timestamps: Fix syncing, logging and comments

For timestamps added before CBMEM coming online and call to
timestamp_sync_cache_to_cbmem(), ts_table->base_time was
subtracted twice. The second time though, the value of zero
was subtracted.

Make the stamps logged on the console relative to base_time too,
such that cbmem -1 and cbmem -c outputs will match.

Remove comments about postponing initialisation of timestamps
to ramstage, that does not happen anymore.

Change-Id: Ia786c12c68c8921c0d09bc58a29fefdc72bf0c6d
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38301
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

1 files changed, 6 insertions, 9 deletions

diff --git a/src/lib/timestamp.c b/src/lib/timestamp.c
index d2206f6134..9cbe30807c 100644
--- a/src/lib/timestamp.c
+++ b/src/lib/timestamp.c
@@ -128,7 +128,7 @@ static void timestamp_add_table_entry(struct timestamp_table *ts_table,
 
 	tse = &ts_table->entries[ts_table->num_entries++];
 	tse->entry_id = id;
-	tse->entry_stamp = ts_time - ts_table->base_time;
+	tse->entry_stamp = ts_time;
 
 	if (ts_table->num_entries == ts_table->max_entries)
 		printk(BIOS_ERR, "ERROR: Timestamp table full\n");
@@ -148,6 +148,7 @@ void timestamp_add(enum timestamp_id id, uint64_t ts_time)
 		return;
 	}
 
+	ts_time -= ts_table->base_time;
 	timestamp_add_table_entry(ts_table, id, ts_time);
 
 	if (CONFIG(TIMESTAMPS_ON_CONSOLE))
@@ -206,22 +207,18 @@ static void timestamp_sync_cache_to_cbmem(struct timestamp_table *ts_cbmem_table
 	 *
 	 * If you try to initialize timestamps before ramstage but don't define
 	 * a TIMESTAMP region, all operations will fail (safely), and coreboot
-	 * will behave as if timestamps only get initialized in ramstage.
-	 *
-	 * If timestamps only get initialized in ramstage, the base_time from
-	 * timestamp_init() will get ignored and all timestamps will be 0-based.
+	 * will behave as if timestamps collection was disabled.
 	 */
 
+	/* Inherit cache base_time. */
+	ts_cbmem_table->base_time = ts_cache_table->base_time;
+
 	for (i = 0; i < ts_cache_table->num_entries; i++) {
 		struct timestamp_entry *tse = &ts_cache_table->entries[i];
 		timestamp_add_table_entry(ts_cbmem_table, tse->entry_id,
 					  tse->entry_stamp);
 	}
 
-	/* Freshly added cbmem table has base_time 0. Inherit cache base_time */
-	if (ts_cbmem_table->base_time == 0)
-		ts_cbmem_table->base_time = ts_cache_table->base_time;
-
 	/* Cache no longer required. */
 	ts_cache_table->num_entries = 0;
 }