mirror of
git://projects.qi-hardware.com/openwrt-xburst.git
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356 lines
7.9 KiB
C
356 lines
7.9 KiB
C
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/*
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* Ralink RT288X/RT305X built-in hardware watchdog timer
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*
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* Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
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*
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* This driver was based on: drivers/watchdog/ixp4xx_wdt.c
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* Author: Deepak Saxena <dsaxena@plexity.net>
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* Copyright 2004 (c) MontaVista, Software, Inc.
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*
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* which again was based on sa1100 driver,
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* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
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*
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* parts of the driver are based on Ralink's 2.6.21 BSP
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published
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* by the Free Software Foundation.
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*/
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#include <linux/bitops.h>
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#include <linux/errno.h>
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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/moduleparam.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include <linux/watchdog.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#define DRIVER_NAME "ramips-wdt"
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#define RAMIPS_WDT_TIMEOUT 20 /* seconds */
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#define RAMIPS_WDT_PRESCALE 65536
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#define TIMER_REG_TMRSTAT 0x00
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#define TIMER_REG_TMR1LOAD 0x20
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#define TIMER_REG_TMR1CTL 0x28
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#define TMRSTAT_TMR1RST BIT(5)
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#define TMR1CTL_ENABLE BIT(7)
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#define TMR1CTL_MODE_SHIFT 4
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#define TMR1CTL_MODE_MASK 0x3
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#define TMR1CTL_MODE_FREE_RUNNING 0x0
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#define TMR1CTL_MODE_PERIODIC 0x1
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#define TMR1CTL_MODE_TIMEOUT 0x2
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#define TMR1CTL_MODE_WDT 0x3
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#define TMR1CTL_PRESCALE_MASK 0xf
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#define TMR1CTL_PRESCALE_65536 0xf
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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 "
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"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int ramips_wdt_timeout = RAMIPS_WDT_TIMEOUT;
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module_param_named(timeout, ramips_wdt_timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
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"(default=" __MODULE_STRING(RAMIPS_WDT_TIMEOUT) "s)");
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static unsigned long ramips_wdt_flags;
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#define WDT_FLAGS_BUSY 0
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#define WDT_FLAGS_EXPECT_CLOSE 1
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static struct clk *ramips_wdt_clk;
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static unsigned long ramips_wdt_freq;
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static int ramips_wdt_max_timeout;
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static void __iomem *ramips_wdt_base;
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static inline void ramips_wdt_wr(unsigned reg, u32 val)
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{
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__raw_writel(val, ramips_wdt_base + reg);
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}
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static inline u32 ramips_wdt_rr(unsigned reg)
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{
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return __raw_readl(ramips_wdt_base + reg);
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}
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static inline void ramips_wdt_keepalive(void)
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{
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ramips_wdt_wr(TIMER_REG_TMR1LOAD, ramips_wdt_timeout * ramips_wdt_freq);
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}
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static inline void ramips_wdt_enable(void)
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{
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u32 t;
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ramips_wdt_keepalive();
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t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
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t |= TMR1CTL_ENABLE;
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ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
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}
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static inline void ramips_wdt_disable(void)
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{
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u32 t;
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ramips_wdt_keepalive();
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t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
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t &= ~TMR1CTL_ENABLE;
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ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
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}
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static int ramips_wdt_set_timeout(int val)
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{
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if (val < 1 || val > ramips_wdt_max_timeout) {
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pr_crit(DRIVER_NAME
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": timeout value %d must be 0 < timeout < %d\n",
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val, ramips_wdt_max_timeout);
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return -EINVAL;
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}
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ramips_wdt_timeout = val;
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ramips_wdt_keepalive();
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return 0;
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}
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static int ramips_wdt_open(struct inode *inode, struct file *file)
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{
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u32 t;
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if (test_and_set_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags))
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return -EBUSY;
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clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
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t = ramips_wdt_rr(TIMER_REG_TMR1CTL);
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t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |
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TMR1CTL_PRESCALE_MASK);
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t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |
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TMR1CTL_PRESCALE_65536);
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ramips_wdt_wr(TIMER_REG_TMR1CTL, t);
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ramips_wdt_enable();
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return nonseekable_open(inode, file);
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}
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static int ramips_wdt_release(struct inode *inode, struct file *file)
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{
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if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags))
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ramips_wdt_disable();
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else {
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pr_crit(DRIVER_NAME ": device closed unexpectedly, "
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"watchdog timer will not stop!\n");
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ramips_wdt_keepalive();
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}
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clear_bit(WDT_FLAGS_BUSY, &ramips_wdt_flags);
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clear_bit(WDT_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
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return 0;
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}
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static ssize_t ramips_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_FLAGS_EXPECT_CLOSE, &ramips_wdt_flags);
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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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set_bit(WDT_FLAGS_EXPECT_CLOSE,
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&ramips_wdt_flags);
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}
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}
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ramips_wdt_keepalive();
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}
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return len;
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}
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static const struct watchdog_info ramips_wdt_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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.firmware_version = 0,
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.identity = "RAMIPS watchdog",
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};
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static long ramips_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int err;
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int t;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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err = copy_to_user(argp, &ramips_wdt_info,
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sizeof(ramips_wdt_info)) ? -EFAULT : 0;
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break;
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case WDIOC_GETSTATUS:
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err = put_user(0, p);
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break;
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case WDIOC_KEEPALIVE:
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ramips_wdt_keepalive();
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err = 0;
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break;
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case WDIOC_SETTIMEOUT:
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err = get_user(t, p);
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if (err)
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break;
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err = ramips_wdt_set_timeout(t);
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if (err)
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break;
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/* fallthrough */
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case WDIOC_GETTIMEOUT:
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err = put_user(ramips_wdt_timeout, p);
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break;
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default:
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err = -ENOTTY;
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break;
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}
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return err;
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}
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static const struct file_operations ramips_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = ramips_wdt_write,
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.unlocked_ioctl = ramips_wdt_ioctl,
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.open = ramips_wdt_open,
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.release = ramips_wdt_release,
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};
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static struct miscdevice ramips_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &ramips_wdt_fops,
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};
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static int __devinit ramips_wdt_probe(struct platform_device *pdev)
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{
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struct resource *res;
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int err;
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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, "no memory resource found\n");
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return -EINVAL;
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}
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ramips_wdt_base = ioremap(res->start, resource_size(res));
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if (!ramips_wdt_base)
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return -ENOMEM;
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ramips_wdt_clk = clk_get(&pdev->dev, "wdt");
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if (IS_ERR(ramips_wdt_clk)) {
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err = PTR_ERR(ramips_wdt_clk);
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goto err_unmap;
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}
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err = clk_enable(ramips_wdt_clk);
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if (err)
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goto err_clk_put;
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ramips_wdt_freq = clk_get_rate(ramips_wdt_clk) / RAMIPS_WDT_PRESCALE;
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if (!ramips_wdt_freq) {
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err = -EINVAL;
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goto err_clk_disable;
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}
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ramips_wdt_max_timeout = (0xfffful / ramips_wdt_freq);
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if (ramips_wdt_timeout < 1 ||
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ramips_wdt_timeout > ramips_wdt_max_timeout) {
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ramips_wdt_timeout = ramips_wdt_max_timeout;
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dev_info(&pdev->dev,
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"timeout value must be 0 < timeout < %d, using %d\n",
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ramips_wdt_max_timeout, ramips_wdt_timeout);
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}
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err = misc_register(&ramips_wdt_miscdev);
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if (err) {
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dev_err(&pdev->dev,
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"unable to register misc device, err=%d\n", err);
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goto err_clk_disable;
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}
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return 0;
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err_clk_disable:
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clk_disable(ramips_wdt_clk);
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err_clk_put:
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clk_put(ramips_wdt_clk);
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err_unmap:
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iounmap(ramips_wdt_base);
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return err;
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}
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static int __devexit ramips_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&ramips_wdt_miscdev);
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clk_disable(ramips_wdt_clk);
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clk_put(ramips_wdt_clk);
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iounmap(ramips_wdt_base);
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return 0;
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}
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static void ramips_wdt_shutdown(struct platform_device *pdev)
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{
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ramips_wdt_disable();
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}
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static struct platform_driver ramips_wdt_driver = {
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.remove = __devexit_p(ramips_wdt_remove),
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.shutdown = ramips_wdt_shutdown,
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.driver = {
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.name = DRIVER_NAME,
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.owner = THIS_MODULE,
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},
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};
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static int __init ramips_wdt_init(void)
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{
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return platform_driver_probe(&ramips_wdt_driver, ramips_wdt_probe);
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}
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module_init(ramips_wdt_init);
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static void __exit ramips_wdt_exit(void)
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{
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platform_driver_unregister(&ramips_wdt_driver);
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}
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module_exit(ramips_wdt_exit);
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MODULE_DESCRIPTION("Ralink RT288X/RT305X hardware watchdog driver");
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MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("platform:" DRIVER_NAME);
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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