Revert "coreboot_table: don't add CMOS checksum twice."

This reverts commit e6606518243d9beda31693d40493b5f7a1a3e2e0.

After some discussion on IRC we decided to revert it as libpayload can
only read the copy that was removed (and other users like nvramtool can
only read the other copy). So we need both copies at this time.

Signed-off-by: Nico Huber <nico.h@gmx.de>
Change-Id: I6cf6b2a1523d771bb52f3d5720b1b16ed4b348db
Reviewed-on: http://review.coreboot.org/11696
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/src/lib/coreboot_table.c b/src/lib/coreboot_table.c
index 6859bf2..35341ab 100644
--- a/src/lib/coreboot_table.c
+++ b/src/lib/coreboot_table.c
@@ -34,6 +34,9 @@
 #include <cbmem.h>
 #include <bootmem.h>
 #include <spi_flash.h>
+#if CONFIG_USE_OPTION_TABLE
+#include <option_table.h>
+#endif
 #if CONFIG_CHROMEOS
 #if CONFIG_HAVE_ACPI_TABLES
 #include <arch/acpi.h>
@@ -333,6 +336,26 @@
 	return mainboard;
 }
 
+#if CONFIG_USE_OPTION_TABLE
+static struct cmos_checksum *lb_cmos_checksum(struct lb_header *header)
+{
+	struct lb_record *rec;
+	struct cmos_checksum *cmos_checksum;
+	rec = lb_new_record(header);
+	cmos_checksum = (struct cmos_checksum *)rec;
+	cmos_checksum->tag = LB_TAG_OPTION_CHECKSUM;
+
+	cmos_checksum->size = (sizeof(*cmos_checksum));
+
+	cmos_checksum->range_start = LB_CKS_RANGE_START * 8;
+	cmos_checksum->range_end = ( LB_CKS_RANGE_END * 8 ) + 7;
+	cmos_checksum->location = LB_CKS_LOC * 8;
+	cmos_checksum->type = CHECKSUM_PCBIOS;
+
+	return cmos_checksum;
+}
+#endif
+
 static void lb_strings(struct lb_header *header)
 {
 	static const struct {
@@ -435,6 +458,8 @@
 			struct lb_record *rec_dest = lb_new_record(head);
 			/* Copy the option config table, it's already a lb_record... */
 			memcpy(rec_dest,  option_table, option_table->size);
+			/* Create cmos checksum entry in coreboot table */
+			lb_cmos_checksum(head);
 		} else {
 			printk(BIOS_ERR, "cmos_layout.bin could not be found!\n");
 		}