linux/arch/ppc/syslib/m8xx_wdt.c
Marcelo Tosatti e37b0c9670 [PATCH] ppc32 8xx: use io accessor macros instead of direct memory reference
Convert core 8xx drivers to use in_xxxbe/in_xxx macros instead of direct
memory references.

Other than making IO accesses explicit (which is a plus for readability), a
common set of macros provides a unified place for the volatile flag to
constraint compiler code reordering.

There are several unlucky places at the moment which lack the volatile
flag.

Signed-off-by: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-29 13:55:27 +10:00

107 lines
2.5 KiB
C

/*
* m8xx_wdt.c - MPC8xx watchdog driver
*
* Author: Florian Schirmer <jolt@tuxbox.org>
*
* 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
* the terms of the GNU General Public License version 2. This program
* is licensed "as is" without any warranty of any kind, whether express
* or implied.
*/
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/8xx_immap.h>
#include <syslib/m8xx_wdt.h>
static int wdt_timeout;
static irqreturn_t m8xx_wdt_interrupt(int, void *, struct pt_regs *);
static struct irqaction m8xx_wdt_irqaction = {
.handler = m8xx_wdt_interrupt,
.name = "watchdog",
};
void m8xx_wdt_reset(void)
{
volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
out_be16(imap->im_siu_conf.sc_swsr, 0x556c); /* write magic1 */
out_be16(imap->im_siu_conf.sc_swsr, 0xaa39); /* write magic2 */
}
static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
{
volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
m8xx_wdt_reset();
out_be16(imap->im_sit.sit_piscr, in_be16(imap->im_sit.sit_piscr | PISCR_PS)); /* clear irq */
return IRQ_HANDLED;
}
void __init m8xx_wdt_handler_install(bd_t * binfo)
{
volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
u32 pitc;
u32 sypcr;
u32 pitrtclk;
sypcr = in_be32(imap->im_siu_conf.sc_sypcr);
if (!(sypcr & 0x04)) {
printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
sypcr);
return;
}
m8xx_wdt_reset();
printk(KERN_NOTICE
"m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
(sypcr >> 16), sypcr & 0x01);
wdt_timeout = (sypcr >> 16) & 0xFFFF;
if (!wdt_timeout)
wdt_timeout = 0xFFFF;
if (sypcr & 0x01)
wdt_timeout *= 2048;
/*
* Fire trigger if half of the wdt ticked down
*/
if (imap->im_sit.sit_rtcsc & RTCSC_38K)
pitrtclk = 9600;
else
pitrtclk = 8192;
if ((wdt_timeout) > (UINT_MAX / pitrtclk))
pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
else
pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
out_be32(imap->im_sit.sit_pitc, pitc << 16);
out_be16(imap->im_sit.sit_piscr, (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE);
if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction))
panic("m8xx_wdt: error setting up the watchdog irq!");
printk(KERN_NOTICE
"m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
wdt_timeout /= binfo->bi_intfreq;
}
int m8xx_wdt_get_timeout(void)
{
return wdt_timeout;
}