diff options
Diffstat (limited to 'drivers/watchdog/sa1100_wdt.c')
| -rw-r--r-- | drivers/watchdog/sa1100_wdt.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/watchdog/sa1100_wdt.c b/drivers/watchdog/sa1100_wdt.c new file mode 100644 index 000000000..82ac5d19f --- /dev/null +++ b/drivers/watchdog/sa1100_wdt.c @@ -0,0 +1,254 @@ +// 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/platform_device.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> + +#define REG_OSMR0 0x0000 /* OS timer Match Reg. 0 */ +#define REG_OSMR1 0x0004 /* OS timer Match Reg. 1 */ +#define REG_OSMR2 0x0008 /* OS timer Match Reg. 2 */ +#define REG_OSMR3 0x000c /* OS timer Match Reg. 3 */ +#define REG_OSCR 0x0010 /* OS timer Counter Reg. */ +#define REG_OSSR 0x0014 /* OS timer Status Reg. */ +#define REG_OWER 0x0018 /* OS timer Watch-dog Enable Reg. */ +#define REG_OIER 0x001C /* OS timer Interrupt Enable Reg. */ + +#define OSSR_M3 (1 << 3) /* Match status channel 3 */ +#define OSSR_M2 (1 << 2) /* Match status channel 2 */ +#define OSSR_M1 (1 << 1) /* Match status channel 1 */ +#define OSSR_M0 (1 << 0) /* Match status channel 0 */ + +#define OWER_WME (1 << 0) /* Watchdog Match Enable */ + +#define OIER_E3 (1 << 3) /* Interrupt enable channel 3 */ +#define OIER_E2 (1 << 2) /* Interrupt enable channel 2 */ +#define OIER_E1 (1 << 1) /* Interrupt enable channel 1 */ +#define OIER_E0 (1 << 0) /* Interrupt enable channel 0 */ + +static unsigned long oscr_freq; +static unsigned long sa1100wdt_users; +static unsigned int pre_margin; +static int boot_status; +static void __iomem *reg_base; + +static inline void sa1100_wr(u32 val, u32 offset) +{ + writel_relaxed(val, reg_base + offset); +} + +static inline u32 sa1100_rd(u32 offset) +{ + return readl_relaxed(reg_base + offset); +} + +/* + * 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 */ + sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_OSMR3); + sa1100_wr(OSSR_M3, REG_OSSR); + sa1100_wr(OWER_WME, REG_OWER); + sa1100_wr(sa1100_rd(REG_OIER) | OIER_E3, REG_OIER); + return stream_open(inode, file); +} + +/* + * The watchdog cannot be disabled. + * + * Previous comments suggested that turning off the interrupt by + * clearing REG_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. */ + sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_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: + sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_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; + sa1100_wr(sa1100_rd(REG_OSCR) + pre_margin, REG_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 = 60; /* (secs) Default is 1 minute */ +static struct clk *clk; + +static int sa1100dog_probe(struct platform_device *pdev) +{ + int ret; + int *platform_data; + struct resource *res; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -ENXIO; + reg_base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + ret = PTR_ERR_OR_ZERO(reg_base); + if (ret) + return 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); + + platform_data = pdev->dev.platform_data; + if (platform_data && *platform_data) + boot_status = WDIOF_CARDRESET; + 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 int sa1100dog_remove(struct platform_device *pdev) +{ + misc_deregister(&sa1100dog_miscdev); + clk_disable_unprepare(clk); + clk_put(clk); + + return 0; +} + +static struct platform_driver sa1100dog_driver = { + .driver.name = "sa1100_wdt", + .probe = sa1100dog_probe, + .remove = sa1100dog_remove, +}; +module_platform_driver(sa1100dog_driver); + +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"); |