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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Tom Rinifd162302005-04-16 15:24:23 -070014#include <linux/irq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/kernel.h>
16#include <linux/sched.h>
17#include <asm/8xx_immap.h>
18#include <syslib/m8xx_wdt.h>
19
20static int wdt_timeout;
21
Tom Rinifd162302005-04-16 15:24:23 -070022static irqreturn_t m8xx_wdt_interrupt(int, void *, struct pt_regs *);
23static struct irqaction m8xx_wdt_irqaction = {
24 .handler = m8xx_wdt_interrupt,
25 .name = "watchdog",
26};
27
Linus Torvalds1da177e2005-04-16 15:20:36 -070028void m8xx_wdt_reset(void)
29{
30 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
31
32 imap->im_siu_conf.sc_swsr = 0x556c; /* write magic1 */
33 imap->im_siu_conf.sc_swsr = 0xaa39; /* write magic2 */
34}
35
36static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
37{
38 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
39
40 m8xx_wdt_reset();
41
42 imap->im_sit.sit_piscr |= PISCR_PS; /* clear irq */
43
44 return IRQ_HANDLED;
45}
46
47void __init m8xx_wdt_handler_install(bd_t * binfo)
48{
49 volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
50 u32 pitc;
51 u32 sypcr;
52 u32 pitrtclk;
53
54 sypcr = imap->im_siu_conf.sc_sypcr;
55
56 if (!(sypcr & 0x04)) {
57 printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
58 sypcr);
59 return;
60 }
61
62 m8xx_wdt_reset();
63
64 printk(KERN_NOTICE
65 "m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
66 (sypcr >> 16), sypcr & 0x01);
67
68 wdt_timeout = (sypcr >> 16) & 0xFFFF;
69
70 if (!wdt_timeout)
71 wdt_timeout = 0xFFFF;
72
73 if (sypcr & 0x01)
74 wdt_timeout *= 2048;
75
76 /*
77 * Fire trigger if half of the wdt ticked down
78 */
79
80 if (imap->im_sit.sit_rtcsc & RTCSC_38K)
81 pitrtclk = 9600;
82 else
83 pitrtclk = 8192;
84
85 if ((wdt_timeout) > (UINT_MAX / pitrtclk))
86 pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
87 else
88 pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
89
90 imap->im_sit.sit_pitc = pitc << 16;
91 imap->im_sit.sit_piscr =
92 (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE;
93
Tom Rinifd162302005-04-16 15:24:23 -070094 if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction))
95 panic("m8xx_wdt: error setting up the watchdog irq!");
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 printk(KERN_NOTICE
98 "m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
99
100 wdt_timeout /= binfo->bi_intfreq;
101}
102
103int m8xx_wdt_get_timeout(void)
104{
105 return wdt_timeout;
106}