+++ /dev/null
-/*
- * Watchdog driver for Atmel AT32AP700X devices
- *
- * Copyright (C) 2005-2006 Atmel Corporation
- *
- * 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.
- *
- *
- * Errata: WDT Clear is blocked after WDT Reset
- *
- * A watchdog timer event will, after reset, block writes to the WDT_CLEAR
- * register, preventing the program to clear the next Watchdog Timer Reset.
- *
- * If you still want to use the WDT after a WDT reset a small code can be
- * insterted at the startup checking the AVR32_PM.rcause register for WDT reset
- * and use a GPIO pin to reset the system. This method requires that one of the
- * GPIO pins are available and connected externally to the RESET_N pin. After
- * the GPIO pin has pulled down the reset line the GPIO will be reset and leave
- * the pin tristated with pullup.
- */
-
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/miscdevice.h>
-#include <linux/fs.h>
-#include <linux/platform_device.h>
-#include <linux/watchdog.h>
-#include <linux/uaccess.h>
-#include <linux/io.h>
-#include <linux/spinlock.h>
-#include <linux/slab.h>
-
-#define TIMEOUT_MIN 1
-#define TIMEOUT_MAX 2
-#define TIMEOUT_DEFAULT TIMEOUT_MAX
-
-/* module parameters */
-static int timeout = TIMEOUT_DEFAULT;
-module_param(timeout, int, 0);
-MODULE_PARM_DESC(timeout,
- "Timeout value. Limited to be 1 or 2 seconds. (default="
- __MODULE_STRING(TIMEOUT_DEFAULT) ")");
-
-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) ")");
-
-/* Watchdog registers and write/read macro */
-#define WDT_CTRL 0x00
-#define WDT_CTRL_EN 0
-#define WDT_CTRL_PSEL 8
-#define WDT_CTRL_KEY 24
-
-#define WDT_CLR 0x04
-
-#define WDT_RCAUSE 0x10
-#define WDT_RCAUSE_POR 0
-#define WDT_RCAUSE_EXT 2
-#define WDT_RCAUSE_WDT 3
-#define WDT_RCAUSE_JTAG 4
-#define WDT_RCAUSE_SERP 5
-
-#define WDT_BIT(name) (1 << WDT_##name)
-#define WDT_BF(name, value) ((value) << WDT_##name)
-
-#define wdt_readl(dev, reg) \
- __raw_readl((dev)->regs + WDT_##reg)
-#define wdt_writel(dev, reg, value) \
- __raw_writel((value), (dev)->regs + WDT_##reg)
-
-struct wdt_at32ap700x {
- void __iomem *regs;
- spinlock_t io_lock;
- int timeout;
- int boot_status;
- unsigned long users;
- struct miscdevice miscdev;
-};
-
-static struct wdt_at32ap700x *wdt;
-static char expect_release;
-
-/*
- * Disable the watchdog.
- */
-static inline void at32_wdt_stop(void)
-{
- unsigned long psel;
-
- spin_lock(&wdt->io_lock);
- psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f);
- wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55));
- wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa));
- spin_unlock(&wdt->io_lock);
-}
-
-/*
- * Enable and reset the watchdog.
- */
-static inline void at32_wdt_start(void)
-{
- /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */
- unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe;
-
- spin_lock(&wdt->io_lock);
- wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
- | WDT_BF(CTRL_PSEL, psel)
- | WDT_BF(CTRL_KEY, 0x55));
- wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN)
- | WDT_BF(CTRL_PSEL, psel)
- | WDT_BF(CTRL_KEY, 0xaa));
- spin_unlock(&wdt->io_lock);
-}
-
-/*
- * Pat the watchdog timer.
- */
-static inline void at32_wdt_pat(void)
-{
- spin_lock(&wdt->io_lock);
- wdt_writel(wdt, CLR, 0x42);
- spin_unlock(&wdt->io_lock);
-}
-
-/*
- * Watchdog device is opened, and watchdog starts running.
- */
-static int at32_wdt_open(struct inode *inode, struct file *file)
-{
- if (test_and_set_bit(1, &wdt->users))
- return -EBUSY;
-
- at32_wdt_start();
- return nonseekable_open(inode, file);
-}
-
-/*
- * Close the watchdog device.
- */
-static int at32_wdt_close(struct inode *inode, struct file *file)
-{
- if (expect_release == 42) {
- at32_wdt_stop();
- } else {
- dev_dbg(wdt->miscdev.parent,
- "unexpected close, not stopping watchdog!\n");
- at32_wdt_pat();
- }
- clear_bit(1, &wdt->users);
- expect_release = 0;
- return 0;
-}
-
-/*
- * Change the watchdog time interval.
- */
-static int at32_wdt_settimeout(int time)
-{
- /*
- * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is
- * 2 ^ 16 allowing up to 2 seconds timeout.
- */
- if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX))
- return -EINVAL;
-
- /*
- * Set new watchdog time. It will be used when at32_wdt_start() is
- * called.
- */
- wdt->timeout = time;
- return 0;
-}
-
-/*
- * Get the watchdog status.
- */
-static int at32_wdt_get_status(void)
-{
- int rcause;
- int status = 0;
-
- rcause = wdt_readl(wdt, RCAUSE);
-
- switch (rcause) {
- case WDT_BIT(RCAUSE_EXT):
- status = WDIOF_EXTERN1;
- break;
- case WDT_BIT(RCAUSE_WDT):
- status = WDIOF_CARDRESET;
- break;
- case WDT_BIT(RCAUSE_POR): /* fall through */
- case WDT_BIT(RCAUSE_JTAG): /* fall through */
- case WDT_BIT(RCAUSE_SERP): /* fall through */
- default:
- break;
- }
-
- return status;
-}
-
-static const struct watchdog_info at32_wdt_info = {
- .identity = "at32ap700x watchdog",
- .options = WDIOF_SETTIMEOUT |
- WDIOF_KEEPALIVEPING |
- WDIOF_MAGICCLOSE,
-};
-
-/*
- * Handle commands from user-space.
- */
-static long at32_wdt_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, &at32_wdt_info,
- sizeof(at32_wdt_info)) ? -EFAULT : 0;
- break;
- case WDIOC_GETSTATUS:
- ret = put_user(0, p);
- break;
- case WDIOC_GETBOOTSTATUS:
- ret = put_user(wdt->boot_status, p);
- break;
- case WDIOC_SETOPTIONS:
- ret = get_user(time, p);
- if (ret)
- break;
- if (time & WDIOS_DISABLECARD)
- at32_wdt_stop();
- if (time & WDIOS_ENABLECARD)
- at32_wdt_start();
- ret = 0;
- break;
- case WDIOC_KEEPALIVE:
- at32_wdt_pat();
- ret = 0;
- break;
- case WDIOC_SETTIMEOUT:
- ret = get_user(time, p);
- if (ret)
- break;
- ret = at32_wdt_settimeout(time);
- if (ret)
- break;
- /* Enable new time value */
- at32_wdt_start();
- /* fall through */
- case WDIOC_GETTIMEOUT:
- ret = put_user(wdt->timeout, p);
- break;
- }
-
- return ret;
-}
-
-static ssize_t at32_wdt_write(struct file *file, const char __user *data,
- size_t len, loff_t *ppos)
-{
- /* See if we got the magic character 'V' and reload the timer */
- if (len) {
- if (!nowayout) {
- size_t i;
-
- /*
- * note: just in case someone wrote the magic
- * character five months ago...
- */
- expect_release = 0;
-
- /*
- * scan to see whether or not we got the magic
- * character
- */
- for (i = 0; i != len; i++) {
- char c;
- if (get_user(c, data + i))
- return -EFAULT;
- if (c == 'V')
- expect_release = 42;
- }
- }
- /* someone wrote to us, we should pat the watchdog */
- at32_wdt_pat();
- }
- return len;
-}
-
-static const struct file_operations at32_wdt_fops = {
- .owner = THIS_MODULE,
- .llseek = no_llseek,
- .unlocked_ioctl = at32_wdt_ioctl,
- .open = at32_wdt_open,
- .release = at32_wdt_close,
- .write = at32_wdt_write,
-};
-
-static int __init at32_wdt_probe(struct platform_device *pdev)
-{
- struct resource *regs;
- int ret;
-
- if (wdt) {
- dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n");
- return -EBUSY;
- }
-
- regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- if (!regs) {
- dev_dbg(&pdev->dev, "missing mmio resource\n");
- return -ENXIO;
- }
-
- wdt = devm_kzalloc(&pdev->dev, sizeof(struct wdt_at32ap700x),
- GFP_KERNEL);
- if (!wdt)
- return -ENOMEM;
-
- wdt->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
- if (!wdt->regs) {
- ret = -ENOMEM;
- dev_dbg(&pdev->dev, "could not map I/O memory\n");
- goto err_free;
- }
-
- spin_lock_init(&wdt->io_lock);
- wdt->boot_status = at32_wdt_get_status();
-
- /* Work-around for watchdog silicon errata. */
- if (wdt->boot_status & WDIOF_CARDRESET) {
- dev_info(&pdev->dev, "CPU must be reset with external "
- "reset or POR due to silicon errata.\n");
- ret = -EIO;
- goto err_free;
- } else {
- wdt->users = 0;
- }
-
- wdt->miscdev.minor = WATCHDOG_MINOR;
- wdt->miscdev.name = "watchdog";
- wdt->miscdev.fops = &at32_wdt_fops;
- wdt->miscdev.parent = &pdev->dev;
-
- platform_set_drvdata(pdev, wdt);
-
- if (at32_wdt_settimeout(timeout)) {
- at32_wdt_settimeout(TIMEOUT_DEFAULT);
- dev_dbg(&pdev->dev,
- "default timeout invalid, set to %d sec.\n",
- TIMEOUT_DEFAULT);
- }
-
- ret = misc_register(&wdt->miscdev);
- if (ret) {
- dev_dbg(&pdev->dev, "failed to register wdt miscdev\n");
- goto err_free;
- }
-
- dev_info(&pdev->dev,
- "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n",
- wdt->regs, wdt->timeout, nowayout);
-
- return 0;
-
-err_free:
- wdt = NULL;
- return ret;
-}
-
-static int __exit at32_wdt_remove(struct platform_device *pdev)
-{
- if (wdt && platform_get_drvdata(pdev) == wdt) {
- /* Stop the timer before we leave */
- if (!nowayout)
- at32_wdt_stop();
-
- misc_deregister(&wdt->miscdev);
- wdt = NULL;
- }
- return 0;
-}
-
-static void at32_wdt_shutdown(struct platform_device *pdev)
-{
- at32_wdt_stop();
-}
-
-#ifdef CONFIG_PM
-static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message)
-{
- at32_wdt_stop();
- return 0;
-}
-
-static int at32_wdt_resume(struct platform_device *pdev)
-{
- if (wdt->users)
- at32_wdt_start();
- return 0;
-}
-#else
-#define at32_wdt_suspend NULL
-#define at32_wdt_resume NULL
-#endif
-
-/* work with hotplug and coldplug */
-MODULE_ALIAS("platform:at32_wdt");
-
-static struct platform_driver at32_wdt_driver = {
- .remove = __exit_p(at32_wdt_remove),
- .suspend = at32_wdt_suspend,
- .resume = at32_wdt_resume,
- .driver = {
- .name = "at32_wdt",
- },
- .shutdown = at32_wdt_shutdown,
-};
-
-module_platform_driver_probe(at32_wdt_driver, at32_wdt_probe);
-
-MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
-MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X");
-MODULE_LICENSE("GPL");
projects / platform / kernel / linux-starfive.git / commitdiff