1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * WDT driver for Lenovo SE10.
  4 */
  5
  6#include <linux/delay.h>
  7#include <linux/dmi.h>
  8#include <linux/io.h>
  9#include <linux/module.h>
 10#include <linux/moduleparam.h>
 11#include <linux/platform_device.h>
 12#include <linux/string.h>
 13#include <linux/types.h>
 14#include <linux/watchdog.h>
 15
 16#define STATUS_PORT	0x6C
 17#define CMD_PORT	0x6C
 18#define DATA_PORT	0x68
 19#define OUTBUF_FULL	0x01
 20#define INBUF_EMPTY	0x02
 21#define CFG_LDN		0x07
 22#define CFG_BRAM_LDN	0x10 /* for BRAM Base */
 23#define CFG_PORT	0x2E
 24#define CFG_SIZE           2
 25#define CMD_SIZE           4
 26#define BRAM_SIZE          2
 27
 28#define UNLOCK_KEY	0x87
 29#define LOCK_KEY	0xAA
 30
 31#define CUS_WDT_SWI	0x1A
 32#define CUS_WDT_CFG	0x1B
 33#define CUS_WDT_FEED	0xB0
 34#define CUS_WDT_CNT	0xB1
 35
 36#define DRVNAME	"lenovo-se10-wdt"
 37
 38/*The timeout range is 1-255 seconds*/
 39#define MIN_TIMEOUT 1
 40#define MAX_TIMEOUT 255
 41#define MAX_WAIT    10
 42
 43#define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
 44static unsigned short bram_base;
 45static struct platform_device *se10_pdev;
 46
 47static int timeout; /* in seconds */
 48module_param(timeout, int, 0);
 49MODULE_PARM_DESC(timeout,
 50		 "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
 51		 __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
 52
 53static bool nowayout = WATCHDOG_NOWAYOUT;
 54module_param(nowayout, bool, 0);
 55MODULE_PARM_DESC(nowayout,
 56		 "Watchdog cannot be stopped once started (default="
 57		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 58
 59struct se10_wdt {
 60	struct watchdog_device wdd;
 61};
 62
 63static int set_bram(unsigned char offset, unsigned char val)
 64{
 65	if (!request_muxed_region(bram_base, BRAM_SIZE, DRVNAME))
 66		return -EBUSY;
 67	outb(offset, bram_base);
 68	outb(val, bram_base + 1);
 69	release_region(bram_base, BRAM_SIZE);
 70	return 0;
 71}
 72
 73static void wait_for_buffer(int condition)
 74{
 75	int loop = 0;
 76
 77	while (1) {
 78		if (inb(STATUS_PORT) & condition || loop > MAX_WAIT)
 79			break;
 80		loop++;
 81		usleep_range(10, 125);
 82	}
 83}
 84
 85static void send_cmd(unsigned char cmd)
 86{
 87	wait_for_buffer(INBUF_EMPTY);
 88	outb(cmd, CMD_PORT);
 89	wait_for_buffer(INBUF_EMPTY);
 90}
 91
 92static void lpc_write(unsigned char index, unsigned char data)
 93{
 94	outb(index, CFG_PORT);
 95	outb(data, CFG_PORT + 1);
 96}
 97
 98static unsigned char lpc_read(unsigned char index)
 99{
100	outb(index, CFG_PORT);
101	return inb(CFG_PORT + 1);
102}
103
104static int wdt_start(struct watchdog_device *wdog)
105{
106	return set_bram(CUS_WDT_SWI, 0x80);
107}
108
109static int wdt_set_timeout(struct watchdog_device *wdog, unsigned int timeout)
110{
111	wdog->timeout = timeout;
112	return set_bram(CUS_WDT_CFG, wdog->timeout);
113}
114
115static int wdt_stop(struct watchdog_device *wdog)
116{
117	return set_bram(CUS_WDT_SWI, 0);
118}
119
120static unsigned int wdt_get_time(struct watchdog_device *wdog)
121{
122	unsigned char time;
123
124	if (!request_muxed_region(CMD_PORT, CMD_SIZE, DRVNAME))
125		return -EBUSY;
126	send_cmd(CUS_WDT_CNT);
127	wait_for_buffer(OUTBUF_FULL);
128	time = inb(DATA_PORT);
129	release_region(CMD_PORT, CMD_SIZE);
130	return time;
131}
132
133static int wdt_ping(struct watchdog_device *wdog)
134{
135	if (!request_muxed_region(CMD_PORT, CMD_SIZE, DRVNAME))
136		return -EBUSY;
137	send_cmd(CUS_WDT_FEED);
138	release_region(CMD_PORT, CMD_SIZE);
139	return 0;
140}
141
142static const struct watchdog_info wdt_info = {
143	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
144	.identity = "Lenovo SE10 Watchdog",
145};
146
147static const struct watchdog_ops se10_wdt_ops = {
148	.owner = THIS_MODULE,
149	.start = wdt_start,
150	.stop = wdt_stop,
151	.ping = wdt_ping,
152	.set_timeout = wdt_set_timeout,
153	.get_timeleft = wdt_get_time,
154};
155
156static unsigned int get_chipID(void)
157{
158	unsigned char msb, lsb;
159
160	outb(UNLOCK_KEY, CFG_PORT);
161	outb(0x01, CFG_PORT);
162	outb(0x55, CFG_PORT);
163	outb(0x55, CFG_PORT);
164	msb = lpc_read(0x20);
165	lsb = lpc_read(0x21);
166	outb(LOCK_KEY, CFG_PORT);
167	return (msb * 256 + lsb);
168}
169
170static int se10_wdt_probe(struct platform_device *pdev)
171{
172	struct device *dev = &pdev->dev;
173	struct se10_wdt *priv;
174	unsigned int chip_id;
175	int ret;
176
177	if (!request_muxed_region(CFG_PORT, CFG_SIZE, DRVNAME))
178		return -EBUSY;
179
180	chip_id = get_chipID();
181	if (chip_id != 0x5632) {
182		release_region(CFG_PORT, CFG_SIZE);
183		return -ENODEV;
184	}
185
186	lpc_write(CFG_LDN, CFG_BRAM_LDN);
187	bram_base = (lpc_read(0x60) << 8) | lpc_read(0x61);
188	release_region(CFG_PORT, CFG_SIZE);
189
190	dev_info(dev, "Found Lenovo SE10 0x%x\n", chip_id);
191
192	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
193	if (!priv)
194		return -ENOMEM;
195
196	watchdog_set_drvdata(&priv->wdd, priv);
197
198	priv->wdd.parent = dev;
199	priv->wdd.info = &wdt_info;
200	priv->wdd.ops = &se10_wdt_ops;
201	priv->wdd.timeout = WATCHDOG_TIMEOUT; /* Set default timeout */
202	priv->wdd.min_timeout = MIN_TIMEOUT;
203	priv->wdd.max_timeout = MAX_TIMEOUT;
204
205	set_bram(CUS_WDT_CFG, WATCHDOG_TIMEOUT); /* Set time to default */
206
207	watchdog_init_timeout(&priv->wdd, timeout, dev);
208	watchdog_set_nowayout(&priv->wdd, nowayout);
209	watchdog_stop_on_reboot(&priv->wdd);
210	watchdog_stop_on_unregister(&priv->wdd);
211
212	ret = devm_watchdog_register_device(dev, &priv->wdd);
213
214	dev_dbg(&pdev->dev, "initialized. timeout=%d sec (nowayout=%d)\n",
215		priv->wdd.timeout, nowayout);
216
217	return ret;
218}
219
220static struct platform_driver se10_wdt_driver = {
221	.driver = {
222		.name = DRVNAME,
223	},
224	.probe  = se10_wdt_probe,
225};
226
227static int se10_create_platform_device(const struct dmi_system_id *id)
228{
229	int err;
230
231	se10_pdev = platform_device_alloc("lenovo-se10-wdt", -1);
232	if (!se10_pdev)
233		return -ENOMEM;
234
235	err = platform_device_add(se10_pdev);
236	if (err)
237		platform_device_put(se10_pdev);
238
239	return err;
240}
241
242static const struct dmi_system_id se10_dmi_table[] __initconst = {
243	{
244		.ident = "LENOVO-SE10",
245		.matches = {
246			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
247			DMI_MATCH(DMI_PRODUCT_NAME, "12NH"),
248		},
249		.callback = se10_create_platform_device,
250	},
251	{
252		.ident = "LENOVO-SE10",
253		.matches = {
254			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
255			DMI_MATCH(DMI_PRODUCT_NAME, "12NJ"),
256		},
257		.callback = se10_create_platform_device,
258	},
259	{
260		.ident = "LENOVO-SE10",
261		.matches = {
262			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
263			DMI_MATCH(DMI_PRODUCT_NAME, "12NK"),
264		},
265		.callback = se10_create_platform_device,
266	},
267	{
268		.ident = "LENOVO-SE10",
269		.matches = {
270			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
271			DMI_MATCH(DMI_PRODUCT_NAME, "12NL"),
272		},
273		.callback = se10_create_platform_device,
274	},
275	{
276		.ident = "LENOVO-SE10",
277		.matches = {
278			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
279			DMI_MATCH(DMI_PRODUCT_NAME, "12NM"),
280		},
281		.callback = se10_create_platform_device,
282	},
283	{}
284};
285MODULE_DEVICE_TABLE(dmi, se10_dmi_table);
286
287static int __init se10_wdt_init(void)
288{
289	if (!dmi_check_system(se10_dmi_table))
290		return -ENODEV;
291
292	return platform_driver_register(&se10_wdt_driver);
293}
294
295static void __exit se10_wdt_exit(void)
296{
297	if (se10_pdev)
298		platform_device_unregister(se10_pdev);
299	platform_driver_unregister(&se10_wdt_driver);
300}
301
302module_init(se10_wdt_init);
303module_exit(se10_wdt_exit);
304
305MODULE_LICENSE("GPL");
306MODULE_AUTHOR("David Ober<dober@lenovo.com>");
307MODULE_AUTHOR("Mark Pearson <mpearson-lenovo@squebb.ca>");
308MODULE_DESCRIPTION("WDT driver for Lenovo SE10");