xref: /aosp_15_r20/external/coreboot/src/drivers/intel/ptt/ptt.c (revision b9411a12aaaa7e1e6a6fb7c5e057f44ee179a49c)
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 */
read_register(int reg_addr)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  */
ptt_active(void)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 }
54