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326 lines
7.9 KiB
326 lines
7.9 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* IDT Interprise 79RC32434 watchdog driver |
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* |
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* Copyright (C) 2006, Ondrej Zajicek <[email protected]> |
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* Copyright (C) 2008, Florian Fainelli <[email protected]> |
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* |
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* based on |
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* SoftDog 0.05: A Software Watchdog Device |
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* |
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* (c) Copyright 1996 Alan Cox <[email protected]>, |
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* All Rights Reserved. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> /* For module specific items */ |
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#include <linux/moduleparam.h> /* For new moduleparam's */ |
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#include <linux/types.h> /* For standard types (like size_t) */ |
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#include <linux/errno.h> /* For the -ENODEV/... values */ |
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#include <linux/kernel.h> /* For printk/panic/... */ |
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#include <linux/fs.h> /* For file operations */ |
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#include <linux/miscdevice.h> /* For struct miscdevice */ |
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#include <linux/watchdog.h> /* For the watchdog specific items */ |
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#include <linux/init.h> /* For __init/__exit/... */ |
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#include <linux/platform_device.h> /* For platform_driver framework */ |
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#include <linux/spinlock.h> /* For spin_lock/spin_unlock/... */ |
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#include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
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#include <linux/io.h> /* For devm_ioremap */ |
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#include <asm/mach-rc32434/integ.h> /* For the Watchdog registers */ |
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#define VERSION "1.0" |
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static struct { |
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unsigned long inuse; |
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spinlock_t io_lock; |
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} rc32434_wdt_device; |
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static struct integ __iomem *wdt_reg; |
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static int expect_close; |
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/* Board internal clock speed in Hz, |
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* the watchdog timer ticks at. */ |
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extern unsigned int idt_cpu_freq; |
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/* translate wtcompare value to seconds and vice versa */ |
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#define WTCOMP2SEC(x) (x / idt_cpu_freq) |
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#define SEC2WTCOMP(x) (x * idt_cpu_freq) |
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/* Use a default timeout of 20s. This should be |
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* safe for CPU clock speeds up to 400MHz, as |
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* ((2 ^ 32) - 1) / (400MHz / 2) = 21s. */ |
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#define WATCHDOG_TIMEOUT 20 |
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static int timeout = WATCHDOG_TIMEOUT; |
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module_param(timeout, int, 0); |
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MODULE_PARM_DESC(timeout, "Watchdog timeout value, in seconds (default=" |
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__MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
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static bool nowayout = WATCHDOG_NOWAYOUT; |
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module_param(nowayout, bool, 0); |
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
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/* apply or and nand masks to data read from addr and write back */ |
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#define SET_BITS(addr, or, nand) \ |
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writel((readl(&addr) | or) & ~nand, &addr) |
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static int rc32434_wdt_set(int new_timeout) |
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{ |
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int max_to = WTCOMP2SEC((u32)-1); |
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if (new_timeout < 0 || new_timeout > max_to) { |
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pr_err("timeout value must be between 0 and %d\n", max_to); |
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return -EINVAL; |
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} |
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timeout = new_timeout; |
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spin_lock(&rc32434_wdt_device.io_lock); |
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writel(SEC2WTCOMP(timeout), &wdt_reg->wtcompare); |
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spin_unlock(&rc32434_wdt_device.io_lock); |
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return 0; |
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} |
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static void rc32434_wdt_start(void) |
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{ |
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u32 or, nand; |
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spin_lock(&rc32434_wdt_device.io_lock); |
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/* zero the counter before enabling */ |
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writel(0, &wdt_reg->wtcount); |
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/* don't generate a non-maskable interrupt, |
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* do a warm reset instead */ |
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nand = 1 << RC32434_ERR_WNE; |
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or = 1 << RC32434_ERR_WRE; |
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/* reset the ERRCS timeout bit in case it's set */ |
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nand |= 1 << RC32434_ERR_WTO; |
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SET_BITS(wdt_reg->errcs, or, nand); |
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/* set the timeout (either default or based on module param) */ |
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rc32434_wdt_set(timeout); |
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/* reset WTC timeout bit and enable WDT */ |
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nand = 1 << RC32434_WTC_TO; |
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or = 1 << RC32434_WTC_EN; |
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SET_BITS(wdt_reg->wtc, or, nand); |
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spin_unlock(&rc32434_wdt_device.io_lock); |
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pr_info("Started watchdog timer\n"); |
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} |
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static void rc32434_wdt_stop(void) |
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{ |
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spin_lock(&rc32434_wdt_device.io_lock); |
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/* Disable WDT */ |
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SET_BITS(wdt_reg->wtc, 0, 1 << RC32434_WTC_EN); |
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spin_unlock(&rc32434_wdt_device.io_lock); |
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pr_info("Stopped watchdog timer\n"); |
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} |
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static void rc32434_wdt_ping(void) |
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{ |
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spin_lock(&rc32434_wdt_device.io_lock); |
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writel(0, &wdt_reg->wtcount); |
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spin_unlock(&rc32434_wdt_device.io_lock); |
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} |
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static int rc32434_wdt_open(struct inode *inode, struct file *file) |
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{ |
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if (test_and_set_bit(0, &rc32434_wdt_device.inuse)) |
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return -EBUSY; |
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if (nowayout) |
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__module_get(THIS_MODULE); |
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rc32434_wdt_start(); |
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rc32434_wdt_ping(); |
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return stream_open(inode, file); |
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} |
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static int rc32434_wdt_release(struct inode *inode, struct file *file) |
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{ |
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if (expect_close == 42) { |
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rc32434_wdt_stop(); |
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module_put(THIS_MODULE); |
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} else { |
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pr_crit("device closed unexpectedly. WDT will not stop!\n"); |
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rc32434_wdt_ping(); |
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} |
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clear_bit(0, &rc32434_wdt_device.inuse); |
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return 0; |
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} |
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static ssize_t rc32434_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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/* In case it was set long ago */ |
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expect_close = 0; |
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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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expect_close = 42; |
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} |
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} |
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rc32434_wdt_ping(); |
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return len; |
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} |
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return 0; |
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} |
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static long rc32434_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 new_timeout; |
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unsigned int value; |
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static const struct watchdog_info ident = { |
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.options = WDIOF_SETTIMEOUT | |
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WDIOF_KEEPALIVEPING | |
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WDIOF_MAGICCLOSE, |
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.identity = "RC32434_WDT Watchdog", |
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}; |
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switch (cmd) { |
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case WDIOC_GETSUPPORT: |
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if (copy_to_user(argp, &ident, sizeof(ident))) |
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return -EFAULT; |
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break; |
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case WDIOC_GETSTATUS: |
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case WDIOC_GETBOOTSTATUS: |
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value = 0; |
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if (copy_to_user(argp, &value, sizeof(int))) |
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return -EFAULT; |
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break; |
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case WDIOC_SETOPTIONS: |
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if (copy_from_user(&value, argp, sizeof(int))) |
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return -EFAULT; |
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switch (value) { |
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case WDIOS_ENABLECARD: |
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rc32434_wdt_start(); |
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break; |
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case WDIOS_DISABLECARD: |
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rc32434_wdt_stop(); |
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break; |
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default: |
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return -EINVAL; |
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} |
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break; |
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case WDIOC_KEEPALIVE: |
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rc32434_wdt_ping(); |
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break; |
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case WDIOC_SETTIMEOUT: |
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if (copy_from_user(&new_timeout, argp, sizeof(int))) |
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return -EFAULT; |
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if (rc32434_wdt_set(new_timeout)) |
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return -EINVAL; |
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fallthrough; |
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case WDIOC_GETTIMEOUT: |
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return copy_to_user(argp, &timeout, sizeof(int)) ? -EFAULT : 0; |
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default: |
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return -ENOTTY; |
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} |
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return 0; |
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} |
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static const struct file_operations rc32434_wdt_fops = { |
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.owner = THIS_MODULE, |
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.llseek = no_llseek, |
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.write = rc32434_wdt_write, |
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.unlocked_ioctl = rc32434_wdt_ioctl, |
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.compat_ioctl = compat_ptr_ioctl, |
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.open = rc32434_wdt_open, |
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.release = rc32434_wdt_release, |
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}; |
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static struct miscdevice rc32434_wdt_miscdev = { |
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.minor = WATCHDOG_MINOR, |
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.name = "watchdog", |
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.fops = &rc32434_wdt_fops, |
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}; |
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static int rc32434_wdt_probe(struct platform_device *pdev) |
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{ |
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int ret; |
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struct resource *r; |
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r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rb532_wdt_res"); |
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if (!r) { |
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pr_err("failed to retrieve resources\n"); |
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return -ENODEV; |
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} |
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wdt_reg = devm_ioremap(&pdev->dev, r->start, resource_size(r)); |
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if (!wdt_reg) { |
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pr_err("failed to remap I/O resources\n"); |
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return -ENXIO; |
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} |
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spin_lock_init(&rc32434_wdt_device.io_lock); |
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/* Make sure the watchdog is not running */ |
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rc32434_wdt_stop(); |
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/* Check that the heartbeat value is within it's range; |
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* if not reset to the default */ |
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if (rc32434_wdt_set(timeout)) { |
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rc32434_wdt_set(WATCHDOG_TIMEOUT); |
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pr_info("timeout value must be between 0 and %d\n", |
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WTCOMP2SEC((u32)-1)); |
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} |
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ret = misc_register(&rc32434_wdt_miscdev); |
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if (ret < 0) { |
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pr_err("failed to register watchdog device\n"); |
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return ret; |
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} |
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pr_info("Watchdog Timer version " VERSION ", timer margin: %d sec\n", |
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timeout); |
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return 0; |
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} |
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static int rc32434_wdt_remove(struct platform_device *pdev) |
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{ |
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misc_deregister(&rc32434_wdt_miscdev); |
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return 0; |
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} |
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static void rc32434_wdt_shutdown(struct platform_device *pdev) |
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{ |
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rc32434_wdt_stop(); |
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} |
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static struct platform_driver rc32434_wdt_driver = { |
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.probe = rc32434_wdt_probe, |
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.remove = rc32434_wdt_remove, |
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.shutdown = rc32434_wdt_shutdown, |
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.driver = { |
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.name = "rc32434_wdt", |
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} |
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}; |
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module_platform_driver(rc32434_wdt_driver); |
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MODULE_AUTHOR("Ondrej Zajicek <[email protected]>," |
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"Florian Fainelli <[email protected]>"); |
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MODULE_DESCRIPTION("Driver for the IDT RC32434 SoC watchdog"); |
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MODULE_LICENSE("GPL");
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