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 <linux/platform_device.h>
  26
  27 #include <asm/mv64x60.h>
  28 #include <asm/uaccess.h>
  29 #include <asm/io.h>
  30
  31 /* MV64x60 WDC (config) register access definitions */
  32 #define MV64x60_WDC_CTL1_MASK   (3 << 24)
  33 #define MV64x60_WDC_CTL1(val)   ((val & 3) << 24)
  34 #define MV64x60_WDC_CTL2_MASK   (3 << 26)
  35 #define MV64x60_WDC_CTL2(val)   ((val & 3) << 26)
  36
  37 /* Flags bits */
  38 #define MV64x60_WDOG_FLAG_OPENED        0
  39 #define MV64x60_WDOG_FLAG_ENABLED       1
  40
  41 static unsigned long wdt_flags;
  42 static int wdt_status;
  43 static void __iomem *mv64x60_regs;
  44 static int mv64x60_wdt_timeout;
  45
  46 static void mv64x60_wdt_reg_write(u32 val)
  47 {
  48         /* Allow write only to CTL1 / CTL2 fields, retaining values in
  49          * other fields.
  50          */
  51         u32 data = readl(mv64x60_regs + MV64x60_WDT_WDC);
  52         data &= ~(MV64x60_WDC_CTL1_MASK | MV64x60_WDC_CTL2_MASK);
  53         data |= val;
  54         writel(data, mv64x60_regs + MV64x60_WDT_WDC);
  55 }
  56
  57 static void mv64x60_wdt_service(void)
  58 {
  59         /* Write 01 followed by 10 to CTL2 */
  60         mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x01));
  61         mv64x60_wdt_reg_write(MV64x60_WDC_CTL2(0x02));
  62 }
  63
  64 static void mv64x60_wdt_handler_disable(void)
  65 {
  66         if (test_and_clear_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
  67                 /* Write 01 followed by 10 to CTL1 */
  68                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
  69                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
  70                 printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
  71         }
  72 }
  73
  74 static void mv64x60_wdt_handler_enable(void)
  75 {
  76         if (!test_and_set_bit(MV64x60_WDOG_FLAG_ENABLED, &wdt_flags)) {
  77                 /* Write 01 followed by 10 to CTL1 */
  78                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x01));
  79                 mv64x60_wdt_reg_write(MV64x60_WDC_CTL1(0x02));
  80                 printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
  81         }
  82 }
  83
  84 static int mv64x60_wdt_open(struct inode *inode, struct file *file)
  85 {
  86         if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
  87                 return -EBUSY;
  88
  89         mv64x60_wdt_service();
  90         mv64x60_wdt_handler_enable();
  91
  92         nonseekable_open(inode, file);
  93
  94         return 0;
  95 }
  96
  97 static int mv64x60_wdt_release(struct inode *inode, struct file *file)
  98 {
  99         mv64x60_wdt_service();
 100
 101 #if !defined(CONFIG_WATCHDOG_NOWAYOUT)
 102         mv64x60_wdt_handler_disable();
 103 #endif
 104
 105         clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
 106
 107         return 0;
 108 }
 109
 110 static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
 111                                  size_t len, loff_t * ppos)
 112 {
 113         if (len)
 114                 mv64x60_wdt_service();
 115
 116         return len;
 117 }
 118
 119 static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
 120                              unsigned int cmd, unsigned long arg)
 121 {
 122         int timeout;
 123         void __user *argp = (void __user *)arg;
 124         static struct watchdog_info info = {
 125                 .options = WDIOF_KEEPALIVEPING,
 126                 .firmware_version = 0,
 127                 .identity = "MV64x60 watchdog",
 128         };
 129
 130         switch (cmd) {
 131         case WDIOC_GETSUPPORT:
 132                 if (copy_to_user(argp, &info, sizeof(info)))
 133                         return -EFAULT;
 134                 break;
 135
 136         case WDIOC_GETSTATUS:
 137         case WDIOC_GETBOOTSTATUS:
 138                 if (put_user(wdt_status, (int __user *)argp))
 139                         return -EFAULT;
 140                 wdt_status &= ~WDIOF_KEEPALIVEPING;
 141                 break;
 142
 143         case WDIOC_GETTEMP:
 144                 return -EOPNOTSUPP;
 145
 146         case WDIOC_SETOPTIONS:
 147                 return -EOPNOTSUPP;
 148
 149         case WDIOC_KEEPALIVE:
 150                 mv64x60_wdt_service();
 151                 wdt_status |= WDIOF_KEEPALIVEPING;
 152                 break;
 153
 154         case WDIOC_SETTIMEOUT:
 155                 return -EOPNOTSUPP;
 156
 157         case WDIOC_GETTIMEOUT:
 158                 timeout = mv64x60_wdt_timeout * HZ;
 159                 if (put_user(timeout, (int __user *)argp))
 160                         return -EFAULT;
 161                 break;
 162
 163         default:
 164                 return -ENOIOCTLCMD;
 165         }
 166
 167         return 0;
 168 }
 169
 170 static struct file_operations mv64x60_wdt_fops = {
 171         .owner = THIS_MODULE,
 172         .llseek = no_llseek,
 173         .write = mv64x60_wdt_write,
 174         .ioctl = mv64x60_wdt_ioctl,
 175         .open = mv64x60_wdt_open,
 176         .release = mv64x60_wdt_release,
 177 };
 178
 179 static struct miscdevice mv64x60_wdt_miscdev = {
 180         .minor = WATCHDOG_MINOR,
 181         .name = "watchdog",
 182         .fops = &mv64x60_wdt_fops,
 183 };
 184
 185 static int __devinit mv64x60_wdt_probe(struct device *dev)
 186 {
 187         struct platform_device *pd = to_platform_device(dev);
 188         struct mv64x60_wdt_pdata *pdata = pd->dev.platform_data;
 189         int bus_clk = 133;
 190
 191         mv64x60_wdt_timeout = 10;
 192         if (pdata) {
 193                 mv64x60_wdt_timeout = pdata->timeout;
 194                 bus_clk = pdata->bus_clk;
 195         }
 196
 197         mv64x60_regs = mv64x60_get_bridge_vbase();
 198
 199         writel((mv64x60_wdt_timeout * (bus_clk * 1000000)) >> 8,
 200                mv64x60_regs + MV64x60_WDT_WDC);
 201
 202         return misc_register(&mv64x60_wdt_miscdev);
 203 }
 204
 205 static int __devexit mv64x60_wdt_remove(struct device *dev)
 206 {
 207         misc_deregister(&mv64x60_wdt_miscdev);
 208
 209         mv64x60_wdt_service();
 210         mv64x60_wdt_handler_disable();
 211
 212         return 0;
 213 }
 214
 215 static struct device_driver mv64x60_wdt_driver = {
 216         .owner = THIS_MODULE,
 217         .name = MV64x60_WDT_NAME,
 218         .bus = &platform_bus_type,
 219         .probe = mv64x60_wdt_probe,
 220         .remove = __devexit_p(mv64x60_wdt_remove),
 221 };
 222
 223 static struct platform_device *mv64x60_wdt_dev;
 224
 225 static int __init mv64x60_wdt_init(void)
 226 {
 227         int ret;
 228
 229         printk(KERN_INFO "MV64x60 watchdog driver\n");
 230
 231         mv64x60_wdt_dev = platform_device_register_simple(MV64x60_WDT_NAME,
 232                                                           -1, NULL, 0);
 233         if (IS_ERR(mv64x60_wdt_dev)) {
 234                 ret = PTR_ERR(mv64x60_wdt_dev);
 235                 goto out;
 236         }
 237
 238         ret = driver_register(&mv64x60_wdt_driver);
 239       out:
 240         return ret;
 241 }
 242
 243 static void __exit mv64x60_wdt_exit(void)
 244 {
 245         driver_unregister(&mv64x60_wdt_driver);
 246         platform_device_unregister(mv64x60_wdt_dev);
 247 }
 248
 249 module_init(mv64x60_wdt_init);
 250 module_exit(mv64x60_wdt_exit);
 251
 252 MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
 253 MODULE_DESCRIPTION("MV64x60 watchdog driver");
 254 MODULE_LICENSE("GPL");
 255 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);