cbmem: export base_time in timestamp table

It's helpful to know the base_time (1st timestamp) in the
timestamp table because it provides more information like
the accumulated time before the first timestamp was recorded.

In order to maximize this information report the base time
as an entry that is printed. It's called '1st timestamp'.
The implementation turns all the timestamp entries into absolute
times so one can observe both absolute and relative time for
each marker.

Change-Id: I1334a2d980e3bcc2968a3bd6493c68b9efcca7ae
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10883
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
diff --git a/util/cbmem/cbmem.c b/util/cbmem/cbmem.c
index aa73c6a..a11935e 100644
--- a/util/cbmem/cbmem.c
+++ b/util/cbmem/cbmem.c
@@ -413,6 +413,8 @@
 	u32 id;
 	const char *name;
 } timestamp_ids[] = {
+	/* Marker to report base_time. */
+	{ 0,			"1st timestamp" },
 	{ TS_START_ROMSTAGE,	"start of rom stage" },
 	{ TS_BEFORE_INITRAM,	"before ram initialization" },
 	{ TS_AFTER_INITRAM,	"after ram initialization" },
@@ -504,6 +506,7 @@
 	int i;
 	struct timestamp_table *tst_p;
 	size_t size;
+	uint64_t prev_stamp;
 
 	if (timestamps.tag != LB_TAG_TIMESTAMPS) {
 		fprintf(stderr, "No timestamps found in coreboot table.\n");
@@ -519,10 +522,19 @@
 	unmap_memory();
 	tst_p = map_memory_size((unsigned long)timestamps.cbmem_addr, size);
 
+	/* Report the base time within the table. */
+	prev_stamp = 0;
+	timestamp_print_entry(0,  tst_p->base_time, prev_stamp);
+	prev_stamp = tst_p->base_time;
+
 	for (i = 0; i < tst_p->num_entries; i++) {
-		const struct timestamp_entry *tse_p = tst_p->entries + i;
-		timestamp_print_entry(tse_p->entry_id, tse_p->entry_stamp,
-			i ? tse_p[-1].entry_stamp : 0);
+		uint64_t stamp;
+		const struct timestamp_entry *tse = &tst_p->entries[i];
+
+		/* Make all timestamps absolute. */
+		stamp = tse->entry_stamp + tst_p->base_time;
+		timestamp_print_entry(tse->entry_id, stamp, prev_stamp);
+		prev_stamp = stamp;
 	}
 
 	unmap_memory();