1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Watchdog driver for TQMx86 PLD.
  4 *
  5 * The watchdog supports power of 2 timeouts from 1 to 4096sec.
  6 * Once started, it cannot be stopped.
  7 *
  8 * Based on the vendor code written by Vadim V.Vlasov
  9 * <vvlasov@dev.rtsoft.ru>
 10 */
 11
 12#include <linux/io.h>
 13#include <linux/log2.h>
 14#include <linux/module.h>
 15#include <linux/platform_device.h>
 16#include <linux/timer.h>
 17#include <linux/watchdog.h>
 18
 19/* default timeout (secs) */
 20#define WDT_TIMEOUT 32
 21
 22static unsigned int timeout;
 23module_param(timeout, uint, 0);
 24MODULE_PARM_DESC(timeout,
 25	"Watchdog timeout in seconds. (1<=timeout<=4096, default="
 26				__MODULE_STRING(WDT_TIMEOUT) ")");
 27struct tqmx86_wdt {
 28	struct watchdog_device wdd;
 29	void __iomem *io_base;
 30};
 31
 32#define TQMX86_WDCFG	0x00 /* Watchdog Configuration Register */
 33#define TQMX86_WDCS	0x01 /* Watchdog Config/Status Register */
 34
 35static int tqmx86_wdt_start(struct watchdog_device *wdd)
 36{
 37	struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
 38
 39	iowrite8(0x81, priv->io_base + TQMX86_WDCS);
 40
 41	return 0;
 42}
 43
 44static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
 45{
 46	struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
 47	u8 val;
 48
 49	t = roundup_pow_of_two(t);
 50	val = ilog2(t) | 0x90;
 51	val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
 52	iowrite8(val, priv->io_base + TQMX86_WDCFG);
 53
 54	wdd->timeout = t;
 55
 56	return 0;
 57}
 58
 59static const struct watchdog_info tqmx86_wdt_info = {
 60	.options	= WDIOF_SETTIMEOUT |
 61			  WDIOF_KEEPALIVEPING,
 62	.identity	= "TQMx86 Watchdog",
 63};
 64
 65static const struct watchdog_ops tqmx86_wdt_ops = {
 66	.owner		= THIS_MODULE,
 67	.start		= tqmx86_wdt_start,
 68	.set_timeout	= tqmx86_wdt_set_timeout,
 69};
 70
 71static int tqmx86_wdt_probe(struct platform_device *pdev)
 72{
 73	struct device *dev = &pdev->dev;
 74	struct tqmx86_wdt *priv;
 75	struct resource *res;
 76	int err;
 77
 78	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 79	if (!priv)
 80		return -ENOMEM;
 81
 82	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 83	if (!res)
 84		return -ENODEV;
 85
 86	priv->io_base = devm_ioport_map(dev, res->start, resource_size(res));
 87	if (!priv->io_base)
 88		return -ENOMEM;
 89
 90	watchdog_set_drvdata(&priv->wdd, priv);
 91
 92	priv->wdd.parent = dev;
 93	priv->wdd.info = &tqmx86_wdt_info;
 94	priv->wdd.ops = &tqmx86_wdt_ops;
 95	priv->wdd.min_timeout = 1;
 96	priv->wdd.max_timeout = 4096;
 97	priv->wdd.max_hw_heartbeat_ms = 4096*1000;
 98	priv->wdd.timeout = WDT_TIMEOUT;
 99
100	watchdog_init_timeout(&priv->wdd, timeout, dev);
101	watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);
102
103	tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);
104
105	err = devm_watchdog_register_device(dev, &priv->wdd);
106	if (err)
107		return err;
108
109	dev_info(dev, "TQMx86 watchdog\n");
110
111	return 0;
112}
113
114static struct platform_driver tqmx86_wdt_driver = {
115	.driver		= {
116		.name	= "tqmx86-wdt",
117	},
118	.probe		= tqmx86_wdt_probe,
119};
120
121module_platform_driver(tqmx86_wdt_driver);
122
123MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
124MODULE_DESCRIPTION("TQMx86 Watchdog");
125MODULE_ALIAS("platform:tqmx86-wdt");
126MODULE_LICENSE("GPL");