0b6dd8a640
Cleanup the s3c2410_wdt driver's exit point by using labels instead of multiple returns. Also remove the checks for the resources having been allocate in the exit, as we will now either have fully allocated or not allocated the resources at-all. Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
549 lines
12 KiB
C
549 lines
12 KiB
C
/* linux/drivers/char/watchdog/s3c2410_wdt.c
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*
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* Copyright (c) 2004 Simtec Electronics
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* Ben Dooks <ben@simtec.co.uk>
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*
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* S3C2410 Watchdog Timer Support
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*
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* Based on, softdog.c by Alan Cox,
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* (c) Copyright 1996 Alan Cox <alan@redhat.com>
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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 as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Changelog:
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* 05-Oct-2004 BJD Added semaphore init to stop crashes on open
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* Fixed tmr_count / wdt_count confusion
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* Added configurable debug
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*
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* 11-Jan-2005 BJD Fixed divide-by-2 in timeout code
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*
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* 25-Jan-2005 DA Added suspend/resume support
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* Replaced reboot notifier with .shutdown method
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*
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* 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA
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*/
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/types.h>
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#include <linux/timer.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/interrupt.h>
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#include <linux/clk.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#include <asm/arch/map.h>
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#undef S3C24XX_VA_WATCHDOG
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#define S3C24XX_VA_WATCHDOG (0)
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#include <asm/arch/regs-watchdog.h>
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#define PFX "s3c2410-wdt: "
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#define CONFIG_S3C2410_WATCHDOG_ATBOOT (0)
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#define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15)
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static int nowayout = WATCHDOG_NOWAYOUT;
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static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME;
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static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT;
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static int soft_noboot = 0;
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static int debug = 0;
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module_param(tmr_margin, int, 0);
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module_param(tmr_atboot, int, 0);
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module_param(nowayout, int, 0);
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module_param(soft_noboot, int, 0);
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module_param(debug, int, 0);
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MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")");
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MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT));
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
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MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)");
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MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)");
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typedef enum close_state {
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CLOSE_STATE_NOT,
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CLOSE_STATE_ALLOW=0x4021
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} close_state_t;
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static DECLARE_MUTEX(open_lock);
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static struct resource *wdt_mem;
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static struct resource *wdt_irq;
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static struct clk *wdt_clock;
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static void __iomem *wdt_base;
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static unsigned int wdt_count;
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static close_state_t allow_close;
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/* watchdog control routines */
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#define DBG(msg...) do { \
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if (debug) \
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printk(KERN_INFO msg); \
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} while(0)
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/* functions */
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static int s3c2410wdt_keepalive(void)
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{
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writel(wdt_count, wdt_base + S3C2410_WTCNT);
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return 0;
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}
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static int s3c2410wdt_stop(void)
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{
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unsigned long wtcon;
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wtcon = readl(wdt_base + S3C2410_WTCON);
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wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN);
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writel(wtcon, wdt_base + S3C2410_WTCON);
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return 0;
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}
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static int s3c2410wdt_start(void)
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{
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unsigned long wtcon;
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s3c2410wdt_stop();
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wtcon = readl(wdt_base + S3C2410_WTCON);
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wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128;
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if (soft_noboot) {
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wtcon |= S3C2410_WTCON_INTEN;
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wtcon &= ~S3C2410_WTCON_RSTEN;
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} else {
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wtcon &= ~S3C2410_WTCON_INTEN;
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wtcon |= S3C2410_WTCON_RSTEN;
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}
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DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n",
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__FUNCTION__, wdt_count, wtcon);
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writel(wdt_count, wdt_base + S3C2410_WTDAT);
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writel(wdt_count, wdt_base + S3C2410_WTCNT);
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writel(wtcon, wdt_base + S3C2410_WTCON);
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return 0;
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}
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static int s3c2410wdt_set_heartbeat(int timeout)
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{
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unsigned int freq = clk_get_rate(wdt_clock);
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unsigned int count;
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unsigned int divisor = 1;
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unsigned long wtcon;
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if (timeout < 1)
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return -EINVAL;
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freq /= 128;
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count = timeout * freq;
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DBG("%s: count=%d, timeout=%d, freq=%d\n",
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__FUNCTION__, count, timeout, freq);
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/* if the count is bigger than the watchdog register,
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then work out what we need to do (and if) we can
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actually make this value
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*/
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if (count >= 0x10000) {
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for (divisor = 1; divisor <= 0x100; divisor++) {
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if ((count / divisor) < 0x10000)
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break;
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}
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if ((count / divisor) >= 0x10000) {
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printk(KERN_ERR PFX "timeout %d too big\n", timeout);
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return -EINVAL;
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}
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}
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tmr_margin = timeout;
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DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n",
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__FUNCTION__, timeout, divisor, count, count/divisor);
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count /= divisor;
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wdt_count = count;
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/* update the pre-scaler */
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wtcon = readl(wdt_base + S3C2410_WTCON);
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wtcon &= ~S3C2410_WTCON_PRESCALE_MASK;
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wtcon |= S3C2410_WTCON_PRESCALE(divisor-1);
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writel(count, wdt_base + S3C2410_WTDAT);
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writel(wtcon, wdt_base + S3C2410_WTCON);
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return 0;
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}
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/*
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* /dev/watchdog handling
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*/
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static int s3c2410wdt_open(struct inode *inode, struct file *file)
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{
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if(down_trylock(&open_lock))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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allow_close = CLOSE_STATE_NOT;
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/* start the timer */
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s3c2410wdt_start();
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return nonseekable_open(inode, file);
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}
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static int s3c2410wdt_release(struct inode *inode, struct file *file)
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{
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/*
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* Shut off the timer.
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* Lock it in if it's a module and we set nowayout
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*/
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if (allow_close == CLOSE_STATE_ALLOW) {
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s3c2410wdt_stop();
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} else {
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printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
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s3c2410wdt_keepalive();
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}
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allow_close = CLOSE_STATE_NOT;
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up(&open_lock);
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return 0;
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}
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static ssize_t s3c2410wdt_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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/*
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* Refresh the timer.
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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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/* In case it was set long ago */
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allow_close = CLOSE_STATE_NOT;
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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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allow_close = CLOSE_STATE_ALLOW;
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}
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}
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s3c2410wdt_keepalive();
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}
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return len;
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}
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#define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE
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static struct watchdog_info s3c2410_wdt_ident = {
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.options = OPTIONS,
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.firmware_version = 0,
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.identity = "S3C2410 Watchdog",
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};
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static int s3c2410wdt_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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void __user *argp = (void __user *)arg;
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int __user *p = argp;
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int new_margin;
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switch (cmd) {
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default:
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return -ENOTTY;
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case WDIOC_GETSUPPORT:
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return copy_to_user(argp, &s3c2410_wdt_ident,
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sizeof(s3c2410_wdt_ident)) ? -EFAULT : 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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s3c2410wdt_keepalive();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, p))
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return -EFAULT;
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if (s3c2410wdt_set_heartbeat(new_margin))
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return -EINVAL;
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s3c2410wdt_keepalive();
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return put_user(tmr_margin, p);
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case WDIOC_GETTIMEOUT:
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return put_user(tmr_margin, p);
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}
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}
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/* kernel interface */
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static const struct file_operations s3c2410wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = s3c2410wdt_write,
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.ioctl = s3c2410wdt_ioctl,
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.open = s3c2410wdt_open,
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.release = s3c2410wdt_release,
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};
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static struct miscdevice s3c2410wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &s3c2410wdt_fops,
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};
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/* interrupt handler code */
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static irqreturn_t s3c2410wdt_irq(int irqno, void *param)
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{
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printk(KERN_INFO PFX "Watchdog timer expired!\n");
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s3c2410wdt_keepalive();
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return IRQ_HANDLED;
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}
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/* device interface */
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static int s3c2410wdt_probe(struct platform_device *pdev)
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{
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struct resource *res;
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int started = 0;
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int ret;
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int size;
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DBG("%s: probe=%p\n", __FUNCTION__, pdev);
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/* get the memory region for the watchdog timer */
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (res == NULL) {
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printk(KERN_INFO PFX "failed to get memory region resouce\n");
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return -ENOENT;
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}
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size = (res->end-res->start)+1;
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wdt_mem = request_mem_region(res->start, size, pdev->name);
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if (wdt_mem == NULL) {
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printk(KERN_INFO PFX "failed to get memory region\n");
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ret = -ENOENT;
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goto err_req;
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}
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wdt_base = ioremap(res->start, size);
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if (wdt_base == 0) {
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printk(KERN_INFO PFX "failed to ioremap() region\n");
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ret = -EINVAL;
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goto err_req;
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}
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DBG("probe: mapped wdt_base=%p\n", wdt_base);
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res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
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if (res == NULL) {
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printk(KERN_INFO PFX "failed to get irq resource\n");
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ret = -ENOENT;
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goto err_map;
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}
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ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, pdev);
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if (ret != 0) {
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printk(KERN_INFO PFX "failed to install irq (%d)\n", ret);
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goto err_map;
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}
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wdt_clock = clk_get(&pdev->dev, "watchdog");
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if (wdt_clock == NULL) {
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printk(KERN_INFO PFX "failed to find watchdog clock source\n");
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ret = -ENOENT;
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goto err_irq;
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}
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clk_enable(wdt_clock);
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/* see if we can actually set the requested timer margin, and if
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* not, try the default value */
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if (s3c2410wdt_set_heartbeat(tmr_margin)) {
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started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
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if (started == 0) {
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printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n",
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CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME);
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} else {
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printk(KERN_INFO PFX "default timer value is out of range, cannot start\n");
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}
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}
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ret = misc_register(&s3c2410wdt_miscdev);
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if (ret) {
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printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n",
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WATCHDOG_MINOR, ret);
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goto err_clk;
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}
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if (tmr_atboot && started == 0) {
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printk(KERN_INFO PFX "Starting Watchdog Timer\n");
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s3c2410wdt_start();
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} else if (!tmr_atboot) {
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/* if we're not enabling the watchdog, then ensure it is
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* disabled if it has been left running from the bootloader
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* or other source */
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s3c2410wdt_stop();
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}
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return 0;
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err_clk:
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clk_disable(wdt_clock);
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clk_put(wdt_clock);
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err_irq:
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free_irq(wdt_irq->start, pdev);
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err_map:
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iounmap(wdt_base);
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err_req:
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release_resource(wdt_mem);
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kfree(wdt_mem);
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return ret;
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}
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static int s3c2410wdt_remove(struct platform_device *dev)
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{
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release_resource(wdt_mem);
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kfree(wdt_mem);
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wdt_mem = NULL;
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free_irq(wdt_irq->start, dev);
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wdt_irq = NULL;
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clk_disable(wdt_clock);
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clk_put(wdt_clock);
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wdt_clock = NULL;
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iounmap(wdt_base);
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misc_deregister(&s3c2410wdt_miscdev);
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return 0;
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}
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static void s3c2410wdt_shutdown(struct platform_device *dev)
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{
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s3c2410wdt_stop();
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}
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#ifdef CONFIG_PM
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static unsigned long wtcon_save;
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static unsigned long wtdat_save;
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static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state)
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{
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/* Save watchdog state, and turn it off. */
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wtcon_save = readl(wdt_base + S3C2410_WTCON);
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wtdat_save = readl(wdt_base + S3C2410_WTDAT);
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/* Note that WTCNT doesn't need to be saved. */
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s3c2410wdt_stop();
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return 0;
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}
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static int s3c2410wdt_resume(struct platform_device *dev)
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{
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/* Restore watchdog state. */
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writel(wtdat_save, wdt_base + S3C2410_WTDAT);
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writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */
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writel(wtcon_save, wdt_base + S3C2410_WTCON);
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printk(KERN_INFO PFX "watchdog %sabled\n",
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(wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis");
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return 0;
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}
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#else
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#define s3c2410wdt_suspend NULL
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#define s3c2410wdt_resume NULL
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#endif /* CONFIG_PM */
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static struct platform_driver s3c2410wdt_driver = {
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.probe = s3c2410wdt_probe,
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.remove = s3c2410wdt_remove,
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.shutdown = s3c2410wdt_shutdown,
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.suspend = s3c2410wdt_suspend,
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.resume = s3c2410wdt_resume,
|
|
.driver = {
|
|
.owner = THIS_MODULE,
|
|
.name = "s3c2410-wdt",
|
|
},
|
|
};
|
|
|
|
|
|
static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n";
|
|
|
|
static int __init watchdog_init(void)
|
|
{
|
|
printk(banner);
|
|
return platform_driver_register(&s3c2410wdt_driver);
|
|
}
|
|
|
|
static void __exit watchdog_exit(void)
|
|
{
|
|
platform_driver_unregister(&s3c2410wdt_driver);
|
|
}
|
|
|
|
module_init(watchdog_init);
|
|
module_exit(watchdog_exit);
|
|
|
|
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, "
|
|
"Dimitry Andric <dimitry.andric@tomtom.com>");
|
|
MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver");
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|