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| 1 | /* |
| 2 | * drivers/watchdog/m54xx_wdt.c |
| 3 | * |
| 4 | * Watchdog driver for ColdFire MCF547x & MCF548x processors |
| 5 | * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be> |
| 6 | * |
| 7 | * Adapted from the IXP4xx watchdog driver, which carries these notices: |
| 8 | * |
| 9 | * Author: Deepak Saxena <dsaxena@plexity.net> |
| 10 | * |
| 11 | * Copyright 2004 (c) MontaVista, Software, Inc. |
| 12 | * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> |
| 13 | * |
| 14 | * This file is licensed under the terms of the GNU General Public |
| 15 | * License version 2. This program is licensed "as is" without any |
| 16 | * warranty of any kind, whether express or implied. |
| 17 | */ |
| 18 | |
| 19 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 20 | |
| 21 | #include <linux/module.h> |
| 22 | #include <linux/moduleparam.h> |
| 23 | #include <linux/types.h> |
| 24 | #include <linux/kernel.h> |
| 25 | #include <linux/fs.h> |
| 26 | #include <linux/miscdevice.h> |
| 27 | #include <linux/watchdog.h> |
| 28 | #include <linux/init.h> |
| 29 | #include <linux/bitops.h> |
| 30 | #include <linux/ioport.h> |
| 31 | #include <linux/uaccess.h> |
| 32 | |
| 33 | #include <asm/coldfire.h> |
| 34 | #include <asm/m54xxsim.h> |
| 35 | #include <asm/m54xxgpt.h> |
| 36 | |
| 37 | static bool nowayout = WATCHDOG_NOWAYOUT; |
| 38 | static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */ |
| 39 | static unsigned long wdt_status; |
| 40 | |
| 41 | #define WDT_IN_USE 0 |
| 42 | #define WDT_OK_TO_CLOSE 1 |
| 43 | |
| 44 | static void wdt_enable(void) |
| 45 | { |
| 46 | unsigned int gms0; |
| 47 | |
| 48 | /* preserve GPIO usage, if any */ |
| 49 | gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0); |
| 50 | if (gms0 & MCF_GPT_GMS_TMS_GPIO) |
| 51 | gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK |
| 52 | | MCF_GPT_GMS_OD); |
| 53 | else |
| 54 | gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD; |
| 55 | __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); |
| 56 | __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) | |
| 57 | MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0); |
| 58 | gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE; |
| 59 | __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); |
| 60 | } |
| 61 | |
| 62 | static void wdt_disable(void) |
| 63 | { |
| 64 | unsigned int gms0; |
| 65 | |
| 66 | /* disable watchdog */ |
| 67 | gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0); |
| 68 | gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE); |
| 69 | __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); |
| 70 | } |
| 71 | |
| 72 | static void wdt_keepalive(void) |
| 73 | { |
| 74 | unsigned int gms0; |
| 75 | |
| 76 | gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0); |
| 77 | gms0 |= MCF_GPT_GMS_OCPW(0xA5); |
| 78 | __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); |
| 79 | } |
| 80 | |
| 81 | static int m54xx_wdt_open(struct inode *inode, struct file *file) |
| 82 | { |
| 83 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
| 84 | return -EBUSY; |
| 85 | |
| 86 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 87 | wdt_enable(); |
| 88 | return nonseekable_open(inode, file); |
| 89 | } |
| 90 | |
| 91 | static ssize_t m54xx_wdt_write(struct file *file, const char *data, |
| 92 | size_t len, loff_t *ppos) |
| 93 | { |
| 94 | if (len) { |
| 95 | if (!nowayout) { |
| 96 | size_t i; |
| 97 | |
| 98 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 99 | |
| 100 | for (i = 0; i != len; i++) { |
| 101 | char c; |
| 102 | |
| 103 | if (get_user(c, data + i)) |
| 104 | return -EFAULT; |
| 105 | if (c == 'V') |
| 106 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 107 | } |
| 108 | } |
| 109 | wdt_keepalive(); |
| 110 | } |
| 111 | return len; |
| 112 | } |
| 113 | |
| 114 | static const struct watchdog_info ident = { |
| 115 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
| 116 | WDIOF_KEEPALIVEPING, |
| 117 | .identity = "Coldfire M54xx Watchdog", |
| 118 | }; |
| 119 | |
| 120 | static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd, |
| 121 | unsigned long arg) |
| 122 | { |
| 123 | int ret = -ENOTTY; |
| 124 | int time; |
| 125 | |
| 126 | switch (cmd) { |
| 127 | case WDIOC_GETSUPPORT: |
| 128 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
| 129 | sizeof(ident)) ? -EFAULT : 0; |
| 130 | break; |
| 131 | |
| 132 | case WDIOC_GETSTATUS: |
| 133 | ret = put_user(0, (int *)arg); |
| 134 | break; |
| 135 | |
| 136 | case WDIOC_GETBOOTSTATUS: |
| 137 | ret = put_user(0, (int *)arg); |
| 138 | break; |
| 139 | |
| 140 | case WDIOC_KEEPALIVE: |
| 141 | wdt_keepalive(); |
| 142 | ret = 0; |
| 143 | break; |
| 144 | |
| 145 | case WDIOC_SETTIMEOUT: |
| 146 | ret = get_user(time, (int *)arg); |
| 147 | if (ret) |
| 148 | break; |
| 149 | |
| 150 | if (time <= 0 || time > 30) { |
| 151 | ret = -EINVAL; |
| 152 | break; |
| 153 | } |
| 154 | |
| 155 | heartbeat = time; |
| 156 | wdt_enable(); |
| 157 | /* Fall through */ |
| 158 | |
| 159 | case WDIOC_GETTIMEOUT: |
| 160 | ret = put_user(heartbeat, (int *)arg); |
| 161 | break; |
| 162 | } |
| 163 | return ret; |
| 164 | } |
| 165 | |
| 166 | static int m54xx_wdt_release(struct inode *inode, struct file *file) |
| 167 | { |
| 168 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
| 169 | wdt_disable(); |
| 170 | else { |
| 171 | pr_crit("Device closed unexpectedly - timer will not stop\n"); |
| 172 | wdt_keepalive(); |
| 173 | } |
| 174 | clear_bit(WDT_IN_USE, &wdt_status); |
| 175 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 176 | |
| 177 | return 0; |
| 178 | } |
| 179 | |
| 180 | |
| 181 | static const struct file_operations m54xx_wdt_fops = { |
| 182 | .owner = THIS_MODULE, |
| 183 | .llseek = no_llseek, |
| 184 | .write = m54xx_wdt_write, |
| 185 | .unlocked_ioctl = m54xx_wdt_ioctl, |
| 186 | .open = m54xx_wdt_open, |
| 187 | .release = m54xx_wdt_release, |
| 188 | }; |
| 189 | |
| 190 | static struct miscdevice m54xx_wdt_miscdev = { |
| 191 | .minor = WATCHDOG_MINOR, |
| 192 | .name = "watchdog", |
| 193 | .fops = &m54xx_wdt_fops, |
| 194 | }; |
| 195 | |
| 196 | static int __init m54xx_wdt_init(void) |
| 197 | { |
| 198 | if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4, |
| 199 | "Coldfire M54xx Watchdog")) { |
| 200 | pr_warn("I/O region busy\n"); |
| 201 | return -EBUSY; |
| 202 | } |
| 203 | pr_info("driver is loaded\n"); |
| 204 | |
| 205 | return misc_register(&m54xx_wdt_miscdev); |
| 206 | } |
| 207 | |
| 208 | static void __exit m54xx_wdt_exit(void) |
| 209 | { |
| 210 | misc_deregister(&m54xx_wdt_miscdev); |
| 211 | release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4); |
| 212 | } |
| 213 | |
| 214 | module_init(m54xx_wdt_init); |
| 215 | module_exit(m54xx_wdt_exit); |
| 216 | |
| 217 | MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>"); |
| 218 | MODULE_DESCRIPTION("Coldfire M54xx Watchdog"); |
| 219 | |
| 220 | module_param(heartbeat, int, 0); |
| 221 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)"); |
| 222 | |
| 223 | module_param(nowayout, bool, 0); |
| 224 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
| 225 | |
| 226 | MODULE_LICENSE("GPL"); |
| 227 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 228 |
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