1 files changed, 75 insertions, 35 deletions

diff --git a/drivers/char/watchdog/shwdt.c b/drivers/char/watchdog/shwdt.c
index 1355038f1044..e5b8c64f1d65 100644
--- a/drivers/char/watchdog/shwdt.c
+++ b/drivers/char/watchdog/shwdt.c
@@ -27,7 +27,7 @@
 #include <linux/notifier.h>
 #include <linux/ioport.h>
 #include <linux/fs.h>
-
+#include <linux/mm.h>
 #include <asm/io.h>
 #include <asm/uaccess.h>
 #include <asm/watchdog.h>
@@ -125,7 +125,6 @@ static void sh_wdt_start(void)
 
 /**
  *      sh_wdt_stop - Stop the Watchdog
- *
  *      Stops the watchdog.
  */
 static void sh_wdt_stop(void)
@@ -141,22 +140,20 @@ static void sh_wdt_stop(void)
 
 /**
  *      sh_wdt_keepalive - Keep the Userspace Watchdog Alive
- *
  *      The Userspace watchdog got a KeepAlive: schedule the next heartbeat.
  */
-static void sh_wdt_keepalive(void)
+static inline void sh_wdt_keepalive(void)
 {
         next_heartbeat = jiffies + (heartbeat * HZ);
 }
 
 /**
  *      sh_wdt_set_heartbeat - Set the Userspace Watchdog heartbeat
- *
  *      Set the Userspace Watchdog heartbeat
  */
 static int sh_wdt_set_heartbeat(int t)
 {
-        if ((t < 1) || (t > 3600)) /* arbitrary upper limit */
+        if (unlikely((t < 1) || (t > 3600))) /* arbitrary upper limit */
                 return -EINVAL;
 
         heartbeat = t;
@@ -165,7 +162,6 @@ static int sh_wdt_set_heartbeat(int t)
 
 /**
  *      sh_wdt_ping - Ping the Watchdog
- *
  *      @data: Unused
  *
  *      Clears overflow bit, resets timer counter.
@@ -182,14 +178,13 @@ static void sh_wdt_ping(unsigned long data)
                 sh_wdt_write_cnt(0);
 
                 mod_timer(&timer, next_ping_period(clock_division_ratio));
-        } else {
-                printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
-        }
+        } else
+                printk(KERN_WARNING PFX "Heartbeat lost! Will not ping "
+                       "the watchdog\n");
 }
 
 /**
  *      sh_wdt_open - Open the Device
- *
  *      @inode: inode of device
  *      @file: file handle of device
  *
@@ -209,7 +204,6 @@ static int sh_wdt_open(struct inode *inode, struct file *file)
 
 /**
  *      sh_wdt_close - Close the Device
- *
  *      @inode: inode of device
  *      @file: file handle of device
  *
@@ -220,7 +214,8 @@ static int sh_wdt_close(struct inode *inode, struct file *file)
         if (shwdt_expect_close == 42) {
                 sh_wdt_stop();
         } else {
-                printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
+                printk(KERN_CRIT PFX "Unexpected close, not "
+                       "stopping watchdog!\n");
                 sh_wdt_keepalive();
         }
 
@@ -232,7 +227,6 @@ static int sh_wdt_close(struct inode *inode, struct file *file)
 
 /**
  *      sh_wdt_write - Write to Device
- *
  *      @file: file handle of device
  *      @buf: buffer to write
  *      @count: length of buffer
@@ -264,8 +258,56 @@ static ssize_t sh_wdt_write(struct file *file, const char *buf,
 }
 
 /**
- *      sh_wdt_ioctl - Query Device
+ *      sh_wdt_mmap - map WDT/CPG registers into userspace
+ *      @file: file structure for the device
+ *      @vma: VMA to map the registers into
+ *
+ *      A simple mmap() implementation for the corner cases where the counter
+ *      needs to be mapped in userspace directly. Due to the relatively small
+ *      size of the area, neighbouring registers not necessarily tied to the
+ *      CPG will also be accessible through the register page, so this remains
+ *      configurable for users that really know what they're doing.
  *
+ *      Additionaly, the register page maps in the CPG register base relative
+ *      to the nearest page-aligned boundary, which requires that userspace do
+ *      the appropriate CPU subtype math for calculating the page offset for
+ *      the counter value.
+ */
+static int sh_wdt_mmap(struct file *file, struct vm_area_struct *vma)
+{
+        int ret = -ENOSYS;
+
+#ifdef CONFIG_SH_WDT_MMAP
+        unsigned long addr;
+
+        /* Only support the simple cases where we map in a register page. */
+        if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
+                return -EINVAL;
+
+        /*
+         * Pick WTCNT as the start, it's usually the first register after the
+         * FRQCR, and neither one are generally page-aligned out of the box.
+         */
+        addr = WTCNT & ~(PAGE_SIZE - 1);
+
+        vma->vm_flags |= VM_IO;
+        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+
+        if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
+                               PAGE_SIZE, vma->vm_page_prot)) {
+                printk(KERN_ERR PFX "%s: io_remap_pfn_range failed\n",
+                       __FUNCTION__);
+                return -EAGAIN;
+        }
+
+        ret = 0;
+#endif
+
+        return ret;
+}
+
+/**
+ *      sh_wdt_ioctl - Query Device
  *      @inode: inode of device
  *      @file: file handle of device
  *      @cmd: watchdog command
@@ -326,7 +368,6 @@ static int sh_wdt_ioctl(struct inode *inode, struct file *file,
 
 /**
  *      sh_wdt_notify_sys - Notifier Handler
- *
  *      @this: notifier block
  *      @code: notifier event
  *      @unused: unused
@@ -337,9 +378,8 @@ static int sh_wdt_ioctl(struct inode *inode, struct file *file,
 static int sh_wdt_notify_sys(struct notifier_block *this,
                              unsigned long code, void *unused)
 {
-        if (code == SYS_DOWN || code == SYS_HALT) {
+        if (code == SYS_DOWN || code == SYS_HALT)
                 sh_wdt_stop();
-        }
 
         return NOTIFY_DONE;
 }
@@ -351,10 +391,12 @@ static const struct file_operations sh_wdt_fops = {
         .ioctl          = sh_wdt_ioctl,
         .open           = sh_wdt_open,
         .release        = sh_wdt_close,
+        .mmap           = sh_wdt_mmap,
 };
 
 static struct watchdog_info sh_wdt_info = {
-        .options                = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+        .options                = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
+                                  WDIOF_MAGICCLOSE,
         .firmware_version       = 1,
         .identity               = "SH WDT",
 };
@@ -371,7 +413,6 @@ static struct miscdevice sh_wdt_miscdev = {
 
 /**
  *      sh_wdt_init - Initialize module
- *
  *      Registers the device and notifier handler. Actual device
  *      initialization is handled by sh_wdt_open().
  */
@@ -381,15 +422,15 @@ static int __init sh_wdt_init(void)
 
         if ((clock_division_ratio < 0x5) || (clock_division_ratio > 0x7)) {
                 clock_division_ratio = WTCSR_CKS_4096;
-                printk(KERN_INFO PFX "clock_division_ratio value must be 0x5<=x<=0x7, using %d\n",
-                        clock_division_ratio);
+                printk(KERN_INFO PFX "clock_division_ratio value must "
+                       "be 0x5<=x<=0x7, using %d\n", clock_division_ratio);
         }
 
-        if (sh_wdt_set_heartbeat(heartbeat))
-        {
+        rc = sh_wdt_set_heartbeat(heartbeat);
+        if (unlikely(rc)) {
                 heartbeat = WATCHDOG_HEARTBEAT;
-                printk(KERN_INFO PFX "heartbeat value must be 1<=x<=3600, using %d\n",
-                        heartbeat);
+                printk(KERN_INFO PFX "heartbeat value must "
+                       "be 1<=x<=3600, using %d\n", heartbeat);
         }
 
         init_timer(&timer);
@@ -397,15 +438,16 @@ static int __init sh_wdt_init(void)
         timer.data = 0;
 
         rc = register_reboot_notifier(&sh_wdt_notifier);
-        if (rc) {
-                printk(KERN_ERR PFX "Can't register reboot notifier (err=%d)\n", rc);
+        if (unlikely(rc)) {
+                printk(KERN_ERR PFX "Can't register reboot notifier (err=%d)\n",
+                       rc);
                 return rc;
         }
 
         rc = misc_register(&sh_wdt_miscdev);
-        if (rc) {
-                printk(KERN_ERR PFX "Can't register miscdev on minor=%d (err=%d)\n",
-                        sh_wdt_miscdev.minor, rc);
+        if (unlikely(rc)) {
+                printk(KERN_ERR PFX "Can't register miscdev on "
+                       "minor=%d (err=%d)\n", sh_wdt_miscdev.minor, rc);
                 unregister_reboot_notifier(&sh_wdt_notifier);
                 return rc;
         }
@@ -418,7 +460,6 @@ static int __init sh_wdt_init(void)
 
 /**
  *      sh_wdt_exit - Deinitialize module
- *
  *      Unregisters the device and notifier handler. Actual device
  *      deinitialization is handled by sh_wdt_close().
  */
@@ -434,14 +475,13 @@ MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
 
 module_param(clock_division_ratio, int, 0);
-MODULE_PARM_DESC(clock_division_ratio, "Clock division ratio. Valid ranges are from 0x5 (1.31ms) to 0x7 (5.25ms). Defaults to 0x7.");
+MODULE_PARM_DESC(clock_division_ratio, "Clock division ratio. Valid ranges are from 0x5 (1.31ms) to 0x7 (5.25ms). (default=" __MODULE_STRING(clock_division_ratio) ")");
 
 module_param(heartbeat, int, 0);
 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (1<=heartbeat<=3600, default=" __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
 
 module_param(nowayout, int, 0);
-MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
 module_init(sh_wdt_init);
 module_exit(sh_wdt_exit);
-