1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * intel TCO vendor specific watchdog driver support
4 *
5 * (c) Copyright 2006-2009 Wim Van Sebroeck <wim@iguana.be>.
6 *
7 * Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
8 * provide warranty for any of this software. This material is
9 * provided "AS-IS" and at no charge.
10 */
11
12 /*
13 * Includes, defines, variables, module parameters, ...
14 */
15
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18 /* Module and version information */
19 #define DRV_NAME "iTCO_vendor_support"
20 #define DRV_VERSION "1.04"
21
22 /* Includes */
23 #include <linux/module.h> /* For module specific items */
24 #include <linux/moduleparam.h> /* For new moduleparam's */
25 #include <linux/types.h> /* For standard types (like size_t) */
26 #include <linux/errno.h> /* For the -ENODEV/... values */
27 #include <linux/kernel.h> /* For printk/panic/... */
28 #include <linux/init.h> /* For __init/__exit/... */
29 #include <linux/ioport.h> /* For io-port access */
30 #include <linux/io.h> /* For inb/outb/... */
31
32 #include "iTCO_vendor.h"
33
34 /* List of vendor support modes */
35 /* SuperMicro Pentium 3 Era 370SSE+-OEM1/P3TSSE */
36 #define SUPERMICRO_OLD_BOARD 1
37 /* SuperMicro Pentium 4 / Xeon 4 / EMT64T Era Systems - no longer supported */
38 #define SUPERMICRO_NEW_BOARD 2
39 /* Broken BIOS */
40 #define BROKEN_BIOS 911
41
42 int iTCO_vendorsupport;
43 EXPORT_SYMBOL(iTCO_vendorsupport);
44
45 module_param_named(vendorsupport, iTCO_vendorsupport, int, 0);
46 MODULE_PARM_DESC(vendorsupport, "iTCO vendor specific support mode, default="
47 "0 (none), 1=SuperMicro Pent3, 911=Broken SMI BIOS");
48
49 /*
50 * Vendor Specific Support
51 */
52
53 /*
54 * Vendor Support: 1
55 * Board: Super Micro Computer Inc. 370SSE+-OEM1/P3TSSE
56 * iTCO chipset: ICH2
57 *
58 * Code contributed by: R. Seretny <lkpatches@paypc.com>
59 * Documentation obtained by R. Seretny from SuperMicro Technical Support
60 *
61 * To enable Watchdog function:
62 * BIOS setup -> Power -> TCO Logic SMI Enable -> Within5Minutes
63 * This setting enables SMI to clear the watchdog expired flag.
64 * If BIOS or CPU fail which may cause SMI hang, then system will
65 * reboot. When application starts to use watchdog function,
66 * application has to take over the control from SMI.
67 *
68 * For P3TSSE, J36 jumper needs to be removed to enable the Watchdog
69 * function.
70 *
71 * Note: The system will reboot when Expire Flag is set TWICE.
72 * So, if the watchdog timer is 20 seconds, then the maximum hang
73 * time is about 40 seconds, and the minimum hang time is about
74 * 20.6 seconds.
75 */
76
77 static void supermicro_old_pre_start(struct resource *smires)
78 {
79 unsigned long val32;
80
81 /* Bit 13: TCO_EN -> 0 = Disables TCO logic generating an SMI# */
82 val32 = inl(smires->start);
83 val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */
84 outl(val32, smires->start); /* Needed to activate watchdog */
85 }
86
87 static void supermicro_old_pre_stop(struct resource *smires)
88 {
89 unsigned long val32;
90
91 /* Bit 13: TCO_EN -> 1 = Enables the TCO logic to generate SMI# */
92 val32 = inl(smires->start);
93 val32 |= 0x00002000; /* Turn on SMI clearing watchdog */
94 outl(val32, smires->start); /* Needed to deactivate watchdog */
95 }
96
97 /*
98 * Vendor Support: 911
99 * Board: Some Intel ICHx based motherboards
100 * iTCO chipset: ICH7+
101 *
102 * Some Intel motherboards have a broken BIOS implementation: i.e.
103 * the SMI handler clear's the TIMEOUT bit in the TC01_STS register
104 * and does not reload the time. Thus the TCO watchdog does not reboot
105 * the system.
106 *
107 * These are the conclusions of Andriy Gapon <avg@icyb.net.ua> after
108 * debugging: the SMI handler is quite simple - it tests value in
109 * TCO1_CNT against 0x800, i.e. checks TCO_TMR_HLT. If the bit is set
110 * the handler goes into an infinite loop, apparently to allow the
111 * second timeout and reboot. Otherwise it simply clears TIMEOUT bit
112 * in TCO1_STS and that's it.
113 * So the logic seems to be reversed, because it is hard to see how
114 * TIMEOUT can get set to 1 and SMI generated when TCO_TMR_HLT is set
115 * (other than a transitional effect).
116 *
117 * The only fix found to get the motherboard(s) to reboot is to put
118 * the glb_smi_en bit to 0. This is a dirty hack that bypasses the
119 * broken code by disabling Global SMI.
120 *
121 * WARNING: globally disabling SMI could possibly lead to dramatic
122 * problems, especially on laptops! I.e. various ACPI things where
123 * SMI is used for communication between OS and firmware.
124 *
125 * Don't use this fix if you don't need to!!!
126 */
127
128 static void broken_bios_start(struct resource *smires)
129 {
130 unsigned long val32;
131
132 val32 = inl(smires->start);
133 /* Bit 13: TCO_EN -> 0 = Disables TCO logic generating an SMI#
134 Bit 0: GBL_SMI_EN -> 0 = No SMI# will be generated by ICH. */
135 val32 &= 0xffffdffe;
136 outl(val32, smires->start);
137 }
138
139 static void broken_bios_stop(struct resource *smires)
140 {
141 unsigned long val32;
142
143 val32 = inl(smires->start);
144 /* Bit 13: TCO_EN -> 1 = Enables TCO logic generating an SMI#
145 Bit 0: GBL_SMI_EN -> 1 = Turn global SMI on again. */
146 val32 |= 0x00002001;
147 outl(val32, smires->start);
148 }
149
150 /*
151 * Generic Support Functions
152 */
153
154 void iTCO_vendor_pre_start(struct resource *smires,
155 unsigned int heartbeat)
156 {
157 switch (iTCO_vendorsupport) {
158 case SUPERMICRO_OLD_BOARD:
159 supermicro_old_pre_start(smires);
160 break;
161 case BROKEN_BIOS:
162 broken_bios_start(smires);
163 break;
164 }
165 }
166 EXPORT_SYMBOL(iTCO_vendor_pre_start);
167
168 void iTCO_vendor_pre_stop(struct resource *smires)
169 {
170 switch (iTCO_vendorsupport) {
171 case SUPERMICRO_OLD_BOARD:
172 supermicro_old_pre_stop(smires);
173 break;
174 case BROKEN_BIOS:
175 broken_bios_stop(smires);
176 break;
177 }
178 }
179 EXPORT_SYMBOL(iTCO_vendor_pre_stop);
180
181 int iTCO_vendor_check_noreboot_on(void)
182 {
183 switch (iTCO_vendorsupport) {
184 case SUPERMICRO_OLD_BOARD:
185 return 0;
186 default:
187 return 1;
188 }
189 }
190 EXPORT_SYMBOL(iTCO_vendor_check_noreboot_on);
191
192 static int __init iTCO_vendor_init_module(void)
193 {
194 if (iTCO_vendorsupport == SUPERMICRO_NEW_BOARD) {
195 pr_warn("Option vendorsupport=%d is no longer supported, "
196 "please use the w83627hf_wdt driver instead\n",
197 SUPERMICRO_NEW_BOARD);
198 return -EINVAL;
199 }
200 pr_info("vendor-support=%d\n", iTCO_vendorsupport);
201 return 0;
202 }
203
204 static void __exit iTCO_vendor_exit_module(void)
205 {
206 pr_info("Module Unloaded\n");
207 }
208
209 module_init(iTCO_vendor_init_module);
210 module_exit(iTCO_vendor_exit_module);
211
212 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>, "
213 "R. Seretny <lkpatches@paypc.com>");
214 MODULE_DESCRIPTION("Intel TCO Vendor Specific WatchDog Timer Driver Support");
215 MODULE_VERSION(DRV_VERSION);
216 MODULE_LICENSE("GPL");