diff options
| -rw-r--r-- | arch/i386/boot/apm.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/arch/i386/boot/apm.c b/arch/i386/boot/apm.c new file mode 100644 index 00000000000..a34087c370c --- /dev/null +++ b/arch/i386/boot/apm.c @@ -0,0 +1,97 @@ +/* -*- linux-c -*- ------------------------------------------------------- * + * + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright 2007 rPath, Inc. - All Rights Reserved + * + * 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. + * + * ----------------------------------------------------------------------- */ + +/* + * arch/i386/boot/apm.c + * + * Get APM BIOS information + */ + +#include "boot.h" + +#if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE) + +int query_apm_bios(void) +{ + u16 ax, bx, cx, dx, di; + u32 ebx, esi; + u8 err; + + /* APM BIOS installation check */ + ax = 0x5300; + bx = cx = 0; + asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0" + : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx) + : : "esi", "edi"); + + if (err) + return -1; /* No APM BIOS */ + + if (bx != 0x504d) /* "PM" signature */ + return -1; + + if (cx & 0x02) /* 32 bits supported? */ + return -1; + + /* Disconnect first, just in case */ + ax = 0x5304; + asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp" + : "+a" (ax) + : : "ebx", "ecx", "edx", "esi", "edi"); + + /* Paranoia */ + ebx = esi = 0; + cx = dx = di = 0; + + /* 32-bit connect */ + asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %6" + : "=a" (ax), "+b" (ebx), "+c" (cx), "+d" (dx), + "+S" (esi), "+D" (di), "=m" (err) + : "a" (0x5303)); + + boot_params.apm_bios_info.cseg = ax; + boot_params.apm_bios_info.offset = ebx; + boot_params.apm_bios_info.cseg_16 = cx; + boot_params.apm_bios_info.dseg = dx; + boot_params.apm_bios_info.cseg_len = (u16)esi; + boot_params.apm_bios_info.cseg_16_len = esi >> 16; + boot_params.apm_bios_info.dseg_len = di; + + if (err) + return -1; + + /* Redo the installation check as the 32-bit connect; + some BIOSes return different flags this way... */ + + ax = 0x5300; + bx = cx = 0; + asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0" + : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx) + : : "esi", "edi"); + + if (err || bx != 0x504d) { + /* Failure with 32-bit connect, try to disconect and ignore */ + ax = 0x5304; + bx = 0; + asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp" + : "+a" (ax), "+b" (bx) + : : "ecx", "edx", "esi", "edi"); + return -1; + } + + boot_params.apm_bios_info.version = ax; + boot_params.apm_bios_info.flags = cx; + return 0; +} + +#endif |