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 
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 
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 
77 static int wd_ping(struct watchdog_device *wdd)
78 {
79 	inb(WD_TRIGGER_IOADR);
80 	return 0;
81 }
82 
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 
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 
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 
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 		if (!devm_request_region(dev, gp_status_reg_227e_res.start,
159 					 resource_size(&gp_status_reg_227e_res),
160 					 KBUILD_MODNAME)) {
161 			dev_err(dev,
162 				"Unable to register IO resource at %pR\n",
163 				&gp_status_reg_227e_res);
164 			return -EBUSY;
165 		}
166 		fallthrough;
167 	case SIMATIC_IPC_DEVICE_427E:
168 		wdd_data.parent = dev;
169 		break;
170 	default:
171 		return -EINVAL;
172 	}
173 
174 	if (!devm_request_region(dev, io_resource_enable.start,
175 				 resource_size(&io_resource_enable),
176 				 io_resource_enable.name)) {
177 		dev_err(dev,
178 			"Unable to register IO resource at %#x\n",
179 			WD_ENABLE_IOADR);
180 		return -EBUSY;
181 	}
182 
183 	if (!devm_request_region(dev, io_resource_trigger.start,
184 				 resource_size(&io_resource_trigger),
185 				 io_resource_trigger.name)) {
186 		dev_err(dev,
187 			"Unable to register IO resource at %#x\n",
188 			WD_TRIGGER_IOADR);
189 		return -EBUSY;
190 	}
191 
192 	if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
193 		res = &mem_resource;
194 
195 		ret = p2sb_bar(NULL, 0, res);
196 		if (ret)
197 			return ret;
198 
199 		/* do the final address calculation */
200 		res->start = res->start + (GPIO_COMMUNITY0_PORT_ID << 16) +
201 			     PAD_CFG_DW0_GPP_A_23;
202 		res->end = res->start + SZ_4 - 1;
203 
204 		wd_reset_base_addr = devm_ioremap_resource(dev, res);
205 		if (IS_ERR(wd_reset_base_addr))
206 			return PTR_ERR(wd_reset_base_addr);
207 	}
208 
209 	wdd_data.bootstatus = wd_setup(plat->devmode);
210 	if (wdd_data.bootstatus)
211 		dev_warn(dev, "last reboot caused by watchdog reset\n");
212 
213 	watchdog_set_nowayout(&wdd_data, nowayout);
214 	watchdog_stop_on_reboot(&wdd_data);
215 	return devm_watchdog_register_device(dev, &wdd_data);
216 }
217 
218 static struct platform_driver simatic_ipc_wdt_driver = {
219 	.probe = simatic_ipc_wdt_probe,
220 	.driver = {
221 		.name = KBUILD_MODNAME,
222 	},
223 };
224 
225 module_platform_driver(simatic_ipc_wdt_driver);
226 
227 MODULE_LICENSE("GPL v2");
228 MODULE_ALIAS("platform:" KBUILD_MODNAME);
229 MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
230