src/drivers/intel/ptt: Add PTT Support

Add function which checks if Intel Platform Trust Technology / Intel
integrated TPM is enabled/active.

Change-Id: If93bb5e1a3a59b5045f4e44359683876fb387a71
Signed-off-by: Christian Walter <christian.walter@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34380
Reviewed-by: Philipp Deppenwiese <zaolin.daisuki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/src/drivers/intel/ptt/ptt.c b/src/drivers/intel/ptt/ptt.c
new file mode 100644
index 0000000000..738de50a8f
--- /dev/null
+++ b/src/drivers/intel/ptt/ptt.c
@@ -0,0 +1,53 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <soc/pci_devs.h>
+#include <device/pci_ops.h>
+#include <console/console.h>
+#include <timer.h>
+
+#include "ptt.h"
+
+#define PCI_ME_HFSTS4 0x64
+#define PTT_ENABLE (1 << 19)
+
+/* Dump Intel ME register */
+static uint32_t read_register(int reg_addr)
+{
+	if (!PCH_DEV_CSE)
+		return 0xFFFFFFFF;
+
+	return pci_read_config32(PCH_DEV_CSE, reg_addr);
+}
+
+/*
+ * ptt_active()
+ *
+ * Check if PTT Flag is set - so that PTT is active.
+ *
+ * Return true if active, false otherwise.
+ */
+bool ptt_active(void)
+{
+	uint32_t fwsts4 = read_register(PCI_ME_HFSTS4);
+
+	if (fwsts4 == 0xFFFFFFFF)
+		return false;
+
+	if ((fwsts4 & PTT_ENABLE) == 0) {
+		printk(BIOS_DEBUG, "Intel ME Establishment bit not valid.\n");
+		return false;
+	}
+
+	return true;
+}