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>

1 files changed, 43 insertions, 0 deletions

diff --git a/arch/i386/boot/mca.c b/arch/i386/boot/mca.c
new file mode 100644
index 000000000000..9b68bd1aef19
--- /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;
+}