src/soc/amd/common/vboot/vboot_bootblock.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <bootblock_common.h>
   4 #include <cpu/x86/tsc.h>
   5 #include <psp_verstage/psp_transfer.h>
   6 #include <symbols.h>
   7 #include <timestamp.h>
   8 #include <types.h>
   9
  10 /*
  11  * Verstage on PSP uses the weak timestamp_tick_freq_mhz implementation returning 1, so the
  12  * unit of the timestamps in the transfer buffer is microseconds. The x86 side uses the TSC
  13  * rate as reference for the timestamps, so the values from the PSP transfer buffer need to be
  14  * multiplied by the TSC frequency in MHz.
  15  */
  16 static uint64_t timestamp_from_usec(uint64_t usec)
  17 {
  18         return usec * tsc_freq_mhz();
  19 }
  20
  21 void boot_with_psp_timestamp(uint64_t base_timestamp)
  22 {
  23         const struct transfer_info_struct *info = (const struct transfer_info_struct *)
  24                 (void *)(uintptr_t)_transfer_buffer;
  25
  26         if (!transfer_buffer_valid(info) || info->timestamp == 0)
  27                 return;
  28
  29         replay_transfer_buffer_cbmemc();
  30
  31         /*
  32          * info->timestamp is PSP's timestamp (in microseconds)
  33          * when x86 processor is released.
  34          */
  35         uint64_t psp_last_ts_usec = info->timestamp;
  36
  37         int i;
  38         struct timestamp_table *psp_ts_table =
  39                 (struct timestamp_table *)(void *)
  40                 ((uintptr_t)_transfer_buffer + info->timestamp_offset);
  41         /* new base_timestamp will be offset for all PSP timestamps. */
  42         base_timestamp -= timestamp_from_usec(psp_last_ts_usec);
  43
  44         for (i = 0; i < psp_ts_table->num_entries; i++) {
  45                 struct timestamp_entry *tse = &psp_ts_table->entries[i];
  46                 /*
  47                  * We ignore the time between x86 processor release and bootblock.
  48                  * Since timestamp_add subtracts base_time, we first add old base_time
  49                  * to make it absolute then add base_timestamp again since
  50                  * it'll be a new base_time.
  51                  *
  52                  * Verstage on PSP uses a 1 microsecond timestamp granularity while the x86
  53                  * part of coreboot uses the TSC tick time as granularity, so this needs to be
  54                  * converted.
  55                  */
  56                 tse->entry_stamp = timestamp_from_usec(psp_ts_table->base_time +
  57                                                        tse->entry_stamp) + base_timestamp;
  58         }
  59
  60         bootblock_main_with_timestamp(base_timestamp, psp_ts_table->entries,
  61                                       psp_ts_table->num_entries);
  62 }