diff options
Diffstat (limited to 'drivers/watchdog/iop_wdt.c')
| -rw-r--r-- | drivers/watchdog/iop_wdt.c | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/drivers/watchdog/iop_wdt.c b/drivers/watchdog/iop_wdt.c new file mode 100644 index 000000000..6bf68d475 --- /dev/null +++ b/drivers/watchdog/iop_wdt.c @@ -0,0 +1,250 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/char/watchdog/iop_wdt.c + * + * WDT driver for Intel I/O Processors + * Copyright (C) 2005, Intel Corporation. + * + * Based on ixp4xx driver, Copyright 2004 (c) MontaVista, Software, Inc. + * + * Curt E Bruns <curt.e.bruns@intel.com> + * Peter Milne <peter.milne@d-tacq.com> + * Dan Williams <dan.j.williams@intel.com> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/device.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/uaccess.h> +#include <mach/hardware.h> + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned long wdt_status; +static unsigned long boot_status; +static DEFINE_SPINLOCK(wdt_lock); + +#define WDT_IN_USE 0 +#define WDT_OK_TO_CLOSE 1 +#define WDT_ENABLED 2 + +static unsigned long iop_watchdog_timeout(void) +{ + return (0xffffffffUL / get_iop_tick_rate()); +} + +/** + * wdt_supports_disable - determine if we are accessing a iop13xx watchdog + * or iop3xx by whether it has a disable command + */ +static int wdt_supports_disable(void) +{ + int can_disable; + + if (IOP_WDTCR_EN_ARM != IOP_WDTCR_DIS_ARM) + can_disable = 1; + else + can_disable = 0; + + return can_disable; +} + +static void wdt_enable(void) +{ + /* Arm and enable the Timer to starting counting down from 0xFFFF.FFFF + * Takes approx. 10.7s to timeout + */ + spin_lock(&wdt_lock); + write_wdtcr(IOP_WDTCR_EN_ARM); + write_wdtcr(IOP_WDTCR_EN); + spin_unlock(&wdt_lock); +} + +/* returns 0 if the timer was successfully disabled */ +static int wdt_disable(void) +{ + /* Stop Counting */ + if (wdt_supports_disable()) { + spin_lock(&wdt_lock); + write_wdtcr(IOP_WDTCR_DIS_ARM); + write_wdtcr(IOP_WDTCR_DIS); + clear_bit(WDT_ENABLED, &wdt_status); + spin_unlock(&wdt_lock); + pr_info("Disabled\n"); + return 0; + } else + return 1; +} + +static int iop_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(WDT_IN_USE, &wdt_status)) + return -EBUSY; + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + wdt_enable(); + set_bit(WDT_ENABLED, &wdt_status); + return stream_open(inode, file); +} + +static ssize_t iop_wdt_write(struct file *file, const char *data, size_t len, + loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + set_bit(WDT_OK_TO_CLOSE, &wdt_status); + } + } + wdt_enable(); + } + return len; +} + +static const struct watchdog_info ident = { + .options = WDIOF_CARDRESET | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, + .identity = "iop watchdog", +}; + +static long iop_wdt_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + int options; + int ret = -ENOTTY; + int __user *argp = (int __user *)arg; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user(argp, &ident, sizeof(ident))) + ret = -EFAULT; + else + ret = 0; + break; + + case WDIOC_GETSTATUS: + ret = put_user(0, argp); + break; + + case WDIOC_GETBOOTSTATUS: + ret = put_user(boot_status, argp); + break; + + case WDIOC_SETOPTIONS: + if (get_user(options, (int *)arg)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) { + if (!nowayout) { + if (wdt_disable() == 0) { + set_bit(WDT_OK_TO_CLOSE, &wdt_status); + ret = 0; + } else + ret = -ENXIO; + } else + ret = 0; + } + if (options & WDIOS_ENABLECARD) { + wdt_enable(); + ret = 0; + } + break; + + case WDIOC_KEEPALIVE: + wdt_enable(); + ret = 0; + break; + + case WDIOC_GETTIMEOUT: + ret = put_user(iop_watchdog_timeout(), argp); + break; + } + return ret; +} + +static int iop_wdt_release(struct inode *inode, struct file *file) +{ + int state = 1; + if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) + if (test_bit(WDT_ENABLED, &wdt_status)) + state = wdt_disable(); + + /* if the timer is not disabled reload and notify that we are still + * going down + */ + if (state != 0) { + wdt_enable(); + pr_crit("Device closed unexpectedly - reset in %lu seconds\n", + iop_watchdog_timeout()); + } + + clear_bit(WDT_IN_USE, &wdt_status); + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + return 0; +} + +static const struct file_operations iop_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = iop_wdt_write, + .unlocked_ioctl = iop_wdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = iop_wdt_open, + .release = iop_wdt_release, +}; + +static struct miscdevice iop_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &iop_wdt_fops, +}; + +static int __init iop_wdt_init(void) +{ + int ret; + + /* check if the reset was caused by the watchdog timer */ + boot_status = (read_rcsr() & IOP_RCSR_WDT) ? WDIOF_CARDRESET : 0; + + /* Configure Watchdog Timeout to cause an Internal Bus (IB) Reset + * NOTE: An IB Reset will Reset both cores in the IOP342 + */ + write_wdtsr(IOP13XX_WDTCR_IB_RESET); + + /* Register after we have the device set up so we cannot race + with an open */ + ret = misc_register(&iop_wdt_miscdev); + if (ret == 0) + pr_info("timeout %lu sec\n", iop_watchdog_timeout()); + + return ret; +} + +static void __exit iop_wdt_exit(void) +{ + misc_deregister(&iop_wdt_miscdev); +} + +module_init(iop_wdt_init); +module_exit(iop_wdt_exit); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); + +MODULE_AUTHOR("Curt E Bruns <curt.e.bruns@intel.com>"); +MODULE_DESCRIPTION("iop watchdog timer driver"); +MODULE_LICENSE("GPL"); |