7 files changed, 555 insertions, 38 deletions

diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 52ea94b891f5..1b21c3a911d9 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -439,6 +439,14 @@ config SGI_MBCS
          If you have an SGI Altix with an attached SABrick
          say Y or M here, otherwise say N.
 
+config MSPEC
+        tristate "Memory special operations driver"
+        depends on IA64
+        help
+          If you have an ia64 and you want to enable memory special
+          operations support (formerly known as fetchop), say Y here,
+          otherwise say N.
+
 source "drivers/serial/Kconfig"
 
 config UNIX98_PTYS
@@ -739,7 +747,7 @@ config NVRAM
 
 config RTC
         tristate "Enhanced Real Time Clock Support"
-        depends on !PPC && !PARISC && !IA64 && !M68K && (!SPARC || PCI) && !FRV && !ARM
+        depends on !PPC && !PARISC && !IA64 && !M68K && (!SPARC || PCI) && !FRV && !ARM && !SUPERH
         ---help---
           If you say Y here and create a character special file /dev/rtc with
           major number 10 and minor number 135 using mknod ("man mknod"), you
diff --git a/drivers/char/Makefile b/drivers/char/Makefile
index 8c6dfc621520..b583d0cd9fbe 100644
--- a/drivers/char/Makefile
+++ b/drivers/char/Makefile
@@ -47,6 +47,7 @@ obj-$(CONFIG_HVC_RTAS)		+= hvc_rtas.o
 obj-$(CONFIG_HVC_DRIVER)        += hvc_console.o
 obj-$(CONFIG_RAW_DRIVER)        += raw.o
 obj-$(CONFIG_SGI_SNSC)          += snsc.o snsc_event.o
+obj-$(CONFIG_MSPEC)             += mspec.o
 obj-$(CONFIG_MMTIMER)           += mmtimer.o
 obj-$(CONFIG_VIOCONS)           += viocons.o
 obj-$(CONFIG_VIOTAPE)           += viotape.o
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 8afba339f05a..58b0eb581114 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -868,8 +868,8 @@ int hpet_alloc(struct hpet_data *hdp)
         do_div(temp, period);
         hpetp->hp_tick_freq = temp; /* ticks per second */
 
-        printk(KERN_INFO "hpet%d: at MMIO 0x%lx (virtual 0x%p), IRQ%s",
-                hpetp->hp_which, hdp->hd_phys_address, hdp->hd_address,
+        printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
+                hpetp->hp_which, hdp->hd_phys_address,
                 hpetp->hp_ntimer > 1 ? "s" : "");
         for (i = 0; i < hpetp->hp_ntimer; i++)
                 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 917b20402664..4ac70ec697f0 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -238,6 +238,32 @@ static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 }
 #endif
 
+#ifndef CONFIG_MMU
+static unsigned long get_unmapped_area_mem(struct file *file,
+                                           unsigned long addr,
+                                           unsigned long len,
+                                           unsigned long pgoff,
+                                           unsigned long flags)
+{
+        if (!valid_mmap_phys_addr_range(pgoff, len))
+                return (unsigned long) -EINVAL;
+        return pgoff;
+}
+
+/* can't do an in-place private mapping if there's no MMU */
+static inline int private_mapping_ok(struct vm_area_struct *vma)
+{
+        return vma->vm_flags & VM_MAYSHARE;
+}
+#else
+#define get_unmapped_area_mem   NULL
+
+static inline int private_mapping_ok(struct vm_area_struct *vma)
+{
+        return 1;
+}
+#endif
+
 static int mmap_mem(struct file * file, struct vm_area_struct * vma)
 {
         size_t size = vma->vm_end - vma->vm_start;
@@ -245,6 +271,9 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma)
         if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size))
                 return -EINVAL;
 
+        if (!private_mapping_ok(vma))
+                return -ENOSYS;
+
         vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff,
                                                  size,
                                                  vma->vm_page_prot);
@@ -782,6 +811,7 @@ static const struct file_operations mem_fops = {
         .write          = write_mem,
         .mmap           = mmap_mem,
         .open           = open_mem,
+        .get_unmapped_area = get_unmapped_area_mem,
 };
 
 static const struct file_operations kmem_fops = {
@@ -790,6 +820,7 @@ static const struct file_operations kmem_fops = {
         .write          = write_kmem,
         .mmap           = mmap_kmem,
         .open           = open_kmem,
+        .get_unmapped_area = get_unmapped_area_mem,
 };
 
 static const struct file_operations null_fops = {
@@ -815,6 +846,10 @@ static const struct file_operations zero_fops = {
         .mmap           = mmap_zero,
 };
 
+/*
+ * capabilities for /dev/zero
+ * - permits private mappings, "copies" are taken of the source of zeros
+ */
 static struct backing_dev_info zero_bdi = {
         .capabilities   = BDI_CAP_MAP_COPY,
 };
@@ -862,9 +897,13 @@ static int memory_open(struct inode * inode, struct file * filp)
         switch (iminor(inode)) {
                 case 1:
                         filp->f_op = &mem_fops;
+                        filp->f_mapping->backing_dev_info =
+                                &directly_mappable_cdev_bdi;
                         break;
                 case 2:
                         filp->f_op = &kmem_fops;
+                        filp->f_mapping->backing_dev_info =
+                                &directly_mappable_cdev_bdi;
                         break;
                 case 3:
                         filp->f_op = &null_fops;
diff --git a/drivers/char/mspec.c b/drivers/char/mspec.c
new file mode 100644
index 000000000000..5426b1e5595f
--- /dev/null
+++ b/drivers/char/mspec.c
@@ -0,0 +1,421 @@
+/*
+ * Copyright (C) 2001-2006 Silicon Graphics, Inc.  All rights
+ * reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License
+ * as published by the Free Software Foundation.
+ */
+
+/*
+ * SN Platform Special Memory (mspec) Support
+ *
+ * This driver exports the SN special memory (mspec) facility to user
+ * processes.
+ * There are three types of memory made available thru this driver:
+ * fetchops, uncached and cached.
+ *
+ * Fetchops are atomic memory operations that are implemented in the
+ * memory controller on SGI SN hardware.
+ *
+ * Uncached are used for memory write combining feature of the ia64
+ * cpu.
+ *
+ * Cached are used for areas of memory that are used as cached addresses
+ * on our partition and used as uncached addresses from other partitions.
+ * Due to a design constraint of the SN2 Shub, you can not have processors
+ * on the same FSB perform both a cached and uncached reference to the
+ * same cache line.  These special memory cached regions prevent the
+ * kernel from ever dropping in a TLB entry and therefore prevent the
+ * processor from ever speculating a cache line from this page.
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/miscdevice.h>
+#include <linux/spinlock.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/numa.h>
+#include <asm/page.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/atomic.h>
+#include <asm/tlbflush.h>
+#include <asm/uncached.h>
+#include <asm/sn/addrs.h>
+#include <asm/sn/arch.h>
+#include <asm/sn/mspec.h>
+#include <asm/sn/sn_cpuid.h>
+#include <asm/sn/io.h>
+#include <asm/sn/bte.h>
+#include <asm/sn/shubio.h>
+
+
+#define FETCHOP_ID      "SGI Fetchop,"
+#define CACHED_ID       "Cached,"
+#define UNCACHED_ID     "Uncached"
+#define REVISION        "4.0"
+#define MSPEC_BASENAME  "mspec"
+
+/*
+ * Page types allocated by the device.
+ */
+enum {
+        MSPEC_FETCHOP = 1,
+        MSPEC_CACHED,
+        MSPEC_UNCACHED
+};
+
+static int is_sn2;
+
+/*
+ * One of these structures is allocated when an mspec region is mmaped. The
+ * structure is pointed to by the vma->vm_private_data field in the vma struct.
+ * This structure is used to record the addresses of the mspec pages.
+ */
+struct vma_data {
+        atomic_t refcnt;        /* Number of vmas sharing the data. */
+        spinlock_t lock;        /* Serialize access to the vma. */
+        int count;              /* Number of pages allocated. */
+        int type;               /* Type of pages allocated. */
+        unsigned long maddr[0]; /* Array of MSPEC addresses. */
+};
+
+/* used on shub2 to clear FOP cache in the HUB */
+static unsigned long scratch_page[MAX_NUMNODES];
+#define SH2_AMO_CACHE_ENTRIES   4
+
+static inline int
+mspec_zero_block(unsigned long addr, int len)
+{
+        int status;
+
+        if (is_sn2) {
+                if (is_shub2()) {
+                        int nid;
+                        void *p;
+                        int i;
+
+                        nid = nasid_to_cnodeid(get_node_number(__pa(addr)));
+                        p = (void *)TO_AMO(scratch_page[nid]);
+
+                        for (i=0; i < SH2_AMO_CACHE_ENTRIES; i++) {
+                                FETCHOP_LOAD_OP(p, FETCHOP_LOAD);
+                                p += FETCHOP_VAR_SIZE;
+                        }
+                }
+
+                status = bte_copy(0, addr & ~__IA64_UNCACHED_OFFSET, len,
+                                  BTE_WACQUIRE | BTE_ZERO_FILL, NULL);
+        } else {
+                memset((char *) addr, 0, len);
+                status = 0;
+        }
+        return status;
+}
+
+/*
+ * mspec_open
+ *
+ * Called when a device mapping is created by a means other than mmap
+ * (via fork, etc.).  Increments the reference count on the underlying
+ * mspec data so it is not freed prematurely.
+ */
+static void
+mspec_open(struct vm_area_struct *vma)
+{
+        struct vma_data *vdata;
+
+        vdata = vma->vm_private_data;
+        atomic_inc(&vdata->refcnt);
+}
+
+/*
+ * mspec_close
+ *
+ * Called when unmapping a device mapping. Frees all mspec pages
+ * belonging to the vma.
+ */
+static void
+mspec_close(struct vm_area_struct *vma)
+{
+        struct vma_data *vdata;
+        int i, pages, result, vdata_size;
+
+        vdata = vma->vm_private_data;
+        if (!atomic_dec_and_test(&vdata->refcnt))
+                return;
+
+        pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+        vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
+        for (i = 0; i < pages; i++) {
+                if (vdata->maddr[i] == 0)
+                        continue;
+                /*
+                 * Clear the page before sticking it back
+                 * into the pool.
+                 */
+                result = mspec_zero_block(vdata->maddr[i], PAGE_SIZE);
+                if (!result)
+                        uncached_free_page(vdata->maddr[i]);
+                else
+                        printk(KERN_WARNING "mspec_close(): "
+                               "failed to zero page %i\n",
+                               result);
+        }
+
+        if (vdata_size <= PAGE_SIZE)
+                kfree(vdata);
+        else
+                vfree(vdata);
+}
+
+
+/*
+ * mspec_nopfn
+ *
+ * Creates a mspec page and maps it to user space.
+ */
+static unsigned long
+mspec_nopfn(struct vm_area_struct *vma, unsigned long address)
+{
+        unsigned long paddr, maddr;
+        unsigned long pfn;
+        int index;
+        struct vma_data *vdata = vma->vm_private_data;
+
+        index = (address - vma->vm_start) >> PAGE_SHIFT;
+        maddr = (volatile unsigned long) vdata->maddr[index];
+        if (maddr == 0) {
+                maddr = uncached_alloc_page(numa_node_id());
+                if (maddr == 0)
+                        return NOPFN_OOM;
+
+                spin_lock(&vdata->lock);
+                if (vdata->maddr[index] == 0) {
+                        vdata->count++;
+                        vdata->maddr[index] = maddr;
+                } else {
+                        uncached_free_page(maddr);
+                        maddr = vdata->maddr[index];
+                }
+                spin_unlock(&vdata->lock);
+        }
+
+        if (vdata->type == MSPEC_FETCHOP)
+                paddr = TO_AMO(maddr);
+        else
+                paddr = __pa(TO_CAC(maddr));
+
+        pfn = paddr >> PAGE_SHIFT;
+
+        return pfn;
+}
+
+static struct vm_operations_struct mspec_vm_ops = {
+        .open = mspec_open,
+        .close = mspec_close,
+        .nopfn = mspec_nopfn
+};
+
+/*
+ * mspec_mmap
+ *
+ * Called when mmaping the device.  Initializes the vma with a fault handler
+ * and private data structure necessary to allocate, track, and free the
+ * underlying pages.
+ */
+static int
+mspec_mmap(struct file *file, struct vm_area_struct *vma, int type)
+{
+        struct vma_data *vdata;
+        int pages, vdata_size;
+
+        if (vma->vm_pgoff != 0)
+                return -EINVAL;
+
+        if ((vma->vm_flags & VM_SHARED) == 0)
+                return -EINVAL;
+
+        if ((vma->vm_flags & VM_WRITE) == 0)
+                return -EPERM;
+
+        pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+        vdata_size = sizeof(struct vma_data) + pages * sizeof(long);
+        if (vdata_size <= PAGE_SIZE)
+                vdata = kmalloc(vdata_size, GFP_KERNEL);
+        else
+                vdata = vmalloc(vdata_size);
+        if (!vdata)
+                return -ENOMEM;
+        memset(vdata, 0, vdata_size);
+
+        vdata->type = type;
+        spin_lock_init(&vdata->lock);
+        vdata->refcnt = ATOMIC_INIT(1);
+        vma->vm_private_data = vdata;
+
+        vma->vm_flags |= (VM_IO | VM_LOCKED | VM_RESERVED | VM_PFNMAP);
+        if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED)
+                vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+        vma->vm_ops = &mspec_vm_ops;
+
+        return 0;
+}
+
+static int
+fetchop_mmap(struct file *file, struct vm_area_struct *vma)
+{
+        return mspec_mmap(file, vma, MSPEC_FETCHOP);
+}
+
+static int
+cached_mmap(struct file *file, struct vm_area_struct *vma)
+{
+        return mspec_mmap(file, vma, MSPEC_CACHED);
+}
+
+static int
+uncached_mmap(struct file *file, struct vm_area_struct *vma)
+{
+        return mspec_mmap(file, vma, MSPEC_UNCACHED);
+}
+
+static struct file_operations fetchop_fops = {
+        .owner = THIS_MODULE,
+        .mmap = fetchop_mmap
+};
+
+static struct miscdevice fetchop_miscdev = {
+        .minor = MISC_DYNAMIC_MINOR,
+        .name = "sgi_fetchop",
+        .fops = &fetchop_fops
+};
+
+static struct file_operations cached_fops = {
+        .owner = THIS_MODULE,
+        .mmap = cached_mmap
+};
+
+static struct miscdevice cached_miscdev = {
+        .minor = MISC_DYNAMIC_MINOR,
+        .name = "mspec_cached",
+        .fops = &cached_fops
+};
+
+static struct file_operations uncached_fops = {
+        .owner = THIS_MODULE,
+        .mmap = uncached_mmap
+};
+
+static struct miscdevice uncached_miscdev = {
+        .minor = MISC_DYNAMIC_MINOR,
+        .name = "mspec_uncached",
+        .fops = &uncached_fops
+};
+
+/*
+ * mspec_init
+ *
+ * Called at boot time to initialize the mspec facility.
+ */
+static int __init
+mspec_init(void)
+{
+        int ret;
+        int nid;
+
+        /*
+         * The fetchop device only works on SN2 hardware, uncached and cached
+         * memory drivers should both be valid on all ia64 hardware
+         */
+        if (ia64_platform_is("sn2")) {
+                is_sn2 = 1;
+                if (is_shub2()) {
+                        ret = -ENOMEM;
+                        for_each_online_node(nid) {
+                                int actual_nid;
+                                int nasid;
+                                unsigned long phys;
+
+                                scratch_page[nid] = uncached_alloc_page(nid);
+                                if (scratch_page[nid] == 0)
+                                        goto free_scratch_pages;
+                                phys = __pa(scratch_page[nid]);
+                                nasid = get_node_number(phys);
+                                actual_nid = nasid_to_cnodeid(nasid);
+                                if (actual_nid != nid)
+                                        goto free_scratch_pages;
+                        }
+                }
+
+                ret = misc_register(&fetchop_miscdev);
+                if (ret) {
+                        printk(KERN_ERR
+                               "%s: failed to register device %i\n",
+                               FETCHOP_ID, ret);
+                        goto free_scratch_pages;
+                }
+        }
+        ret = misc_register(&cached_miscdev);
+        if (ret) {
+                printk(KERN_ERR "%s: failed to register device %i\n",
+                       CACHED_ID, ret);
+                if (is_sn2)
+                        misc_deregister(&fetchop_miscdev);
+                goto free_scratch_pages;
+        }
+        ret = misc_register(&uncached_miscdev);
+        if (ret) {
+                printk(KERN_ERR "%s: failed to register device %i\n",
+                       UNCACHED_ID, ret);
+                misc_deregister(&cached_miscdev);
+                if (is_sn2)
+                        misc_deregister(&fetchop_miscdev);
+                goto free_scratch_pages;
+        }
+
+        printk(KERN_INFO "%s %s initialized devices: %s %s %s\n",
+               MSPEC_BASENAME, REVISION, is_sn2 ? FETCHOP_ID : "",
+               CACHED_ID, UNCACHED_ID);
+
+        return 0;
+
+ free_scratch_pages:
+        for_each_node(nid) {
+                if (scratch_page[nid] != 0)
+                        uncached_free_page(scratch_page[nid]);
+        }
+        return ret;
+}
+
+static void __exit
+mspec_exit(void)
+{
+        int nid;
+
+        misc_deregister(&uncached_miscdev);
+        misc_deregister(&cached_miscdev);
+        if (is_sn2) {
+                misc_deregister(&fetchop_miscdev);
+
+                for_each_node(nid) {
+                        if (scratch_page[nid] != 0)
+                                uncached_free_page(scratch_page[nid]);
+                }
+        }
+}
+
+module_init(mspec_init);
+module_exit(mspec_exit);
+
+MODULE_AUTHOR("Silicon Graphics, Inc. <linux-altix@sgi.com>");
+MODULE_DESCRIPTION("Driver for SGI SN special memory operations");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/watchdog/Kconfig b/drivers/char/watchdog/Kconfig
index fff89c2d88fd..f114d7b5bb2a 100644
--- a/drivers/char/watchdog/Kconfig
+++ b/drivers/char/watchdog/Kconfig
@@ -510,6 +510,14 @@ config SH_WDT
           To compile this driver as a module, choose M here: the
           module will be called shwdt.
 
+config SH_WDT_MMAP
+        bool "Allow mmap of SH WDT"
+        default n
+        depends on SH_WDT
+        help
+          If you say Y here, user applications will be able to mmap the
+          WDT/CPG registers.
+#
 # SPARC64 Architecture
 
 config WATCHDOG_CP1XXX
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);
-