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fa21a580de
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
332 lines
7.7 KiB
C
332 lines
7.7 KiB
C
/*
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* drivers/watchdog/ar7_wdt.c
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*
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* Copyright (C) 2007 Nicolas Thill <nico@openwrt.org>
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* Copyright (c) 2005 Enrik Berkhan <Enrik.Berkhan@akk.org>
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*
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* Some code taken from:
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* National Semiconductor SCx200 Watchdog support
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* Copyright (c) 2001,2002 Christer Weinigel <wingel@nano-system.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/errno.h>
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#include <linux/miscdevice.h>
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#include <linux/platform_device.h>
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#include <linux/watchdog.h>
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#include <linux/fs.h>
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#include <linux/ioport.h>
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#include <linux/io.h>
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#include <linux/uaccess.h>
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#include <linux/clk.h>
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#include <asm/addrspace.h>
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#include <asm/mach-ar7/ar7.h>
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#define LONGNAME "TI AR7 Watchdog Timer"
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MODULE_AUTHOR("Nicolas Thill <nico@openwrt.org>");
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MODULE_DESCRIPTION(LONGNAME);
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MODULE_LICENSE("GPL");
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static int margin = 60;
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module_param(margin, int, 0);
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MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
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#define READ_REG(x) readl((void __iomem *)&(x))
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#define WRITE_REG(x, v) writel((v), (void __iomem *)&(x))
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struct ar7_wdt {
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u32 kick_lock;
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u32 kick;
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u32 change_lock;
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u32 change;
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u32 disable_lock;
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u32 disable;
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u32 prescale_lock;
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u32 prescale;
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};
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static unsigned long wdt_is_open;
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static unsigned expect_close;
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static DEFINE_SPINLOCK(wdt_lock);
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/* XXX currently fixed, allows max margin ~68.72 secs */
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#define prescale_value 0xffff
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/* Resource of the WDT registers */
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static struct resource *ar7_regs_wdt;
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/* Pointer to the remapped WDT IO space */
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static struct ar7_wdt *ar7_wdt;
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static struct clk *vbus_clk;
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static void ar7_wdt_kick(u32 value)
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{
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WRITE_REG(ar7_wdt->kick_lock, 0x5555);
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if ((READ_REG(ar7_wdt->kick_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->kick_lock, 0xaaaa);
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if ((READ_REG(ar7_wdt->kick_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->kick, value);
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return;
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}
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}
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pr_err("failed to unlock WDT kick reg\n");
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}
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static void ar7_wdt_prescale(u32 value)
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{
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WRITE_REG(ar7_wdt->prescale_lock, 0x5a5a);
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if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->prescale_lock, 0xa5a5);
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if ((READ_REG(ar7_wdt->prescale_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->prescale, value);
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return;
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}
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}
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pr_err("failed to unlock WDT prescale reg\n");
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}
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static void ar7_wdt_change(u32 value)
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{
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WRITE_REG(ar7_wdt->change_lock, 0x6666);
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if ((READ_REG(ar7_wdt->change_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->change_lock, 0xbbbb);
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if ((READ_REG(ar7_wdt->change_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->change, value);
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return;
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}
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}
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pr_err("failed to unlock WDT change reg\n");
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}
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static void ar7_wdt_disable(u32 value)
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{
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WRITE_REG(ar7_wdt->disable_lock, 0x7777);
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if ((READ_REG(ar7_wdt->disable_lock) & 3) == 1) {
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WRITE_REG(ar7_wdt->disable_lock, 0xcccc);
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if ((READ_REG(ar7_wdt->disable_lock) & 3) == 2) {
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WRITE_REG(ar7_wdt->disable_lock, 0xdddd);
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if ((READ_REG(ar7_wdt->disable_lock) & 3) == 3) {
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WRITE_REG(ar7_wdt->disable, value);
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return;
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}
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}
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}
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pr_err("failed to unlock WDT disable reg\n");
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}
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static void ar7_wdt_update_margin(int new_margin)
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{
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u32 change;
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u32 vbus_rate;
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vbus_rate = clk_get_rate(vbus_clk);
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change = new_margin * (vbus_rate / prescale_value);
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if (change < 1)
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change = 1;
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if (change > 0xffff)
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change = 0xffff;
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ar7_wdt_change(change);
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margin = change * prescale_value / vbus_rate;
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pr_info("timer margin %d seconds (prescale %d, change %d, freq %d)\n",
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margin, prescale_value, change, vbus_rate);
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}
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static void ar7_wdt_enable_wdt(void)
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{
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pr_debug("enabling watchdog timer\n");
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ar7_wdt_disable(1);
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ar7_wdt_kick(1);
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}
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static void ar7_wdt_disable_wdt(void)
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{
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pr_debug("disabling watchdog timer\n");
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ar7_wdt_disable(0);
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}
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static int ar7_wdt_open(struct inode *inode, struct file *file)
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{
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/* only allow one at a time */
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if (test_and_set_bit(0, &wdt_is_open))
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return -EBUSY;
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ar7_wdt_enable_wdt();
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expect_close = 0;
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return nonseekable_open(inode, file);
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}
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static int ar7_wdt_release(struct inode *inode, struct file *file)
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{
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if (!expect_close)
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pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
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else if (!nowayout)
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ar7_wdt_disable_wdt();
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clear_bit(0, &wdt_is_open);
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return 0;
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}
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static ssize_t ar7_wdt_write(struct file *file, const char *data,
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size_t len, loff_t *ppos)
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{
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/* check for a magic close character */
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if (len) {
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size_t i;
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spin_lock(&wdt_lock);
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ar7_wdt_kick(1);
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spin_unlock(&wdt_lock);
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expect_close = 0;
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for (i = 0; i < len; ++i) {
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char c;
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if (get_user(c, data + i))
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return -EFAULT;
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if (c == 'V')
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expect_close = 1;
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}
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}
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return len;
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}
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static long ar7_wdt_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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static const struct watchdog_info ident = {
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.identity = LONGNAME,
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.firmware_version = 1,
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.options = (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE),
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};
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int new_margin;
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switch (cmd) {
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case WDIOC_GETSUPPORT:
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if (copy_to_user((struct watchdog_info *)arg, &ident,
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sizeof(ident)))
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return -EFAULT;
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return 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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if (put_user(0, (int *)arg))
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return -EFAULT;
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return 0;
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case WDIOC_KEEPALIVE:
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ar7_wdt_kick(1);
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return 0;
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case WDIOC_SETTIMEOUT:
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if (get_user(new_margin, (int *)arg))
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return -EFAULT;
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if (new_margin < 1)
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return -EINVAL;
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spin_lock(&wdt_lock);
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ar7_wdt_update_margin(new_margin);
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ar7_wdt_kick(1);
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spin_unlock(&wdt_lock);
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case WDIOC_GETTIMEOUT:
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if (put_user(margin, (int *)arg))
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return -EFAULT;
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return 0;
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default:
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return -ENOTTY;
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}
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}
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static const struct file_operations ar7_wdt_fops = {
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.owner = THIS_MODULE,
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.write = ar7_wdt_write,
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.unlocked_ioctl = ar7_wdt_ioctl,
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.open = ar7_wdt_open,
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.release = ar7_wdt_release,
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.llseek = no_llseek,
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};
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static struct miscdevice ar7_wdt_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &ar7_wdt_fops,
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};
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static int ar7_wdt_probe(struct platform_device *pdev)
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{
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int rc;
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ar7_regs_wdt =
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platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
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ar7_wdt = devm_ioremap_resource(&pdev->dev, ar7_regs_wdt);
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if (IS_ERR(ar7_wdt))
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return PTR_ERR(ar7_wdt);
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vbus_clk = clk_get(NULL, "vbus");
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if (IS_ERR(vbus_clk)) {
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pr_err("could not get vbus clock\n");
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return PTR_ERR(vbus_clk);
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}
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ar7_wdt_disable_wdt();
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ar7_wdt_prescale(prescale_value);
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ar7_wdt_update_margin(margin);
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rc = misc_register(&ar7_wdt_miscdev);
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if (rc) {
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pr_err("unable to register misc device\n");
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goto out;
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}
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return 0;
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out:
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clk_put(vbus_clk);
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vbus_clk = NULL;
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return rc;
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}
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static int ar7_wdt_remove(struct platform_device *pdev)
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{
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misc_deregister(&ar7_wdt_miscdev);
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clk_put(vbus_clk);
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vbus_clk = NULL;
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return 0;
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}
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static void ar7_wdt_shutdown(struct platform_device *pdev)
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{
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if (!nowayout)
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ar7_wdt_disable_wdt();
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}
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static struct platform_driver ar7_wdt_driver = {
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.probe = ar7_wdt_probe,
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.remove = ar7_wdt_remove,
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.shutdown = ar7_wdt_shutdown,
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.driver = {
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.name = "ar7_wdt",
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},
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};
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module_platform_driver(ar7_wdt_driver);
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