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Kumar Galaa2f40cc2005-09-03 15:55:33 -07001/*
Kumar Galaa2f40cc2005-09-03 15:55:33 -07002 * Watchdog timer for PowerPC Book-E systems
3 *
4 * Author: Matthew McClintock
Kumar Gala4c8d3d92005-11-13 16:06:30 -08005 * Maintainer: Kumar Gala <galak@kernel.crashing.org>
Kumar Galaa2f40cc2005-09-03 15:55:33 -07006 *
Timur Tabi112e7542011-02-08 17:39:46 -06007 * Copyright 2005, 2008, 2010-2011 Freescale Semiconductor Inc.
Kumar Galaa2f40cc2005-09-03 15:55:33 -07008 *
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License as published by the
11 * Free Software Foundation; either version 2 of the License, or (at your
12 * option) any later version.
13 */
14
Joe Perches27c766a2012-02-15 15:06:19 -080015#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
Kumar Galaa2f40cc2005-09-03 15:55:33 -070017#include <linux/module.h>
Chen Gongf172ddc62008-04-29 16:42:05 +080018#include <linux/smp.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070019#include <linux/watchdog.h>
20
21#include <asm/reg_booke.h>
Chris Friesendcfb7482009-08-12 12:02:46 -060022#include <asm/time.h>
23#include <asm/div64.h>
Kumar Galaa2f40cc2005-09-03 15:55:33 -070024
Dave Jiang40ebbcb2007-04-12 13:34:55 -070025/* If the kernel parameter wdt=1, the watchdog will be enabled at boot.
Kumar Galaa2f40cc2005-09-03 15:55:33 -070026 * Also, the wdt_period sets the watchdog timer period timeout.
27 * For E500 cpus the wdt_period sets which bit changing from 0->1 will
28 * trigger a watchog timeout. This watchdog timeout will occur 3 times, the
29 * first time nothing will happen, the second time a watchdog exception will
30 * occur, and the final time the board will reset.
31 */
32
Chen Gongf172ddc62008-04-29 16:42:05 +080033u32 booke_wdt_enabled;
Timur Tabie0dc09f2010-10-13 14:19:36 -050034u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT;
Kumar Galaa2f40cc2005-09-03 15:55:33 -070035
Shaohui Xiebe0884c2012-05-11 13:33:40 +080036#ifdef CONFIG_PPC_FSL_BOOK3E
Chris Friesendcfb7482009-08-12 12:02:46 -060037#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15))
Luuk Paulussen0fb06572010-04-15 15:59:10 +120038#define WDTP_MASK (WDTP(0x3f))
Kumar Galaa2f40cc2005-09-03 15:55:33 -070039#else
40#define WDTP(x) (TCR_WP(x))
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +010041#define WDTP_MASK (TCR_WP_MASK)
Kumar Galaa2f40cc2005-09-03 15:55:33 -070042#endif
43
Tang Yuantiand2deeba2014-05-08 10:04:26 +080044/* Checks wdt=x and wdt_period=xx command-line option */
45notrace int __init early_parse_wdt(char *p)
46{
47 if (p && strncmp(p, "0", 1) != 0)
48 booke_wdt_enabled = 1;
49
50 return 0;
51}
52early_param("wdt", early_parse_wdt);
53
54int __init early_parse_wdt_period(char *p)
55{
56 unsigned long ret;
57 if (p) {
58 if (!kstrtol(p, 0, &ret))
59 booke_wdt_period = ret;
60 }
61
62 return 0;
63}
64early_param("wdt_period", early_parse_wdt_period);
65
Guenter Roeck52e5cc42013-02-05 12:14:23 -080066#ifdef CONFIG_PPC_FSL_BOOK3E
Chen Gongf172ddc62008-04-29 16:42:05 +080067
Chris Friesendcfb7482009-08-12 12:02:46 -060068/* For the specified period, determine the number of seconds
69 * corresponding to the reset time. There will be a watchdog
70 * exception at approximately 3/5 of this time.
71 *
72 * The formula to calculate this is given by:
73 * 2.5 * (2^(63-period+1)) / timebase_freq
74 *
75 * In order to simplify things, we assume that period is
76 * at least 1. This will still result in a very long timeout.
77 */
78static unsigned long long period_to_sec(unsigned int period)
79{
80 unsigned long long tmp = 1ULL << (64 - period);
81 unsigned long tmp2 = ppc_tb_freq;
82
83 /* tmp may be a very large number and we don't want to overflow,
84 * so divide the timebase freq instead of multiplying tmp
85 */
86 tmp2 = tmp2 / 5 * 2;
87
88 do_div(tmp, tmp2);
89 return tmp;
90}
91
92/*
93 * This procedure will find the highest period which will give a timeout
94 * greater than the one required. e.g. for a bus speed of 66666666 and
95 * and a parameter of 2 secs, then this procedure will return a value of 38.
96 */
97static unsigned int sec_to_period(unsigned int secs)
98{
99 unsigned int period;
100 for (period = 63; period > 0; period--) {
101 if (period_to_sec(period) >= secs)
102 return period;
103 }
104 return 0;
105}
106
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800107#define MAX_WDT_TIMEOUT period_to_sec(1)
108
109#else /* CONFIG_PPC_FSL_BOOK3E */
110
111static unsigned long long period_to_sec(unsigned int period)
112{
113 return period;
114}
115
116static unsigned int sec_to_period(unsigned int secs)
117{
118 return secs;
119}
120
121#define MAX_WDT_TIMEOUT 3 /* from Kconfig */
122
123#endif /* !CONFIG_PPC_FSL_BOOK3E */
124
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700125static void __booke_wdt_set(void *data)
126{
127 u32 val;
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800128 struct watchdog_device *wdog = data;
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700129
130 val = mfspr(SPRN_TCR);
131 val &= ~WDTP_MASK;
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800132 val |= WDTP(sec_to_period(wdog->timeout));
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700133
134 mtspr(SPRN_TCR, val);
135}
136
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800137static void booke_wdt_set(void *data)
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700138{
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800139 on_each_cpu(__booke_wdt_set, data, 0);
Randy Vinson6ae98ed2010-12-06 14:02:23 -0700140}
141
Chen Gongf172ddc62008-04-29 16:42:05 +0800142static void __booke_wdt_ping(void *data)
Stefan Roesef31909c2007-02-07 09:45:55 +0100143{
144 mtspr(SPRN_TSR, TSR_ENW|TSR_WIS);
145}
146
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800147static int booke_wdt_ping(struct watchdog_device *wdog)
Chen Gongf172ddc62008-04-29 16:42:05 +0800148{
Ingo Molnarf6f88e92008-07-15 22:08:52 +0200149 on_each_cpu(__booke_wdt_ping, NULL, 0);
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800150
151 return 0;
Chen Gongf172ddc62008-04-29 16:42:05 +0800152}
153
154static void __booke_wdt_enable(void *data)
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700155{
156 u32 val;
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800157 struct watchdog_device *wdog = data;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700158
Stefan Roesef31909c2007-02-07 09:45:55 +0100159 /* clear status before enabling watchdog */
Chen Gongf172ddc62008-04-29 16:42:05 +0800160 __booke_wdt_ping(NULL);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700161 val = mfspr(SPRN_TCR);
Matthias Fuchs0a0e9e02008-11-05 21:53:56 +0100162 val &= ~WDTP_MASK;
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800163 val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(sec_to_period(wdog->timeout)));
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700164
165 mtspr(SPRN_TCR, val);
166}
167
Timur Tabifbdd7142010-09-20 11:23:42 -0500168/**
169 * booke_wdt_disable - disable the watchdog on the given CPU
170 *
171 * This function is called on each CPU. It disables the watchdog on that CPU.
172 *
173 * TCR[WRC] cannot be changed once it has been set to non-zero, but we can
174 * effectively disable the watchdog by setting its period to the maximum value.
175 */
176static void __booke_wdt_disable(void *data)
177{
178 u32 val;
179
180 val = mfspr(SPRN_TCR);
181 val &= ~(TCR_WIE | WDTP_MASK);
182 mtspr(SPRN_TCR, val);
183
184 /* clear status to make sure nothing is pending */
185 __booke_wdt_ping(NULL);
186
187}
188
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800189static int booke_wdt_start(struct watchdog_device *wdog)
190{
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800191 on_each_cpu(__booke_wdt_enable, wdog, 0);
192 pr_debug("watchdog enabled (timeout = %u sec)\n", wdog->timeout);
193
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800194 return 0;
195}
196
197static int booke_wdt_stop(struct watchdog_device *wdog)
198{
199 on_each_cpu(__booke_wdt_disable, NULL, 0);
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800200 pr_debug("watchdog disabled\n");
201
202 return 0;
203}
204
205static int booke_wdt_set_timeout(struct watchdog_device *wdt_dev,
206 unsigned int timeout)
207{
208 if (timeout > MAX_WDT_TIMEOUT)
209 return -EINVAL;
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800210 wdt_dev->timeout = timeout;
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800211 booke_wdt_set(wdt_dev);
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800212
213 return 0;
214}
215
216static struct watchdog_info booke_wdt_info = {
Chen Gongf172ddc62008-04-29 16:42:05 +0800217 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
218 .identity = "PowerPC Book-E Watchdog",
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700219};
220
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800221static struct watchdog_ops booke_wdt_ops = {
Chen Gongf172ddc62008-04-29 16:42:05 +0800222 .owner = THIS_MODULE,
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800223 .start = booke_wdt_start,
224 .stop = booke_wdt_stop,
225 .ping = booke_wdt_ping,
226 .set_timeout = booke_wdt_set_timeout,
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700227};
228
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800229static struct watchdog_device booke_wdt_dev = {
230 .info = &booke_wdt_info,
231 .ops = &booke_wdt_ops,
232 .min_timeout = 1,
233 .max_timeout = 0xFFFF
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700234};
235
236static void __exit booke_wdt_exit(void)
237{
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800238 watchdog_unregister_device(&booke_wdt_dev);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700239}
240
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700241static int __init booke_wdt_init(void)
242{
243 int ret = 0;
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800244 bool nowayout = WATCHDOG_NOWAYOUT;
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700245
Joe Perches27c766a2012-02-15 15:06:19 -0800246 pr_info("powerpc book-e watchdog driver loaded\n");
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800247 booke_wdt_info.firmware_version = cur_cpu_spec->pvr_value;
248 booke_wdt_set_timeout(&booke_wdt_dev,
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800249 period_to_sec(booke_wdt_period));
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800250 watchdog_set_nowayout(&booke_wdt_dev, nowayout);
251 if (booke_wdt_enabled)
Tang Yuantiand2deeba2014-05-08 10:04:26 +0800252 booke_wdt_start(&booke_wdt_dev);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700253
Guenter Roeck52e5cc42013-02-05 12:14:23 -0800254 ret = watchdog_register_device(&booke_wdt_dev);
Kumar Galaa2f40cc2005-09-03 15:55:33 -0700255
256 return ret;
257}
Timur Tabifbdd7142010-09-20 11:23:42 -0500258
259module_init(booke_wdt_init);
260module_exit(booke_wdt_exit);
261
262MODULE_DESCRIPTION("PowerPC Book-E watchdog driver");
263MODULE_LICENSE("GPL");