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linux/drivers/watchdog/it87_wdt.c
Werner Fischer d12971849d watchdog: it87_wdt: Keep WDTCTRL bit 3 unmodified for IT8784/IT8786 
WDTCTRL bit 3 sets the mode choice for the clock input of IT8784/IT8786.
Some motherboards require this bit to be set to 1 (= PCICLK mode),
otherwise the watchdog functionality gets broken. The BIOS of those
motherboards sets WDTCTRL bit 3 already to 1.

Instead of setting all bits of WDTCTRL to 0 by writing 0x00 to it, keep
bit 3 of it unchanged for IT8784/IT8786 chips. In this way, bit 3 keeps
the status as set by the BIOS of the motherboard.

Watchdog tests have been successful with this patch with the following
systems:
  IT8784: Thomas-Krenn LES plus v2 (YANLING YL-KBRL2 V2)
  IT8786: Thomas-Krenn LES plus v3 (YANLING YL-CLU L2)
  IT8786: Thomas-Krenn LES network 6L v2 (YANLING YL-CLU6L)

Link: https://lore.kernel.org/all/140b264d-341f-465b-8715-dacfe84b3f71@roeck-us.net/

Signed-off-by: Werner Fischer <devlists@wefi.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20231213094525.11849-4-devlists@wefi.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2023-12-17 16:14:27 +01:00

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Watchdog Timer Driver
* for ITE IT87xx Environment Control - Low Pin Count Input / Output
*
* (c) Copyright 2007 Oliver Schuster <olivers137@aol.com>
*
* Based on softdog.c by Alan Cox,
* 83977f_wdt.c by Jose Goncalves,
* it87.c by Chris Gauthron, Jean Delvare
*
* Data-sheets: Publicly available at the ITE website
* http://www.ite.com.tw/
*
* Support of the watchdog timers, which are available on
* IT8607, IT8613, IT8620, IT8622, IT8625, IT8628, IT8655, IT8659,
* IT8665, IT8686, IT8702, IT8712, IT8716, IT8718, IT8720, IT8721,
* IT8726, IT8728, IT8772, IT8783, IT8784 and IT8786.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#define WATCHDOG_NAME "IT87 WDT"
/* Defaults for Module Parameter */
#define DEFAULT_TIMEOUT 60
#define DEFAULT_TESTMODE 0
#define DEFAULT_NOWAYOUT WATCHDOG_NOWAYOUT
/* IO Ports */
#define REG 0x2e
#define VAL 0x2f
/* Logical device Numbers LDN */
#define GPIO 0x07
/* Configuration Registers and Functions */
#define LDNREG 0x07
#define CHIPID 0x20
#define CHIPREV 0x22
/* Chip Id numbers */
#define NO_DEV_ID 0xffff
#define IT8607_ID 0x8607
#define IT8613_ID 0x8613
#define IT8620_ID 0x8620
#define IT8622_ID 0x8622
#define IT8625_ID 0x8625
#define IT8628_ID 0x8628
#define IT8655_ID 0x8655
#define IT8659_ID 0x8659
#define IT8665_ID 0x8665
#define IT8686_ID 0x8686
#define IT8702_ID 0x8702
#define IT8705_ID 0x8705
#define IT8712_ID 0x8712
#define IT8716_ID 0x8716
#define IT8718_ID 0x8718
#define IT8720_ID 0x8720
#define IT8721_ID 0x8721
#define IT8726_ID 0x8726 /* the data sheet suggest wrongly 0x8716 */
#define IT8728_ID 0x8728
#define IT8772_ID 0x8772
#define IT8783_ID 0x8783
#define IT8784_ID 0x8784
#define IT8786_ID 0x8786
/* GPIO Configuration Registers LDN=0x07 */
#define WDTCTRL 0x71
#define WDTCFG 0x72
#define WDTVALLSB 0x73
#define WDTVALMSB 0x74
/* GPIO Bits WDTCFG */
#define WDT_TOV1 0x80
#define WDT_KRST 0x40
#define WDT_TOVE 0x20
#define WDT_PWROK 0x10 /* not in it8721 */
#define WDT_INT_MASK 0x0f
static unsigned int max_units, chip_type;
static unsigned int timeout = DEFAULT_TIMEOUT;
static int testmode = DEFAULT_TESTMODE;
static bool nowayout = DEFAULT_NOWAYOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds, default="
__MODULE_STRING(DEFAULT_TIMEOUT));
module_param(testmode, int, 0);
MODULE_PARM_DESC(testmode, "Watchdog test mode (1 = no reboot), default="
__MODULE_STRING(DEFAULT_TESTMODE));
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started, default="
__MODULE_STRING(WATCHDOG_NOWAYOUT));
/* Superio Chip */
static inline int superio_enter(void)
{
/*
* Try to reserve REG and REG + 1 for exclusive access.
*/
if (!request_muxed_region(REG, 2, WATCHDOG_NAME))
return -EBUSY;
outb(0x87, REG);
outb(0x01, REG);
outb(0x55, REG);
outb(0x55, REG);
return 0;
}
static inline void superio_exit(void)
{
outb(0x02, REG);
outb(0x02, VAL);
release_region(REG, 2);
}
static inline void superio_select(int ldn)
{
outb(LDNREG, REG);
outb(ldn, VAL);
}
static inline int superio_inb(int reg)
{
outb(reg, REG);
return inb(VAL);
}
static inline void superio_outb(int val, int reg)
{
outb(reg, REG);
outb(val, VAL);
}
static inline int superio_inw(int reg)
{
int val;
outb(reg++, REG);
val = inb(VAL) << 8;
outb(reg, REG);
val |= inb(VAL);
return val;
}
/* Internal function, should be called after superio_select(GPIO) */
static void _wdt_update_timeout(unsigned int t)
{
unsigned char cfg = WDT_KRST;
if (testmode)
cfg = 0;
if (t <= max_units)
cfg |= WDT_TOV1;
else
t /= 60;
if (chip_type != IT8721_ID)
cfg |= WDT_PWROK;
superio_outb(cfg, WDTCFG);
superio_outb(t, WDTVALLSB);
if (max_units > 255)
superio_outb(t >> 8, WDTVALMSB);
}
static int wdt_update_timeout(unsigned int t)
{
int ret;
ret = superio_enter();
if (ret)
return ret;
superio_select(GPIO);
_wdt_update_timeout(t);
superio_exit();
return 0;
}
static int wdt_round_time(int t)
{
t += 59;
t -= t % 60;
return t;
}
/* watchdog timer handling */
static int wdt_start(struct watchdog_device *wdd)
{
return wdt_update_timeout(wdd->timeout);
}
static int wdt_stop(struct watchdog_device *wdd)
{
return wdt_update_timeout(0);
}
/**
* wdt_set_timeout - set a new timeout value with watchdog ioctl
* @t: timeout value in seconds
*
* The hardware device has a 8 or 16 bit watchdog timer (depends on
* chip version) that can be configured to count seconds or minutes.
*
* Used within WDIOC_SETTIMEOUT watchdog device ioctl.
*/
static int wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
{
int ret = 0;
if (t > max_units)
t = wdt_round_time(t);
wdd->timeout = t;
if (watchdog_hw_running(wdd))
ret = wdt_update_timeout(t);
return ret;
}
static const struct watchdog_info ident = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.firmware_version = 1,
.identity = WATCHDOG_NAME,
};
static const struct watchdog_ops wdt_ops = {
.owner = THIS_MODULE,
.start = wdt_start,
.stop = wdt_stop,
.set_timeout = wdt_set_timeout,
};
static struct watchdog_device wdt_dev = {
.info = &ident,
.ops = &wdt_ops,
.min_timeout = 1,
};
static int __init it87_wdt_init(void)
{
u8 chip_rev;
u8 ctrl;
int rc;
rc = superio_enter();
if (rc)
return rc;
chip_type = superio_inw(CHIPID);
chip_rev = superio_inb(CHIPREV) & 0x0f;
superio_exit();
switch (chip_type) {
case IT8702_ID:
max_units = 255;
break;
case IT8712_ID:
max_units = (chip_rev < 8) ? 255 : 65535;
break;
case IT8607_ID:
case IT8613_ID:
case IT8620_ID:
case IT8622_ID:
case IT8625_ID:
case IT8628_ID:
case IT8655_ID:
case IT8659_ID:
case IT8665_ID:
case IT8686_ID:
case IT8716_ID:
case IT8718_ID:
case IT8720_ID:
case IT8721_ID:
case IT8726_ID:
case IT8728_ID:
case IT8772_ID:
case IT8783_ID:
case IT8784_ID:
case IT8786_ID:
max_units = 65535;
break;
case IT8705_ID:
pr_err("Unsupported Chip found, Chip %04x Revision %02x\n",
chip_type, chip_rev);
return -ENODEV;
case NO_DEV_ID:
pr_err("no device\n");
return -ENODEV;
default:
pr_err("Unknown Chip found, Chip %04x Revision %04x\n",
chip_type, chip_rev);
return -ENODEV;
}
rc = superio_enter();
if (rc)
return rc;
superio_select(GPIO);
superio_outb(WDT_TOV1, WDTCFG);
switch (chip_type) {
case IT8784_ID:
case IT8786_ID:
ctrl = superio_inb(WDTCTRL);
ctrl &= 0x08;
superio_outb(ctrl, WDTCTRL);
break;
default:
superio_outb(0x00, WDTCTRL);
}
superio_exit();
if (timeout < 1 || timeout > max_units * 60) {
timeout = DEFAULT_TIMEOUT;
pr_warn("Timeout value out of range, use default %d sec\n",
DEFAULT_TIMEOUT);
}
if (timeout > max_units)
timeout = wdt_round_time(timeout);
wdt_dev.timeout = timeout;
wdt_dev.max_timeout = max_units * 60;
watchdog_stop_on_reboot(&wdt_dev);
rc = watchdog_register_device(&wdt_dev);
if (rc) {
pr_err("Cannot register watchdog device (err=%d)\n", rc);
return rc;
}
pr_info("Chip IT%04x revision %d initialized. timeout=%d sec (nowayout=%d testmode=%d)\n",
chip_type, chip_rev, timeout, nowayout, testmode);
return 0;
}
static void __exit it87_wdt_exit(void)
{
watchdog_unregister_device(&wdt_dev);
}
module_init(it87_wdt_init);
module_exit(it87_wdt_exit);
MODULE_AUTHOR("Oliver Schuster");
MODULE_DESCRIPTION("Hardware Watchdog Device Driver for IT87xx EC-LPC I/O");
MODULE_LICENSE("GPL");
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