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timestamp: Apply factor to recorded stamps

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If we dont have a constant TSC rate, timestamp table
has odd leaps and may appear to run backwards. Add
functionality to apply a factor such that all stamps
are in the same timebase.

Change-Id: Idab9c2c00e117c4d247db8cc9a2897640fa01edd
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/19330
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
This commit is contained in:
Kyösti Mälkki
2017-07-15 20:42:20 +03:00
parent 01ea8f1fcc
commit 806ea08bb2
2 changed files with 33 additions and 0 deletions
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28
src/lib/timestamp.c
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@ -299,6 +299,34 @@ static void timestamp_sync_cache_to_cbmem(int is_recovery)
ts_cache->cache_state = TIMESTAMP_CACHE_NOT_NEEDED;
}
void timestamp_rescale_table(uint16_t N, uint16_t M)
{
uint32_t i;
struct timestamp_table *ts_table;
if (!timestamp_should_run())
return;
if (N == 0 || M == 0)
return;
ts_table = timestamp_table_get();
/* No timestamp table found */
if (ts_table == NULL) {
printk(BIOS_ERR, "ERROR: No timestamp table found\n");
return;
}
ts_table->base_time /= M;
ts_table->base_time *= N;
for (i = 0; i < ts_table->num_entries; i++) {
struct timestamp_entry *tse = &ts_table->entries[i];
tse->entry_stamp /= M;
tse->entry_stamp *= N;
}
}
ROMSTAGE_CBMEM_INIT_HOOK(timestamp_sync_cache_to_cbmem)
RAMSTAGE_CBMEM_INIT_HOOK(timestamp_sync_cache_to_cbmem)