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![Guenter Roeck](/assets/img/avatar_default.png)
timeout_to_regval() returns a valid error code. Might as well use it. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
454 lines
9.9 KiB
C
454 lines
9.9 KiB
C
/*
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* Watchdog driver for Technologic Systems TS-72xx based SBCs
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* (TS-7200, TS-7250 and TS-7260). These boards have external
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* glue logic CPLD chip, which includes programmable watchdog
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* timer.
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*
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* Copyright (c) 2009 Mika Westerberg <mika.westerberg@iki.fi>
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*
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* This driver is based on ep93xx_wdt and wm831x_wdt drivers.
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/fs.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/miscdevice.h>
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#include <linux/mutex.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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#include <linux/uaccess.h>
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#define TS72XX_WDT_FEED_VAL 0x05
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#define TS72XX_WDT_DEFAULT_TIMEOUT 8
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static int timeout = TS72XX_WDT_DEFAULT_TIMEOUT;
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module_param(timeout, int, 0);
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MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. "
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"(1 <= timeout <= 8, default="
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__MODULE_STRING(TS72XX_WDT_DEFAULT_TIMEOUT)
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")");
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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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/**
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* struct ts72xx_wdt - watchdog control structure
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* @lock: lock that protects this structure
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* @regval: watchdog timeout value suitable for control register
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* @flags: flags controlling watchdog device state
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* @control_reg: watchdog control register
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* @feed_reg: watchdog feed register
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* @pdev: back pointer to platform dev
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*/
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struct ts72xx_wdt {
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struct mutex lock;
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int regval;
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#define TS72XX_WDT_BUSY_FLAG 1
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#define TS72XX_WDT_EXPECT_CLOSE_FLAG 2
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int flags;
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void __iomem *control_reg;
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void __iomem *feed_reg;
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struct platform_device *pdev;
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};
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struct platform_device *ts72xx_wdt_pdev;
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/*
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* TS-72xx Watchdog supports following timeouts (value written
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* to control register):
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* value description
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* -------------------------
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* 0x00 watchdog disabled
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* 0x01 250ms
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* 0x02 500ms
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* 0x03 1s
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* 0x04 reserved
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* 0x05 2s
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* 0x06 4s
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* 0x07 8s
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*
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* Timeouts below 1s are not very usable so we don't
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* allow them at all.
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*
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* We provide two functions that convert between these:
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* timeout_to_regval() and regval_to_timeout().
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*/
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static const struct {
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int timeout;
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int regval;
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} ts72xx_wdt_map[] = {
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{ 1, 3 },
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{ 2, 5 },
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{ 4, 6 },
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{ 8, 7 },
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};
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/**
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* timeout_to_regval() - converts given timeout to control register value
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* @new_timeout: timeout in seconds to be converted
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*
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* Function converts given @new_timeout into valid value that can
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* be programmed into watchdog control register. When conversion is
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* not possible, function returns %-EINVAL.
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*/
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static int timeout_to_regval(int new_timeout)
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{
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int i;
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/* first limit it to 1 - 8 seconds */
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new_timeout = clamp_val(new_timeout, 1, 8);
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for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
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if (ts72xx_wdt_map[i].timeout >= new_timeout)
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return ts72xx_wdt_map[i].regval;
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}
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return -EINVAL;
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}
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/**
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* regval_to_timeout() - converts control register value to timeout
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* @regval: control register value to be converted
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*
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* Function converts given @regval to timeout in seconds (1, 2, 4 or 8).
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* If @regval cannot be converted, function returns %-EINVAL.
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*/
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static int regval_to_timeout(int regval)
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{
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int i;
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for (i = 0; i < ARRAY_SIZE(ts72xx_wdt_map); i++) {
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if (ts72xx_wdt_map[i].regval == regval)
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return ts72xx_wdt_map[i].timeout;
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}
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return -EINVAL;
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}
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/**
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* ts72xx_wdt_kick() - kick the watchdog
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* @wdt: watchdog to be kicked
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*
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* Called with @wdt->lock held.
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*/
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static inline void ts72xx_wdt_kick(struct ts72xx_wdt *wdt)
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{
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__raw_writeb(TS72XX_WDT_FEED_VAL, wdt->feed_reg);
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}
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/**
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* ts72xx_wdt_start() - starts the watchdog timer
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* @wdt: watchdog to be started
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*
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* This function programs timeout to watchdog timer
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* and starts it.
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*
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* Called with @wdt->lock held.
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*/
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static void ts72xx_wdt_start(struct ts72xx_wdt *wdt)
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{
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/*
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* To program the wdt, it first must be "fed" and
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* only after that (within 30 usecs) the configuration
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* can be changed.
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*/
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ts72xx_wdt_kick(wdt);
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__raw_writeb((u8)wdt->regval, wdt->control_reg);
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}
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/**
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* ts72xx_wdt_stop() - stops the watchdog timer
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* @wdt: watchdog to be stopped
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*
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* Called with @wdt->lock held.
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*/
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static void ts72xx_wdt_stop(struct ts72xx_wdt *wdt)
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{
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ts72xx_wdt_kick(wdt);
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__raw_writeb(0, wdt->control_reg);
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}
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static int ts72xx_wdt_open(struct inode *inode, struct file *file)
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{
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struct ts72xx_wdt *wdt = platform_get_drvdata(ts72xx_wdt_pdev);
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int regval;
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/*
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* Try to convert default timeout to valid register
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* value first.
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*/
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regval = timeout_to_regval(timeout);
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if (regval < 0) {
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dev_err(&wdt->pdev->dev,
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"failed to convert timeout (%d) to register value\n",
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timeout);
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return regval;
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}
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if (mutex_lock_interruptible(&wdt->lock))
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return -ERESTARTSYS;
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if ((wdt->flags & TS72XX_WDT_BUSY_FLAG) != 0) {
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mutex_unlock(&wdt->lock);
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return -EBUSY;
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}
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wdt->flags = TS72XX_WDT_BUSY_FLAG;
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wdt->regval = regval;
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file->private_data = wdt;
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ts72xx_wdt_start(wdt);
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mutex_unlock(&wdt->lock);
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return nonseekable_open(inode, file);
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}
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static int ts72xx_wdt_release(struct inode *inode, struct file *file)
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{
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struct ts72xx_wdt *wdt = file->private_data;
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if (mutex_lock_interruptible(&wdt->lock))
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return -ERESTARTSYS;
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if ((wdt->flags & TS72XX_WDT_EXPECT_CLOSE_FLAG) != 0) {
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ts72xx_wdt_stop(wdt);
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} else {
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dev_warn(&wdt->pdev->dev,
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"TS-72XX WDT device closed unexpectly. "
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"Watchdog timer will not stop!\n");
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/*
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* Kick it one more time, to give userland some time
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* to recover (for example, respawning the kicker
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* daemon).
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*/
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ts72xx_wdt_kick(wdt);
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}
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wdt->flags = 0;
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mutex_unlock(&wdt->lock);
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return 0;
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}
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static ssize_t ts72xx_wdt_write(struct file *file,
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const char __user *data,
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size_t len,
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loff_t *ppos)
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{
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struct ts72xx_wdt *wdt = file->private_data;
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if (!len)
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return 0;
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if (mutex_lock_interruptible(&wdt->lock))
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return -ERESTARTSYS;
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ts72xx_wdt_kick(wdt);
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/*
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* Support for magic character closing. User process
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* writes 'V' into the device, just before it is closed.
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* This means that we know that the wdt timer can be
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* stopped after user closes the device.
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*/
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if (!nowayout) {
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int i;
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for (i = 0; i < len; i++) {
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char c;
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/* In case it was set long ago */
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wdt->flags &= ~TS72XX_WDT_EXPECT_CLOSE_FLAG;
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if (get_user(c, data + i)) {
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mutex_unlock(&wdt->lock);
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return -EFAULT;
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}
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if (c == 'V') {
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wdt->flags |= TS72XX_WDT_EXPECT_CLOSE_FLAG;
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break;
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}
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}
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}
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mutex_unlock(&wdt->lock);
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return len;
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}
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static const struct watchdog_info winfo = {
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.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
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WDIOF_MAGICCLOSE,
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.firmware_version = 1,
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.identity = "TS-72XX WDT",
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};
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static long ts72xx_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct ts72xx_wdt *wdt = file->private_data;
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void __user *argp = (void __user *)arg;
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int __user *p = (int __user *)argp;
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int error = 0;
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if (mutex_lock_interruptible(&wdt->lock))
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return -ERESTARTSYS;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user(argp, &winfo, sizeof(winfo)))
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error = -EFAULT;
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break;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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error = put_user(0, p);
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break;
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case WDIOC_KEEPALIVE:
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ts72xx_wdt_kick(wdt);
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break;
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case WDIOC_SETOPTIONS: {
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int options;
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error = get_user(options, p);
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if (error)
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break;
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error = -EINVAL;
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if ((options & WDIOS_DISABLECARD) != 0) {
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ts72xx_wdt_stop(wdt);
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error = 0;
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}
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if ((options & WDIOS_ENABLECARD) != 0) {
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ts72xx_wdt_start(wdt);
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error = 0;
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}
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break;
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}
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case WDIOC_SETTIMEOUT: {
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int new_timeout;
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int regval;
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error = get_user(new_timeout, p);
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if (error)
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break;
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regval = timeout_to_regval(new_timeout);
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if (regval < 0) {
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error = regval;
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break;
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}
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ts72xx_wdt_stop(wdt);
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wdt->regval = regval;
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ts72xx_wdt_start(wdt);
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/*FALLTHROUGH*/
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}
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case WDIOC_GETTIMEOUT:
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error = put_user(regval_to_timeout(wdt->regval), p);
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break;
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default:
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error = -ENOTTY;
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break;
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}
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mutex_unlock(&wdt->lock);
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return error;
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}
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static const struct file_operations ts72xx_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.open = ts72xx_wdt_open,
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.release = ts72xx_wdt_release,
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.write = ts72xx_wdt_write,
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.unlocked_ioctl = ts72xx_wdt_ioctl,
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};
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static struct miscdevice ts72xx_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &ts72xx_wdt_fops,
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};
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static int ts72xx_wdt_probe(struct platform_device *pdev)
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{
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struct ts72xx_wdt *wdt;
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struct resource *r1, *r2;
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int error = 0;
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wdt = devm_kzalloc(&pdev->dev, sizeof(struct ts72xx_wdt), GFP_KERNEL);
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if (!wdt) {
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dev_err(&pdev->dev, "failed to allocate memory\n");
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return -ENOMEM;
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}
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r1 = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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wdt->control_reg = devm_ioremap_resource(&pdev->dev, r1);
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if (IS_ERR(wdt->control_reg))
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return PTR_ERR(wdt->control_reg);
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r2 = platform_get_resource(pdev, IORESOURCE_MEM, 1);
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wdt->feed_reg = devm_ioremap_resource(&pdev->dev, r2);
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if (IS_ERR(wdt->feed_reg))
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return PTR_ERR(wdt->feed_reg);
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platform_set_drvdata(pdev, wdt);
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ts72xx_wdt_pdev = pdev;
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wdt->pdev = pdev;
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mutex_init(&wdt->lock);
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/* make sure that the watchdog is disabled */
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ts72xx_wdt_stop(wdt);
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error = misc_register(&ts72xx_wdt_miscdev);
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if (error) {
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dev_err(&pdev->dev, "failed to register miscdev\n");
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return error;
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}
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dev_info(&pdev->dev, "TS-72xx Watchdog driver\n");
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return 0;
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}
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static int ts72xx_wdt_remove(struct platform_device *pdev)
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{
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int error;
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error = misc_deregister(&ts72xx_wdt_miscdev);
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return error;
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}
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static struct platform_driver ts72xx_wdt_driver = {
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.probe = ts72xx_wdt_probe,
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.remove = ts72xx_wdt_remove,
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.driver = {
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.name = "ts72xx-wdt",
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(ts72xx_wdt_driver);
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MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>");
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MODULE_DESCRIPTION("TS-72xx SBC Watchdog");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:ts72xx-wdt");
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