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// SPDX-License-Identifier: GPL-2.0-only
/*
* Advantech Embedded Controller Watchdog Driver
*
* This driver supports Advantech products with ITE based Embedded Controller.
* It does not support Advantech products with other ECs or without EC.
*
* Copyright (C) 2022 Advantech Europe B.V.
*/
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/watchdog.h>
#define DRIVER_NAME "advantech_ec_wdt"
/* EC IO region */
#define EC_BASE_ADDR 0x299
#define EC_ADDR_EXTENT 2
/* EC minimum IO access delay in ms */
#define EC_MIN_DELAY 10
/* EC interface definitions */
#define EC_ADDR_CMD (EC_BASE_ADDR + 1)
#define EC_ADDR_DATA EC_BASE_ADDR
#define EC_CMD_EC_PROBE 0x30
#define EC_CMD_COMM 0x89
#define EC_CMD_WDT_START 0x28
#define EC_CMD_WDT_STOP 0x29
#define EC_CMD_WDT_RESET 0x2A
#define EC_DAT_EN_DLY_H 0x58
#define EC_DAT_EN_DLY_L 0x59
#define EC_DAT_RST_DLY_H 0x5E
#define EC_DAT_RST_DLY_L 0x5F
#define EC_MAGIC 0x95
/* module parameters */
#define MIN_TIME 1
#define MAX_TIME 6000 /* 100 minutes */
#define DEFAULT_TIME 60
static unsigned int timeout;
static ktime_t ec_timestamp;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout,
"Default Watchdog timer setting (" __MODULE_STRING(DEFAULT_TIME) "s). The range is from " __MODULE_STRING(MIN_TIME) " to " __MODULE_STRING(MAX_TIME) ".");
static void adv_ec_wdt_timing_gate(void)
{
ktime_t time_cur, time_delta;
/* ensure minimum delay between IO accesses*/
time_cur = ktime_get();
time_delta = ktime_to_ms(ktime_sub(time_cur, ec_timestamp));
if (time_delta < EC_MIN_DELAY) {
time_delta = EC_MIN_DELAY - time_delta;
usleep_range(time_delta * 1000, (time_delta + 1) * 1000);
}
ec_timestamp = ktime_get();
}
static void adv_ec_wdt_outb(unsigned char value, unsigned short port)
{
adv_ec_wdt_timing_gate();
outb(value, port);
}
static unsigned char adv_ec_wdt_inb(unsigned short port)
{
adv_ec_wdt_timing_gate();
return inb(port);
}
static int adv_ec_wdt_ping(struct watchdog_device *wdd)
{
adv_ec_wdt_outb(EC_CMD_WDT_RESET, EC_ADDR_CMD);
return 0;
}
static int adv_ec_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
{
unsigned int val;
/* scale time to EC 100 ms base */
val = t * 10;
/* reset enable delay, just in case it was set by BIOS etc. */
adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
adv_ec_wdt_outb(EC_DAT_EN_DLY_H, EC_ADDR_DATA);
adv_ec_wdt_outb(0, EC_ADDR_DATA);
adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
adv_ec_wdt_outb(EC_DAT_EN_DLY_L, EC_ADDR_DATA);
adv_ec_wdt_outb(0, EC_ADDR_DATA);
/* set reset delay */
adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
adv_ec_wdt_outb(EC_DAT_RST_DLY_H, EC_ADDR_DATA);
adv_ec_wdt_outb(val >> 8, EC_ADDR_DATA);
adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
adv_ec_wdt_outb(EC_DAT_RST_DLY_L, EC_ADDR_DATA);
adv_ec_wdt_outb(val & 0xFF, EC_ADDR_DATA);
wdd->timeout = t;
return 0;
}
static int adv_ec_wdt_start(struct watchdog_device *wdd)
{
adv_ec_wdt_set_timeout(wdd, wdd->timeout);
adv_ec_wdt_outb(EC_CMD_WDT_START, EC_ADDR_CMD);
return 0;
}
static int adv_ec_wdt_stop(struct watchdog_device *wdd)
{
adv_ec_wdt_outb(EC_CMD_WDT_STOP, EC_ADDR_CMD);
return 0;
}
static const struct watchdog_info adv_ec_wdt_info = {
.identity = DRIVER_NAME,
.options = WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE |
WDIOF_KEEPALIVEPING,
};
static const struct watchdog_ops adv_ec_wdt_ops = {
.owner = THIS_MODULE,
.start = adv_ec_wdt_start,
.stop = adv_ec_wdt_stop,
.ping = adv_ec_wdt_ping,
.set_timeout = adv_ec_wdt_set_timeout,
};
static struct watchdog_device adv_ec_wdt_dev = {
.info = &adv_ec_wdt_info,
.ops = &adv_ec_wdt_ops,
.min_timeout = MIN_TIME,
.max_timeout = MAX_TIME,
.timeout = DEFAULT_TIME,
};
static int adv_ec_wdt_probe(struct device *dev, unsigned int id)
{
if (!devm_request_region(dev, EC_BASE_ADDR, EC_ADDR_EXTENT, dev_name(dev))) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
EC_BASE_ADDR, EC_BASE_ADDR + EC_ADDR_EXTENT);
return -EBUSY;
}
watchdog_init_timeout(&adv_ec_wdt_dev, timeout, dev);
watchdog_stop_on_reboot(&adv_ec_wdt_dev);
watchdog_stop_on_unregister(&adv_ec_wdt_dev);
return devm_watchdog_register_device(dev, &adv_ec_wdt_dev);
}
static struct isa_driver adv_ec_wdt_driver = {
.probe = adv_ec_wdt_probe,
.driver = {
.name = DRIVER_NAME,
},
};
static int __init adv_ec_wdt_init(void)
{
unsigned int val;
/* quick probe for EC */
if (!request_region(EC_BASE_ADDR, EC_ADDR_EXTENT, DRIVER_NAME))
return -EBUSY;
adv_ec_wdt_outb(EC_CMD_EC_PROBE, EC_ADDR_CMD);
val = adv_ec_wdt_inb(EC_ADDR_DATA);
release_region(EC_BASE_ADDR, EC_ADDR_EXTENT);
if (val != EC_MAGIC)
return -ENODEV;
return isa_register_driver(&adv_ec_wdt_driver, 1);
}
static void __exit adv_ec_wdt_exit(void)
{
isa_unregister_driver(&adv_ec_wdt_driver);
}
module_init(adv_ec_wdt_init);
module_exit(adv_ec_wdt_exit);
MODULE_AUTHOR("Thomas Kastner <thomas.kastner@advantech.com>");
MODULE_DESCRIPTION("Advantech Embedded Controller Watchdog Device Driver");
MODULE_LICENSE("GPL");
MODULE_VERSION("20221019");
MODULE_ALIAS("isa:" DRIVER_NAME);
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