![Dale Farnsworth](/assets/img/avatar_default.png)
Consolidate the timeout config register modification into a single function. Also, use the enabled flag in the config register to determine whether the timer is enabled instead of a separately maintained flag, MV64x60_WDOG_FLAG_ENABLED. Add spinlock protection around enabling/disabling the watchdog timer. Signed-off-by: Dale Farnsworth <dale@farnsworth.org> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
327 lines
7.7 KiB
C
327 lines
7.7 KiB
C
/*
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* mv64x60_wdt.c - MV64X60 (Marvell Discovery) watchdog userspace interface
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*
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* Author: James Chapman <jchapman@katalix.com>
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*
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* Platform-specific setup code should configure the dog to generate
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* interrupt or reset as required. This code only enables/disables
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* and services the watchdog.
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*
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* Derived from mpc8xx_wdt.c, with the following copyright.
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*
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* 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
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* the terms of the GNU General Public License version 2. This program
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* is licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*/
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/watchdog.h>
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#include <linux/platform_device.h>
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#include <linux/mv643xx.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#define MV64x60_WDT_WDC_OFFSET 0
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/*
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* The watchdog configuration register contains a pair of 2-bit fields,
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* 1. a reload field, bits 27-26, which triggers a reload of
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* the countdown register, and
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* 2. an enable field, bits 25-24, which toggles between
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* enabling and disabling the watchdog timer.
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* Bit 31 is a read-only field which indicates whether the
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* watchdog timer is currently enabled.
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*
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* The low 24 bits contain the timer reload value.
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*/
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#define MV64x60_WDC_ENABLE_SHIFT 24
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#define MV64x60_WDC_SERVICE_SHIFT 26
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#define MV64x60_WDC_ENABLED_SHIFT 31
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#define MV64x60_WDC_ENABLED_TRUE 1
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#define MV64x60_WDC_ENABLED_FALSE 0
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/* Flags bits */
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#define MV64x60_WDOG_FLAG_OPENED 0
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static unsigned long wdt_flags;
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static int wdt_status;
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static void __iomem *mv64x60_wdt_regs;
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static int mv64x60_wdt_timeout;
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static int mv64x60_wdt_count;
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static unsigned int bus_clk;
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static char expect_close;
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static DEFINE_SPINLOCK(mv64x60_wdt_spinlock);
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static int nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int mv64x60_wdt_toggle_wdc(int enabled_predicate, int field_shift)
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{
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u32 data;
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u32 enabled;
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int ret = 0;
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spin_lock(&mv64x60_wdt_spinlock);
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data = readl(mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
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enabled = (data >> MV64x60_WDC_ENABLED_SHIFT) & 1;
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/* only toggle the requested field if enabled state matches predicate */
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if ((enabled ^ enabled_predicate) == 0) {
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/* We write a 1, then a 2 -- to the appropriate field */
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data = (1 << field_shift) | mv64x60_wdt_count;
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writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
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data = (2 << field_shift) | mv64x60_wdt_count;
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writel(data, mv64x60_wdt_regs + MV64x60_WDT_WDC_OFFSET);
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ret = 1;
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}
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spin_unlock(&mv64x60_wdt_spinlock);
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return ret;
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}
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static void mv64x60_wdt_service(void)
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{
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mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
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MV64x60_WDC_SERVICE_SHIFT);
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}
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static void mv64x60_wdt_handler_enable(void)
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{
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if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_FALSE,
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MV64x60_WDC_ENABLE_SHIFT)) {
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mv64x60_wdt_service();
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printk(KERN_NOTICE "mv64x60_wdt: watchdog activated\n");
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}
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}
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static void mv64x60_wdt_handler_disable(void)
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{
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if (mv64x60_wdt_toggle_wdc(MV64x60_WDC_ENABLED_TRUE,
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MV64x60_WDC_ENABLE_SHIFT))
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printk(KERN_NOTICE "mv64x60_wdt: watchdog deactivated\n");
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}
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static void mv64x60_wdt_set_timeout(unsigned int timeout)
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{
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/* maximum bus cycle count is 0xFFFFFFFF */
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if (timeout > 0xFFFFFFFF / bus_clk)
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timeout = 0xFFFFFFFF / bus_clk;
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mv64x60_wdt_count = timeout * bus_clk >> 8;
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mv64x60_wdt_timeout = timeout;
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}
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static int mv64x60_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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mv64x60_wdt_handler_enable();
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return nonseekable_open(inode, file);
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}
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static int mv64x60_wdt_release(struct inode *inode, struct file *file)
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{
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if (expect_close == 42)
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mv64x60_wdt_handler_disable();
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else {
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printk(KERN_CRIT
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"mv64x60_wdt: unexpected close, not stopping timer!\n");
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mv64x60_wdt_service();
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}
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expect_close = 0;
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clear_bit(MV64x60_WDOG_FLAG_OPENED, &wdt_flags);
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return 0;
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}
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static ssize_t mv64x60_wdt_write(struct file *file, const char __user *data,
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size_t len, loff_t * ppos)
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{
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if (len) {
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if (!nowayout) {
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size_t i;
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expect_close = 0;
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for (i = 0; i != len; i++) {
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char c;
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if(get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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expect_close = 42;
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}
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}
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mv64x60_wdt_service();
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}
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return len;
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}
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static int mv64x60_wdt_ioctl(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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int timeout;
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int options;
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void __user *argp = (void __user *)arg;
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static struct watchdog_info info = {
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.options = WDIOF_SETTIMEOUT |
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WDIOF_MAGICCLOSE |
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WDIOF_KEEPALIVEPING,
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.firmware_version = 0,
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.identity = "MV64x60 watchdog",
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};
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &info, sizeof(info)))
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return -EFAULT;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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if (put_user(wdt_status, (int __user *)argp))
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return -EFAULT;
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wdt_status &= ~WDIOF_KEEPALIVEPING;
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break;
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case WDIOC_GETTEMP:
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return -EOPNOTSUPP;
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case WDIOC_SETOPTIONS:
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if (get_user(options, (int __user *)argp))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD)
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mv64x60_wdt_handler_disable();
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if (options & WDIOS_ENABLECARD)
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mv64x60_wdt_handler_enable();
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break;
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case WDIOC_KEEPALIVE:
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mv64x60_wdt_service();
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wdt_status |= WDIOF_KEEPALIVEPING;
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break;
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case WDIOC_SETTIMEOUT:
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if (get_user(timeout, (int __user *)argp))
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return -EFAULT;
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mv64x60_wdt_set_timeout(timeout);
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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if (put_user(mv64x60_wdt_timeout, (int __user *)argp))
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return -EFAULT;
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break;
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default:
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return -ENOTTY;
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}
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return 0;
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}
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static const struct file_operations mv64x60_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = mv64x60_wdt_write,
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.ioctl = mv64x60_wdt_ioctl,
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.open = mv64x60_wdt_open,
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.release = mv64x60_wdt_release,
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};
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static struct miscdevice mv64x60_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &mv64x60_wdt_fops,
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};
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static int __devinit mv64x60_wdt_probe(struct platform_device *dev)
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{
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struct mv64x60_wdt_pdata *pdata = dev->dev.platform_data;
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struct resource *r;
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int timeout = 10;
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bus_clk = 133; /* in MHz */
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if (pdata) {
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timeout = pdata->timeout;
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bus_clk = pdata->bus_clk;
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}
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/* Since bus_clk is truncated MHz, actual frequency could be
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* up to 1MHz higher. Round up, since it's better to time out
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* too late than too soon.
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*/
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bus_clk++;
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bus_clk *= 1000000; /* convert to Hz */
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r = platform_get_resource(dev, IORESOURCE_MEM, 0);
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if (!r)
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return -ENODEV;
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mv64x60_wdt_regs = ioremap(r->start, r->end - r->start + 1);
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if (mv64x60_wdt_regs == NULL)
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return -ENOMEM;
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mv64x60_wdt_set_timeout(timeout);
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mv64x60_wdt_handler_disable(); /* in case timer was already running */
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return misc_register(&mv64x60_wdt_miscdev);
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}
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static int __devexit mv64x60_wdt_remove(struct platform_device *dev)
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{
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misc_deregister(&mv64x60_wdt_miscdev);
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mv64x60_wdt_handler_disable();
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iounmap(mv64x60_wdt_regs);
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return 0;
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}
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static struct platform_driver mv64x60_wdt_driver = {
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.probe = mv64x60_wdt_probe,
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.remove = __devexit_p(mv64x60_wdt_remove),
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.driver = {
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.owner = THIS_MODULE,
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.name = MV64x60_WDT_NAME,
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},
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};
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static int __init mv64x60_wdt_init(void)
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{
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printk(KERN_INFO "MV64x60 watchdog driver\n");
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return platform_driver_register(&mv64x60_wdt_driver);
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}
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static void __exit mv64x60_wdt_exit(void)
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{
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platform_driver_unregister(&mv64x60_wdt_driver);
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}
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module_init(mv64x60_wdt_init);
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module_exit(mv64x60_wdt_exit);
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MODULE_AUTHOR("James Chapman <jchapman@katalix.com>");
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MODULE_DESCRIPTION("MV64x60 watchdog driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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