1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Siemens SIMATIC IPC driver for Watchdogs
4 *
5 * Copyright (c) Siemens AG, 2020-2021
6 *
7 * Authors:
8 * Gerd Haeussler <gerd.haeussler.ext@siemens.com>
9 */
10
11 #include <linux/device.h>
12 #include <linux/errno.h>
13 #include <linux/init.h>
14 #include <linux/io.h>
15 #include <linux/ioport.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/pci.h>
19 #include <linux/platform_data/x86/p2sb.h>
20 #include <linux/platform_data/x86/simatic-ipc-base.h>
21 #include <linux/platform_device.h>
22 #include <linux/sizes.h>
23 #include <linux/util_macros.h>
24 #include <linux/watchdog.h>
25
26 #define WD_ENABLE_IOADR 0x62
27 #define WD_TRIGGER_IOADR 0x66
28 #define GPIO_COMMUNITY0_PORT_ID 0xaf
29 #define PAD_CFG_DW0_GPP_A_23 0x4b8
30 #define SAFE_EN_N_427E 0x01
31 #define SAFE_EN_N_227E 0x04
32 #define WD_ENABLED 0x01
33 #define WD_TRIGGERED 0x80
34 #define WD_MACROMODE 0x02
35
36 #define TIMEOUT_MIN 2
37 #define TIMEOUT_DEF 64
38 #define TIMEOUT_MAX 64
39
40 #define GP_STATUS_REG_227E 0x404D /* IO PORT for SAFE_EN_N on 227E */
41
42 static bool nowayout = WATCHDOG_NOWAYOUT;
43 module_param(nowayout, bool, 0000);
44 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
45 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
46
47 static struct resource gp_status_reg_227e_res =
48 DEFINE_RES_IO_NAMED(GP_STATUS_REG_227E, SZ_1, KBUILD_MODNAME);
49
50 static struct resource io_resource_enable =
51 DEFINE_RES_IO_NAMED(WD_ENABLE_IOADR, SZ_1,
52 KBUILD_MODNAME " WD_ENABLE_IOADR");
53
54 static struct resource io_resource_trigger =
55 DEFINE_RES_IO_NAMED(WD_TRIGGER_IOADR, SZ_1,
56 KBUILD_MODNAME " WD_TRIGGER_IOADR");
57
58 /* the actual start will be discovered with p2sb, 0 is a placeholder */
59 static struct resource mem_resource =
60 DEFINE_RES_MEM_NAMED(0, 0, "WD_RESET_BASE_ADR");
61
62 static u32 wd_timeout_table[] = {2, 4, 6, 8, 16, 32, 48, 64 };
63 static void __iomem *wd_reset_base_addr;
64
wd_start(struct watchdog_device * wdd)65 static int wd_start(struct watchdog_device *wdd)
66 {
67 outb(inb(WD_ENABLE_IOADR) | WD_ENABLED, WD_ENABLE_IOADR);
68 return 0;
69 }
70
wd_stop(struct watchdog_device * wdd)71 static int wd_stop(struct watchdog_device *wdd)
72 {
73 outb(inb(WD_ENABLE_IOADR) & ~WD_ENABLED, WD_ENABLE_IOADR);
74 return 0;
75 }
76
wd_ping(struct watchdog_device * wdd)77 static int wd_ping(struct watchdog_device *wdd)
78 {
79 inb(WD_TRIGGER_IOADR);
80 return 0;
81 }
82
wd_set_timeout(struct watchdog_device * wdd,unsigned int t)83 static int wd_set_timeout(struct watchdog_device *wdd, unsigned int t)
84 {
85 int timeout_idx = find_closest(t, wd_timeout_table,
86 ARRAY_SIZE(wd_timeout_table));
87
88 outb((inb(WD_ENABLE_IOADR) & 0xc7) | timeout_idx << 3, WD_ENABLE_IOADR);
89 wdd->timeout = wd_timeout_table[timeout_idx];
90 return 0;
91 }
92
93 static const struct watchdog_info wdt_ident = {
94 .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
95 WDIOF_SETTIMEOUT,
96 .identity = KBUILD_MODNAME,
97 };
98
99 static const struct watchdog_ops wdt_ops = {
100 .owner = THIS_MODULE,
101 .start = wd_start,
102 .stop = wd_stop,
103 .ping = wd_ping,
104 .set_timeout = wd_set_timeout,
105 };
106
wd_secondary_enable(u32 wdtmode)107 static void wd_secondary_enable(u32 wdtmode)
108 {
109 u16 resetbit;
110
111 /* set safe_en_n so we are not just WDIOF_ALARMONLY */
112 if (wdtmode == SIMATIC_IPC_DEVICE_227E) {
113 /* enable SAFE_EN_N on GP_STATUS_REG_227E */
114 resetbit = inb(GP_STATUS_REG_227E);
115 outb(resetbit & ~SAFE_EN_N_227E, GP_STATUS_REG_227E);
116 } else {
117 /* enable SAFE_EN_N on PCH D1600 */
118 resetbit = ioread16(wd_reset_base_addr);
119 iowrite16(resetbit & ~SAFE_EN_N_427E, wd_reset_base_addr);
120 }
121 }
122
wd_setup(u32 wdtmode)123 static int wd_setup(u32 wdtmode)
124 {
125 unsigned int bootstatus = 0;
126 int timeout_idx;
127
128 timeout_idx = find_closest(TIMEOUT_DEF, wd_timeout_table,
129 ARRAY_SIZE(wd_timeout_table));
130
131 if (inb(WD_ENABLE_IOADR) & WD_TRIGGERED)
132 bootstatus |= WDIOF_CARDRESET;
133
134 /* reset alarm bit, set macro mode, and set timeout */
135 outb(WD_TRIGGERED | WD_MACROMODE | timeout_idx << 3, WD_ENABLE_IOADR);
136
137 wd_secondary_enable(wdtmode);
138
139 return bootstatus;
140 }
141
142 static struct watchdog_device wdd_data = {
143 .info = &wdt_ident,
144 .ops = &wdt_ops,
145 .min_timeout = TIMEOUT_MIN,
146 .max_timeout = TIMEOUT_MAX
147 };
148
simatic_ipc_wdt_probe(struct platform_device * pdev)149 static int simatic_ipc_wdt_probe(struct platform_device *pdev)
150 {
151 struct simatic_ipc_platform *plat = pdev->dev.platform_data;
152 struct device *dev = &pdev->dev;
153 struct resource *res;
154 int ret;
155
156 switch (plat->devmode) {
157 case SIMATIC_IPC_DEVICE_227E:
158 res = &gp_status_reg_227e_res;
159 if (!request_muxed_region(res->start, resource_size(res), res->name)) {
160 dev_err(dev,
161 "Unable to register IO resource at %pR\n",
162 &gp_status_reg_227e_res);
163 return -EBUSY;
164 }
165 fallthrough;
166 case SIMATIC_IPC_DEVICE_427E:
167 wdd_data.parent = dev;
168 break;
169 default:
170 return -EINVAL;
171 }
172
173 if (!devm_request_region(dev, io_resource_enable.start,
174 resource_size(&io_resource_enable),
175 io_resource_enable.name)) {
176 dev_err(dev,
177 "Unable to register IO resource at %#x\n",
178 WD_ENABLE_IOADR);
179 return -EBUSY;
180 }
181
182 if (!devm_request_region(dev, io_resource_trigger.start,
183 resource_size(&io_resource_trigger),
184 io_resource_trigger.name)) {
185 dev_err(dev,
186 "Unable to register IO resource at %#x\n",
187 WD_TRIGGER_IOADR);
188 return -EBUSY;
189 }
190
191 if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
192 res = &mem_resource;
193
194 ret = p2sb_bar(NULL, 0, res);
195 if (ret)
196 return ret;
197
198 /* do the final address calculation */
199 res->start = res->start + (GPIO_COMMUNITY0_PORT_ID << 16) +
200 PAD_CFG_DW0_GPP_A_23;
201 res->end = res->start + SZ_4 - 1;
202
203 wd_reset_base_addr = devm_ioremap_resource(dev, res);
204 if (IS_ERR(wd_reset_base_addr))
205 return PTR_ERR(wd_reset_base_addr);
206 }
207
208 wdd_data.bootstatus = wd_setup(plat->devmode);
209 if (wdd_data.bootstatus)
210 dev_warn(dev, "last reboot caused by watchdog reset\n");
211
212 if (plat->devmode == SIMATIC_IPC_DEVICE_227E)
213 release_region(gp_status_reg_227e_res.start,
214 resource_size(&gp_status_reg_227e_res));
215
216 watchdog_set_nowayout(&wdd_data, nowayout);
217 watchdog_stop_on_reboot(&wdd_data);
218 return devm_watchdog_register_device(dev, &wdd_data);
219 }
220
221 static struct platform_driver simatic_ipc_wdt_driver = {
222 .probe = simatic_ipc_wdt_probe,
223 .driver = {
224 .name = KBUILD_MODNAME,
225 },
226 };
227
228 module_platform_driver(simatic_ipc_wdt_driver);
229
230 MODULE_LICENSE("GPL v2");
231 MODULE_ALIAS("platform:" KBUILD_MODNAME);
232 MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
233