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/config.h>
  19 #include <linux/fs.h>
  20 #include <linux/init.h>
  21 #include <linux/kernel.h>
  22 #include <linux/miscdevice.h>
  23 #include <linux/module.h>
  24 #include <linux/watchdog.h>
  25 #include <asm/mv64x60.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/io.h>
  28
  29 /* MV64x60 WDC (config) register access definitions */
  30 #define MV64x60_WDC_CTL1_MASK   (3 << 24)
  31 #define MV64x60_WDC_CTL1(val)   ((val & 3) << 24)
  32 #define MV64x60_WDC_CTL2_MASK   (3 << 26)
  33 #define MV64x60_WDC_CTL2(val)   ((val & 3) << 26)
  34
  35 /* Flags bits */
  36 #define MV64x60_WDOG_FLAG_OPENED        0
  37 #define MV64x60_WDOG_FLAG_ENABLED       1
  38
  39 static unsigned long wdt_flags;
  40 static int wdt_status;
  41 static void __iomem *mv64x60_regs;
  42 static int mv64x60_wdt_timeout;
  43
  44 static void mv64x60_wdt_reg_write(u32 val)
  45 {
  46         /* Allow write only to CTL1 / CTL2 fields, retaining values in
  47          * other fields.
  48          */
  49         u32 data = readl(mv64x60_regs + MV64x60_WDT_WDC);
  50         data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
  51         data |= val;
  52         writel(data, mv64x60_regs + MV64x60_WDT_WDC);
  53 }
  54
  55 static void mv64x60_wdt_service(void)
  56 {
  57         /* Write 01 followed by 10 to CTL2 */
  58         mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
  59         mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
  60 }
  61
  62 static void mv64x60_wdt_handler_disable(void)
  63 {
  64         if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
  65                 /* Write 01 followed by 10 to CTL1 */
  66                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
  67                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
  68                 printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
  69         }
  70 }
  71
  72 static void mv64x60_wdt_handler_enable(void)
  73 {
  74         if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
  75                 /* Write 01 followed by 10 to CTL1 */
  76                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
  77                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
  78                 printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
  79         }
  80 }
  81
  82 static int mv64x60_wdt_open(struct inode *inode, struct file *file)
  83 {
  84         if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
  85                 return -EBUSY;
  86
  87         mv64x60_wdt_service();
  88         mv64x60_wdt_handler_enable();
  89
  90         return 0;
  91 }
  92
  93 static int mv64x60_wdt_release(struct inode *inode, struct file *file)
  94 {
  95         mv64x60_wdt_service();
  96
  97 #if !defined(CONFIG_WATCHDOG_NOWAYOUT)
  98         mv64x60_wdt_handler_disable();
  99 #endif
 100
 101         clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
 102
 103         return 0;
 104 }
 105
 106 static ssize_t mv64x60_wdt_write(struct file *file, const char *data,
 107                                  size_t len, loff_t * ppos)
 108 {
 109         if (*ppos != file->f_pos)
 110                 return -ESPIPE;
 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         static struct watchdog_info info = {
 123                 .options = WDIOF_KEEPALIVEPING,
 124                 .firmware_version = 0,
 125                 .identity = "MV64x60 watchdog",
 126         };
 127
 128         switch (cmd) {
 129         case WDIOC_GETSUPPORT:
 130                 if (copy_to_user((void *)arg, &info, sizeof(info)))
 131                         return -EFAULT;
 132                 break;
 133
 134         case WDIOC_GETSTATUS:
 135         case WDIOC_GETBOOTSTATUS:
 136                 if (put_user(wdt_status, (int *)arg))
 137                         return -EFAULT;
 138                 wdt_status &= ~WDIOF_KEEPALIVEPING;
 139                 break;
 140
 141         case WDIOC_GETTEMP:
 142                 return -EOPNOTSUPP;
 143
 144         case WDIOC_SETOPTIONS:
 145                 return -EOPNOTSUPP;
 146
 147         case WDIOC_KEEPALIVE:
 148                 mv64x60_wdt_service();
 149                 wdt_status |= WDIOF_KEEPALIVEPING;
 150                 break;
 151
 152         case WDIOC_SETTIMEOUT:
 153                 return -EOPNOTSUPP;
 154
 155         case WDIOC_GETTIMEOUT:
 156                 timeout = mv64x60_wdt_timeout * HZ;
 157                 if (put_user(timeout, (int *)arg))
 158                         return -EFAULT;
 159                 break;
 160
 161         default:
 162                 return -ENOIOCTLCMD;
 163         }
 164
 165         return 0;
 166 }
 167
 168 static struct file_operations mv64x60_wdt_fops = {
 169         .owner = THIS_MODULE,
 170         .llseek = no_llseek,
 171         .write = mv64x60_wdt_write,
 172         .ioctl = mv64x60_wdt_ioctl,
 173         .open = mv64x60_wdt_open,
 174         .release = mv64x60_wdt_release,
 175 };
 176
 177 static struct miscdevice mv64x60_wdt_miscdev = {
 178         .minor = WATCHDOG_MINOR,
 179         .name = "watchdog",
 180         .fops = &mv64x60_wdt_fops,
 181 };
 182
 183 static int __devinit mv64x60_wdt_probe(struct device *dev)
 184 {
 185         struct platform_device *pd = to_platform_device(dev);
 186         struct mv64x60_wdt_pdata *pdata = pd->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 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 device_driver mv64x60_wdt_driver = {
 214         .name = MV64x60_WDT_NAME,
 215         .bus = &platform_bus_type,
 216         .probe = mv64x60_wdt_probe,
 217         .remove = __devexit_p(mv64x60_wdt_remove),
 218 };
 219
 220 static struct platform_device *mv64x60_wdt_dev;
 221
 222 static int __init mv64x60_wdt_init(void)
 223 {
 224         int ret;
 225
 226         printk(KERN_INFO "MV64x60 watchdog driver\n");
 227
 228         mv64x60_wdt_dev = platform_device_register_simple(MV64x60_WDT_NAME,
 229                                                           -1, NULL, 0);
 230         if (IS_ERR(mv64x60_wdt_dev)) {
 231                 ret = PTR_ERR(mv64x60_wdt_dev);
 232                 goto out;
 233         }
 234
 235         ret = driver_register(&mv64x60_wdt_driver);
 236       out:
 237         return ret;
 238 }
 239
 240 static void __exit mv64x60_wdt_exit(void)
 241 {
 242         driver_unregister(&mv64x60_wdt_driver);
 243         platform_device_unregister(mv64x60_wdt_dev);
 244 }
 245
 246 module_init(mv64x60_wdt_init);
 247 module_exit(mv64x60_wdt_exit);
 248
 249 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 250 MODULE_DESCRIPTION("MV64x60 watchdog driver");
 251 MODULE_LICENSE("GPL");
 252 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);