316 lines
7.4 KiB
C
316 lines
7.4 KiB
C
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/*
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* Copyright (C) 2010, Paul Cercueil <paul@crapouillou.net>
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* JZ4740 Watchdog driver
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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 as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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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/kernel.h>
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#include <linux/fs.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/init.h>
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#include <linux/bitops.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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#include <linux/device.h>
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#include <linux/clk.h>
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#include <linux/slab.h>
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#include <asm/mach-jz4740/timer.h>
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#define JZ_REG_WDT_TIMER_DATA 0x0
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#define JZ_REG_WDT_COUNTER_ENABLE 0x4
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#define JZ_REG_WDT_TIMER_COUNTER 0x8
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#define JZ_REG_WDT_TIMER_CONTROL 0xC
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#define JZ_WDT_CLOCK_PCLK 0x1
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#define JZ_WDT_CLOCK_RTC 0x2
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#define JZ_WDT_CLOCK_EXT 0x4
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#define WDT_IN_USE 0
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#define WDT_OK_TO_CLOSE 1
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#define JZ_WDT_CLOCK_DIV_SHIFT 3
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#define JZ_WDT_CLOCK_DIV_1 (0 << JZ_WDT_CLOCK_DIV_SHIFT)
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#define JZ_WDT_CLOCK_DIV_4 (1 << JZ_WDT_CLOCK_DIV_SHIFT)
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#define JZ_WDT_CLOCK_DIV_16 (2 << JZ_WDT_CLOCK_DIV_SHIFT)
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#define JZ_WDT_CLOCK_DIV_64 (3 << JZ_WDT_CLOCK_DIV_SHIFT)
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#define JZ_WDT_CLOCK_DIV_256 (4 << JZ_WDT_CLOCK_DIV_SHIFT)
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#define JZ_WDT_CLOCK_DIV_1024 (5 << JZ_WDT_CLOCK_DIV_SHIFT)
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#define DEFAULT_HEARTBEAT 5
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#define MAX_HEARTBEAT 2048
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static struct {
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void __iomem *base;
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struct resource *mem;
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struct clk *rtc_clk;
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unsigned long status;
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} jz4740_wdt;
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static int heartbeat = DEFAULT_HEARTBEAT;
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static void jz4740_wdt_service(void)
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{
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writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
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}
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static void jz4740_wdt_set_heartbeat(int new_heartbeat)
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{
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unsigned int rtc_clk_rate;
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unsigned int timeout_value;
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unsigned short clock_div = JZ_WDT_CLOCK_DIV_1;
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heartbeat = new_heartbeat;
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rtc_clk_rate = clk_get_rate(jz4740_wdt.rtc_clk);
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timeout_value = rtc_clk_rate * heartbeat;
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while (timeout_value > 0xffff) {
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if (clock_div == JZ_WDT_CLOCK_DIV_1024) {
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/* Requested timeout too high;
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* use highest possible value. */
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timeout_value = 0xffff;
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break;
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}
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timeout_value >>= 2;
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clock_div += (1 << JZ_WDT_CLOCK_DIV_SHIFT);
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}
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writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
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writew(clock_div, jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);
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writew((u16)timeout_value, jz4740_wdt.base + JZ_REG_WDT_TIMER_DATA);
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writew(0x0, jz4740_wdt.base + JZ_REG_WDT_TIMER_COUNTER);
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writew(clock_div | JZ_WDT_CLOCK_RTC,
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jz4740_wdt.base + JZ_REG_WDT_TIMER_CONTROL);
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writeb(0x1, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
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}
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static void jz4740_wdt_enable(void)
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{
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jz4740_timer_enable_watchdog();
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jz4740_wdt_set_heartbeat(heartbeat);
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}
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static void jz4740_wdt_disable(void)
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{
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jz4740_timer_disable_watchdog();
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writeb(0x0, jz4740_wdt.base + JZ_REG_WDT_COUNTER_ENABLE);
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}
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static int jz4740_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(WDT_IN_USE, &jz4740_wdt.status))
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return -EBUSY;
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jz4740_wdt_enable();
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return nonseekable_open(inode, file);
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}
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static ssize_t jz4740_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 (data[len-1] == 'V')
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set_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
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else
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clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status);
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jz4740_wdt_service();
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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_KEEPALIVEPING,
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.identity = "jz4740 Watchdog",
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};
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static long jz4740_wdt_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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int ret = -ENOTTY;
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int heartbeat_seconds;
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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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case WDIOC_GETBOOTSTATUS:
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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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jz4740_wdt_service();
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(heartbeat_seconds, (int __user *)arg))
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return -EFAULT;
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jz4740_wdt_set_heartbeat(heartbeat_seconds);
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return 0;
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case WDIOC_GETTIMEOUT:
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return put_user(heartbeat, (int *)arg);
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default:
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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 jz4740_wdt_release(struct inode *inode, struct file *file)
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{
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jz4740_wdt_service();
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if (test_and_clear_bit(WDT_OK_TO_CLOSE, &jz4740_wdt.status))
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jz4740_wdt_disable();
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clear_bit(WDT_IN_USE, &jz4740_wdt.status);
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return 0;
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}
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static const struct file_operations jz4740_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = jz4740_wdt_write,
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.unlocked_ioctl = jz4740_wdt_ioctl,
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.open = jz4740_wdt_open,
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.release = jz4740_wdt_release,
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};
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static struct miscdevice jz4740_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &jz4740_wdt_fops,
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};
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static int __devinit jz4740_wdt_probe(struct platform_device *pdev)
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{
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int ret = 0, size;
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struct resource *res;
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struct device *dev = &pdev->dev;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (res == NULL) {
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dev_err(dev, "failed to get memory region resource\n");
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return -ENXIO;
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}
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size = resource_size(res);
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jz4740_wdt.mem = request_mem_region(res->start, size, pdev->name);
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if (jz4740_wdt.mem == NULL) {
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dev_err(dev, "failed to get memory region\n");
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return -EBUSY;
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}
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jz4740_wdt.base = ioremap_nocache(res->start, size);
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if (jz4740_wdt.base == NULL) {
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dev_err(dev, "failed to map memory region\n");
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ret = -EBUSY;
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goto err_release_region;
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}
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jz4740_wdt.rtc_clk = clk_get(NULL, "rtc");
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if (IS_ERR(jz4740_wdt.rtc_clk)) {
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dev_err(dev, "cannot find RTC clock\n");
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ret = PTR_ERR(jz4740_wdt.rtc_clk);
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goto err_iounmap;
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}
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ret = misc_register(&jz4740_wdt_miscdev);
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if (ret < 0) {
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dev_err(dev, "cannot register misc device\n");
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goto err_disable_clk;
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}
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return 0;
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err_disable_clk:
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clk_put(jz4740_wdt.rtc_clk);
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err_iounmap:
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iounmap(jz4740_wdt.base);
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err_release_region:
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release_mem_region(jz4740_wdt.mem->start,
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resource_size(jz4740_wdt.mem));
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return ret;
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}
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static int __devexit jz4740_wdt_remove(struct platform_device *pdev)
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{
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jz4740_wdt_disable();
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misc_deregister(&jz4740_wdt_miscdev);
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clk_put(jz4740_wdt.rtc_clk);
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iounmap(jz4740_wdt.base);
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jz4740_wdt.base = NULL;
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release_mem_region(jz4740_wdt.mem->start,
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resource_size(jz4740_wdt.mem));
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jz4740_wdt.mem = NULL;
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return 0;
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}
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static struct platform_driver jz4740_wdt_driver = {
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.probe = jz4740_wdt_probe,
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.remove = __devexit_p(jz4740_wdt_remove),
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.driver = {
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.name = "jz4740-wdt",
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.owner = THIS_MODULE,
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},
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};
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static int __init jz4740_wdt_init(void)
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{
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return platform_driver_register(&jz4740_wdt_driver);
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}
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module_init(jz4740_wdt_init);
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static void __exit jz4740_wdt_exit(void)
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{
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platform_driver_unregister(&jz4740_wdt_driver);
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}
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module_exit(jz4740_wdt_exit);
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MODULE_AUTHOR("Paul Cercueil <paul@crapouillou.net>");
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MODULE_DESCRIPTION("jz4740 Watchdog Driver");
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat,
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"Watchdog heartbeat period in seconds from 1 to "
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__MODULE_STRING(MAX_HEARTBEAT) ", default "
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__MODULE_STRING(DEFAULT_HEARTBEAT));
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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MODULE_ALIAS("platform:jz4740-wdt");
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