--- /dev/null +++ b/drivers/watchdog/gemini_wdt.c @@ -0,0 +1,378 @@ +/* + * Watchdog driver for Cortina Systems Gemini SoC + * + * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/io.h> +#include <linux/fs.h> +#include <linux/uaccess.h> +#include <linux/miscdevice.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> +#include <linux/slab.h> + +#define GEMINI_WDCOUNTER 0x0 +#define GEMINI_WDLOAD 0x4 +#define GEMINI_WDRESTART 0x8 + +#define WDRESTART_MAGIC 0x5AB9 + +#define GEMINI_WDCR 0xC + +#define WDCR_CLOCK_5MHZ (1 << 4) +#define WDCR_SYS_RST (1 << 1) +#define WDCR_ENABLE (1 << 0) + +#define WDT_CLOCK 5000000 /* 5 MHz */ +#define WDT_DEFAULT_TIMEOUT 13 +#define WDT_MAX_TIMEOUT (0xFFFFFFFF / WDT_CLOCK) + +/* status bits */ +#define WDT_ACTIVE 0 +#define WDT_OK_TO_CLOSE 1 + +static unsigned int timeout = WDT_DEFAULT_TIMEOUT; +static int nowayout = WATCHDOG_NOWAYOUT; + +static DEFINE_SPINLOCK(gemini_wdt_lock); + +static struct platform_device *gemini_wdt_dev; + +struct gemini_wdt_struct { + struct resource *res; + struct device *dev; + void __iomem *base; + unsigned long status; +}; + +static struct watchdog_info gemini_wdt_info = { + .identity = "Gemini watchdog", + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | + WDIOF_SETTIMEOUT, +}; + +/* Disable the watchdog. */ +static void gemini_wdt_stop(struct gemini_wdt_struct *gemini_wdt) +{ + spin_lock(&gemini_wdt_lock); + + __raw_writel(0, gemini_wdt->base + GEMINI_WDCR); + + clear_bit(WDT_ACTIVE, &gemini_wdt->status); + + spin_unlock(&gemini_wdt_lock); +} + +/* Service the watchdog */ +static void gemini_wdt_service(struct gemini_wdt_struct *gemini_wdt) +{ + __raw_writel(WDRESTART_MAGIC, gemini_wdt->base + GEMINI_WDRESTART); +} + +/* Enable and reset the watchdog. */ +static void gemini_wdt_start(struct gemini_wdt_struct *gemini_wdt) +{ + spin_lock(&gemini_wdt_lock); + + __raw_writel(timeout * WDT_CLOCK, gemini_wdt->base + GEMINI_WDLOAD); + + gemini_wdt_service(gemini_wdt); + + /* set clock before enabling */ + __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST, + gemini_wdt->base + GEMINI_WDCR); + + __raw_writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE, + gemini_wdt->base + GEMINI_WDCR); + + set_bit(WDT_ACTIVE, &gemini_wdt->status); + + spin_unlock(&gemini_wdt_lock); +} + +/* Watchdog device is opened, and watchdog starts running. */ +static int gemini_wdt_open(struct inode *inode, struct file *file) +{ + struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(gemini_wdt_dev); + + if (test_bit(WDT_ACTIVE, &gemini_wdt->status)) + return -EBUSY; + + file->private_data = gemini_wdt; + + gemini_wdt_start(gemini_wdt); + + return nonseekable_open(inode, file); +} + +/* Close the watchdog device. */ +static int gemini_wdt_close(struct inode *inode, struct file *file) +{ + struct gemini_wdt_struct *gemini_wdt = file->private_data; + + /* Disable the watchdog if possible */ + if (test_bit(WDT_OK_TO_CLOSE, &gemini_wdt->status)) + gemini_wdt_stop(gemini_wdt); + else + dev_warn(gemini_wdt->dev, "Device closed unexpectedly - timer will not stop\n"); + + return 0; +} + +/* Handle commands from user-space. */ +static long gemini_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct gemini_wdt_struct *gemini_wdt = file->private_data; + + int value; + + switch (cmd) { + case WDIOC_KEEPALIVE: + gemini_wdt_service(gemini_wdt); + return 0; + + case WDIOC_GETSUPPORT: + return copy_to_user((struct watchdog_info *)arg, &gemini_wdt_info, + sizeof(gemini_wdt_info)) ? -EFAULT : 0; + + case WDIOC_SETTIMEOUT: + if (get_user(value, (int *)arg)) + return -EFAULT; + + if ((value < 1) || (value > WDT_MAX_TIMEOUT)) + return -EINVAL; + + timeout = value; + + /* restart wdt to use new timeout */ + gemini_wdt_stop(gemini_wdt); + gemini_wdt_start(gemini_wdt); + + /* Fall through */ + case WDIOC_GETTIMEOUT: + return put_user(timeout, (int *)arg); + + case WDIOC_GETTIMELEFT: + value = __raw_readl(gemini_wdt->base + GEMINI_WDCOUNTER); + return put_user(value / WDT_CLOCK, (int *)arg); + + default: + return -ENOTTY; + } +} + +/* Refresh the watchdog whenever device is written to. */ +static ssize_t gemini_wdt_write(struct file *file, const char *data, + size_t len, loff_t *ppos) +{ + struct gemini_wdt_struct *gemini_wdt = file->private_data; + + if (len) { + if (!nowayout) { + size_t i; + + clear_bit(WDT_OK_TO_CLOSE, &gemini_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, + &gemini_wdt->status); + } + } + gemini_wdt_service(gemini_wdt); + } + + return len; +} + +static const struct file_operations gemini_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .unlocked_ioctl = gemini_wdt_ioctl, + .open = gemini_wdt_open, + .release = gemini_wdt_close, + .write = gemini_wdt_write, +}; + +static struct miscdevice gemini_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &gemini_wdt_fops, +}; + +static void gemini_wdt_shutdown(struct platform_device *pdev) +{ + struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev); + + gemini_wdt_stop(gemini_wdt); +} + +static int gemini_wdt_probe(struct platform_device *pdev) +{ + int ret; + int res_size; + struct resource *res; + void __iomem *base; + struct gemini_wdt_struct *gemini_wdt; + unsigned int reg; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&pdev->dev, "can't get device resources\n"); + return -ENODEV; + } + + res_size = resource_size(res); + if (!request_mem_region(res->start, res_size, res->name)) { + dev_err(&pdev->dev, "can't allocate %d bytes at %d address\n", + res_size, res->start); + return -ENOMEM; + } + + base = ioremap(res->start, res_size); + if (!base) { + dev_err(&pdev->dev, "ioremap failed\n"); + ret = -EIO; + goto fail0; + } + + gemini_wdt = kzalloc(sizeof(struct gemini_wdt_struct), GFP_KERNEL); + if (!gemini_wdt) { + dev_err(&pdev->dev, "can't allocate interface\n"); + ret = -ENOMEM; + goto fail1; + } + + /* Setup gemini_wdt driver structure */ + gemini_wdt->base = base; + gemini_wdt->res = res; + + /* Set up platform driver data */ + platform_set_drvdata(pdev, gemini_wdt); + gemini_wdt_dev = pdev; + + if (gemini_wdt_miscdev.parent) { + ret = -EBUSY; + goto fail2; + } + + gemini_wdt_miscdev.parent = &pdev->dev; + + reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR); + if (reg & WDCR_ENABLE) { + /* Watchdog was enabled by the bootloader, disable it. */ + reg &= ~(WDCR_ENABLE); + __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR); + } + + ret = misc_register(&gemini_wdt_miscdev); + if (ret) + goto fail2; + + return 0; + +fail2: + platform_set_drvdata(pdev, NULL); + kfree(gemini_wdt); +fail1: + iounmap(base); +fail0: + release_mem_region(res->start, res_size); + + return ret; +} + +static int gemini_wdt_remove(struct platform_device *pdev) +{ + struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev); + + platform_set_drvdata(pdev, NULL); + misc_deregister(&gemini_wdt_miscdev); + gemini_wdt_dev = NULL; + iounmap(gemini_wdt->base); + release_mem_region(gemini_wdt->res->start, resource_size(gemini_wdt->res)); + + kfree(gemini_wdt); + + return 0; +} + +#ifdef CONFIG_PM +static int gemini_wdt_suspend(struct platform_device *pdev, pm_message_t message) +{ + struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev); + unsigned int reg; + + reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR); + reg &= ~(WDCR_WDENABLE); + __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR); + + return 0; +} + +static int gemini_wdt_resume(struct platform_device *pdev) +{ + struct gemini_wdt_struct *gemini_wdt = platform_get_drvdata(pdev); + unsigned int reg; + + if (gemini_wdt->status) { + reg = __raw_readw(gemini_wdt->base + GEMINI_WDCR); + reg |= WDCR_WDENABLE; + __raw_writel(reg, gemini_wdt->base + GEMINI_WDCR); + } + + return 0; +} +#else +#define gemini_wdt_suspend NULL +#define gemini_wdt_resume NULL +#endif + +static struct platform_driver gemini_wdt_driver = { + .probe = gemini_wdt_probe, + .remove = gemini_wdt_remove, + .shutdown = gemini_wdt_shutdown, + .suspend = gemini_wdt_suspend, + .resume = gemini_wdt_resume, + .driver = { + .name = "gemini-wdt", + .owner = THIS_MODULE, + }, +}; + +static int __init gemini_wdt_init(void) +{ + return platform_driver_probe(&gemini_wdt_driver, gemini_wdt_probe); +} + +static void __exit gemini_wdt_exit(void) +{ + platform_driver_unregister(&gemini_wdt_driver); +} + +module_init(gemini_wdt_init); +module_exit(gemini_wdt_exit); + +module_param(timeout, uint, 0); +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds"); + +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); + +MODULE_AUTHOR("Paulius Zaleckas"); +MODULE_DESCRIPTION("Watchdog driver for Gemini"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); +MODULE_ALIAS("platform:gemini-wdt"); --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -198,6 +198,16 @@ config 977_WATCHDOG Not sure? It's safe to say N. +config GEMINI_WATCHDOG + tristate "Gemini watchdog" + depends on ARCH_GEMINI + help + Say Y here if to include support for the watchdog timer + embedded in the Cortina Systems Gemini family of devices. + + To compile this driver as a module, choose M here: the + module will be called gemini_wdt. + config IXP4XX_WATCHDOG tristate "IXP4xx Watchdog" depends on ARCH_IXP4XX --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -37,6 +37,7 @@ obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt. obj-$(CONFIG_TWL4030_WATCHDOG) += twl4030_wdt.o obj-$(CONFIG_21285_WATCHDOG) += wdt285.o obj-$(CONFIG_977_WATCHDOG) += wdt977.o +obj-$(CONFIG_GEMINI_WATCHDOG) += gemini_wdt.o obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o