diff options
Diffstat (limited to 'drivers/watchdog/advantech_ec_wdt.c')
| -rw-r--r-- | drivers/watchdog/advantech_ec_wdt.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/drivers/watchdog/advantech_ec_wdt.c b/drivers/watchdog/advantech_ec_wdt.c new file mode 100644 index 000000000000..7c380f90ca58 --- /dev/null +++ b/drivers/watchdog/advantech_ec_wdt.c @@ -0,0 +1,205 @@ +// 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); |