drivers/watchdog/iTCO_vendor_support.c

   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 static int vendorsupport;
  43 module_param(vendorsupport, int, 0);
  44 MODULE_PARM_DESC(vendorsupport, "iTCO vendor specific support mode, default="
  45                         "0 (none), 1=SuperMicro Pent3, 911=Broken SMI BIOS");
  46
  47 /*
  48  *      Vendor Specific Support
  49  */
  50
  51 /*
  52  *      Vendor Support: 1
  53  *      Board: Super Micro Computer Inc. 370SSE+-OEM1/P3TSSE
  54  *      iTCO chipset: ICH2
  55  *
  56  *      Code contributed by: R. Seretny <lkpatches@paypc.com>
  57  *      Documentation obtained by R. Seretny from SuperMicro Technical Support
  58  *
  59  *      To enable Watchdog function:
  60  *          BIOS setup -> Power -> TCO Logic SMI Enable -> Within5Minutes
  61  *          This setting enables SMI to clear the watchdog expired flag.
  62  *          If BIOS or CPU fail which may cause SMI hang, then system will
  63  *          reboot. When application starts to use watchdog function,
  64  *          application has to take over the control from SMI.
  65  *
  66  *          For P3TSSE, J36 jumper needs to be removed to enable the Watchdog
  67  *          function.
  68  *
  69  *          Note: The system will reboot when Expire Flag is set TWICE.
  70  *          So, if the watchdog timer is 20 seconds, then the maximum hang
  71  *          time is about 40 seconds, and the minimum hang time is about
  72  *          20.6 seconds.
  73  */
  74
  75 static void supermicro_old_pre_start(struct resource *smires)
  76 {
  77         unsigned long val32;
  78
  79         /* Bit 13: TCO_EN -> 0 = Disables TCO logic generating an SMI# */
  80         val32 = inl(smires->start);
  81         val32 &= 0xffffdfff;    /* Turn off SMI clearing watchdog */
  82         outl(val32, smires->start);     /* Needed to activate watchdog */
  83 }
  84
  85 static void supermicro_old_pre_stop(struct resource *smires)
  86 {
  87         unsigned long val32;
  88
  89         /* Bit 13: TCO_EN -> 1 = Enables the TCO logic to generate SMI# */
  90         val32 = inl(smires->start);
  91         val32 |= 0x00002000;    /* Turn on SMI clearing watchdog */
  92         outl(val32, smires->start);     /* Needed to deactivate watchdog */
  93 }
  94
  95 /*
  96  *      Vendor Support: 911
  97  *      Board: Some Intel ICHx based motherboards
  98  *      iTCO chipset: ICH7+
  99  *
 100  *      Some Intel motherboards have a broken BIOS implementation: i.e.
 101  *      the SMI handler clear's the TIMEOUT bit in the TC01_STS register
 102  *      and does not reload the time. Thus the TCO watchdog does not reboot
 103  *      the system.
 104  *
 105  *      These are the conclusions of Andriy Gapon <avg@icyb.net.ua> after
 106  *      debugging: the SMI handler is quite simple - it tests value in
 107  *      TCO1_CNT against 0x800, i.e. checks TCO_TMR_HLT. If the bit is set
 108  *      the handler goes into an infinite loop, apparently to allow the
 109  *      second timeout and reboot. Otherwise it simply clears TIMEOUT bit
 110  *      in TCO1_STS and that's it.
 111  *      So the logic seems to be reversed, because it is hard to see how
 112  *      TIMEOUT can get set to 1 and SMI generated when TCO_TMR_HLT is set
 113  *      (other than a transitional effect).
 114  *
 115  *      The only fix found to get the motherboard(s) to reboot is to put
 116  *      the glb_smi_en bit to 0. This is a dirty hack that bypasses the
 117  *      broken code by disabling Global SMI.
 118  *
 119  *      WARNING: globally disabling SMI could possibly lead to dramatic
 120  *      problems, especially on laptops! I.e. various ACPI things where
 121  *      SMI is used for communication between OS and firmware.
 122  *
 123  *      Don't use this fix if you don't need to!!!
 124  */
 125
 126 static void broken_bios_start(struct resource *smires)
 127 {
 128         unsigned long val32;
 129
 130         val32 = inl(smires->start);
 131         /* Bit 13: TCO_EN     -> 0 = Disables TCO logic generating an SMI#
 132            Bit  0: GBL_SMI_EN -> 0 = No SMI# will be generated by ICH. */
 133         val32 &= 0xffffdffe;
 134         outl(val32, smires->start);
 135 }
 136
 137 static void broken_bios_stop(struct resource *smires)
 138 {
 139         unsigned long val32;
 140
 141         val32 = inl(smires->start);
 142         /* Bit 13: TCO_EN     -> 1 = Enables TCO logic generating an SMI#
 143            Bit  0: GBL_SMI_EN -> 1 = Turn global SMI on again. */
 144         val32 |= 0x00002001;
 145         outl(val32, smires->start);
 146 }
 147
 148 /*
 149  *      Generic Support Functions
 150  */
 151
 152 void iTCO_vendor_pre_start(struct resource *smires,
 153                            unsigned int heartbeat)
 154 {
 155         switch (vendorsupport) {
 156         case SUPERMICRO_OLD_BOARD:
 157                 supermicro_old_pre_start(smires);
 158                 break;
 159         case BROKEN_BIOS:
 160                 broken_bios_start(smires);
 161                 break;
 162         }
 163 }
 164 EXPORT_SYMBOL(iTCO_vendor_pre_start);
 165
 166 void iTCO_vendor_pre_stop(struct resource *smires)
 167 {
 168         switch (vendorsupport) {
 169         case SUPERMICRO_OLD_BOARD:
 170                 supermicro_old_pre_stop(smires);
 171                 break;
 172         case BROKEN_BIOS:
 173                 broken_bios_stop(smires);
 174                 break;
 175         }
 176 }
 177 EXPORT_SYMBOL(iTCO_vendor_pre_stop);
 178
 179 int iTCO_vendor_check_noreboot_on(void)
 180 {
 181         switch (vendorsupport) {
 182         case SUPERMICRO_OLD_BOARD:
 183                 return 0;
 184         default:
 185                 return 1;
 186         }
 187 }
 188 EXPORT_SYMBOL(iTCO_vendor_check_noreboot_on);
 189
 190 static int __init iTCO_vendor_init_module(void)
 191 {
 192         if (vendorsupport == SUPERMICRO_NEW_BOARD) {
 193                 pr_warn("Option vendorsupport=%d is no longer supported, "
 194                         "please use the w83627hf_wdt driver instead\n",
 195                         SUPERMICRO_NEW_BOARD);
 196                 return -EINVAL;
 197         }
 198         pr_info("vendor-support=%d\n", vendorsupport);
 199         return 0;
 200 }
 201
 202 static void __exit iTCO_vendor_exit_module(void)
 203 {
 204         pr_info("Module Unloaded\n");
 205 }
 206
 207 module_init(iTCO_vendor_init_module);
 208 module_exit(iTCO_vendor_exit_module);
 209
 210 MODULE_AUTHOR("Wim Van Sebroeck <wim@iguana.be>, "
 211                 "R. Seretny <lkpatches@paypc.com>");
 212 MODULE_DESCRIPTION("Intel TCO Vendor Specific WatchDog Timer Driver Support");
 213 MODULE_VERSION(DRV_VERSION);
 214 MODULE_LICENSE("GPL");