Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 1 | /* |
| 2 | * drivers/watchdog/orion5x_wdt.c |
| 3 | * |
| 4 | * Watchdog driver for Orion5x processors |
| 5 | * |
| 6 | * Author: Sylver Bruneau <sylver.bruneau@googlemail.com> |
| 7 | * |
| 8 | * This file is licensed under the terms of the GNU General Public |
| 9 | * License version 2. This program is licensed "as is" without any |
| 10 | * warranty of any kind, whether express or implied. |
| 11 | */ |
| 12 | |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/moduleparam.h> |
| 15 | #include <linux/types.h> |
| 16 | #include <linux/kernel.h> |
| 17 | #include <linux/fs.h> |
| 18 | #include <linux/miscdevice.h> |
| 19 | #include <linux/watchdog.h> |
| 20 | #include <linux/init.h> |
| 21 | #include <linux/uaccess.h> |
| 22 | #include <linux/io.h> |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 23 | #include <linux/spinlock.h> |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 24 | |
| 25 | /* |
| 26 | * Watchdog timer block registers. |
| 27 | */ |
| 28 | #define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000) |
| 29 | #define WDT_EN 0x0010 |
| 30 | #define WDT_VAL (TIMER_VIRT_BASE + 0x0024) |
| 31 | |
Wim Van Sebroeck | c9a0c8a | 2009-02-25 13:33:01 +0100 | [diff] [blame] | 32 | #define ORION5X_TCLK 166666667 |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 33 | #define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK) |
| 34 | #define WDT_IN_USE 0 |
| 35 | #define WDT_OK_TO_CLOSE 1 |
| 36 | |
| 37 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 38 | static int heartbeat = WDT_MAX_DURATION; /* (seconds) */ |
| 39 | static unsigned long wdt_status; |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 40 | static spinlock_t wdt_lock; |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 41 | |
| 42 | static void wdt_enable(void) |
| 43 | { |
| 44 | u32 reg; |
| 45 | |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 46 | spin_lock(&wdt_lock); |
| 47 | |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 48 | /* Set watchdog duration */ |
| 49 | writel(ORION5X_TCLK * heartbeat, WDT_VAL); |
| 50 | |
| 51 | /* Clear watchdog timer interrupt */ |
| 52 | reg = readl(BRIDGE_CAUSE); |
| 53 | reg &= ~WDT_INT_REQ; |
| 54 | writel(reg, BRIDGE_CAUSE); |
| 55 | |
| 56 | /* Enable watchdog timer */ |
| 57 | reg = readl(TIMER_CTRL); |
| 58 | reg |= WDT_EN; |
| 59 | writel(reg, TIMER_CTRL); |
| 60 | |
| 61 | /* Enable reset on watchdog */ |
| 62 | reg = readl(CPU_RESET_MASK); |
| 63 | reg |= WDT_RESET; |
| 64 | writel(reg, CPU_RESET_MASK); |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 65 | |
| 66 | spin_unlock(&wdt_lock); |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 67 | } |
| 68 | |
| 69 | static void wdt_disable(void) |
| 70 | { |
| 71 | u32 reg; |
| 72 | |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 73 | spin_lock(&wdt_lock); |
| 74 | |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 75 | /* Disable reset on watchdog */ |
| 76 | reg = readl(CPU_RESET_MASK); |
| 77 | reg &= ~WDT_RESET; |
| 78 | writel(reg, CPU_RESET_MASK); |
| 79 | |
| 80 | /* Disable watchdog timer */ |
| 81 | reg = readl(TIMER_CTRL); |
| 82 | reg &= ~WDT_EN; |
| 83 | writel(reg, TIMER_CTRL); |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 84 | |
| 85 | spin_unlock(&wdt_lock); |
| 86 | } |
| 87 | |
| 88 | static int orion5x_wdt_get_timeleft(int *time_left) |
| 89 | { |
| 90 | spin_lock(&wdt_lock); |
| 91 | *time_left = readl(WDT_VAL) / ORION5X_TCLK; |
| 92 | spin_unlock(&wdt_lock); |
| 93 | return 0; |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 94 | } |
| 95 | |
| 96 | static int orion5x_wdt_open(struct inode *inode, struct file *file) |
| 97 | { |
| 98 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
| 99 | return -EBUSY; |
| 100 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 101 | wdt_enable(); |
| 102 | return nonseekable_open(inode, file); |
| 103 | } |
| 104 | |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 105 | static ssize_t orion5x_wdt_write(struct file *file, const char *data, |
| 106 | size_t len, loff_t *ppos) |
| 107 | { |
| 108 | if (len) { |
| 109 | if (!nowayout) { |
| 110 | size_t i; |
| 111 | |
| 112 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 113 | for (i = 0; i != len; i++) { |
| 114 | char c; |
| 115 | |
| 116 | if (get_user(c, data + i)) |
| 117 | return -EFAULT; |
| 118 | if (c == 'V') |
| 119 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 120 | } |
| 121 | } |
| 122 | wdt_enable(); |
| 123 | } |
| 124 | return len; |
| 125 | } |
| 126 | |
| 127 | static struct watchdog_info ident = { |
| 128 | .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | |
| 129 | WDIOF_KEEPALIVEPING, |
| 130 | .identity = "Orion5x Watchdog", |
| 131 | }; |
| 132 | |
| 133 | |
| 134 | static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd, |
| 135 | unsigned long arg) |
| 136 | { |
| 137 | int ret = -ENOTTY; |
| 138 | int time; |
| 139 | |
| 140 | switch (cmd) { |
| 141 | case WDIOC_GETSUPPORT: |
| 142 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
| 143 | sizeof(ident)) ? -EFAULT : 0; |
| 144 | break; |
| 145 | |
| 146 | case WDIOC_GETSTATUS: |
| 147 | case WDIOC_GETBOOTSTATUS: |
| 148 | ret = put_user(0, (int *)arg); |
| 149 | break; |
| 150 | |
| 151 | case WDIOC_KEEPALIVE: |
| 152 | wdt_enable(); |
| 153 | ret = 0; |
| 154 | break; |
| 155 | |
| 156 | case WDIOC_SETTIMEOUT: |
| 157 | ret = get_user(time, (int *)arg); |
| 158 | if (ret) |
| 159 | break; |
| 160 | |
| 161 | if (time <= 0 || time > WDT_MAX_DURATION) { |
| 162 | ret = -EINVAL; |
| 163 | break; |
| 164 | } |
| 165 | heartbeat = time; |
| 166 | wdt_enable(); |
| 167 | /* Fall through */ |
| 168 | |
| 169 | case WDIOC_GETTIMEOUT: |
| 170 | ret = put_user(heartbeat, (int *)arg); |
| 171 | break; |
| 172 | |
| 173 | case WDIOC_GETTIMELEFT: |
| 174 | if (orion5x_wdt_get_timeleft(&time)) { |
| 175 | ret = -EINVAL; |
| 176 | break; |
| 177 | } |
| 178 | ret = put_user(time, (int *)arg); |
| 179 | break; |
| 180 | } |
| 181 | return ret; |
| 182 | } |
| 183 | |
| 184 | static int orion5x_wdt_release(struct inode *inode, struct file *file) |
| 185 | { |
| 186 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
| 187 | wdt_disable(); |
| 188 | else |
| 189 | printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - " |
| 190 | "timer will not stop\n"); |
| 191 | clear_bit(WDT_IN_USE, &wdt_status); |
| 192 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 193 | |
| 194 | return 0; |
| 195 | } |
| 196 | |
| 197 | |
| 198 | static const struct file_operations orion5x_wdt_fops = { |
| 199 | .owner = THIS_MODULE, |
| 200 | .llseek = no_llseek, |
| 201 | .write = orion5x_wdt_write, |
| 202 | .unlocked_ioctl = orion5x_wdt_ioctl, |
| 203 | .open = orion5x_wdt_open, |
| 204 | .release = orion5x_wdt_release, |
| 205 | }; |
| 206 | |
| 207 | static struct miscdevice orion5x_wdt_miscdev = { |
| 208 | .minor = WATCHDOG_MINOR, |
| 209 | .name = "watchdog", |
| 210 | .fops = &orion5x_wdt_fops, |
| 211 | }; |
| 212 | |
| 213 | static int __init orion5x_wdt_init(void) |
| 214 | { |
| 215 | int ret; |
| 216 | |
Wim Van Sebroeck | 6d0f0df | 2008-10-02 09:32:45 +0000 | [diff] [blame] | 217 | spin_lock_init(&wdt_lock); |
| 218 | |
Sylver Bruneau | 22ac923 | 2008-06-26 10:47:45 +0200 | [diff] [blame] | 219 | ret = misc_register(&orion5x_wdt_miscdev); |
| 220 | if (ret == 0) |
| 221 | printk("Orion5x Watchdog Timer: heartbeat %d sec\n", |
| 222 | heartbeat); |
| 223 | |
| 224 | return ret; |
| 225 | } |
| 226 | |
| 227 | static void __exit orion5x_wdt_exit(void) |
| 228 | { |
| 229 | misc_deregister(&orion5x_wdt_miscdev); |
| 230 | } |
| 231 | |
| 232 | module_init(orion5x_wdt_init); |
| 233 | module_exit(orion5x_wdt_exit); |
| 234 | |
| 235 | MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>"); |
| 236 | MODULE_DESCRIPTION("Orion5x Processor Watchdog"); |
| 237 | |
| 238 | module_param(heartbeat, int, 0); |
| 239 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is " |
| 240 | __MODULE_STRING(WDT_MAX_DURATION) ")"); |
| 241 | |
| 242 | module_param(nowayout, int, 0); |
| 243 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); |
| 244 | |
| 245 | MODULE_LICENSE("GPL"); |
| 246 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |