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");
217