diff options
Diffstat (limited to 'drivers/watchdog/geodewdt.c')
| -rw-r--r-- | drivers/watchdog/geodewdt.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/watchdog/geodewdt.c b/drivers/watchdog/geodewdt.c new file mode 100644 index 000000000..0b699c783 --- /dev/null +++ b/drivers/watchdog/geodewdt.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Watchdog timer for machines with the CS5535/CS5536 companion chip + * + * Copyright (C) 2006-2007, Advanced Micro Devices, Inc. + * Copyright (C) 2009 Andres Salomon <dilinger@collabora.co.uk> + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/fs.h> +#include <linux/platform_device.h> +#include <linux/reboot.h> +#include <linux/uaccess.h> + +#include <linux/cs5535.h> + +#define GEODEWDT_HZ 500 +#define GEODEWDT_SCALE 6 +#define GEODEWDT_MAX_SECONDS 131 + +#define WDT_FLAGS_OPEN 1 +#define WDT_FLAGS_ORPHAN 2 + +#define DRV_NAME "geodewdt" +#define WATCHDOG_NAME "Geode GX/LX WDT" +#define WATCHDOG_TIMEOUT 60 + +static int timeout = WATCHDOG_TIMEOUT; +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, + "Watchdog timeout in seconds. 1<= timeout <=131, default=" + __MODULE_STRING(WATCHDOG_TIMEOUT) "."); + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +static struct platform_device *geodewdt_platform_device; +static unsigned long wdt_flags; +static struct cs5535_mfgpt_timer *wdt_timer; +static int safe_close; + +static void geodewdt_ping(void) +{ + /* Stop the counter */ + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); + + /* Reset the counter */ + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); + + /* Enable the counter */ + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); +} + +static void geodewdt_disable(void) +{ + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); +} + +static int geodewdt_set_heartbeat(int val) +{ + if (val < 1 || val > GEODEWDT_MAX_SECONDS) + return -EINVAL; + + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, 0); + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, val * GEODEWDT_HZ); + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_COUNTER, 0); + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, MFGPT_SETUP_CNTEN); + + timeout = val; + return 0; +} + +static int geodewdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(WDT_FLAGS_OPEN, &wdt_flags)) + return -EBUSY; + + if (!test_and_clear_bit(WDT_FLAGS_ORPHAN, &wdt_flags)) + __module_get(THIS_MODULE); + + geodewdt_ping(); + return stream_open(inode, file); +} + +static int geodewdt_release(struct inode *inode, struct file *file) +{ + if (safe_close) { + geodewdt_disable(); + module_put(THIS_MODULE); + } else { + pr_crit("Unexpected close - watchdog is not stopping\n"); + geodewdt_ping(); + + set_bit(WDT_FLAGS_ORPHAN, &wdt_flags); + } + + clear_bit(WDT_FLAGS_OPEN, &wdt_flags); + safe_close = 0; + return 0; +} + +static ssize_t geodewdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + safe_close = 0; + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + + if (c == 'V') + safe_close = 1; + } + } + + geodewdt_ping(); + } + return len; +} + +static long geodewdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int interval; + + static const struct watchdog_info ident = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING + | WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = WATCHDOG_NAME, + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &ident, + sizeof(ident)) ? -EFAULT : 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + + case WDIOC_SETOPTIONS: + { + int options, ret = -EINVAL; + + if (get_user(options, p)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) { + geodewdt_disable(); + ret = 0; + } + + if (options & WDIOS_ENABLECARD) { + geodewdt_ping(); + ret = 0; + } + + return ret; + } + case WDIOC_KEEPALIVE: + geodewdt_ping(); + return 0; + + case WDIOC_SETTIMEOUT: + if (get_user(interval, p)) + return -EFAULT; + + if (geodewdt_set_heartbeat(interval)) + return -EINVAL; + fallthrough; + case WDIOC_GETTIMEOUT: + return put_user(timeout, p); + + default: + return -ENOTTY; + } + + return 0; +} + +static const struct file_operations geodewdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = geodewdt_write, + .unlocked_ioctl = geodewdt_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = geodewdt_open, + .release = geodewdt_release, +}; + +static struct miscdevice geodewdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &geodewdt_fops, +}; + +static int __init geodewdt_probe(struct platform_device *dev) +{ + int ret; + + wdt_timer = cs5535_mfgpt_alloc_timer(MFGPT_TIMER_ANY, MFGPT_DOMAIN_WORKING); + if (!wdt_timer) { + pr_err("No timers were available\n"); + return -ENODEV; + } + + /* Set up the timer */ + + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_SETUP, + GEODEWDT_SCALE | (3 << 8)); + + /* Set up comparator 2 to reset when the event fires */ + cs5535_mfgpt_toggle_event(wdt_timer, MFGPT_CMP2, MFGPT_EVENT_RESET, 1); + + /* Set up the initial timeout */ + + cs5535_mfgpt_write(wdt_timer, MFGPT_REG_CMP2, + timeout * GEODEWDT_HZ); + + ret = misc_register(&geodewdt_miscdev); + + return ret; +} + +static int geodewdt_remove(struct platform_device *dev) +{ + misc_deregister(&geodewdt_miscdev); + return 0; +} + +static void geodewdt_shutdown(struct platform_device *dev) +{ + geodewdt_disable(); +} + +static struct platform_driver geodewdt_driver = { + .remove = geodewdt_remove, + .shutdown = geodewdt_shutdown, + .driver = { + .name = DRV_NAME, + }, +}; + +static int __init geodewdt_init(void) +{ + int ret; + + geodewdt_platform_device = platform_device_register_simple(DRV_NAME, + -1, NULL, 0); + if (IS_ERR(geodewdt_platform_device)) + return PTR_ERR(geodewdt_platform_device); + + ret = platform_driver_probe(&geodewdt_driver, geodewdt_probe); + if (ret) + goto err; + + return 0; +err: + platform_device_unregister(geodewdt_platform_device); + return ret; +} + +static void __exit geodewdt_exit(void) +{ + platform_device_unregister(geodewdt_platform_device); + platform_driver_unregister(&geodewdt_driver); +} + +module_init(geodewdt_init); +module_exit(geodewdt_exit); + +MODULE_AUTHOR("Advanced Micro Devices, Inc"); +MODULE_DESCRIPTION("Geode GX/LX Watchdog Driver"); +MODULE_LICENSE("GPL"); |