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watchdog: Adding support for ARM Primecell SP805 Watchdog
Technical Reference Manual can be found at: http://infocenter.arm.com/help/topic/com.arm.doc.ddi0270b/DDI0270.pdf Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
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@ -73,6 +73,13 @@ config WM8350_WATCHDOG
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# ARM Architecture
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config ARM_SP805_WATCHDOG
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tristate "ARM SP805 Watchdog"
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depends on ARM_AMBA
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help
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ARM Primecell SP805 Watchdog timer. This will reboot your system when
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the timeout is reached.
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config AT91RM9200_WATCHDOG
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tristate "AT91RM9200 watchdog"
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depends on ARCH_AT91RM9200
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@ -25,6 +25,7 @@ obj-$(CONFIG_USBPCWATCHDOG) += pcwd_usb.o
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# ALPHA Architecture
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# ARM Architecture
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obj-$(CONFIG_ARM_SP805_WATCHDOG) += sp805_wdt.o
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obj-$(CONFIG_AT91RM9200_WATCHDOG) += at91rm9200_wdt.o
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obj-$(CONFIG_AT91SAM9X_WATCHDOG) += at91sam9_wdt.o
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obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
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387
drivers/watchdog/sp805_wdt.c
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387
drivers/watchdog/sp805_wdt.c
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@ -0,0 +1,387 @@
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/*
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* drivers/char/watchdog/sp805-wdt.c
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*
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* Watchdog driver for ARM SP805 watchdog module
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*
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* Copyright (C) 2010 ST Microelectronics
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* Viresh Kumar<viresh.kumar@st.com>
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2 or later. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/device.h>
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#include <linux/resource.h>
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#include <linux/amba/bus.h>
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#include <linux/bitops.h>
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#include <linux/clk.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/math64.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/types.h>
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#include <linux/uaccess.h>
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#include <linux/watchdog.h>
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/* default timeout in seconds */
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#define DEFAULT_TIMEOUT 60
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#define MODULE_NAME "sp805-wdt"
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/* watchdog register offsets and masks */
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#define WDTLOAD 0x000
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#define LOAD_MIN 0x00000001
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#define LOAD_MAX 0xFFFFFFFF
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#define WDTVALUE 0x004
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#define WDTCONTROL 0x008
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/* control register masks */
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#define INT_ENABLE (1 << 0)
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#define RESET_ENABLE (1 << 1)
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#define WDTINTCLR 0x00C
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#define WDTRIS 0x010
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#define WDTMIS 0x014
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#define INT_MASK (1 << 0)
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#define WDTLOCK 0xC00
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#define UNLOCK 0x1ACCE551
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#define LOCK 0x00000001
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/**
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* struct sp805_wdt: sp805 wdt device structure
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*
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* lock: spin lock protecting dev structure and io access
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* base: base address of wdt
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* clk: clock structure of wdt
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* dev: amba device structure of wdt
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* status: current status of wdt
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* load_val: load value to be set for current timeout
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* timeout: current programmed timeout
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*/
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struct sp805_wdt {
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spinlock_t lock;
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void __iomem *base;
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struct clk *clk;
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struct amba_device *adev;
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unsigned long status;
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#define WDT_BUSY 0
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#define WDT_CAN_BE_CLOSED 1
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unsigned int load_val;
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unsigned int timeout;
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};
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/* local variables */
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static struct sp805_wdt *wdt;
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static int nowayout = WATCHDOG_NOWAYOUT;
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/* This routine finds load value that will reset system in required timout */
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static void wdt_setload(unsigned int timeout)
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{
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u64 load, rate;
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rate = clk_get_rate(wdt->clk);
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/*
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* sp805 runs counter with given value twice, after the end of first
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* counter it gives an interrupt and then starts counter again. If
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* interrupt already occured then it resets the system. This is why
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* load is half of what should be required.
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*/
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load = div_u64(rate, 2) * timeout - 1;
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load = (load > LOAD_MAX) ? LOAD_MAX : load;
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load = (load < LOAD_MIN) ? LOAD_MIN : load;
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spin_lock(&wdt->lock);
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wdt->load_val = load;
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/* roundup timeout to closest positive integer value */
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wdt->timeout = div_u64((load + 1) * 2 + (rate / 2), rate);
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spin_unlock(&wdt->lock);
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}
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/* returns number of seconds left for reset to occur */
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static u32 wdt_timeleft(void)
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{
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u64 load, rate;
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rate = clk_get_rate(wdt->clk);
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spin_lock(&wdt->lock);
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load = readl(wdt->base + WDTVALUE);
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/*If the interrupt is inactive then time left is WDTValue + WDTLoad. */
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if (!(readl(wdt->base + WDTRIS) & INT_MASK))
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load += wdt->load_val + 1;
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spin_unlock(&wdt->lock);
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return div_u64(load, rate);
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}
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/* enables watchdog timers reset */
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static void wdt_enable(void)
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{
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spin_lock(&wdt->lock);
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writel(UNLOCK, wdt->base + WDTLOCK);
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writel(wdt->load_val, wdt->base + WDTLOAD);
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writel(INT_MASK, wdt->base + WDTINTCLR);
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writel(INT_ENABLE | RESET_ENABLE, wdt->base + WDTCONTROL);
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writel(LOCK, wdt->base + WDTLOCK);
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spin_unlock(&wdt->lock);
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}
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/* disables watchdog timers reset */
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static void wdt_disable(void)
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{
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spin_lock(&wdt->lock);
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writel(UNLOCK, wdt->base + WDTLOCK);
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writel(0, wdt->base + WDTCONTROL);
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writel(0, wdt->base + WDTLOAD);
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writel(LOCK, wdt->base + WDTLOCK);
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spin_unlock(&wdt->lock);
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}
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static ssize_t sp805_wdt_write(struct file *file, const char *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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clear_bit(WDT_CAN_BE_CLOSED, &wdt->status);
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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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/* Check for Magic Close character */
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if (c == 'V') {
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set_bit(WDT_CAN_BE_CLOSED,
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&wdt->status);
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break;
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}
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}
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}
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wdt_enable();
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}
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return len;
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}
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static const struct watchdog_info ident = {
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.options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
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.identity = MODULE_NAME,
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};
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static long sp805_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int ret = -ENOTTY;
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unsigned int timeout;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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ret = copy_to_user((struct watchdog_info *)arg, &ident,
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sizeof(ident)) ? -EFAULT : 0;
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break;
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case WDIOC_GETSTATUS:
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ret = put_user(0, (int *)arg);
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break;
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case WDIOC_KEEPALIVE:
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wdt_enable();
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ret = 0;
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break;
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case WDIOC_SETTIMEOUT:
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ret = get_user(timeout, (unsigned int *)arg);
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if (ret)
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break;
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wdt_setload(timeout);
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wdt_enable();
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/* Fall through */
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case WDIOC_GETTIMEOUT:
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ret = put_user(wdt->timeout, (unsigned int *)arg);
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break;
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case WDIOC_GETTIMELEFT:
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ret = put_user(wdt_timeleft(), (unsigned int *)arg);
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break;
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}
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return ret;
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}
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static int sp805_wdt_open(struct inode *inode, struct file *file)
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{
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int ret = 0;
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if (test_and_set_bit(WDT_BUSY, &wdt->status))
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return -EBUSY;
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ret = clk_enable(wdt->clk);
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if (ret) {
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dev_err(&wdt->adev->dev, "clock enable fail");
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goto err;
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}
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wdt_enable();
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/* can not be closed, once enabled */
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clear_bit(WDT_CAN_BE_CLOSED, &wdt->status);
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return nonseekable_open(inode, file);
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err:
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clear_bit(WDT_BUSY, &wdt->status);
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return ret;
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}
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static int sp805_wdt_release(struct inode *inode, struct file *file)
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{
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if (!test_bit(WDT_CAN_BE_CLOSED, &wdt->status)) {
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clear_bit(WDT_BUSY, &wdt->status);
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dev_warn(&wdt->adev->dev, "Device closed unexpectedly\n");
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return 0;
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}
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wdt_disable();
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clk_disable(wdt->clk);
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clear_bit(WDT_BUSY, &wdt->status);
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return 0;
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}
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static const struct file_operations sp805_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = sp805_wdt_write,
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.unlocked_ioctl = sp805_wdt_ioctl,
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.open = sp805_wdt_open,
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.release = sp805_wdt_release,
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};
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static struct miscdevice sp805_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &sp805_wdt_fops,
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};
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static int __devinit
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sp805_wdt_probe(struct amba_device *adev, struct amba_id *id)
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{
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int ret = 0;
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if (!request_mem_region(adev->res.start, resource_size(&adev->res),
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"sp805_wdt")) {
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dev_warn(&adev->dev, "Failed to get memory region resource\n");
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ret = -ENOENT;
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goto err;
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}
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wdt = kzalloc(sizeof(*wdt), GFP_KERNEL);
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if (!wdt) {
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dev_warn(&adev->dev, "Kzalloc failed\n");
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ret = -ENOMEM;
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goto err_kzalloc;
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}
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wdt->clk = clk_get(&adev->dev, NULL);
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if (IS_ERR(wdt->clk)) {
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dev_warn(&adev->dev, "Clock not found\n");
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ret = PTR_ERR(wdt->clk);
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goto err_clk_get;
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}
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wdt->base = ioremap(adev->res.start, resource_size(&adev->res));
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if (!wdt->base) {
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ret = -ENOMEM;
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dev_warn(&adev->dev, "ioremap fail\n");
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goto err_ioremap;
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}
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wdt->adev = adev;
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spin_lock_init(&wdt->lock);
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wdt_setload(DEFAULT_TIMEOUT);
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ret = misc_register(&sp805_wdt_miscdev);
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if (ret < 0) {
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dev_warn(&adev->dev, "cannot register misc device\n");
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goto err_misc_register;
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}
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dev_info(&adev->dev, "registration successful\n");
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return 0;
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err_misc_register:
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iounmap(wdt->base);
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err_ioremap:
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clk_put(wdt->clk);
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err_clk_get:
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kfree(wdt);
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wdt = NULL;
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err_kzalloc:
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release_mem_region(adev->res.start, resource_size(&adev->res));
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err:
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dev_err(&adev->dev, "Probe Failed!!!\n");
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return ret;
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}
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static int __devexit sp805_wdt_remove(struct amba_device *adev)
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{
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misc_deregister(&sp805_wdt_miscdev);
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iounmap(wdt->base);
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clk_put(wdt->clk);
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kfree(wdt);
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release_mem_region(adev->res.start, resource_size(&adev->res));
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return 0;
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}
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static struct amba_id sp805_wdt_ids[] __initdata = {
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{
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.id = 0x00141805,
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.mask = 0x00ffffff,
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},
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{ 0, 0 },
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};
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static struct amba_driver sp805_wdt_driver = {
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.drv = {
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.name = MODULE_NAME,
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},
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.id_table = sp805_wdt_ids,
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.probe = sp805_wdt_probe,
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.remove = __devexit_p(sp805_wdt_remove),
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};
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static int __init sp805_wdt_init(void)
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{
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return amba_driver_register(&sp805_wdt_driver);
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}
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module_init(sp805_wdt_init);
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static void __exit sp805_wdt_exit(void)
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{
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amba_driver_unregister(&sp805_wdt_driver);
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}
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module_exit(sp805_wdt_exit);
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module_param(nowayout, int, 0);
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MODULE_PARM_DESC(nowayout,
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"Set to 1 to keep watchdog running after device release");
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MODULE_AUTHOR("Viresh Kumar <viresh.kumar@st.com>");
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MODULE_DESCRIPTION("ARM SP805 Watchdog Driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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