From: H. Peter Anvin <[email protected]>
APM probing code for the new x86 setup code. This implements the
same functionality as the assembly version.
Signed-off-by: H. Peter Anvin <[email protected]>
---
arch/i386/boot/apm.c | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 97 insertions(+), 0 deletions(-)
create mode 100644 arch/i386/boot/apm.c
diff --git a/arch/i386/boot/apm.c b/arch/i386/boot/apm.c
new file mode 100644
index 0000000..a34087c
--- /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
+ * ([email protected])
+ *
+ * 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
--
1.5.2.2
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