linux/drivers/watchdog/ar7_wdt.c
Uwe Kleine-König e676c92e9a watchdog: ar7: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230303213716.2123717-5-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-04-22 12:53:41 +02:00

316 lines
6.9 KiB
C

// 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);