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bd490f8222
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20200707171121.GA13472@embeddedor Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
332 lines
7.3 KiB
C
332 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* GE watchdog userspace interface
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*
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* Author: Martyn Welch <martyn.welch@ge.com>
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*
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* Copyright 2008 GE Intelligent Platforms Embedded Systems, Inc.
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*
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* Based on: mv64x60_wdt.c (MV64X60 watchdog userspace interface)
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* Author: James Chapman <jchapman@katalix.com>
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*/
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/* TODO:
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* This driver does not provide support for the hardwares capability of sending
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* an interrupt at a programmable threshold.
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*
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* This driver currently can only support 1 watchdog - there are 2 in the
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* hardware that this driver supports. Thus one could be configured as a
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* process-based watchdog (via /dev/watchdog), the second (using the interrupt
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* capabilities) a kernel-based watchdog.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/compiler.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#include <sysdev/fsl_soc.h>
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/*
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* The watchdog configuration register contains a pair of 2-bit fields,
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* 1. a reload field, bits 27-26, which triggers a reload of
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* the countdown register, and
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* 2. an enable field, bits 25-24, which toggles between
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* enabling and disabling the watchdog timer.
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* Bit 31 is a read-only field which indicates whether the
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* watchdog timer is currently enabled.
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*
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* The low 24 bits contain the timer reload value.
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*/
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#define GEF_WDC_ENABLE_SHIFT 24
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#define GEF_WDC_SERVICE_SHIFT 26
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#define GEF_WDC_ENABLED_SHIFT 31
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#define GEF_WDC_ENABLED_TRUE 1
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#define GEF_WDC_ENABLED_FALSE 0
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/* Flags bits */
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#define GEF_WDOG_FLAG_OPENED 0
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static unsigned long wdt_flags;
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static int wdt_status;
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static void __iomem *gef_wdt_regs;
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static int gef_wdt_timeout;
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static int gef_wdt_count;
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static unsigned int bus_clk;
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static char expect_close;
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static DEFINE_SPINLOCK(gef_wdt_spinlock);
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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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static int gef_wdt_toggle_wdc(int enabled_predicate, int field_shift)
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{
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u32 data;
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u32 enabled;
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int ret = 0;
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spin_lock(&gef_wdt_spinlock);
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data = ioread32be(gef_wdt_regs);
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enabled = (data >> GEF_WDC_ENABLED_SHIFT) & 1;
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/* only toggle the requested field if enabled state matches predicate */
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if ((enabled ^ enabled_predicate) == 0) {
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/* We write a 1, then a 2 -- to the appropriate field */
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data = (1 << field_shift) | gef_wdt_count;
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iowrite32be(data, gef_wdt_regs);
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data = (2 << field_shift) | gef_wdt_count;
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iowrite32be(data, gef_wdt_regs);
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ret = 1;
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}
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spin_unlock(&gef_wdt_spinlock);
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return ret;
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}
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static void gef_wdt_service(void)
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{
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gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
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GEF_WDC_SERVICE_SHIFT);
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}
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static void gef_wdt_handler_enable(void)
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{
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if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_FALSE,
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GEF_WDC_ENABLE_SHIFT)) {
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gef_wdt_service();
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pr_notice("watchdog activated\n");
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}
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}
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static void gef_wdt_handler_disable(void)
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{
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if (gef_wdt_toggle_wdc(GEF_WDC_ENABLED_TRUE,
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GEF_WDC_ENABLE_SHIFT))
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pr_notice("watchdog deactivated\n");
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}
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static void gef_wdt_set_timeout(unsigned int timeout)
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{
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/* maximum bus cycle count is 0xFFFFFFFF */
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if (timeout > 0xFFFFFFFF / bus_clk)
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timeout = 0xFFFFFFFF / bus_clk;
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/* Register only holds upper 24 bits, bit shifted into lower 24 */
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gef_wdt_count = (timeout * bus_clk) >> 8;
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gef_wdt_timeout = timeout;
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}
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static ssize_t gef_wdt_write(struct file *file, const char __user *data,
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size_t len, loff_t *ppos)
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{
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if (len) {
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if (!nowayout) {
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size_t i;
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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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gef_wdt_service();
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}
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return len;
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}
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static long gef_wdt_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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int timeout;
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int options;
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void __user *argp = (void __user *)arg;
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static const struct watchdog_info info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE |
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WDIOF_KEEPALIVEPING,
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.firmware_version = 0,
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.identity = "GE 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, &info, sizeof(info)))
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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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if (put_user(wdt_status, (int __user *)argp))
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return -EFAULT;
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wdt_status &= ~WDIOF_KEEPALIVEPING;
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break;
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case WDIOC_SETOPTIONS:
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if (get_user(options, (int __user *)argp))
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return -EFAULT;
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if (options & WDIOS_DISABLECARD)
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gef_wdt_handler_disable();
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if (options & WDIOS_ENABLECARD)
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gef_wdt_handler_enable();
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break;
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case WDIOC_KEEPALIVE:
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gef_wdt_service();
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wdt_status |= WDIOF_KEEPALIVEPING;
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break;
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case WDIOC_SETTIMEOUT:
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if (get_user(timeout, (int __user *)argp))
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return -EFAULT;
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gef_wdt_set_timeout(timeout);
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fallthrough;
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case WDIOC_GETTIMEOUT:
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if (put_user(gef_wdt_timeout, (int __user *)argp))
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return -EFAULT;
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break;
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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 int gef_wdt_open(struct inode *inode, struct file *file)
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{
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if (test_and_set_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags))
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return -EBUSY;
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if (nowayout)
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__module_get(THIS_MODULE);
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gef_wdt_handler_enable();
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return stream_open(inode, file);
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}
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static int gef_wdt_release(struct inode *inode, struct file *file)
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{
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if (expect_close == 42)
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gef_wdt_handler_disable();
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else {
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pr_crit("unexpected close, not stopping timer!\n");
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gef_wdt_service();
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}
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expect_close = 0;
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clear_bit(GEF_WDOG_FLAG_OPENED, &wdt_flags);
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return 0;
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}
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static const struct file_operations gef_wdt_fops = {
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.owner = THIS_MODULE,
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.llseek = no_llseek,
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.write = gef_wdt_write,
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.unlocked_ioctl = gef_wdt_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.open = gef_wdt_open,
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.release = gef_wdt_release,
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};
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static struct miscdevice gef_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &gef_wdt_fops,
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};
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static int gef_wdt_probe(struct platform_device *dev)
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{
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int timeout = 10;
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u32 freq;
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bus_clk = 133; /* in MHz */
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freq = fsl_get_sys_freq();
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if (freq != -1)
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bus_clk = freq;
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/* Map devices registers into memory */
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gef_wdt_regs = of_iomap(dev->dev.of_node, 0);
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if (gef_wdt_regs == NULL)
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return -ENOMEM;
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gef_wdt_set_timeout(timeout);
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gef_wdt_handler_disable(); /* in case timer was already running */
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return misc_register(&gef_wdt_miscdev);
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}
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static int gef_wdt_remove(struct platform_device *dev)
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{
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misc_deregister(&gef_wdt_miscdev);
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gef_wdt_handler_disable();
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iounmap(gef_wdt_regs);
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return 0;
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}
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static const struct of_device_id gef_wdt_ids[] = {
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{
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.compatible = "gef,fpga-wdt",
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},
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{},
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};
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MODULE_DEVICE_TABLE(of, gef_wdt_ids);
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static struct platform_driver gef_wdt_driver = {
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.driver = {
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.name = "gef_wdt",
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.of_match_table = gef_wdt_ids,
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},
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.probe = gef_wdt_probe,
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.remove = gef_wdt_remove,
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};
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static int __init gef_wdt_init(void)
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{
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pr_info("GE watchdog driver\n");
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return platform_driver_register(&gef_wdt_driver);
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}
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static void __exit gef_wdt_exit(void)
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{
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platform_driver_unregister(&gef_wdt_driver);
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}
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module_init(gef_wdt_init);
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module_exit(gef_wdt_exit);
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MODULE_AUTHOR("Martyn Welch <martyn.welch@ge.com>");
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MODULE_DESCRIPTION("GE watchdog driver");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS("platform:gef_wdt");
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