// 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 [31mCONFIG_DEBUG_FS[0m
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 [31mCONFIG_DEBUG_FS[0m
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 int 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;
return 0;
}
static struct platform_driver ie6xx_wdt_driver = {
.probe = ie6xx_wdt_probe,
.remove = 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);