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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * m8xx_wdt.c - MPC8xx watchdog driver
3 *
4 * Author: Florian Schirmer <jolt@tuxbox.org>
5 *
6 * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
7 * the terms of the GNU General Public License version 2. This program
8 * is licensed "as is" without any warranty of any kind, whether express
9 * or implied.
10 */
11
12#include <linux/init.h>
13#include <linux/interrupt.h>
14#include <linux/irq.h>
15#include <linux/kernel.h>
16#include <linux/sched.h>
17#include <asm/io.h>
18#include <asm/8xx_immap.h>
19#include <syslib/m8xx_wdt.h>
20
21static int wdt_timeout;
22
23static irqreturn_t m8xx_wdt_interrupt(int, void *, struct pt_regs *);
24static struct irqaction m8xx_wdt_irqaction = {
25 .handler = m8xx_wdt_interrupt,
26 .name = "watchdog",
27};
28
29void m8xx_wdt_reset(void)
30{
31 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
32
33 out_be16(&imap->im_siu_conf.sc_swsr, 0x556c); /* write magic1 */
34 out_be16(&imap->im_siu_conf.sc_swsr, 0xaa39); /* write magic2 */
35}
36
37static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
38{
39 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
40
41 m8xx_wdt_reset();
42
43 out_be16(&imap->im_sit.sit_piscr, in_be16(&imap->im_sit.sit_piscr) | PISCR_PS); /* clear irq */
44
45 return IRQ_HANDLED;
46}
47
48void __init m8xx_wdt_handler_install(bd_t * binfo)
49{
50 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
51 u32 pitc;
52 u32 sypcr;
53 u32 pitrtclk;
54
55 sypcr = in_be32(&imap->im_siu_conf.sc_sypcr);
56
57 if (!(sypcr & 0x04)) {
58 printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
59 sypcr);
60 return;
61 }
62
63 m8xx_wdt_reset();
64
65 printk(KERN_NOTICE
66 "m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
67 (sypcr >> 16), sypcr & 0x01);
68
69 wdt_timeout = (sypcr >> 16) & 0xFFFF;
70
71 if (!wdt_timeout)
72 wdt_timeout = 0xFFFF;
73
74 if (sypcr & 0x01)
75 wdt_timeout *= 2048;
76
77 /*
78 * Fire trigger if half of the wdt ticked down
79 */
80
81 if (imap->im_sit.sit_rtcsc & RTCSC_38K)
82 pitrtclk = 9600;
83 else
84 pitrtclk = 8192;
85
86 if ((wdt_timeout) > (UINT_MAX / pitrtclk))
87 pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
88 else
89 pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
90
91 out_be32(&imap->im_sit.sit_pitc, pitc << 16);
92
93 out_be16(&imap->im_sit.sit_piscr, (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE);
94
95 if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction))
96 panic("m8xx_wdt: error setting up the watchdog irq!");
97
98 printk(KERN_NOTICE
99 "m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
100
101 wdt_timeout /= binfo->bi_intfreq;
102}
103
104int m8xx_wdt_get_timeout(void)
105{
106 return wdt_timeout;
107}