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354 lines
7.6 KiB
354 lines
7.6 KiB
/*
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* Copyright (C) 2008-2009 Avionic Design GmbH
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/fs.h>
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#include <linux/io.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/platform_device.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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#define WATCHDOG_NAME "adx-wdt"
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/* register offsets */
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#define ADX_WDT_CONTROL 0x00
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#define ADX_WDT_CONTROL_ENABLE (1 << 0)
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#define ADX_WDT_CONTROL_nRESET (1 << 1)
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#define ADX_WDT_TIMEOUT 0x08
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static struct platform_device *adx_wdt_dev;
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static unsigned long driver_open;
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#define WDT_STATE_STOP 0
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#define WDT_STATE_START 1
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struct adx_wdt {
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void __iomem *base;
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unsigned long timeout;
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unsigned int state;
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unsigned int wake;
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spinlock_t lock;
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};
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static struct watchdog_info adx_wdt_info = {
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.identity = "Avionic Design Xanthos Watchdog",
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
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};
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static void adx_wdt_start_locked(struct adx_wdt *wdt)
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{
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u32 ctrl;
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ctrl = readl(wdt->base + ADX_WDT_CONTROL);
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ctrl |= ADX_WDT_CONTROL_ENABLE;
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writel(ctrl, wdt->base + ADX_WDT_CONTROL);
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wdt->state = WDT_STATE_START;
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}
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static void adx_wdt_start(struct adx_wdt *wdt)
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{
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unsigned long flags;
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spin_lock_irqsave(&wdt->lock, flags);
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adx_wdt_start_locked(wdt);
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spin_unlock_irqrestore(&wdt->lock, flags);
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}
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static void adx_wdt_stop_locked(struct adx_wdt *wdt)
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{
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u32 ctrl;
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ctrl = readl(wdt->base + ADX_WDT_CONTROL);
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ctrl &= ~ADX_WDT_CONTROL_ENABLE;
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writel(ctrl, wdt->base + ADX_WDT_CONTROL);
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wdt->state = WDT_STATE_STOP;
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}
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static void adx_wdt_stop(struct adx_wdt *wdt)
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{
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unsigned long flags;
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spin_lock_irqsave(&wdt->lock, flags);
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adx_wdt_stop_locked(wdt);
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spin_unlock_irqrestore(&wdt->lock, flags);
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}
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static void adx_wdt_set_timeout(struct adx_wdt *wdt, unsigned long seconds)
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{
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unsigned long timeout = seconds * 1000;
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unsigned long flags;
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unsigned int state;
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spin_lock_irqsave(&wdt->lock, flags);
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state = wdt->state;
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adx_wdt_stop_locked(wdt);
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writel(timeout, wdt->base + ADX_WDT_TIMEOUT);
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if (state == WDT_STATE_START)
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adx_wdt_start_locked(wdt);
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wdt->timeout = timeout;
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spin_unlock_irqrestore(&wdt->lock, flags);
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}
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static void adx_wdt_get_timeout(struct adx_wdt *wdt, unsigned long *seconds)
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{
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*seconds = wdt->timeout / 1000;
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}
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static void adx_wdt_keepalive(struct adx_wdt *wdt)
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{
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unsigned long flags;
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spin_lock_irqsave(&wdt->lock, flags);
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writel(wdt->timeout, wdt->base + ADX_WDT_TIMEOUT);
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spin_unlock_irqrestore(&wdt->lock, flags);
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}
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static int adx_wdt_open(struct inode *inode, struct file *file)
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{
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struct adx_wdt *wdt = platform_get_drvdata(adx_wdt_dev);
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if (test_and_set_bit(0, &driver_open))
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return -EBUSY;
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file->private_data = wdt;
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adx_wdt_set_timeout(wdt, 30);
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adx_wdt_start(wdt);
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return nonseekable_open(inode, file);
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}
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static int adx_wdt_release(struct inode *inode, struct file *file)
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{
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struct adx_wdt *wdt = file->private_data;
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adx_wdt_stop(wdt);
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clear_bit(0, &driver_open);
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return 0;
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}
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static long adx_wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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struct adx_wdt *wdt = file->private_data;
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void __user *argp = (void __user *)arg;
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unsigned long __user *p = argp;
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unsigned long seconds = 0;
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unsigned int options;
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long ret = -EINVAL;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &adx_wdt_info, sizeof(adx_wdt_info)))
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return -EFAULT;
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else
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return 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0, p);
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case WDIOC_KEEPALIVE:
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adx_wdt_keepalive(wdt);
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(seconds, p))
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return -EFAULT;
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adx_wdt_set_timeout(wdt, seconds);
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/* fallthrough */
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case WDIOC_GETTIMEOUT:
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adx_wdt_get_timeout(wdt, &seconds);
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return put_user(seconds, p);
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case WDIOC_SETOPTIONS:
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if (copy_from_user(&options, argp, sizeof(options)))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD) {
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adx_wdt_stop(wdt);
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ret = 0;
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}
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if (options & WDIOS_ENABLECARD) {
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adx_wdt_start(wdt);
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ret = 0;
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}
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return ret;
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default:
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break;
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}
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return -ENOTTY;
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}
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static ssize_t adx_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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struct adx_wdt *wdt = file->private_data;
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if (len)
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adx_wdt_keepalive(wdt);
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return len;
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}
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static const struct file_operations adx_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.open = adx_wdt_open,
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.release = adx_wdt_release,
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.unlocked_ioctl = adx_wdt_ioctl,
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.write = adx_wdt_write,
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};
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static struct miscdevice adx_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &adx_wdt_fops,
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};
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static int __devinit adx_wdt_probe(struct platform_device *pdev)
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{
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struct resource *res;
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struct adx_wdt *wdt;
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int ret = 0;
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u32 ctrl;
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wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
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if (!wdt) {
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dev_err(&pdev->dev, "cannot allocate WDT structure\n");
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return -ENOMEM;
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}
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spin_lock_init(&wdt->lock);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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dev_err(&pdev->dev, "cannot obtain I/O memory region\n");
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return -ENXIO;
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}
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res = devm_request_mem_region(&pdev->dev, res->start,
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res->end - res->start + 1, res->name);
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if (!res) {
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dev_err(&pdev->dev, "cannot request I/O memory region\n");
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return -ENXIO;
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}
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wdt->base = devm_ioremap_nocache(&pdev->dev, res->start,
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res->end - res->start + 1);
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if (!wdt->base) {
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dev_err(&pdev->dev, "cannot remap I/O memory region\n");
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return -ENXIO;
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}
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/* disable watchdog and reboot on timeout */
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ctrl = readl(wdt->base + ADX_WDT_CONTROL);
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ctrl &= ~ADX_WDT_CONTROL_ENABLE;
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ctrl &= ~ADX_WDT_CONTROL_nRESET;
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writel(ctrl, wdt->base + ADX_WDT_CONTROL);
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platform_set_drvdata(pdev, wdt);
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adx_wdt_dev = pdev;
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ret = misc_register(&adx_wdt_miscdev);
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if (ret) {
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dev_err(&pdev->dev, "cannot register miscdev on minor %d "
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"(err=%d)\n", WATCHDOG_MINOR, ret);
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return ret;
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}
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return 0;
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}
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static int __devexit adx_wdt_remove(struct platform_device *pdev)
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{
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struct adx_wdt *wdt = platform_get_drvdata(pdev);
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misc_deregister(&adx_wdt_miscdev);
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adx_wdt_stop(wdt);
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platform_set_drvdata(pdev, NULL);
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return 0;
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}
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static void adx_wdt_shutdown(struct platform_device *pdev)
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{
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struct adx_wdt *wdt = platform_get_drvdata(pdev);
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adx_wdt_stop(wdt);
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}
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#ifdef CONFIG_PM
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static int adx_wdt_suspend(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct adx_wdt *wdt = platform_get_drvdata(pdev);
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wdt->wake = (wdt->state == WDT_STATE_START) ? 1 : 0;
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adx_wdt_stop(wdt);
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return 0;
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}
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static int adx_wdt_resume(struct device *dev)
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{
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struct platform_device *pdev = to_platform_device(dev);
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struct adx_wdt *wdt = platform_get_drvdata(pdev);
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if (wdt->wake)
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adx_wdt_start(wdt);
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return 0;
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}
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static const struct dev_pm_ops adx_wdt_pm_ops = {
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.suspend = adx_wdt_suspend,
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.resume = adx_wdt_resume,
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};
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# define ADX_WDT_PM_OPS (&adx_wdt_pm_ops)
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#else
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# define ADX_WDT_PM_OPS NULL
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#endif
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static struct platform_driver adx_wdt_driver = {
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.probe = adx_wdt_probe,
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.remove = __devexit_p(adx_wdt_remove),
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.shutdown = adx_wdt_shutdown,
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.driver = {
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.name = WATCHDOG_NAME,
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.owner = THIS_MODULE,
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.pm = ADX_WDT_PM_OPS,
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},
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};
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static int __init adx_wdt_init(void)
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{
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return platform_driver_register(&adx_wdt_driver);
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}
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static void __exit adx_wdt_exit(void)
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{
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platform_driver_unregister(&adx_wdt_driver);
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}
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module_init(adx_wdt_init);
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module_exit(adx_wdt_exit);
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MODULE_DESCRIPTION("Avionic Design Xanthos Watchdog Driver");
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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