MCA support for new x86 setup code
MCA probing support for the new x86 setup code. This implements the
same functionality as the assembly version.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/i386/boot/mca.c b/arch/i386/boot/mca.c
new file mode 100644
index 0000000..9b68bd1
--- /dev/null
+++ b/arch/i386/boot/mca.c
@@ -0,0 +1,43 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ * Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * 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/mca.c
+ *
+ * Get the MCA system description table
+ */
+
+#include "boot.h"
+
+int query_mca(void)
+{
+ u8 err;
+ u16 es, bx, len;
+
+ asm("pushw %%es ; "
+ "int $0x15 ; "
+ "setc %0 ; "
+ "movw %%es, %1 ; "
+ "popw %%es"
+ : "=acdSDm" (err), "=acdSDm" (es), "=b" (bx)
+ : "a" (0xc000));
+
+ if (err)
+ return -1; /* No MCA present */
+
+ set_fs(es);
+ len = rdfs16(bx);
+
+ if (len > sizeof(boot_params.sys_desc_table))
+ len = sizeof(boot_params.sys_desc_table);
+
+ copy_from_fs(&boot_params.sys_desc_table, bx, len);
+ return 0;
+}