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![Jean Delvare](/assets/img/avatar_default.png)
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements. Either the device is enumerated and the driver already has a module alias (e.g. PCI, USB etc.) that will get the right driver loaded automatically. Or the device is not enumerated and loading its driver will lead to more or less intrusive hardware poking. Such hardware poking should be limited to a bare minimum, so the user should really decide which drivers should be tried and in what order. Trying them all in arbitrary order can't do any good. On top of that, loading that many drivers at once bloats the kernel log. Also many drivers will stay loaded afterward, bloating the output of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets loaded as a dependency) can't even be unloaded! If defining char-major-10-130 is needed then it should happen in user-space. Signed-off-by: Jean Delvare <jdelvare@suse.de> Acked-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Ben Dooks <ben-linux@fluff.org> Cc: Kukjin Kim <kgene.kim@samsung.com> Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk> Cc: Jim Cromie <jim.cromie@gmail.com>
333 lines
7.7 KiB
C
333 lines
7.7 KiB
C
/*
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* drivers/watchdog/ar7_wdt.c
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*
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* Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
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* Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
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*
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* Some code taken from:
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* National Semiconductor SCx200 Watchdog support
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* Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/errno.h>
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#include <linux/init.h>
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#include <linux/miscdevice.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/ioport.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#include <linux/clk.h>
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#include <asm/addrspace.h>
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#include <asm/mach-ar7/ar7.h>
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#define LONGNAME "TI AR7 Watchdog Timer"
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MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
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MODULE_DESCRIPTION(LONGNAME);
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MODULE_LICENSE("GPL");
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static int margin = 60;
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module_param(margin, int, 0);
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MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
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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, "Disable watchdog shutdown on close");
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#define READ_REG(x) readl((void __iomem *)&(x))
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#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
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struct ar7_wdt {
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u32 kick_lock;
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u32 kick;
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u32 change_lock;
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u32 change;
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u32 disable_lock;
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u32 disable;
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u32 prescale_lock;
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u32 prescale;
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};
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static unsigned long wdt_is_open;
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static unsigned expect_close;
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static DEFINE_SPINLOCK(wdt_lock);
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/* XXX currently fixed, allows max margin ~68.72 secs */
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#define prescale_value 0xffff
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/* Resource of the WDT registers */
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static struct resource *ar7_regs_wdt;
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/* Pointer to the remapped WDT IO space */
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static struct ar7_wdt *ar7_wdt;
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static struct clk *vbus_clk;
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static void ar7_wdt_kick(u32 value)
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{
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WRITE_REG(ar7_wdt->kick_lock, 0x5555);
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if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
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if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->kick, value);
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return;
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}
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}
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pr_err("failed to unlock WDT kick reg\n");
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}
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static void ar7_wdt_prescale(u32 value)
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{
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WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
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if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
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if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->prescale, value);
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return;
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}
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}
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pr_err("failed to unlock WDT prescale reg\n");
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}
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static void ar7_wdt_change(u32 value)
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{
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WRITE_REG(ar7_wdt->change_lock, 0x6666);
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if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
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if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->change, value);
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return;
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}
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}
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pr_err("failed to unlock WDT change reg\n");
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}
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static void ar7_wdt_disable(u32 value)
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{
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WRITE_REG(ar7_wdt->disable_lock, 0x7777);
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if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
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if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
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WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
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if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->disable, value);
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return;
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}
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}
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}
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pr_err("failed to unlock WDT disable reg\n");
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}
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static void ar7_wdt_update_margin(int new_margin)
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{
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u32 change;
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u32 vbus_rate;
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vbus_rate = clk_get_rate(vbus_clk);
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change = new_margin * (vbus_rate / prescale_value);
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if (change < 1)
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change = 1;
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if (change > 0xffff)
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change = 0xffff;
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ar7_wdt_change(change);
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margin = change * prescale_value / vbus_rate;
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pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
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margin, prescale_value, change, vbus_rate);
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}
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static void ar7_wdt_enable_wdt(void)
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{
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pr_debug("enabling watchdog timer\n");
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ar7_wdt_disable(1);
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ar7_wdt_kick(1);
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}
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static void ar7_wdt_disable_wdt(void)
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{
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pr_debug("disabling watchdog timer\n");
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ar7_wdt_disable(0);
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}
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static int ar7_wdt_open(struct inode *inode, struct file *file)
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{
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/* only allow one at a time */
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if (test_and_set_bit(0, &wdt_is_open))
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return -EBUSY;
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ar7_wdt_enable_wdt();
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expect_close = 0;
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return nonseekable_open(inode, file);
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}
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static int ar7_wdt_release(struct inode *inode, struct file *file)
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{
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if (!expect_close)
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pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
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else if (!nowayout)
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ar7_wdt_disable_wdt();
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clear_bit(0, &wdt_is_open);
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return 0;
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}
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static ssize_t ar7_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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/* check for a magic close character */
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if (len) {
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size_t i;
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spin_lock(&wdt_lock);
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ar7_wdt_kick(1);
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spin_unlock(&wdt_lock);
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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 = 1;
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}
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}
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return len;
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}
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static long ar7_wdt_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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static const struct watchdog_info ident = {
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.identity = LONGNAME,
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.firmware_version = 1,
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.options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE),
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};
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int new_margin;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user((struct watchdog_info *)arg, &ident,
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sizeof(ident)))
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return -EFAULT;
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return 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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if (put_user(0, (int *)arg))
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return -EFAULT;
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return 0;
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case WDIOC_KEEPALIVE:
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ar7_wdt_kick(1);
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, (int *)arg))
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return -EFAULT;
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if (new_margin < 1)
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return -EINVAL;
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spin_lock(&wdt_lock);
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ar7_wdt_update_margin(new_margin);
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ar7_wdt_kick(1);
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spin_unlock(&wdt_lock);
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case WDIOC_GETTIMEOUT:
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if (put_user(margin, (int *)arg))
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return -EFAULT;
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return 0;
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations ar7_wdt_fops = {
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.owner = THIS_MODULE,
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.write = ar7_wdt_write,
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.unlocked_ioctl = ar7_wdt_ioctl,
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.open = ar7_wdt_open,
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.release = ar7_wdt_release,
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.llseek = no_llseek,
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};
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static struct miscdevice ar7_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &ar7_wdt_fops,
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};
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static int ar7_wdt_probe(struct platform_device *pdev)
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{
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int rc;
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ar7_regs_wdt =
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platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
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ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
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if (IS_ERR(ar7_wdt))
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return PTR_ERR(ar7_wdt);
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vbus_clk = clk_get(NULL, "vbus");
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if (IS_ERR(vbus_clk)) {
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pr_err("could not get vbus clock\n");
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return PTR_ERR(vbus_clk);
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}
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ar7_wdt_disable_wdt();
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ar7_wdt_prescale(prescale_value);
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ar7_wdt_update_margin(margin);
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rc = misc_register(&ar7_wdt_miscdev);
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if (rc) {
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pr_err("unable to register misc device\n");
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goto out;
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}
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return 0;
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out:
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clk_put(vbus_clk);
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vbus_clk = NULL;
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return rc;
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}
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static int ar7_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&ar7_wdt_miscdev);
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clk_put(vbus_clk);
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vbus_clk = NULL;
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return 0;
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}
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static void ar7_wdt_shutdown(struct platform_device *pdev)
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{
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if (!nowayout)
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ar7_wdt_disable_wdt();
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}
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static struct platform_driver ar7_wdt_driver = {
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.probe = ar7_wdt_probe,
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.remove = ar7_wdt_remove,
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.shutdown = ar7_wdt_shutdown,
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.driver = {
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.owner = THIS_MODULE,
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.name = "ar7_wdt",
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},
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};
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module_platform_driver(ar7_wdt_driver);
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