src/drivers/intel/ptt/ptt.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #include <console/console.h>
   4 #include <device/mmio.h>
   5 #include <device/pci_ops.h>
   6 #include <security/intel/txt/txt_register.h>
   7 #include <soc/pci_devs.h>
   8 #include <stdint.h>
   9
  10 #include "ptt.h"
  11
  12 #define PCI_ME_HFSTS4 0x64
  13 #define PTT_ENABLE (1 << 19)
  14
  15 /* Dump Intel ME register */
  16 static uint32_t read_register(int reg_addr)
  17 {
  18         if (!PCH_DEV_CSE)
  19                 return 0xFFFFFFFF;
  20
  21         return pci_read_config32(PCH_DEV_CSE, reg_addr);
  22 }
  23
  24 /*
  25  * ptt_active()
  26  *
  27  * Check if PTT Flag is set - so that PTT is active.
  28  *
  29  * Return true if active, false otherwise.
  30  */
  31 bool ptt_active(void)
  32 {
  33         uint32_t sts_ftif;
  34         uint32_t fwsts4 = read_register(PCI_ME_HFSTS4);
  35
  36         if (fwsts4 == 0xFFFFFFFF)
  37                 return false;
  38
  39         if ((fwsts4 & PTT_ENABLE) == 0) {
  40                 printk(BIOS_DEBUG, "Intel ME Establishment bit not valid.\n");
  41                 sts_ftif = read32p(TXT_STS_FTIF);
  42
  43                 if (sts_ftif != 0 && sts_ftif != UINT32_MAX) {
  44                         if ((sts_ftif & TXT_PTT_PRESENT) == TXT_PTT_PRESENT) {
  45                                 printk(BIOS_DEBUG, "TXT_STS_FTIF: PTT present and active\n");
  46                                 return true;
  47                         }
  48                 }
  49                 return false;
  50         }
  51
  52         return true;
  53 }