1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Advantech Embedded Controller Watchdog Driver
4 *
5 * This driver supports Advantech products with ITE based Embedded Controller.
6 * It does not support Advantech products with other ECs or without EC.
7 *
8 * Copyright (C) 2022 Advantech Europe B.V.
9 */
10
11 #include <linux/delay.h>
12 #include <linux/io.h>
13 #include <linux/isa.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/moduleparam.h>
17 #include <linux/watchdog.h>
18
19 #define DRIVER_NAME "advantech_ec_wdt"
20
21 /* EC IO region */
22 #define EC_BASE_ADDR 0x299
23 #define EC_ADDR_EXTENT 2
24
25 /* EC minimum IO access delay in ms */
26 #define EC_MIN_DELAY 10
27
28 /* EC interface definitions */
29 #define EC_ADDR_CMD (EC_BASE_ADDR + 1)
30 #define EC_ADDR_DATA EC_BASE_ADDR
31 #define EC_CMD_EC_PROBE 0x30
32 #define EC_CMD_COMM 0x89
33 #define EC_CMD_WDT_START 0x28
34 #define EC_CMD_WDT_STOP 0x29
35 #define EC_CMD_WDT_RESET 0x2A
36 #define EC_DAT_EN_DLY_H 0x58
37 #define EC_DAT_EN_DLY_L 0x59
38 #define EC_DAT_RST_DLY_H 0x5E
39 #define EC_DAT_RST_DLY_L 0x5F
40 #define EC_MAGIC 0x95
41
42 /* module parameters */
43 #define MIN_TIME 1
44 #define MAX_TIME 6000 /* 100 minutes */
45 #define DEFAULT_TIME 60
46
47 static unsigned int timeout;
48 static ktime_t ec_timestamp;
49
50 module_param(timeout, uint, 0);
51 MODULE_PARM_DESC(timeout,
52 "Default Watchdog timer setting (" __MODULE_STRING(DEFAULT_TIME) "s). The range is from " __MODULE_STRING(MIN_TIME) " to " __MODULE_STRING(MAX_TIME) ".");
53
adv_ec_wdt_timing_gate(void)54 static void adv_ec_wdt_timing_gate(void)
55 {
56 ktime_t time_cur, time_delta;
57
58 /* ensure minimum delay between IO accesses*/
59 time_cur = ktime_get();
60 time_delta = ktime_to_ms(ktime_sub(time_cur, ec_timestamp));
61 if (time_delta < EC_MIN_DELAY) {
62 time_delta = EC_MIN_DELAY - time_delta;
63 usleep_range(time_delta * 1000, (time_delta + 1) * 1000);
64 }
65 ec_timestamp = ktime_get();
66 }
67
adv_ec_wdt_outb(unsigned char value,unsigned short port)68 static void adv_ec_wdt_outb(unsigned char value, unsigned short port)
69 {
70 adv_ec_wdt_timing_gate();
71 outb(value, port);
72 }
73
adv_ec_wdt_inb(unsigned short port)74 static unsigned char adv_ec_wdt_inb(unsigned short port)
75 {
76 adv_ec_wdt_timing_gate();
77 return inb(port);
78 }
79
adv_ec_wdt_ping(struct watchdog_device * wdd)80 static int adv_ec_wdt_ping(struct watchdog_device *wdd)
81 {
82 adv_ec_wdt_outb(EC_CMD_WDT_RESET, EC_ADDR_CMD);
83 return 0;
84 }
85
adv_ec_wdt_set_timeout(struct watchdog_device * wdd,unsigned int t)86 static int adv_ec_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
87 {
88 unsigned int val;
89
90 /* scale time to EC 100 ms base */
91 val = t * 10;
92
93 /* reset enable delay, just in case it was set by BIOS etc. */
94 adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
95 adv_ec_wdt_outb(EC_DAT_EN_DLY_H, EC_ADDR_DATA);
96 adv_ec_wdt_outb(0, EC_ADDR_DATA);
97
98 adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
99 adv_ec_wdt_outb(EC_DAT_EN_DLY_L, EC_ADDR_DATA);
100 adv_ec_wdt_outb(0, EC_ADDR_DATA);
101
102 /* set reset delay */
103 adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
104 adv_ec_wdt_outb(EC_DAT_RST_DLY_H, EC_ADDR_DATA);
105 adv_ec_wdt_outb(val >> 8, EC_ADDR_DATA);
106
107 adv_ec_wdt_outb(EC_CMD_COMM, EC_ADDR_CMD);
108 adv_ec_wdt_outb(EC_DAT_RST_DLY_L, EC_ADDR_DATA);
109 adv_ec_wdt_outb(val & 0xFF, EC_ADDR_DATA);
110
111 wdd->timeout = t;
112 return 0;
113 }
114
adv_ec_wdt_start(struct watchdog_device * wdd)115 static int adv_ec_wdt_start(struct watchdog_device *wdd)
116 {
117 adv_ec_wdt_set_timeout(wdd, wdd->timeout);
118 adv_ec_wdt_outb(EC_CMD_WDT_START, EC_ADDR_CMD);
119
120 return 0;
121 }
122
adv_ec_wdt_stop(struct watchdog_device * wdd)123 static int adv_ec_wdt_stop(struct watchdog_device *wdd)
124 {
125 adv_ec_wdt_outb(EC_CMD_WDT_STOP, EC_ADDR_CMD);
126
127 return 0;
128 }
129
130 static const struct watchdog_info adv_ec_wdt_info = {
131 .identity = DRIVER_NAME,
132 .options = WDIOF_SETTIMEOUT |
133 WDIOF_MAGICCLOSE |
134 WDIOF_KEEPALIVEPING,
135 };
136
137 static const struct watchdog_ops adv_ec_wdt_ops = {
138 .owner = THIS_MODULE,
139 .start = adv_ec_wdt_start,
140 .stop = adv_ec_wdt_stop,
141 .ping = adv_ec_wdt_ping,
142 .set_timeout = adv_ec_wdt_set_timeout,
143 };
144
145 static struct watchdog_device adv_ec_wdt_dev = {
146 .info = &adv_ec_wdt_info,
147 .ops = &adv_ec_wdt_ops,
148 .min_timeout = MIN_TIME,
149 .max_timeout = MAX_TIME,
150 .timeout = DEFAULT_TIME,
151 };
152
adv_ec_wdt_probe(struct device * dev,unsigned int id)153 static int adv_ec_wdt_probe(struct device *dev, unsigned int id)
154 {
155 if (!devm_request_region(dev, EC_BASE_ADDR, EC_ADDR_EXTENT, dev_name(dev))) {
156 dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
157 EC_BASE_ADDR, EC_BASE_ADDR + EC_ADDR_EXTENT);
158 return -EBUSY;
159 }
160
161 watchdog_init_timeout(&adv_ec_wdt_dev, timeout, dev);
162 watchdog_stop_on_reboot(&adv_ec_wdt_dev);
163 watchdog_stop_on_unregister(&adv_ec_wdt_dev);
164
165 return devm_watchdog_register_device(dev, &adv_ec_wdt_dev);
166 }
167
168 static struct isa_driver adv_ec_wdt_driver = {
169 .probe = adv_ec_wdt_probe,
170 .driver = {
171 .name = DRIVER_NAME,
172 },
173 };
174
adv_ec_wdt_init(void)175 static int __init adv_ec_wdt_init(void)
176 {
177 unsigned int val;
178
179 /* quick probe for EC */
180 if (!request_region(EC_BASE_ADDR, EC_ADDR_EXTENT, DRIVER_NAME))
181 return -EBUSY;
182
183 adv_ec_wdt_outb(EC_CMD_EC_PROBE, EC_ADDR_CMD);
184 val = adv_ec_wdt_inb(EC_ADDR_DATA);
185 release_region(EC_BASE_ADDR, EC_ADDR_EXTENT);
186
187 if (val != EC_MAGIC)
188 return -ENODEV;
189
190 return isa_register_driver(&adv_ec_wdt_driver, 1);
191 }
192
adv_ec_wdt_exit(void)193 static void __exit adv_ec_wdt_exit(void)
194 {
195 isa_unregister_driver(&adv_ec_wdt_driver);
196 }
197
198 module_init(adv_ec_wdt_init);
199 module_exit(adv_ec_wdt_exit);
200
201 MODULE_AUTHOR("Thomas Kastner <thomas.kastner@advantech.com>");
202 MODULE_DESCRIPTION("Advantech Embedded Controller Watchdog Device Driver");
203 MODULE_LICENSE("GPL");
204 MODULE_VERSION("20221019");
205 MODULE_ALIAS("isa:" DRIVER_NAME);
206