// SPDX-License-Identifier: GPL-2.0+ /* * intel TCO vendor specific watchdog driver support * * (c) Copyright 2006-2009 Wim Van Sebroeck <[email protected]>. * * Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor * provide warranty for any of this software. This material is * provided "AS-IS" and at no charge. */ /* * Includes, defines, variables, module parameters, ... */ #define pr_fmt(fmt) … /* Module and version information */ #define DRV_NAME … #define DRV_VERSION … /* Includes */ #include <linux/module.h> /* For module specific items */ #include <linux/moduleparam.h> /* For new moduleparam's */ #include <linux/types.h> /* For standard types (like size_t) */ #include <linux/errno.h> /* For the -ENODEV/... values */ #include <linux/kernel.h> /* For printk/panic/... */ #include <linux/init.h> /* For __init/__exit/... */ #include <linux/ioport.h> /* For io-port access */ #include <linux/io.h> /* For inb/outb/... */ #include "iTCO_vendor.h" /* List of vendor support modes */ /* SuperMicro Pentium 3 Era 370SSE+-OEM1/P3TSSE */ #define SUPERMICRO_OLD_BOARD … /* SuperMicro Pentium 4 / Xeon 4 / EMT64T Era Systems - no longer supported */ #define SUPERMICRO_NEW_BOARD … /* Broken BIOS */ #define BROKEN_BIOS … int iTCO_vendorsupport; EXPORT_SYMBOL(…); module_param_named(vendorsupport, iTCO_vendorsupport, int, 0); MODULE_PARM_DESC(…) …; /* * Vendor Specific Support */ /* * Vendor Support: 1 * Board: Super Micro Computer Inc. 370SSE+-OEM1/P3TSSE * iTCO chipset: ICH2 * * Code contributed by: R. Seretny <[email protected]> * Documentation obtained by R. Seretny from SuperMicro Technical Support * * To enable Watchdog function: * BIOS setup -> Power -> TCO Logic SMI Enable -> Within5Minutes * This setting enables SMI to clear the watchdog expired flag. * If BIOS or CPU fail which may cause SMI hang, then system will * reboot. When application starts to use watchdog function, * application has to take over the control from SMI. * * For P3TSSE, J36 jumper needs to be removed to enable the Watchdog * function. * * Note: The system will reboot when Expire Flag is set TWICE. * So, if the watchdog timer is 20 seconds, then the maximum hang * time is about 40 seconds, and the minimum hang time is about * 20.6 seconds. */ static void supermicro_old_pre_start(struct resource *smires) { … } static void supermicro_old_pre_stop(struct resource *smires) { … } /* * Vendor Support: 911 * Board: Some Intel ICHx based motherboards * iTCO chipset: ICH7+ * * Some Intel motherboards have a broken BIOS implementation: i.e. * the SMI handler clear's the TIMEOUT bit in the TC01_STS register * and does not reload the time. Thus the TCO watchdog does not reboot * the system. * * These are the conclusions of Andriy Gapon <[email protected]> after * debugging: the SMI handler is quite simple - it tests value in * TCO1_CNT against 0x800, i.e. checks TCO_TMR_HLT. If the bit is set * the handler goes into an infinite loop, apparently to allow the * second timeout and reboot. Otherwise it simply clears TIMEOUT bit * in TCO1_STS and that's it. * So the logic seems to be reversed, because it is hard to see how * TIMEOUT can get set to 1 and SMI generated when TCO_TMR_HLT is set * (other than a transitional effect). * * The only fix found to get the motherboard(s) to reboot is to put * the glb_smi_en bit to 0. This is a dirty hack that bypasses the * broken code by disabling Global SMI. * * WARNING: globally disabling SMI could possibly lead to dramatic * problems, especially on laptops! I.e. various ACPI things where * SMI is used for communication between OS and firmware. * * Don't use this fix if you don't need to!!! */ static void broken_bios_start(struct resource *smires) { … } static void broken_bios_stop(struct resource *smires) { … } /* * Generic Support Functions */ void iTCO_vendor_pre_start(struct resource *smires, unsigned int heartbeat) { … } EXPORT_SYMBOL(…); void iTCO_vendor_pre_stop(struct resource *smires) { … } EXPORT_SYMBOL(…); int iTCO_vendor_check_noreboot_on(void) { … } EXPORT_SYMBOL(…); static int __init iTCO_vendor_init_module(void) { … } static void __exit iTCO_vendor_exit_module(void) { … } module_init(…) …; module_exit(iTCO_vendor_exit_module); MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_VERSION(…); MODULE_LICENSE(…) …;
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