+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (c) 2009 Nuvoton technology corporation.
- *
- * Wan ZongShun <mcuos.com@gmail.com>
- */
-
-#include <linux/bitops.h>
-#include <linux/errno.h>
-#include <linux/fs.h>
-#include <linux/io.h>
-#include <linux/clk.h>
-#include <linux/kernel.h>
-#include <linux/miscdevice.h>
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <linux/interrupt.h>
-#include <linux/types.h>
-#include <linux/watchdog.h>
-#include <linux/uaccess.h>
-
-#define REG_WTCR 0x1c
-#define WTCLK (0x01 << 10)
-#define WTE (0x01 << 7) /*wdt enable*/
-#define WTIS (0x03 << 4)
-#define WTIF (0x01 << 3)
-#define WTRF (0x01 << 2)
-#define WTRE (0x01 << 1)
-#define WTR (0x01 << 0)
-/*
- * The watchdog time interval can be calculated via following formula:
- * WTIS real time interval (formula)
- * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds
- * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds
- * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds
- * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds
- *
- * The external crystal freq is 15Mhz in the nuc900 evaluation board.
- * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds,
- * 0x03 = +- 16.92 seconds..
- */
-#define WDT_HW_TIMEOUT 0x02
-#define WDT_TIMEOUT (HZ/2)
-#define WDT_HEARTBEAT 15
-
-static int heartbeat = WDT_HEARTBEAT;
-module_param(heartbeat, int, 0);
-MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
- "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
-
-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) ")");
-
-struct nuc900_wdt {
- struct clk *wdt_clock;
- struct platform_device *pdev;
- void __iomem *wdt_base;
- char expect_close;
- struct timer_list timer;
- spinlock_t wdt_lock;
- unsigned long next_heartbeat;
-};
-
-static unsigned long nuc900wdt_busy;
-static struct nuc900_wdt *nuc900_wdt;
-
-static inline void nuc900_wdt_keepalive(void)
-{
- unsigned int val;
-
- spin_lock(&nuc900_wdt->wdt_lock);
-
- val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
- val |= (WTR | WTIF);
- __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
-
- spin_unlock(&nuc900_wdt->wdt_lock);
-}
-
-static inline void nuc900_wdt_start(void)
-{
- unsigned int val;
-
- spin_lock(&nuc900_wdt->wdt_lock);
-
- val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
- val |= (WTRE | WTE | WTR | WTCLK | WTIF);
- val &= ~WTIS;
- val |= (WDT_HW_TIMEOUT << 0x04);
- __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
-
- spin_unlock(&nuc900_wdt->wdt_lock);
-
- nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
- mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
-}
-
-static inline void nuc900_wdt_stop(void)
-{
- unsigned int val;
-
- del_timer(&nuc900_wdt->timer);
-
- spin_lock(&nuc900_wdt->wdt_lock);
-
- val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR);
- val &= ~WTE;
- __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR);
-
- spin_unlock(&nuc900_wdt->wdt_lock);
-}
-
-static inline void nuc900_wdt_ping(void)
-{
- nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ;
-}
-
-static int nuc900_wdt_open(struct inode *inode, struct file *file)
-{
-
- if (test_and_set_bit(0, &nuc900wdt_busy))
- return -EBUSY;
-
- nuc900_wdt_start();
-
- return stream_open(inode, file);
-}
-
-static int nuc900_wdt_close(struct inode *inode, struct file *file)
-{
- if (nuc900_wdt->expect_close == 42)
- nuc900_wdt_stop();
- else {
- dev_crit(&nuc900_wdt->pdev->dev,
- "Unexpected close, not stopping watchdog!\n");
- nuc900_wdt_ping();
- }
-
- nuc900_wdt->expect_close = 0;
- clear_bit(0, &nuc900wdt_busy);
- return 0;
-}
-
-static const struct watchdog_info nuc900_wdt_info = {
- .identity = "nuc900 watchdog",
- .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
- WDIOF_MAGICCLOSE,
-};
-
-static long nuc900_wdt_ioctl(struct file *file,
- unsigned int cmd, unsigned long arg)
-{
- void __user *argp = (void __user *)arg;
- int __user *p = argp;
- int new_value;
-
- switch (cmd) {
- case WDIOC_GETSUPPORT:
- return copy_to_user(argp, &nuc900_wdt_info,
- sizeof(nuc900_wdt_info)) ? -EFAULT : 0;
- case WDIOC_GETSTATUS:
- case WDIOC_GETBOOTSTATUS:
- return put_user(0, p);
-
- case WDIOC_KEEPALIVE:
- nuc900_wdt_ping();
- return 0;
-
- case WDIOC_SETTIMEOUT:
- if (get_user(new_value, p))
- return -EFAULT;
-
- heartbeat = new_value;
- nuc900_wdt_ping();
-
- return put_user(new_value, p);
- case WDIOC_GETTIMEOUT:
- return put_user(heartbeat, p);
- default:
- return -ENOTTY;
- }
-}
-
-static ssize_t nuc900_wdt_write(struct file *file, const char __user *data,
- size_t len, loff_t *ppos)
-{
- if (!len)
- return 0;
-
- /* Scan for magic character */
- if (!nowayout) {
- size_t i;
-
- nuc900_wdt->expect_close = 0;
-
- for (i = 0; i < len; i++) {
- char c;
- if (get_user(c, data + i))
- return -EFAULT;
- if (c == 'V') {
- nuc900_wdt->expect_close = 42;
- break;
- }
- }
- }
-
- nuc900_wdt_ping();
- return len;
-}
-
-static void nuc900_wdt_timer_ping(struct timer_list *unused)
-{
- if (time_before(jiffies, nuc900_wdt->next_heartbeat)) {
- nuc900_wdt_keepalive();
- mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT);
- } else
- dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n");
-}
-
-static const struct file_operations nuc900wdt_fops = {
- .owner = THIS_MODULE,
- .llseek = no_llseek,
- .unlocked_ioctl = nuc900_wdt_ioctl,
- .open = nuc900_wdt_open,
- .release = nuc900_wdt_close,
- .write = nuc900_wdt_write,
-};
-
-static struct miscdevice nuc900wdt_miscdev = {
- .minor = WATCHDOG_MINOR,
- .name = "watchdog",
- .fops = &nuc900wdt_fops,
-};
-
-static int nuc900wdt_probe(struct platform_device *pdev)
-{
- int ret = 0;
-
- nuc900_wdt = devm_kzalloc(&pdev->dev, sizeof(*nuc900_wdt),
- GFP_KERNEL);
- if (!nuc900_wdt)
- return -ENOMEM;
-
- nuc900_wdt->pdev = pdev;
-
- spin_lock_init(&nuc900_wdt->wdt_lock);
-
- nuc900_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);
- if (IS_ERR(nuc900_wdt->wdt_base))
- return PTR_ERR(nuc900_wdt->wdt_base);
-
- nuc900_wdt->wdt_clock = devm_clk_get(&pdev->dev, NULL);
- if (IS_ERR(nuc900_wdt->wdt_clock)) {
- dev_err(&pdev->dev, "failed to find watchdog clock source\n");
- return PTR_ERR(nuc900_wdt->wdt_clock);
- }
-
- clk_enable(nuc900_wdt->wdt_clock);
-
- timer_setup(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0);
-
- ret = misc_register(&nuc900wdt_miscdev);
- if (ret) {
- dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n",
- WATCHDOG_MINOR, ret);
- goto err_clk;
- }
-
- return 0;
-
-err_clk:
- clk_disable(nuc900_wdt->wdt_clock);
- return ret;
-}
-
-static int nuc900wdt_remove(struct platform_device *pdev)
-{
- misc_deregister(&nuc900wdt_miscdev);
-
- clk_disable(nuc900_wdt->wdt_clock);
-
- return 0;
-}
-
-static struct platform_driver nuc900wdt_driver = {
- .probe = nuc900wdt_probe,
- .remove = nuc900wdt_remove,
- .driver = {
- .name = "nuc900-wdt",
- },
-};
-
-module_platform_driver(nuc900wdt_driver);
-
-MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>");
-MODULE_DESCRIPTION("Watchdog driver for NUC900");
-MODULE_LICENSE("GPL");
-MODULE_ALIAS("platform:nuc900-wdt");
projects / platform / kernel / linux-starfive.git / commitdiff