drivers/char/watchdog/mv64x60_wdt.c

   1 /*
   2  * mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
   3  *
   4  * Author: James Chapman <jchapman@katalix.com>
   5  *
   6  * Platform-specific setup code should configure the dog to generate
   7  * interrupt or reset as required.  This code only enables/disables
   8  * and services the watchdog.
   9  *
  10  * Derived from mpc8xx_wdt.c, with the following copyright.
  11  *
  12  * 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
  13  * the terms of the GNU General Public License version 2. This program
  14  * is licensed "as is" without any warranty of any kind, whether express
  15  * or implied.
  16  */
  17
  18 #include <linux/fs.h>
  19 #include <linux/init.h>
  20 #include <linux/kernel.h>
  21 #include <linux/miscdevice.h>
  22 #include <linux/module.h>
  23 #include <linux/watchdog.h>
  24 #include <linux/platform_device.h>
  25
  26 #include <asm/mv64x60.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/io.h>
  29
  30 /* MV64x60 WDC (config) register access definitions */
  31 #define MV64x60_WDC_CTL1_MASK   (3 << 24)
  32 #define MV64x60_WDC_CTL1(val)   ((val & 3) << 24)
  33 #define MV64x60_WDC_CTL2_MASK   (3 << 26)
  34 #define MV64x60_WDC_CTL2(val)   ((val & 3) << 26)
  35
  36 /* Flags bits */
  37 #define MV64x60_WDOG_FLAG_OPENED        0
  38 #define MV64x60_WDOG_FLAG_ENABLED       1
  39
  40 static unsigned long wdt_flags;
  41 static int wdt_status;
  42 static void __iomem *mv64x60_regs;
  43 static int mv64x60_wdt_timeout;
  44
  45 static void mv64x60_wdt_reg_write(u32 val)
  46 {
  47         /* Allow write only to CTL1 / CTL2 fields, retaining values in
  48          * other fields.
  49          */
  50         u32 data = readl(mv64x60_regs + MV64x60_WDT_WDC);
  51         data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
  52         data |= val;
  53         writel(data, mv64x60_regs + MV64x60_WDT_WDC);
  54 }
  55
  56 static void mv64x60_wdt_service(void)
  57 {
  58         /* Write 01 followed by 10 to CTL2 */
  59         mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
  60         mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
  61 }
  62
  63 static void mv64x60_wdt_handler_disable(void)
  64 {
  65         if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
  66                 /* Write 01 followed by 10 to CTL1 */
  67                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
  68                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
  69                 printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
  70         }
  71 }
  72
  73 static void mv64x60_wdt_handler_enable(void)
  74 {
  75         if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
  76                 /* Write 01 followed by 10 to CTL1 */
  77                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
  78                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
  79                 printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
  80         }
  81 }
  82
  83 static int mv64x60_wdt_open(struct inode *inode, struct file *file)
  84 {
  85         if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
  86                 return -EBUSY;
  87
  88         mv64x60_wdt_service();
  89         mv64x60_wdt_handler_enable();
  90
  91         nonseekable_open(inode, file);
  92
  93         return 0;
  94 }
  95
  96 static int mv64x60_wdt_release(struct inode *inode, struct file *file)
  97 {
  98         mv64x60_wdt_service();
  99
 100 #if !defined(CONFIG_WATCHDOG_NOWAYOUT)
 101         mv64x60_wdt_handler_disable();
 102 #endif
 103
 104         clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
 105
 106         return 0;
 107 }
 108
 109 static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
 110                                  size_t len, loff_t * ppos)
 111 {
 112         if (len)
 113                 mv64x60_wdt_service();
 114
 115         return len;
 116 }
 117
 118 static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
 119                              unsigned int cmd, unsigned long arg)
 120 {
 121         int timeout;
 122         void __user *argp = (void __user *)arg;
 123         static struct watchdog_info info = {
 124                 .options = WDIOF_KEEPALIVEPING,
 125                 .firmware_version = 0,
 126                 .identity = "MV64x60 watchdog",
 127         };
 128
 129         switch (cmd) {
 130         case WDIOC_GETSUPPORT:
 131                 if (copy_to_user(argp, &info, sizeof(info)))
 132                         return -EFAULT;
 133                 break;
 134
 135         case WDIOC_GETSTATUS:
 136         case WDIOC_GETBOOTSTATUS:
 137                 if (put_user(wdt_status, (int __user *)argp))
 138                         return -EFAULT;
 139                 wdt_status &= ~WDIOF_KEEPALIVEPING;
 140                 break;
 141
 142         case WDIOC_GETTEMP:
 143                 return -EOPNOTSUPP;
 144
 145         case WDIOC_SETOPTIONS:
 146                 return -EOPNOTSUPP;
 147
 148         case WDIOC_KEEPALIVE:
 149                 mv64x60_wdt_service();
 150                 wdt_status |= WDIOF_KEEPALIVEPING;
 151                 break;
 152
 153         case WDIOC_SETTIMEOUT:
 154                 return -EOPNOTSUPP;
 155
 156         case WDIOC_GETTIMEOUT:
 157                 timeout = mv64x60_wdt_timeout * HZ;
 158                 if (put_user(timeout, (int __user *)argp))
 159                         return -EFAULT;
 160                 break;
 161
 162         default:
 163                 return -ENOTTY;
 164         }
 165
 166         return 0;
 167 }
 168
 169 static const struct file_operations mv64x60_wdt_fops = {
 170         .owner = THIS_MODULE,
 171         .llseek = no_llseek,
 172         .write = mv64x60_wdt_write,
 173         .ioctl = mv64x60_wdt_ioctl,
 174         .open = mv64x60_wdt_open,
 175         .release = mv64x60_wdt_release,
 176 };
 177
 178 static struct miscdevice mv64x60_wdt_miscdev = {
 179         .minor = WATCHDOG_MINOR,
 180         .name = "watchdog",
 181         .fops = &mv64x60_wdt_fops,
 182 };
 183
 184 static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
 185 {
 186         struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
 187         int bus_clk = 133;
 188
 189         mv64x60_wdt_timeout = 10;
 190         if (pdata) {
 191                 mv64x60_wdt_timeout = pdata->timeout;
 192                 bus_clk = pdata->bus_clk;
 193         }
 194
 195         mv64x60_regs = mv64x60_get_bridge_vbase();
 196
 197         writel((mv64x60_wdt_timeout * (bus_clk * 1000000)) >> 8,
 198                mv64x60_regs + MV64x60_WDT_WDC);
 199
 200         return misc_register(&mv64x60_wdt_miscdev);
 201 }
 202
 203 static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
 204 {
 205         misc_deregister(&mv64x60_wdt_miscdev);
 206
 207         mv64x60_wdt_service();
 208         mv64x60_wdt_handler_disable();
 209
 210         return 0;
 211 }
 212
 213 static struct platform_driver mv64x60_wdt_driver = {
 214         .probe = mv64x60_wdt_probe,
 215         .remove = __devexit_p(mv64x60_wdt_remove),
 216         .driver = {
 217                 .owner = THIS_MODULE,
 218                 .name = MV64x60_WDT_NAME,
 219         },
 220 };
 221
 222 static struct platform_device *mv64x60_wdt_dev;
 223
 224 static int __init mv64x60_wdt_init(void)
 225 {
 226         int ret;
 227
 228         printk(KERN_INFO "MV64x60 watchdog driver\n");
 229
 230         mv64x60_wdt_dev = platform_device_alloc(MV64x60_WDT_NAME, -1);
 231         if (!mv64x60_wdt_dev) {
 232                 ret = -ENOMEM;
 233                 goto out;
 234         }
 235
 236         ret = platform_device_add(mv64x60_wdt_dev);
 237         if (ret) {
 238                 platform_device_put(mv64x60_wdt_dev);
 239                 goto out;
 240         }
 241
 242         ret = platform_driver_register(&mv64x60_wdt_driver);
 243         if (ret) {
 244                 platform_device_unregister(mv64x60_wdt_dev);
 245                 goto out;
 246         }
 247
 248  out:
 249         return ret;
 250 }
 251
 252 static void __exit mv64x60_wdt_exit(void)
 253 {
 254         platform_driver_unregister(&mv64x60_wdt_driver);
 255         platform_device_unregister(mv64x60_wdt_dev);
 256 }
 257
 258 module_init(mv64x60_wdt_init);
 259 module_exit(mv64x60_wdt_exit);
 260
 261 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 262 MODULE_DESCRIPTION("MV64x60 watchdog driver");
 263 MODULE_LICENSE("GPL");
 264 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);