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linux/drivers/watchdog/ie6xx_wdt.c
Uwe Kleine-König e395a47159 watchdog: ie6xx: 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/20230303213716.2123717-16-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 12:53:46 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel Atom E6xx Watchdog driver
*
* Copyright (C) 2011 Alexander Stein
* <alexander.stein@systec-electronic.com>
*/
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/spinlock.h>
#define DRIVER_NAME "ie6xx_wdt"
#define PV1 0x00
#define PV2 0x04
#define RR0 0x0c
#define RR1 0x0d
#define WDT_RELOAD 0x01
#define WDT_TOUT 0x02
#define WDTCR 0x10
#define WDT_PRE_SEL 0x04
#define WDT_RESET_SEL 0x08
#define WDT_RESET_EN 0x10
#define WDT_TOUT_EN 0x20
#define DCR 0x14
#define WDTLR 0x18
#define WDT_LOCK 0x01
#define WDT_ENABLE 0x02
#define WDT_TOUT_CNF 0x03
#define MIN_TIME 1
#define MAX_TIME (10 * 60) /* 10 minutes */
#define DEFAULT_TIME 60
static unsigned int timeout = DEFAULT_TIME;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Default Watchdog timer setting ("
__MODULE_STRING(DEFAULT_TIME) "s)."
"The range is from 1 to 600");
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) ")");
static u8 resetmode = 0x10;
module_param(resetmode, byte, 0);
MODULE_PARM_DESC(resetmode,
"Resetmode bits: 0x08 warm reset (cold reset otherwise), "
"0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");
static struct {
unsigned short sch_wdtba;
spinlock_t unlock_sequence;
#ifdef CONFIG_DEBUG_FS
struct dentry *debugfs;
#endif
} ie6xx_wdt_data;
/*
* This is needed to write to preload and reload registers
* struct ie6xx_wdt_data.unlock_sequence must be used
* to prevent sequence interrupts
*/
static void ie6xx_wdt_unlock_registers(void)
{
outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);
outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);
}
static int ie6xx_wdt_ping(struct watchdog_device *wdd)
{
spin_lock(&ie6xx_wdt_data.unlock_sequence);
ie6xx_wdt_unlock_registers();
outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);
spin_unlock(&ie6xx_wdt_data.unlock_sequence);
return 0;
}
static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
{
u32 preload;
u64 clock;
u8 wdtcr;
/* Watchdog clock is PCI Clock (33MHz) */
clock = 33000000;
/* and the preload value is loaded into [34:15] of the down counter */
preload = (t * clock) >> 15;
/*
* Manual states preload must be one less.
* Does not wrap as t is at least 1
*/
preload -= 1;
spin_lock(&ie6xx_wdt_data.unlock_sequence);
/* Set ResetMode & Enable prescaler for range 10ms to 10 min */
wdtcr = resetmode & 0x38;
outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);
ie6xx_wdt_unlock_registers();
outl(0, ie6xx_wdt_data.sch_wdtba + PV1);
ie6xx_wdt_unlock_registers();
outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);
ie6xx_wdt_unlock_registers();
outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);
spin_unlock(&ie6xx_wdt_data.unlock_sequence);
wdd->timeout = t;
return 0;
}
static int ie6xx_wdt_start(struct watchdog_device *wdd)
{
ie6xx_wdt_set_timeout(wdd, wdd->timeout);
/* Enable the watchdog timer */
spin_lock(&ie6xx_wdt_data.unlock_sequence);
outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);
spin_unlock(&ie6xx_wdt_data.unlock_sequence);
return 0;
}
static int ie6xx_wdt_stop(struct watchdog_device *wdd)
{
if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)
return -1;
/* Disable the watchdog timer */
spin_lock(&ie6xx_wdt_data.unlock_sequence);
outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);
spin_unlock(&ie6xx_wdt_data.unlock_sequence);
return 0;
}
static const struct watchdog_info ie6xx_wdt_info = {
.identity = "Intel Atom E6xx Watchdog",
.options = WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
};
static const struct watchdog_ops ie6xx_wdt_ops = {
.owner = THIS_MODULE,
.start = ie6xx_wdt_start,
.stop = ie6xx_wdt_stop,
.ping = ie6xx_wdt_ping,
.set_timeout = ie6xx_wdt_set_timeout,
};
static struct watchdog_device ie6xx_wdt_dev = {
.info = &ie6xx_wdt_info,
.ops = &ie6xx_wdt_ops,
.min_timeout = MIN_TIME,
.max_timeout = MAX_TIME,
};
#ifdef CONFIG_DEBUG_FS
static int ie6xx_wdt_show(struct seq_file *s, void *unused)
{
seq_printf(s, "PV1 = 0x%08x\n",
inl(ie6xx_wdt_data.sch_wdtba + PV1));
seq_printf(s, "PV2 = 0x%08x\n",
inl(ie6xx_wdt_data.sch_wdtba + PV2));
seq_printf(s, "RR = 0x%08x\n",
inw(ie6xx_wdt_data.sch_wdtba + RR0));
seq_printf(s, "WDTCR = 0x%08x\n",
inw(ie6xx_wdt_data.sch_wdtba + WDTCR));
seq_printf(s, "DCR = 0x%08x\n",
inl(ie6xx_wdt_data.sch_wdtba + DCR));
seq_printf(s, "WDTLR = 0x%08x\n",
inw(ie6xx_wdt_data.sch_wdtba + WDTLR));
seq_printf(s, "\n");
return 0;
}
DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt);
static void ie6xx_wdt_debugfs_init(void)
{
/* /sys/kernel/debug/ie6xx_wdt */
ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",
S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops);
}
static void ie6xx_wdt_debugfs_exit(void)
{
debugfs_remove(ie6xx_wdt_data.debugfs);
}
#else
static void ie6xx_wdt_debugfs_init(void)
{
}
static void ie6xx_wdt_debugfs_exit(void)
{
}
#endif
static int ie6xx_wdt_probe(struct platform_device *pdev)
{
struct resource *res;
u8 wdtlr;
int ret;
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
if (!res)
return -ENODEV;
if (!request_region(res->start, resource_size(res), pdev->name)) {
dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",
(u64)res->start);
return -EBUSY;
}
ie6xx_wdt_data.sch_wdtba = res->start;
dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);
ie6xx_wdt_dev.timeout = timeout;
watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);
ie6xx_wdt_dev.parent = &pdev->dev;
spin_lock_init(&ie6xx_wdt_data.unlock_sequence);
wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);
if (wdtlr & WDT_LOCK)
dev_warn(&pdev->dev,
"Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);
ie6xx_wdt_debugfs_init();
ret = watchdog_register_device(&ie6xx_wdt_dev);
if (ret)
goto misc_register_error;
return 0;
misc_register_error:
ie6xx_wdt_debugfs_exit();
release_region(res->start, resource_size(res));
ie6xx_wdt_data.sch_wdtba = 0;
return ret;
}
static void ie6xx_wdt_remove(struct platform_device *pdev)
{
struct resource *res;
res = platform_get_resource(pdev, IORESOURCE_IO, 0);
ie6xx_wdt_stop(NULL);
watchdog_unregister_device(&ie6xx_wdt_dev);
ie6xx_wdt_debugfs_exit();
release_region(res->start, resource_size(res));
ie6xx_wdt_data.sch_wdtba = 0;
}
static struct platform_driver ie6xx_wdt_driver = {
.probe = ie6xx_wdt_probe,
.remove_new = ie6xx_wdt_remove,
.driver = {
.name = DRIVER_NAME,
},
};
static int __init ie6xx_wdt_init(void)
{
/* Check boot parameters to verify that their initial values */
/* are in range. */
if ((timeout < MIN_TIME) ||
(timeout > MAX_TIME)) {
pr_err("Watchdog timer: value of timeout %d (dec) "
"is out of range from %d to %d (dec)\n",
timeout, MIN_TIME, MAX_TIME);
return -EINVAL;
}
return platform_driver_register(&ie6xx_wdt_driver);
}
static void __exit ie6xx_wdt_exit(void)
{
platform_driver_unregister(&ie6xx_wdt_driver);
}
late_initcall(ie6xx_wdt_init);
module_exit(ie6xx_wdt_exit);
MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" DRIVER_NAME);
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