diff options
| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
| commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
| tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /arch/x86/boot/apm.c | |
| parent | Initial commit. (diff) | |
| download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip | |
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/x86/boot/apm.c')
| -rw-r--r-- | arch/x86/boot/apm.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/x86/boot/apm.c b/arch/x86/boot/apm.c new file mode 100644 index 000000000..ee274834e --- /dev/null +++ b/arch/x86/boot/apm.c @@ -0,0 +1,75 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * Copyright 2009 Intel Corporation; author H. Peter Anvin + * + * Original APM BIOS checking by Stephen Rothwell, May 1994 + * (sfr@canb.auug.org.au) + * + * This file is part of the Linux kernel, and is made available under + * the terms of the GNU General Public License version 2. + * + * ----------------------------------------------------------------------- */ + +/* + * Get APM BIOS information + */ + +#include "boot.h" + +int query_apm_bios(void) +{ + struct biosregs ireg, oreg; + + /* APM BIOS installation check */ + initregs(&ireg); + ireg.ah = 0x53; + intcall(0x15, &ireg, &oreg); + + if (oreg.flags & X86_EFLAGS_CF) + return -1; /* No APM BIOS */ + + if (oreg.bx != 0x504d) /* "PM" signature */ + return -1; + + if (!(oreg.cx & 0x02)) /* 32 bits supported? */ + return -1; + + /* Disconnect first, just in case */ + ireg.al = 0x04; + intcall(0x15, &ireg, NULL); + + /* 32-bit connect */ + ireg.al = 0x03; + intcall(0x15, &ireg, &oreg); + + boot_params.apm_bios_info.cseg = oreg.ax; + boot_params.apm_bios_info.offset = oreg.ebx; + boot_params.apm_bios_info.cseg_16 = oreg.cx; + boot_params.apm_bios_info.dseg = oreg.dx; + boot_params.apm_bios_info.cseg_len = oreg.si; + boot_params.apm_bios_info.cseg_16_len = oreg.hsi; + boot_params.apm_bios_info.dseg_len = oreg.di; + + if (oreg.flags & X86_EFLAGS_CF) + return -1; + + /* Redo the installation check as the 32-bit connect; + some BIOSes return different flags this way... */ + + ireg.al = 0x00; + intcall(0x15, &ireg, &oreg); + + if ((oreg.eflags & X86_EFLAGS_CF) || oreg.bx != 0x504d) { + /* Failure with 32-bit connect, try to disconect and ignore */ + ireg.al = 0x04; + intcall(0x15, &ireg, NULL); + return -1; + } + + boot_params.apm_bios_info.version = oreg.ax; + boot_params.apm_bios_info.flags = oreg.cx; + return 0; +} + |