175d67a54SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only
2101ce87bSAlexander Stein /*
3101ce87bSAlexander Stein * Intel Atom E6xx Watchdog driver
4101ce87bSAlexander Stein *
5101ce87bSAlexander Stein * Copyright (C) 2011 Alexander Stein
6101ce87bSAlexander Stein * <alexander.stein@systec-electronic.com>
7101ce87bSAlexander Stein */
8101ce87bSAlexander Stein
9101ce87bSAlexander Stein #include <linux/module.h>
10101ce87bSAlexander Stein #include <linux/moduleparam.h>
11101ce87bSAlexander Stein #include <linux/platform_device.h>
12491d9e2aSRandy Dunlap #include <linux/io.h>
13101ce87bSAlexander Stein #include <linux/kernel.h>
14101ce87bSAlexander Stein #include <linux/types.h>
15101ce87bSAlexander Stein #include <linux/watchdog.h>
16101ce87bSAlexander Stein #include <linux/seq_file.h>
17101ce87bSAlexander Stein #include <linux/debugfs.h>
18101ce87bSAlexander Stein #include <linux/uaccess.h>
19101ce87bSAlexander Stein #include <linux/spinlock.h>
20101ce87bSAlexander Stein
21101ce87bSAlexander Stein #define DRIVER_NAME "ie6xx_wdt"
22101ce87bSAlexander Stein
23101ce87bSAlexander Stein #define PV1 0x00
24101ce87bSAlexander Stein #define PV2 0x04
25101ce87bSAlexander Stein
26101ce87bSAlexander Stein #define RR0 0x0c
27101ce87bSAlexander Stein #define RR1 0x0d
28101ce87bSAlexander Stein #define WDT_RELOAD 0x01
29101ce87bSAlexander Stein #define WDT_TOUT 0x02
30101ce87bSAlexander Stein
31101ce87bSAlexander Stein #define WDTCR 0x10
32101ce87bSAlexander Stein #define WDT_PRE_SEL 0x04
33101ce87bSAlexander Stein #define WDT_RESET_SEL 0x08
34101ce87bSAlexander Stein #define WDT_RESET_EN 0x10
35101ce87bSAlexander Stein #define WDT_TOUT_EN 0x20
36101ce87bSAlexander Stein
37101ce87bSAlexander Stein #define DCR 0x14
38101ce87bSAlexander Stein
39101ce87bSAlexander Stein #define WDTLR 0x18
40101ce87bSAlexander Stein #define WDT_LOCK 0x01
41101ce87bSAlexander Stein #define WDT_ENABLE 0x02
42101ce87bSAlexander Stein #define WDT_TOUT_CNF 0x03
43101ce87bSAlexander Stein
44101ce87bSAlexander Stein #define MIN_TIME 1
45101ce87bSAlexander Stein #define MAX_TIME (10 * 60) /* 10 minutes */
46101ce87bSAlexander Stein #define DEFAULT_TIME 60
47101ce87bSAlexander Stein
48101ce87bSAlexander Stein static unsigned int timeout = DEFAULT_TIME;
49101ce87bSAlexander Stein module_param(timeout, uint, 0);
50101ce87bSAlexander Stein MODULE_PARM_DESC(timeout,
51101ce87bSAlexander Stein "Default Watchdog timer setting ("
52101ce87bSAlexander Stein __MODULE_STRING(DEFAULT_TIME) "s)."
53101ce87bSAlexander Stein "The range is from 1 to 600");
54101ce87bSAlexander Stein
55101ce87bSAlexander Stein static bool nowayout = WATCHDOG_NOWAYOUT;
56101ce87bSAlexander Stein module_param(nowayout, bool, 0);
57101ce87bSAlexander Stein MODULE_PARM_DESC(nowayout,
58101ce87bSAlexander Stein "Watchdog cannot be stopped once started (default="
59101ce87bSAlexander Stein __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
60101ce87bSAlexander Stein
61101ce87bSAlexander Stein static u8 resetmode = 0x10;
62101ce87bSAlexander Stein module_param(resetmode, byte, 0);
63101ce87bSAlexander Stein MODULE_PARM_DESC(resetmode,
64101ce87bSAlexander Stein "Resetmode bits: 0x08 warm reset (cold reset otherwise), "
65101ce87bSAlexander Stein "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)");
66101ce87bSAlexander Stein
67101ce87bSAlexander Stein static struct {
68101ce87bSAlexander Stein unsigned short sch_wdtba;
69053bc576SSebastian Andrzej Siewior spinlock_t unlock_sequence;
70101ce87bSAlexander Stein #ifdef CONFIG_DEBUG_FS
71101ce87bSAlexander Stein struct dentry *debugfs;
72101ce87bSAlexander Stein #endif
73101ce87bSAlexander Stein } ie6xx_wdt_data;
74101ce87bSAlexander Stein
75101ce87bSAlexander Stein /*
76101ce87bSAlexander Stein * This is needed to write to preload and reload registers
77101ce87bSAlexander Stein * struct ie6xx_wdt_data.unlock_sequence must be used
78101ce87bSAlexander Stein * to prevent sequence interrupts
79101ce87bSAlexander Stein */
ie6xx_wdt_unlock_registers(void)80101ce87bSAlexander Stein static void ie6xx_wdt_unlock_registers(void)
81101ce87bSAlexander Stein {
82101ce87bSAlexander Stein outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0);
83101ce87bSAlexander Stein outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0);
84101ce87bSAlexander Stein }
85101ce87bSAlexander Stein
ie6xx_wdt_ping(struct watchdog_device * wdd)86101ce87bSAlexander Stein static int ie6xx_wdt_ping(struct watchdog_device *wdd)
87101ce87bSAlexander Stein {
88101ce87bSAlexander Stein spin_lock(&ie6xx_wdt_data.unlock_sequence);
89101ce87bSAlexander Stein ie6xx_wdt_unlock_registers();
90101ce87bSAlexander Stein outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1);
91101ce87bSAlexander Stein spin_unlock(&ie6xx_wdt_data.unlock_sequence);
92101ce87bSAlexander Stein return 0;
93101ce87bSAlexander Stein }
94101ce87bSAlexander Stein
ie6xx_wdt_set_timeout(struct watchdog_device * wdd,unsigned int t)95101ce87bSAlexander Stein static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
96101ce87bSAlexander Stein {
97101ce87bSAlexander Stein u32 preload;
98101ce87bSAlexander Stein u64 clock;
99101ce87bSAlexander Stein u8 wdtcr;
100101ce87bSAlexander Stein
101101ce87bSAlexander Stein /* Watchdog clock is PCI Clock (33MHz) */
102101ce87bSAlexander Stein clock = 33000000;
103101ce87bSAlexander Stein /* and the preload value is loaded into [34:15] of the down counter */
104101ce87bSAlexander Stein preload = (t * clock) >> 15;
105101ce87bSAlexander Stein /*
106101ce87bSAlexander Stein * Manual states preload must be one less.
107101ce87bSAlexander Stein * Does not wrap as t is at least 1
108101ce87bSAlexander Stein */
109101ce87bSAlexander Stein preload -= 1;
110101ce87bSAlexander Stein
111101ce87bSAlexander Stein spin_lock(&ie6xx_wdt_data.unlock_sequence);
112101ce87bSAlexander Stein
113101ce87bSAlexander Stein /* Set ResetMode & Enable prescaler for range 10ms to 10 min */
114101ce87bSAlexander Stein wdtcr = resetmode & 0x38;
115101ce87bSAlexander Stein outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR);
116101ce87bSAlexander Stein
117101ce87bSAlexander Stein ie6xx_wdt_unlock_registers();
118101ce87bSAlexander Stein outl(0, ie6xx_wdt_data.sch_wdtba + PV1);
119101ce87bSAlexander Stein
120101ce87bSAlexander Stein ie6xx_wdt_unlock_registers();
121101ce87bSAlexander Stein outl(preload, ie6xx_wdt_data.sch_wdtba + PV2);
122101ce87bSAlexander Stein
123101ce87bSAlexander Stein ie6xx_wdt_unlock_registers();
124101ce87bSAlexander Stein outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1);
125101ce87bSAlexander Stein
126101ce87bSAlexander Stein spin_unlock(&ie6xx_wdt_data.unlock_sequence);
127101ce87bSAlexander Stein
128101ce87bSAlexander Stein wdd->timeout = t;
129101ce87bSAlexander Stein return 0;
130101ce87bSAlexander Stein }
131101ce87bSAlexander Stein
ie6xx_wdt_start(struct watchdog_device * wdd)132101ce87bSAlexander Stein static int ie6xx_wdt_start(struct watchdog_device *wdd)
133101ce87bSAlexander Stein {
134101ce87bSAlexander Stein ie6xx_wdt_set_timeout(wdd, wdd->timeout);
135101ce87bSAlexander Stein
136101ce87bSAlexander Stein /* Enable the watchdog timer */
137101ce87bSAlexander Stein spin_lock(&ie6xx_wdt_data.unlock_sequence);
138101ce87bSAlexander Stein outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR);
139101ce87bSAlexander Stein spin_unlock(&ie6xx_wdt_data.unlock_sequence);
140101ce87bSAlexander Stein
141101ce87bSAlexander Stein return 0;
142101ce87bSAlexander Stein }
143101ce87bSAlexander Stein
ie6xx_wdt_stop(struct watchdog_device * wdd)144101ce87bSAlexander Stein static int ie6xx_wdt_stop(struct watchdog_device *wdd)
145101ce87bSAlexander Stein {
146101ce87bSAlexander Stein if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK)
147101ce87bSAlexander Stein return -1;
148101ce87bSAlexander Stein
149101ce87bSAlexander Stein /* Disable the watchdog timer */
150101ce87bSAlexander Stein spin_lock(&ie6xx_wdt_data.unlock_sequence);
151101ce87bSAlexander Stein outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR);
152101ce87bSAlexander Stein spin_unlock(&ie6xx_wdt_data.unlock_sequence);
153101ce87bSAlexander Stein
154101ce87bSAlexander Stein return 0;
155101ce87bSAlexander Stein }
156101ce87bSAlexander Stein
157101ce87bSAlexander Stein static const struct watchdog_info ie6xx_wdt_info = {
158101ce87bSAlexander Stein .identity = "Intel Atom E6xx Watchdog",
159101ce87bSAlexander Stein .options = WDIOF_SETTIMEOUT |
160101ce87bSAlexander Stein WDIOF_MAGICCLOSE |
161101ce87bSAlexander Stein WDIOF_KEEPALIVEPING,
162101ce87bSAlexander Stein };
163101ce87bSAlexander Stein
164101ce87bSAlexander Stein static const struct watchdog_ops ie6xx_wdt_ops = {
165101ce87bSAlexander Stein .owner = THIS_MODULE,
166101ce87bSAlexander Stein .start = ie6xx_wdt_start,
167101ce87bSAlexander Stein .stop = ie6xx_wdt_stop,
168101ce87bSAlexander Stein .ping = ie6xx_wdt_ping,
169101ce87bSAlexander Stein .set_timeout = ie6xx_wdt_set_timeout,
170101ce87bSAlexander Stein };
171101ce87bSAlexander Stein
172101ce87bSAlexander Stein static struct watchdog_device ie6xx_wdt_dev = {
173101ce87bSAlexander Stein .info = &ie6xx_wdt_info,
174101ce87bSAlexander Stein .ops = &ie6xx_wdt_ops,
175101ce87bSAlexander Stein .min_timeout = MIN_TIME,
176101ce87bSAlexander Stein .max_timeout = MAX_TIME,
177101ce87bSAlexander Stein };
178101ce87bSAlexander Stein
179101ce87bSAlexander Stein #ifdef CONFIG_DEBUG_FS
180101ce87bSAlexander Stein
ie6xx_wdt_show(struct seq_file * s,void * unused)181248e655bSYangtao Li static int ie6xx_wdt_show(struct seq_file *s, void *unused)
182101ce87bSAlexander Stein {
183101ce87bSAlexander Stein seq_printf(s, "PV1 = 0x%08x\n",
184101ce87bSAlexander Stein inl(ie6xx_wdt_data.sch_wdtba + PV1));
185101ce87bSAlexander Stein seq_printf(s, "PV2 = 0x%08x\n",
186101ce87bSAlexander Stein inl(ie6xx_wdt_data.sch_wdtba + PV2));
187101ce87bSAlexander Stein seq_printf(s, "RR = 0x%08x\n",
188101ce87bSAlexander Stein inw(ie6xx_wdt_data.sch_wdtba + RR0));
189101ce87bSAlexander Stein seq_printf(s, "WDTCR = 0x%08x\n",
190101ce87bSAlexander Stein inw(ie6xx_wdt_data.sch_wdtba + WDTCR));
191101ce87bSAlexander Stein seq_printf(s, "DCR = 0x%08x\n",
192101ce87bSAlexander Stein inl(ie6xx_wdt_data.sch_wdtba + DCR));
193101ce87bSAlexander Stein seq_printf(s, "WDTLR = 0x%08x\n",
194101ce87bSAlexander Stein inw(ie6xx_wdt_data.sch_wdtba + WDTLR));
195101ce87bSAlexander Stein
196101ce87bSAlexander Stein seq_printf(s, "\n");
197101ce87bSAlexander Stein return 0;
198101ce87bSAlexander Stein }
199101ce87bSAlexander Stein
200248e655bSYangtao Li DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt);
201101ce87bSAlexander Stein
ie6xx_wdt_debugfs_init(void)2022d991a16SBill Pemberton static void ie6xx_wdt_debugfs_init(void)
203101ce87bSAlexander Stein {
204101ce87bSAlexander Stein /* /sys/kernel/debug/ie6xx_wdt */
205101ce87bSAlexander Stein ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt",
206248e655bSYangtao Li S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops);
207101ce87bSAlexander Stein }
208101ce87bSAlexander Stein
ie6xx_wdt_debugfs_exit(void)2090402450fSGerard Snitselaar static void ie6xx_wdt_debugfs_exit(void)
210101ce87bSAlexander Stein {
211101ce87bSAlexander Stein debugfs_remove(ie6xx_wdt_data.debugfs);
212101ce87bSAlexander Stein }
213101ce87bSAlexander Stein
214101ce87bSAlexander Stein #else
ie6xx_wdt_debugfs_init(void)2152d991a16SBill Pemberton static void ie6xx_wdt_debugfs_init(void)
216101ce87bSAlexander Stein {
217101ce87bSAlexander Stein }
218101ce87bSAlexander Stein
ie6xx_wdt_debugfs_exit(void)2190402450fSGerard Snitselaar static void ie6xx_wdt_debugfs_exit(void)
220101ce87bSAlexander Stein {
221101ce87bSAlexander Stein }
222101ce87bSAlexander Stein #endif
223101ce87bSAlexander Stein
ie6xx_wdt_probe(struct platform_device * pdev)2242d991a16SBill Pemberton static int ie6xx_wdt_probe(struct platform_device *pdev)
225101ce87bSAlexander Stein {
226101ce87bSAlexander Stein struct resource *res;
227101ce87bSAlexander Stein u8 wdtlr;
228101ce87bSAlexander Stein int ret;
229101ce87bSAlexander Stein
230101ce87bSAlexander Stein res = platform_get_resource(pdev, IORESOURCE_IO, 0);
231101ce87bSAlexander Stein if (!res)
232101ce87bSAlexander Stein return -ENODEV;
233101ce87bSAlexander Stein
234101ce87bSAlexander Stein if (!request_region(res->start, resource_size(res), pdev->name)) {
235744f6f4dSRandy Dunlap dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n",
236744f6f4dSRandy Dunlap (u64)res->start);
237101ce87bSAlexander Stein return -EBUSY;
238101ce87bSAlexander Stein }
239101ce87bSAlexander Stein
240101ce87bSAlexander Stein ie6xx_wdt_data.sch_wdtba = res->start;
241101ce87bSAlexander Stein dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba);
242101ce87bSAlexander Stein
243101ce87bSAlexander Stein ie6xx_wdt_dev.timeout = timeout;
244101ce87bSAlexander Stein watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout);
2456551881cSPratyush Anand ie6xx_wdt_dev.parent = &pdev->dev;
246101ce87bSAlexander Stein
247101ce87bSAlexander Stein spin_lock_init(&ie6xx_wdt_data.unlock_sequence);
248101ce87bSAlexander Stein
249101ce87bSAlexander Stein wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR);
250101ce87bSAlexander Stein if (wdtlr & WDT_LOCK)
251101ce87bSAlexander Stein dev_warn(&pdev->dev,
252101ce87bSAlexander Stein "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr);
253101ce87bSAlexander Stein
254101ce87bSAlexander Stein ie6xx_wdt_debugfs_init();
255101ce87bSAlexander Stein
256101ce87bSAlexander Stein ret = watchdog_register_device(&ie6xx_wdt_dev);
2578f952c01SWolfram Sang if (ret)
258101ce87bSAlexander Stein goto misc_register_error;
259101ce87bSAlexander Stein
260101ce87bSAlexander Stein return 0;
261101ce87bSAlexander Stein
262101ce87bSAlexander Stein misc_register_error:
263101ce87bSAlexander Stein ie6xx_wdt_debugfs_exit();
264101ce87bSAlexander Stein release_region(res->start, resource_size(res));
265101ce87bSAlexander Stein ie6xx_wdt_data.sch_wdtba = 0;
266101ce87bSAlexander Stein return ret;
267101ce87bSAlexander Stein }
268101ce87bSAlexander Stein
ie6xx_wdt_remove(struct platform_device * pdev)269*e395a471SUwe Kleine-König static void ie6xx_wdt_remove(struct platform_device *pdev)
270101ce87bSAlexander Stein {
271101ce87bSAlexander Stein struct resource *res;
272101ce87bSAlexander Stein
273101ce87bSAlexander Stein res = platform_get_resource(pdev, IORESOURCE_IO, 0);
274101ce87bSAlexander Stein ie6xx_wdt_stop(NULL);
275101ce87bSAlexander Stein watchdog_unregister_device(&ie6xx_wdt_dev);
276101ce87bSAlexander Stein ie6xx_wdt_debugfs_exit();
277101ce87bSAlexander Stein release_region(res->start, resource_size(res));
278101ce87bSAlexander Stein ie6xx_wdt_data.sch_wdtba = 0;
279101ce87bSAlexander Stein }
280101ce87bSAlexander Stein
281101ce87bSAlexander Stein static struct platform_driver ie6xx_wdt_driver = {
282101ce87bSAlexander Stein .probe = ie6xx_wdt_probe,
283*e395a471SUwe Kleine-König .remove_new = ie6xx_wdt_remove,
284101ce87bSAlexander Stein .driver = {
285101ce87bSAlexander Stein .name = DRIVER_NAME,
286101ce87bSAlexander Stein },
287101ce87bSAlexander Stein };
288101ce87bSAlexander Stein
ie6xx_wdt_init(void)289101ce87bSAlexander Stein static int __init ie6xx_wdt_init(void)
290101ce87bSAlexander Stein {
291101ce87bSAlexander Stein /* Check boot parameters to verify that their initial values */
292101ce87bSAlexander Stein /* are in range. */
293101ce87bSAlexander Stein if ((timeout < MIN_TIME) ||
294101ce87bSAlexander Stein (timeout > MAX_TIME)) {
295101ce87bSAlexander Stein pr_err("Watchdog timer: value of timeout %d (dec) "
296101ce87bSAlexander Stein "is out of range from %d to %d (dec)\n",
297101ce87bSAlexander Stein timeout, MIN_TIME, MAX_TIME);
298101ce87bSAlexander Stein return -EINVAL;
299101ce87bSAlexander Stein }
300101ce87bSAlexander Stein
301101ce87bSAlexander Stein return platform_driver_register(&ie6xx_wdt_driver);
302101ce87bSAlexander Stein }
303101ce87bSAlexander Stein
ie6xx_wdt_exit(void)304101ce87bSAlexander Stein static void __exit ie6xx_wdt_exit(void)
305101ce87bSAlexander Stein {
306101ce87bSAlexander Stein platform_driver_unregister(&ie6xx_wdt_driver);
307101ce87bSAlexander Stein }
308101ce87bSAlexander Stein
309101ce87bSAlexander Stein late_initcall(ie6xx_wdt_init);
310101ce87bSAlexander Stein module_exit(ie6xx_wdt_exit);
311101ce87bSAlexander Stein
312101ce87bSAlexander Stein MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>");
313101ce87bSAlexander Stein MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver");
314101ce87bSAlexander Stein MODULE_LICENSE("GPL");
315101ce87bSAlexander Stein MODULE_ALIAS("platform:" DRIVER_NAME);
316