define M_CONTROL 0xf8
#define M_SEC 0xf9
#define M_MIN 0xfa
#define M_HOUR 0xfb
#define M_DAY 0xfc
#define M_DATE 0xfd
#define M_MONTH 0xfe
#define M_YEAR 0xff
#define C_WRITE 0x80
#define C_READ 0x40
#define C_SIGN 0x20
#define C_CALIB 0x1f
int sun3x_hwclk(int set, struct rtc_time *t)
{
volatile struct mostek_dt *h =
(struct mostek_dt *)(SUN3X_EEPROM+M_CONTROL);
unsigned long flags;
local_irq_save(flags);
if(set) {
h->csr |= C_WRITE;
h->sec = bin2bcd(t->tm_sec);
h->min = bin2bcd(t->tm_min);
h->hour = bin2bcd(t->tm_hour);
h->wday = bin2bcd(t->tm_wday);
h->mday = bin2bcd(t->tm_mday);
h->month = bin2bcd(t->tm_mon + 1);
h->year = bin2bcd(t->tm_year % 100);
h->csr &= ~C_WRITE;
} else {
h->csr |= C_READ;
t->tm_sec = bcd2bin(h->sec);
t->tm_min = bcd2bin(h->min);
t->tm_hour = bcd2bin(h->hour);
t->tm_wday = bcd2bin(h->wday);
t->tm_mday = bcd2bin(h->mday);
t->tm_mon = bcd2bin(h->month) - 1;
t->tm_year = bcd2bin(h->year);
h->csr &= ~C_READ;
if (t->tm_year < 70)
t->tm_year += 100;
}
local_irq_restore(flags);
return 0;
}
/* Not much we can do here */
u32 sun3x_gettimeoffset(void)
{
return 0L;
}
#if 0
static irqreturn_t sun3x_timer_tick(int irq, void *dev_id)
{
irq_handler_t timer_routine = dev_id;
unsigned long flags;
local_irq_save(flags);
/* Clear the pending interrupt - pulse the enable line low */
disable_irq(5);
enable_irq(5);
timer_routine(0, NULL);
local_irq_restore(flags);
return IRQ_HANDLED;
}
#endif
void __init sun3x_sched_init(irq_handler_t vector)
{
sun3_disable_interrupts();
/* Pulse enable low to get the clock started */
sun3_disable_irq(5);
sun3_enable_irq(5);
sun3_enable_interrupts();
}