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;
22int m8xx_has_internal_rtc = 0;
23
24static irqreturn_t m8xx_wdt_interrupt(int, void *);
25static struct irqaction m8xx_wdt_irqaction = {
26	.handler = m8xx_wdt_interrupt,
27	.name = "watchdog",
28};
29
30void m8xx_wdt_reset(void)
31{
32	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
33
34	out_be16(&imap->im_siu_conf.sc_swsr, 0x556c);	/* write magic1 */
35	out_be16(&imap->im_siu_conf.sc_swsr, 0xaa39);	/* write magic2 */
36}
37
38static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev)
39{
40	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
41
42	m8xx_wdt_reset();
43
44	setbits16(&imap->im_sit.sit_piscr, PISCR_PS);
45	return IRQ_HANDLED;
46}
47
48#define SYPCR_SWP 0x1
49#define SYPCR_SWE 0x4
50
51
52void __init m8xx_wdt_install_irq(volatile immap_t *imap, bd_t *binfo)
53{
54	u32 pitc;
55	u32 pitrtclk;
56
57	/*
58	 * Fire trigger if half of the wdt ticked down
59	 */
60
61	if (imap->im_sit.sit_rtcsc & RTCSC_38K)
62		pitrtclk = 9600;
63	else
64		pitrtclk = 8192;
65
66	if ((wdt_timeout) > (UINT_MAX / pitrtclk))
67		pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
68	else
69		pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
70
71	out_be32(&imap->im_sit.sit_pitc, pitc << 16);
72
73	out_be16(&imap->im_sit.sit_piscr, (mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE);
74
75	if (setup_irq(PIT_INTERRUPT, &m8xx_wdt_irqaction))
76		panic("m8xx_wdt: error setting up the watchdog irq!");
77
78	printk(KERN_NOTICE
79	       "m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
80
81}
82
83static void m8xx_wdt_timer_func(unsigned long data);
84
85static struct timer_list m8xx_wdt_timer =
86	TIMER_INITIALIZER(m8xx_wdt_timer_func, 0, 0);
87
88void m8xx_wdt_stop_timer(void)
89{
90	del_timer(&m8xx_wdt_timer);
91}
92
93void m8xx_wdt_install_timer(void)
94{
95	m8xx_wdt_timer.expires = jiffies + (HZ/2);
96	add_timer(&m8xx_wdt_timer);
97}
98
99static void m8xx_wdt_timer_func(unsigned long data)
100{
101	m8xx_wdt_reset();
102	m8xx_wdt_install_timer();
103}
104
105void __init m8xx_wdt_handler_install(bd_t * binfo)
106{
107	volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
108	u32 sypcr;
109
110	sypcr = in_be32(&imap->im_siu_conf.sc_sypcr);
111
112	if (!(sypcr & SYPCR_SWE)) {
113		printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
114		       sypcr);
115		return;
116	}
117
118	m8xx_wdt_reset();
119
120	printk(KERN_NOTICE
121	       "m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
122	       (sypcr >> 16), sypcr & SYPCR_SWP);
123
124	wdt_timeout = (sypcr >> 16) & 0xFFFF;
125
126	if (!wdt_timeout)
127		wdt_timeout = 0xFFFF;
128
129	if (sypcr & SYPCR_SWP)
130		wdt_timeout *= 2048;
131
132	m8xx_has_internal_rtc = in_be16(&imap->im_sit.sit_rtcsc) & RTCSC_RTE;
133
134	/* if the internal RTC is off use a kernel timer */
135	if (!m8xx_has_internal_rtc) {
136		if (wdt_timeout < (binfo->bi_intfreq/HZ))
137			printk(KERN_ERR "m8xx_wdt: timeout too short for ktimer!\n");
138		m8xx_wdt_install_timer();
139	} else
140		m8xx_wdt_install_irq(imap, binfo);
141
142	wdt_timeout /= binfo->bi_intfreq;
143}
144
145int m8xx_wdt_get_timeout(void)
146{
147	return wdt_timeout;
148}
149