path: root/drivers/watchdog/lenovo_se30g2_se60_wdt.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * WDT driver for Lenovo SE30G2 & SE60.
 */

#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/watchdog.h>

#define CFG_PORT 0x2E
#define CFG_SIZE 2

#define CFG_LDN	     0x07
#define CFG_BRAM_LDN 0x10

#define BRAM_SIZE 2

#define BRAM_WDT_REG 0x48

#define DRVNAME "lenovo-se30g2-se60-wdt"

/*The timeout range is 1-255 seconds*/
#define MIN_TIMEOUT 1
#define MAX_TIMEOUT 255
#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */

static unsigned short bram_base;
static struct platform_device *se_30g2_60_pdev;

static int timeout; /* in seconds */
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout,
		 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
		 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");

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) ")");

struct se_30g2_60_wdt {
	struct watchdog_device wdd;
};

static void enter_pnp_mode(void)
{
	outb(0x87, CFG_PORT);
	outb(0x01, CFG_PORT);
	outb(0x55, CFG_PORT);
	outb(0x55, CFG_PORT);
}

static void exit_pnp_mode(void)
{
	outb(0x2, CFG_PORT);
	outb(0x2, CFG_PORT + 1);
}

static void lpc_write(unsigned char index, unsigned char data)
{
	outb(index, CFG_PORT);
	outb(data, CFG_PORT + 1);
}

static unsigned char lpc_read(unsigned char index)
{
	outb(index, CFG_PORT);
	return inb(CFG_PORT + 1);
}

static unsigned short lpc_chip_id(void)
{
	unsigned char msb, lsb;

	msb = lpc_read(0x20);
	lsb = lpc_read(0x21);

	return (msb << 8 | lsb);
}

static void bram_write(unsigned char reg, unsigned char val)
{
	outb(reg | 0x80, bram_base);
	outb(val, bram_base + 1);
}

static unsigned char bram_read(unsigned char reg)
{
	unsigned char val;

	outb(reg | 0x80, bram_base);
	val = inb(bram_base + 1);
	return val;
}

static int wdt_read(unsigned short *val)
{
	if (!request_muxed_region(bram_base, BRAM_SIZE, DRVNAME))
		return -EACCES;

	*val = ((bram_read(BRAM_WDT_REG) & 0xFF) << 8);
	*val |= bram_read(BRAM_WDT_REG + 1) & 0xFF;
	release_region(bram_base, BRAM_SIZE);

	return 0;
}

static int wdt_write(unsigned short val)
{
	if (!request_muxed_region(bram_base, BRAM_SIZE, DRVNAME))
		return -EACCES;

	bram_write(BRAM_WDT_REG, (val >> 8) & 0xFF);
	bram_write(BRAM_WDT_REG + 1, val & 0xFF);
	release_region(bram_base, BRAM_SIZE);

	return 0;
}

static int wdt_start(struct watchdog_device *wdog)
{
	return wdt_write(wdog->timeout);
}

static int wdt_stop(struct watchdog_device *wdog)
{
	return wdt_write(0);
}

static int wdt_ping(struct watchdog_device *wdog)
{
	return wdt_write(wdog->timeout);
}

static unsigned int wdt_get_timeleft(struct watchdog_device *wdog)
{
	unsigned short val;
	int err;

	err = wdt_read(&val);
	return err ? 0 : val;
}

static const struct watchdog_info wdt_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "Lenovo SE30G2 SE60 WDOG",
};

static const struct watchdog_ops se_30g2_60_wdt_ops = {
	.owner = THIS_MODULE,
	.start = wdt_start,
	.stop = wdt_stop,
	.ping = wdt_ping,
	.get_timeleft = wdt_get_timeleft,
};

static int se_30g2_60_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct se_30g2_60_wdt *priv;
	unsigned int chip_id;
	int ret;

	if (!request_muxed_region(CFG_PORT, CFG_SIZE, DRVNAME))
		return -EBUSY;

	/* identify the chip */
	enter_pnp_mode();
	chip_id = lpc_chip_id();
	if (chip_id != 0x5782) {
		exit_pnp_mode();
		release_region(CFG_PORT, CFG_SIZE);
		return -ENODEV;
	}

	/* probe the BRAM base address */
	lpc_write(CFG_LDN, CFG_BRAM_LDN);
	bram_base = (lpc_read(0x60) << 8) | lpc_read(0x61);
	exit_pnp_mode();
	release_region(CFG_PORT, CFG_SIZE);
	dev_info(dev, "Found Lenovo SE30G2 SE60 0x%x\n", chip_id);

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	watchdog_set_drvdata(&priv->wdd, priv);

	priv->wdd.parent = dev;
	priv->wdd.info = &wdt_info;
	priv->wdd.ops = &se_30g2_60_wdt_ops;
	priv->wdd.timeout = WATCHDOG_TIMEOUT; /* Set default timeout */
	priv->wdd.min_timeout = MIN_TIMEOUT;
	priv->wdd.max_timeout = MAX_TIMEOUT;

	watchdog_init_timeout(&priv->wdd, timeout, dev);
	watchdog_set_nowayout(&priv->wdd, nowayout);
	watchdog_stop_on_reboot(&priv->wdd);
	watchdog_stop_on_unregister(&priv->wdd);

	ret = devm_watchdog_register_device(dev, &priv->wdd);

	dev_dbg(&pdev->dev, "initialized. timeout=%d sec (nowayout=%d)\n",
		priv->wdd.timeout, nowayout);

	return ret;
}

static struct platform_driver se_30g2_60_wdt_driver = {
	.driver = {
		.name = DRVNAME,
	},
	.probe = se_30g2_60_wdt_probe,
};

static int se_30g2_60_create_device(const struct dmi_system_id *id)
{
	int err;

	se_30g2_60_pdev = platform_device_alloc("lenovo-se30g2-se60-wdt", -1);
	if (!se_30g2_60_pdev)
		return -ENOMEM;

	err = platform_device_add(se_30g2_60_pdev);
	if (err) {
		platform_device_put(se_30g2_60_pdev);
		se_30g2_60_pdev = NULL;
	}

	return err;
}

static const struct dmi_system_id se_30g2_60[] __initconst = {
	{
		.ident = "LENOVO-SE30G2",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
			DMI_MATCH(DMI_BOARD_NAME, "33BD"),
		},
		.callback = se_30g2_60_create_device,
	},
	{
		.ident = "LENOVO-SE60",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
			DMI_MATCH(DMI_BOARD_NAME, "33BF"),
		},
		.callback = se_30g2_60_create_device,
	},
	{}
};
MODULE_DEVICE_TABLE(dmi, se_30g2_60);

static int __init se_30g2_60_wdt_init(void)
{
	int err;

	if (!dmi_check_system(se_30g2_60))
		return -ENODEV;

	err = platform_driver_register(&se_30g2_60_wdt_driver);
	if (err && se_30g2_60_pdev) {
		platform_device_unregister(se_30g2_60_pdev);
		se_30g2_60_pdev = NULL;
	}

	return err;
}

static void __exit se_30g2_60_wdt_exit(void)
{
	if (se_30g2_60_pdev)
		platform_device_unregister(se_30g2_60_pdev);
	platform_driver_unregister(&se_30g2_60_wdt_driver);
}

module_init(se_30g2_60_wdt_init);
module_exit(se_30g2_60_wdt_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mark Pearson <mpearson-lenovo@squebb.ca>");
MODULE_DESCRIPTION("WDT driver for Lenovo SE30G2 & SE60");