x86: Move coreboot-table detection into common code

To support detecting booting from coreboot, move the code which locates
the coreboot tables into a common place. Adjust the algorithm slightly to
use a word comparison instead of string, since it is faster.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: correct the comments to 960KB]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/arch/x86/cpu/i386/cpu.c b/arch/x86/cpu/i386/cpu.c
index c8da7f10e9..cc20456c89 100644
--- a/arch/x86/cpu/i386/cpu.c
+++ b/arch/x86/cpu/i386/cpu.c
@@ -447,6 +447,31 @@ int x86_cpu_init_f(void)
 	return 0;
 }
 
+long detect_coreboot_table_at(ulong start, ulong size)
+{
+	u32 *ptr, *end;
+
+	size /= 4;
+	for (ptr = (void *)start, end = ptr + size; ptr < end; ptr += 4) {
+		if (*ptr == 0x4f49424c) /* "LBIO" */
+			return (long)ptr;
+	}
+
+	return -ENOENT;
+}
+
+long locate_coreboot_table(void)
+{
+	long addr;
+
+	/* We look for LBIO in the first 4K of RAM and again at 960KB */
+	addr = detect_coreboot_table_at(0x0, 0x1000);
+	if (addr < 0)
+		addr = detect_coreboot_table_at(0xf0000, 0x1000);
+
+	return addr;
+}
+
 int x86_cpu_reinit_f(void)
 {
 	setup_identity();