Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 1 | /* |
| 2 | * drivers/watchdog/ar7_wdt.c |
| 3 | * |
| 4 | * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org> |
| 5 | * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org> |
| 6 | * |
| 7 | * Some code taken from: |
| 8 | * National Semiconductor SCx200 Watchdog support |
| 9 | * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com> |
| 10 | * |
| 11 | * This program is free software; you can redistribute it and/or modify |
| 12 | * it under the terms of the GNU General Public License as published by |
| 13 | * the Free Software Foundation; either version 2 of the License, or |
| 14 | * (at your option) any later version. |
| 15 | * |
| 16 | * This program is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | * GNU General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU General Public License |
| 22 | * along with this program; if not, write to the Free Software |
| 23 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 24 | */ |
| 25 | |
| 26 | #include <linux/module.h> |
| 27 | #include <linux/moduleparam.h> |
| 28 | #include <linux/errno.h> |
| 29 | #include <linux/init.h> |
| 30 | #include <linux/miscdevice.h> |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 31 | #include <linux/platform_device.h> |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 32 | #include <linux/watchdog.h> |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 33 | #include <linux/fs.h> |
| 34 | #include <linux/ioport.h> |
| 35 | #include <linux/io.h> |
| 36 | #include <linux/uaccess.h> |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 37 | #include <linux/clk.h> |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 38 | |
| 39 | #include <asm/addrspace.h> |
Florian Fainelli | c5e7f5a | 2009-06-03 13:05:48 +0200 | [diff] [blame] | 40 | #include <asm/mach-ar7/ar7.h> |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 41 | |
| 42 | #define DRVNAME "ar7_wdt" |
| 43 | #define LONGNAME "TI AR7 Watchdog Timer" |
| 44 | |
| 45 | MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>"); |
| 46 | MODULE_DESCRIPTION(LONGNAME); |
| 47 | MODULE_LICENSE("GPL"); |
| 48 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 49 | |
| 50 | static int margin = 60; |
| 51 | module_param(margin, int, 0); |
| 52 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); |
| 53 | |
| 54 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 55 | module_param(nowayout, int, 0); |
| 56 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); |
| 57 | |
| 58 | #define READ_REG(x) readl((void __iomem *)&(x)) |
| 59 | #define WRITE_REG(x, v) writel((v), (void __iomem *)&(x)) |
| 60 | |
| 61 | struct ar7_wdt { |
| 62 | u32 kick_lock; |
| 63 | u32 kick; |
| 64 | u32 change_lock; |
| 65 | u32 change; |
| 66 | u32 disable_lock; |
| 67 | u32 disable; |
| 68 | u32 prescale_lock; |
| 69 | u32 prescale; |
| 70 | }; |
| 71 | |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 72 | static unsigned long wdt_is_open; |
| 73 | static spinlock_t wdt_lock; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 74 | static unsigned expect_close; |
| 75 | |
| 76 | /* XXX currently fixed, allows max margin ~68.72 secs */ |
| 77 | #define prescale_value 0xffff |
| 78 | |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 79 | /* Resource of the WDT registers */ |
| 80 | static struct resource *ar7_regs_wdt; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 81 | /* Pointer to the remapped WDT IO space */ |
| 82 | static struct ar7_wdt *ar7_wdt; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 83 | |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 84 | static struct clk *vbus_clk; |
| 85 | |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 86 | static void ar7_wdt_kick(u32 value) |
| 87 | { |
| 88 | WRITE_REG(ar7_wdt->kick_lock, 0x5555); |
| 89 | if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) { |
| 90 | WRITE_REG(ar7_wdt->kick_lock, 0xaaaa); |
| 91 | if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) { |
| 92 | WRITE_REG(ar7_wdt->kick, value); |
| 93 | return; |
| 94 | } |
| 95 | } |
| 96 | printk(KERN_ERR DRVNAME ": failed to unlock WDT kick reg\n"); |
| 97 | } |
| 98 | |
| 99 | static void ar7_wdt_prescale(u32 value) |
| 100 | { |
| 101 | WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a); |
| 102 | if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) { |
| 103 | WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5); |
| 104 | if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) { |
| 105 | WRITE_REG(ar7_wdt->prescale, value); |
| 106 | return; |
| 107 | } |
| 108 | } |
| 109 | printk(KERN_ERR DRVNAME ": failed to unlock WDT prescale reg\n"); |
| 110 | } |
| 111 | |
| 112 | static void ar7_wdt_change(u32 value) |
| 113 | { |
| 114 | WRITE_REG(ar7_wdt->change_lock, 0x6666); |
| 115 | if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) { |
| 116 | WRITE_REG(ar7_wdt->change_lock, 0xbbbb); |
| 117 | if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) { |
| 118 | WRITE_REG(ar7_wdt->change, value); |
| 119 | return; |
| 120 | } |
| 121 | } |
| 122 | printk(KERN_ERR DRVNAME ": failed to unlock WDT change reg\n"); |
| 123 | } |
| 124 | |
| 125 | static void ar7_wdt_disable(u32 value) |
| 126 | { |
| 127 | WRITE_REG(ar7_wdt->disable_lock, 0x7777); |
| 128 | if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) { |
| 129 | WRITE_REG(ar7_wdt->disable_lock, 0xcccc); |
| 130 | if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) { |
| 131 | WRITE_REG(ar7_wdt->disable_lock, 0xdddd); |
| 132 | if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) { |
| 133 | WRITE_REG(ar7_wdt->disable, value); |
| 134 | return; |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | printk(KERN_ERR DRVNAME ": failed to unlock WDT disable reg\n"); |
| 139 | } |
| 140 | |
| 141 | static void ar7_wdt_update_margin(int new_margin) |
| 142 | { |
| 143 | u32 change; |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 144 | u32 vbus_rate; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 145 | |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 146 | vbus_rate = clk_get_rate(vbus_clk); |
| 147 | change = new_margin * (vbus_rate / prescale_value); |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 148 | if (change < 1) |
| 149 | change = 1; |
| 150 | if (change > 0xffff) |
| 151 | change = 0xffff; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 152 | ar7_wdt_change(change); |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 153 | margin = change * prescale_value / vbus_rate; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 154 | printk(KERN_INFO DRVNAME |
| 155 | ": timer margin %d seconds (prescale %d, change %d, freq %d)\n", |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 156 | margin, prescale_value, change, vbus_rate); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 157 | } |
| 158 | |
| 159 | static void ar7_wdt_enable_wdt(void) |
| 160 | { |
| 161 | printk(KERN_DEBUG DRVNAME ": enabling watchdog timer\n"); |
| 162 | ar7_wdt_disable(1); |
| 163 | ar7_wdt_kick(1); |
| 164 | } |
| 165 | |
| 166 | static void ar7_wdt_disable_wdt(void) |
| 167 | { |
| 168 | printk(KERN_DEBUG DRVNAME ": disabling watchdog timer\n"); |
| 169 | ar7_wdt_disable(0); |
| 170 | } |
| 171 | |
| 172 | static int ar7_wdt_open(struct inode *inode, struct file *file) |
| 173 | { |
| 174 | /* only allow one at a time */ |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 175 | if (test_and_set_bit(0, &wdt_is_open)) |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 176 | return -EBUSY; |
| 177 | ar7_wdt_enable_wdt(); |
| 178 | expect_close = 0; |
| 179 | |
| 180 | return nonseekable_open(inode, file); |
| 181 | } |
| 182 | |
| 183 | static int ar7_wdt_release(struct inode *inode, struct file *file) |
| 184 | { |
| 185 | if (!expect_close) |
| 186 | printk(KERN_WARNING DRVNAME |
| 187 | ": watchdog device closed unexpectedly," |
| 188 | "will not disable the watchdog timer\n"); |
| 189 | else if (!nowayout) |
| 190 | ar7_wdt_disable_wdt(); |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 191 | clear_bit(0, &wdt_is_open); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 192 | return 0; |
| 193 | } |
| 194 | |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 195 | static ssize_t ar7_wdt_write(struct file *file, const char *data, |
| 196 | size_t len, loff_t *ppos) |
| 197 | { |
| 198 | /* check for a magic close character */ |
| 199 | if (len) { |
| 200 | size_t i; |
| 201 | |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 202 | spin_lock(&wdt_lock); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 203 | ar7_wdt_kick(1); |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 204 | spin_unlock(&wdt_lock); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 205 | |
| 206 | expect_close = 0; |
| 207 | for (i = 0; i < len; ++i) { |
| 208 | char c; |
Wim Van Sebroeck | 7944d3a | 2008-08-06 20:19:41 +0000 | [diff] [blame] | 209 | if (get_user(c, data + i)) |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 210 | return -EFAULT; |
| 211 | if (c == 'V') |
| 212 | expect_close = 1; |
| 213 | } |
| 214 | |
| 215 | } |
| 216 | return len; |
| 217 | } |
| 218 | |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 219 | static long ar7_wdt_ioctl(struct file *file, |
| 220 | unsigned int cmd, unsigned long arg) |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 221 | { |
Wim Van Sebroeck | 42747d7 | 2009-12-26 18:55:22 +0000 | [diff] [blame] | 222 | static const struct watchdog_info ident = { |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 223 | .identity = LONGNAME, |
| 224 | .firmware_version = 1, |
Wim Van Sebroeck | e73a780 | 2009-05-11 18:33:00 +0000 | [diff] [blame] | 225 | .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
| 226 | WDIOF_MAGICCLOSE), |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 227 | }; |
| 228 | int new_margin; |
| 229 | |
| 230 | switch (cmd) { |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 231 | case WDIOC_GETSUPPORT: |
| 232 | if (copy_to_user((struct watchdog_info *)arg, &ident, |
| 233 | sizeof(ident))) |
| 234 | return -EFAULT; |
| 235 | return 0; |
| 236 | case WDIOC_GETSTATUS: |
| 237 | case WDIOC_GETBOOTSTATUS: |
| 238 | if (put_user(0, (int *)arg)) |
| 239 | return -EFAULT; |
| 240 | return 0; |
| 241 | case WDIOC_KEEPALIVE: |
| 242 | ar7_wdt_kick(1); |
| 243 | return 0; |
| 244 | case WDIOC_SETTIMEOUT: |
| 245 | if (get_user(new_margin, (int *)arg)) |
| 246 | return -EFAULT; |
| 247 | if (new_margin < 1) |
| 248 | return -EINVAL; |
| 249 | |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 250 | spin_lock(&wdt_lock); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 251 | ar7_wdt_update_margin(new_margin); |
| 252 | ar7_wdt_kick(1); |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 253 | spin_unlock(&wdt_lock); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 254 | |
| 255 | case WDIOC_GETTIMEOUT: |
| 256 | if (put_user(margin, (int *)arg)) |
| 257 | return -EFAULT; |
| 258 | return 0; |
Wim Van Sebroeck | 0c06090 | 2008-07-18 11:41:17 +0000 | [diff] [blame] | 259 | default: |
| 260 | return -ENOTTY; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 261 | } |
| 262 | } |
| 263 | |
Jan Engelhardt | b47a166 | 2008-01-22 20:48:10 +0100 | [diff] [blame] | 264 | static const struct file_operations ar7_wdt_fops = { |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 265 | .owner = THIS_MODULE, |
| 266 | .write = ar7_wdt_write, |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 267 | .unlocked_ioctl = ar7_wdt_ioctl, |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 268 | .open = ar7_wdt_open, |
| 269 | .release = ar7_wdt_release, |
| 270 | }; |
| 271 | |
| 272 | static struct miscdevice ar7_wdt_miscdev = { |
| 273 | .minor = WATCHDOG_MINOR, |
| 274 | .name = "watchdog", |
| 275 | .fops = &ar7_wdt_fops, |
| 276 | }; |
| 277 | |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 278 | static int __devinit ar7_wdt_probe(struct platform_device *pdev) |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 279 | { |
| 280 | int rc; |
| 281 | |
Alan Cox | 670d59c | 2008-08-04 17:53:22 +0100 | [diff] [blame] | 282 | spin_lock_init(&wdt_lock); |
| 283 | |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 284 | ar7_regs_wdt = |
| 285 | platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs"); |
| 286 | if (!ar7_regs_wdt) { |
| 287 | printk(KERN_ERR DRVNAME ": could not get registers resource\n"); |
| 288 | rc = -ENODEV; |
| 289 | goto out; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 290 | } |
| 291 | |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 292 | if (!request_mem_region(ar7_regs_wdt->start, |
| 293 | resource_size(ar7_regs_wdt), LONGNAME)) { |
| 294 | printk(KERN_WARNING DRVNAME ": watchdog I/O region busy\n"); |
| 295 | rc = -EBUSY; |
| 296 | goto out; |
| 297 | } |
| 298 | |
| 299 | ar7_wdt = ioremap(ar7_regs_wdt->start, resource_size(ar7_regs_wdt)); |
| 300 | if (!ar7_wdt) { |
| 301 | printk(KERN_ERR DRVNAME ": could not ioremap registers\n"); |
| 302 | rc = -ENXIO; |
Wim Van Sebroeck | d7e9791 | 2009-08-31 13:49:14 +0000 | [diff] [blame] | 303 | goto out_mem_region; |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 304 | } |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 305 | |
Florian Fainelli | 780019d | 2010-01-27 09:10:06 +0100 | [diff] [blame] | 306 | vbus_clk = clk_get(NULL, "vbus"); |
| 307 | if (IS_ERR(vbus_clk)) { |
| 308 | printk(KERN_ERR DRVNAME ": could not get vbus clock\n"); |
| 309 | rc = PTR_ERR(vbus_clk); |
| 310 | goto out_mem_region; |
| 311 | } |
| 312 | |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 313 | ar7_wdt_disable_wdt(); |
| 314 | ar7_wdt_prescale(prescale_value); |
| 315 | ar7_wdt_update_margin(margin); |
| 316 | |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 317 | rc = misc_register(&ar7_wdt_miscdev); |
| 318 | if (rc) { |
| 319 | printk(KERN_ERR DRVNAME ": unable to register misc device\n"); |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 320 | goto out_alloc; |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 321 | } |
| 322 | goto out; |
| 323 | |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 324 | out_alloc: |
| 325 | iounmap(ar7_wdt); |
Wim Van Sebroeck | d7e9791 | 2009-08-31 13:49:14 +0000 | [diff] [blame] | 326 | out_mem_region: |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 327 | release_mem_region(ar7_regs_wdt->start, resource_size(ar7_regs_wdt)); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 328 | out: |
| 329 | return rc; |
| 330 | } |
| 331 | |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 332 | static int __devexit ar7_wdt_remove(struct platform_device *pdev) |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 333 | { |
| 334 | misc_deregister(&ar7_wdt_miscdev); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 335 | iounmap(ar7_wdt); |
Florian Fainelli | 64d4062 | 2009-07-21 12:11:32 +0200 | [diff] [blame] | 336 | release_mem_region(ar7_regs_wdt->start, resource_size(ar7_regs_wdt)); |
| 337 | |
| 338 | return 0; |
| 339 | } |
| 340 | |
| 341 | static void ar7_wdt_shutdown(struct platform_device *pdev) |
| 342 | { |
| 343 | if (!nowayout) |
| 344 | ar7_wdt_disable_wdt(); |
| 345 | } |
| 346 | |
| 347 | static struct platform_driver ar7_wdt_driver = { |
| 348 | .probe = ar7_wdt_probe, |
| 349 | .remove = __devexit_p(ar7_wdt_remove), |
| 350 | .shutdown = ar7_wdt_shutdown, |
| 351 | .driver = { |
| 352 | .owner = THIS_MODULE, |
| 353 | .name = "ar7_wdt", |
| 354 | }, |
| 355 | }; |
| 356 | |
| 357 | static int __init ar7_wdt_init(void) |
| 358 | { |
| 359 | return platform_driver_register(&ar7_wdt_driver); |
| 360 | } |
| 361 | |
| 362 | static void __exit ar7_wdt_cleanup(void) |
| 363 | { |
| 364 | platform_driver_unregister(&ar7_wdt_driver); |
Matteo Croce | c283cf2 | 2007-09-20 18:06:41 +0200 | [diff] [blame] | 365 | } |
| 366 | |
| 367 | module_init(ar7_wdt_init); |
| 368 | module_exit(ar7_wdt_cleanup); |