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
42int iTCO_vendorsupport;
43EXPORT_SYMBOL(iTCO_vendorsupport);
44
45module_param_named(vendorsupport, iTCO_vendorsupport, int, 0);
46MODULE_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
77static 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
87static 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
128static 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
139static 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
154void 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}
166EXPORT_SYMBOL(iTCO_vendor_pre_start);
167
168void 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}
179EXPORT_SYMBOL(iTCO_vendor_pre_stop);
180
181int 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}
190EXPORT_SYMBOL(iTCO_vendor_check_noreboot_on);
191
192static 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
204static void __exit iTCO_vendor_exit_module(void)
205{
206	pr_info("Module Unloaded\n");
207}
208
209module_init(iTCO_vendor_init_module);
210module_exit(iTCO_vendor_exit_module);
211
212MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>, "
213		"R. Seretny <lkpatches@paypc.com>");
214MODULE_DESCRIPTION("Intel TCO Vendor Specific WatchDog Timer Driver Support");
215MODULE_VERSION(DRV_VERSION);
216MODULE_LICENSE("GPL");
217