diff options
Diffstat (limited to 'drivers/watchdog/sa1100_wdt.c')
| -rw-r--r-- | drivers/watchdog/sa1100_wdt.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/watchdog/sa1100_wdt.c b/drivers/watchdog/sa1100_wdt.c new file mode 100644 index 000000000..27846c6bd --- /dev/null +++ b/drivers/watchdog/sa1100_wdt.c @@ -0,0 +1,216 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Watchdog driver for the SA11x0/PXA2xx + * + * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> + * Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk> + * + * Neither Oleg Drokin nor iXcelerator.com admit liability nor provide + * warranty for any of this software. This material is provided + * "AS-IS" and at no charge. + * + * (c) Copyright 2000 Oleg Drokin <green@crimea.edu> + * + * 27/11/2000 Initial release + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/clk.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/bitops.h> +#include <linux/uaccess.h> +#include <linux/timex.h> + +#ifdef CONFIG_ARCH_PXA +#include <mach/regs-ost.h> +#endif + +#include <mach/reset.h> +#include <mach/hardware.h> + +static unsigned long oscr_freq; +static unsigned long sa1100wdt_users; +static unsigned int pre_margin; +static int boot_status; + +/* + * Allow only one person to hold it open + */ +static int sa1100dog_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(1, &sa1100wdt_users)) + return -EBUSY; + + /* Activate SA1100 Watchdog timer */ + writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); + writel_relaxed(OSSR_M3, OSSR); + writel_relaxed(OWER_WME, OWER); + writel_relaxed(readl_relaxed(OIER) | OIER_E3, OIER); + return stream_open(inode, file); +} + +/* + * The watchdog cannot be disabled. + * + * Previous comments suggested that turning off the interrupt by + * clearing OIER[E3] would prevent the watchdog timing out but this + * does not appear to be true (at least on the PXA255). + */ +static int sa1100dog_release(struct inode *inode, struct file *file) +{ + pr_crit("Device closed - timer will not stop\n"); + clear_bit(1, &sa1100wdt_users); + return 0; +} + +static ssize_t sa1100dog_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + if (len) + /* Refresh OSMR3 timer. */ + writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); + return len; +} + +static const struct watchdog_info ident = { + .options = WDIOF_CARDRESET | WDIOF_SETTIMEOUT + | WDIOF_KEEPALIVEPING, + .identity = "SA1100/PXA255 Watchdog", + .firmware_version = 1, +}; + +static long sa1100dog_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret = -ENOTTY; + int time; + void __user *argp = (void __user *)arg; + int __user *p = argp; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user(argp, &ident, + sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + ret = put_user(0, p); + break; + + case WDIOC_GETBOOTSTATUS: + ret = put_user(boot_status, p); + break; + + case WDIOC_KEEPALIVE: + writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); + ret = 0; + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(time, p); + if (ret) + break; + + if (time <= 0 || (oscr_freq * (long long)time >= 0xffffffff)) { + ret = -EINVAL; + break; + } + + pre_margin = oscr_freq * time; + writel_relaxed(readl_relaxed(OSCR) + pre_margin, OSMR3); + fallthrough; + + case WDIOC_GETTIMEOUT: + ret = put_user(pre_margin / oscr_freq, p); + break; + } + return ret; +} + +static const struct file_operations sa1100dog_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = sa1100dog_write, + .unlocked_ioctl = sa1100dog_ioctl, + .compat_ioctl = compat_ptr_ioctl, + .open = sa1100dog_open, + .release = sa1100dog_release, +}; + +static struct miscdevice sa1100dog_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &sa1100dog_fops, +}; + +static int margin __initdata = 60; /* (secs) Default is 1 minute */ +static struct clk *clk; + +static int __init sa1100dog_init(void) +{ + int ret; + + clk = clk_get(NULL, "OSTIMER0"); + if (IS_ERR(clk)) { + pr_err("SA1100/PXA2xx Watchdog Timer: clock not found: %d\n", + (int) PTR_ERR(clk)); + return PTR_ERR(clk); + } + + ret = clk_prepare_enable(clk); + if (ret) { + pr_err("SA1100/PXA2xx Watchdog Timer: clock failed to prepare+enable: %d\n", + ret); + goto err; + } + + oscr_freq = clk_get_rate(clk); + + /* + * Read the reset status, and save it for later. If + * we suspend, RCSR will be cleared, and the watchdog + * reset reason will be lost. + */ + boot_status = (reset_status & RESET_STATUS_WATCHDOG) ? + WDIOF_CARDRESET : 0; + pre_margin = oscr_freq * margin; + + ret = misc_register(&sa1100dog_miscdev); + if (ret == 0) { + pr_info("SA1100/PXA2xx Watchdog Timer: timer margin %d sec\n", + margin); + return 0; + } + + clk_disable_unprepare(clk); +err: + clk_put(clk); + return ret; +} + +static void __exit sa1100dog_exit(void) +{ + misc_deregister(&sa1100dog_miscdev); + clk_disable_unprepare(clk); + clk_put(clk); +} + +module_init(sa1100dog_init); +module_exit(sa1100dog_exit); + +MODULE_AUTHOR("Oleg Drokin <green@crimea.edu>"); +MODULE_DESCRIPTION("SA1100/PXA2xx Watchdog"); + +module_param(margin, int, 0); +MODULE_PARM_DESC(margin, "Watchdog margin in seconds (default 60s)"); + +MODULE_LICENSE("GPL"); |