+++ /dev/null
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * drivers/watchdog/ar7_wdt.c
- *
- * Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
- * Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
- *
- * Some code taken from:
- * National Semiconductor SCx200 Watchdog support
- * Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
- *
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/errno.h>
-#include <linux/miscdevice.h>
-#include <linux/platform_device.h>
-#include <linux/watchdog.h>
-#include <linux/fs.h>
-#include <linux/ioport.h>
-#include <linux/io.h>
-#include <linux/uaccess.h>
-#include <linux/clk.h>
-
-#include <asm/addrspace.h>
-#include <asm/mach-ar7/ar7.h>
-
-#define LONGNAME "TI AR7 Watchdog Timer"
-
-MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
-MODULE_DESCRIPTION(LONGNAME);
-MODULE_LICENSE("GPL");
-
-static int margin = 60;
-module_param(margin, int, 0);
-MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
-
-static bool nowayout = WATCHDOG_NOWAYOUT;
-module_param(nowayout, bool, 0);
-MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
-
-#define READ_REG(x) readl((void __iomem *)&(x))
-#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
-
-struct ar7_wdt {
- u32 kick_lock;
- u32 kick;
- u32 change_lock;
- u32 change;
- u32 disable_lock;
- u32 disable;
- u32 prescale_lock;
- u32 prescale;
-};
-
-static unsigned long wdt_is_open;
-static unsigned expect_close;
-static DEFINE_SPINLOCK(wdt_lock);
-
-/* XXX currently fixed, allows max margin ~68.72 secs */
-#define prescale_value 0xffff
-
-/* Pointer to the remapped WDT IO space */
-static struct ar7_wdt *ar7_wdt;
-
-static struct clk *vbus_clk;
-
-static void ar7_wdt_kick(u32 value)
-{
- WRITE_REG(ar7_wdt->kick_lock, 0x5555);
- if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
- WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
- if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
- WRITE_REG(ar7_wdt->kick, value);
- return;
- }
- }
- pr_err("failed to unlock WDT kick reg\n");
-}
-
-static void ar7_wdt_prescale(u32 value)
-{
- WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
- if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
- WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
- if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
- WRITE_REG(ar7_wdt->prescale, value);
- return;
- }
- }
- pr_err("failed to unlock WDT prescale reg\n");
-}
-
-static void ar7_wdt_change(u32 value)
-{
- WRITE_REG(ar7_wdt->change_lock, 0x6666);
- if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
- WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
- if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
- WRITE_REG(ar7_wdt->change, value);
- return;
- }
- }
- pr_err("failed to unlock WDT change reg\n");
-}
-
-static void ar7_wdt_disable(u32 value)
-{
- WRITE_REG(ar7_wdt->disable_lock, 0x7777);
- if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
- WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
- if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
- WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
- if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
- WRITE_REG(ar7_wdt->disable, value);
- return;
- }
- }
- }
- pr_err("failed to unlock WDT disable reg\n");
-}
-
-static void ar7_wdt_update_margin(int new_margin)
-{
- u32 change;
- u32 vbus_rate;
-
- vbus_rate = clk_get_rate(vbus_clk);
- change = new_margin * (vbus_rate / prescale_value);
- if (change < 1)
- change = 1;
- if (change > 0xffff)
- change = 0xffff;
- ar7_wdt_change(change);
- margin = change * prescale_value / vbus_rate;
- pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
- margin, prescale_value, change, vbus_rate);
-}
-
-static void ar7_wdt_enable_wdt(void)
-{
- pr_debug("enabling watchdog timer\n");
- ar7_wdt_disable(1);
- ar7_wdt_kick(1);
-}
-
-static void ar7_wdt_disable_wdt(void)
-{
- pr_debug("disabling watchdog timer\n");
- ar7_wdt_disable(0);
-}
-
-static int ar7_wdt_open(struct inode *inode, struct file *file)
-{
- /* only allow one at a time */
- if (test_and_set_bit(0, &wdt_is_open))
- return -EBUSY;
- ar7_wdt_enable_wdt();
- expect_close = 0;
-
- return stream_open(inode, file);
-}
-
-static int ar7_wdt_release(struct inode *inode, struct file *file)
-{
- if (!expect_close)
- pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
- else if (!nowayout)
- ar7_wdt_disable_wdt();
- clear_bit(0, &wdt_is_open);
- return 0;
-}
-
-static ssize_t ar7_wdt_write(struct file *file, const char *data,
- size_t len, loff_t *ppos)
-{
- /* check for a magic close character */
- if (len) {
- size_t i;
-
- spin_lock(&wdt_lock);
- ar7_wdt_kick(1);
- spin_unlock(&wdt_lock);
-
- expect_close = 0;
- for (i = 0; i < len; ++i) {
- char c;
- if (get_user(c, data + i))
- return -EFAULT;
- if (c == 'V')
- expect_close = 1;
- }
-
- }
- return len;
-}
-
-static long ar7_wdt_ioctl(struct file *file,
- unsigned int cmd, unsigned long arg)
-{
- static const struct watchdog_info ident = {
- .identity = LONGNAME,
- .firmware_version = 1,
- .options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
- WDIOF_MAGICCLOSE),
- };
- int new_margin;
-
- switch (cmd) {
- case WDIOC_GETSUPPORT:
- if (copy_to_user((struct watchdog_info *)arg, &ident,
- sizeof(ident)))
- return -EFAULT;
- return 0;
- case WDIOC_GETSTATUS:
- case WDIOC_GETBOOTSTATUS:
- if (put_user(0, (int *)arg))
- return -EFAULT;
- return 0;
- case WDIOC_KEEPALIVE:
- ar7_wdt_kick(1);
- return 0;
- case WDIOC_SETTIMEOUT:
- if (get_user(new_margin, (int *)arg))
- return -EFAULT;
- if (new_margin < 1)
- return -EINVAL;
-
- spin_lock(&wdt_lock);
- ar7_wdt_update_margin(new_margin);
- ar7_wdt_kick(1);
- spin_unlock(&wdt_lock);
- fallthrough;
- case WDIOC_GETTIMEOUT:
- if (put_user(margin, (int *)arg))
- return -EFAULT;
- return 0;
- default:
- return -ENOTTY;
- }
-}
-
-static const struct file_operations ar7_wdt_fops = {
- .owner = THIS_MODULE,
- .write = ar7_wdt_write,
- .unlocked_ioctl = ar7_wdt_ioctl,
- .compat_ioctl = compat_ptr_ioctl,
- .open = ar7_wdt_open,
- .release = ar7_wdt_release,
- .llseek = no_llseek,
-};
-
-static struct miscdevice ar7_wdt_miscdev = {
- .minor = WATCHDOG_MINOR,
- .name = "watchdog",
- .fops = &ar7_wdt_fops,
-};
-
-static int ar7_wdt_probe(struct platform_device *pdev)
-{
- int rc;
-
- ar7_wdt = devm_platform_ioremap_resource_byname(pdev, "regs");
- if (IS_ERR(ar7_wdt))
- return PTR_ERR(ar7_wdt);
-
- vbus_clk = clk_get(NULL, "vbus");
- if (IS_ERR(vbus_clk)) {
- pr_err("could not get vbus clock\n");
- return PTR_ERR(vbus_clk);
- }
-
- ar7_wdt_disable_wdt();
- ar7_wdt_prescale(prescale_value);
- ar7_wdt_update_margin(margin);
-
- rc = misc_register(&ar7_wdt_miscdev);
- if (rc) {
- pr_err("unable to register misc device\n");
- goto out;
- }
- return 0;
-
-out:
- clk_put(vbus_clk);
- vbus_clk = NULL;
- return rc;
-}
-
-static void ar7_wdt_remove(struct platform_device *pdev)
-{
- misc_deregister(&ar7_wdt_miscdev);
- clk_put(vbus_clk);
- vbus_clk = NULL;
-}
-
-static void ar7_wdt_shutdown(struct platform_device *pdev)
-{
- if (!nowayout)
- ar7_wdt_disable_wdt();
-}
-
-static struct platform_driver ar7_wdt_driver = {
- .probe = ar7_wdt_probe,
- .remove_new = ar7_wdt_remove,
- .shutdown = ar7_wdt_shutdown,
- .driver = {
- .name = "ar7_wdt",
- },
-};
-
-module_platform_driver(ar7_wdt_driver);
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