efi_selftest: provide unit test for the EFI_TCG2_PROTOCOL

Provide a minimal test for the EFI_TCG2_PROTOCOL.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_selftest/efi_selftest_tcg2.c b/lib/efi_selftest/efi_selftest_tcg2.c
new file mode 100644
index 0000000..1399309
--- /dev/null
+++ b/lib/efi_selftest/efi_selftest_tcg2.c
@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * efi_selftest_devicepath
+ *
+ * Copyright (c) 2020 Heinrich Schuchardt <xypron.glpk@gmx.de>
+ *
+ * Test the EFI_TCG2_PROTOCOL
+ */
+
+#include <efi_selftest.h>
+#include <efi_tcg2.h>
+
+static struct efi_boot_services *boottime;
+static const efi_guid_t guid_tcg2 = EFI_TCG2_PROTOCOL_GUID;
+
+/**
+ * efi_st_tcg2_setup() - setup test
+ *
+ * @handle:	handle of the loaded image
+ * @systable:	system table
+ * @return:	status code
+ */
+static int efi_st_tcg2_setup(const efi_handle_t img_handle,
+			     const struct efi_system_table *systable)
+{
+	boottime = systable->boottime;
+
+	return EFI_ST_SUCCESS;
+}
+
+/**
+ * efi_st_tcg2_execute() - execute test
+ *
+ * Call the GetCapability service of the EFI_TCG2_PROTOCOL.
+ *
+ * Return:	status code
+ */
+static int efi_st_tcg2_execute(void)
+{
+	struct efi_tcg2_protocol *tcg2;
+	struct efi_tcg2_boot_service_capability capability;
+	efi_status_t ret;
+
+	ret = boottime->locate_protocol(&guid_tcg2, NULL, (void **)&tcg2);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("TCG2 protocol is not available.\n");
+		return EFI_ST_FAILURE;
+	}
+	capability.size = sizeof(struct efi_tcg2_boot_service_capability) - 1;
+	ret = tcg2->get_capability(tcg2, &capability);
+	if (ret != EFI_BUFFER_TOO_SMALL) {
+		efi_st_error("tcg2->get_capability on small buffer failed\n");
+		return EFI_ST_FAILURE;
+	}
+	capability.size = sizeof(struct efi_tcg2_boot_service_capability);
+	ret = tcg2->get_capability(tcg2, &capability);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("tcg2->get_capability failed\n");
+		return EFI_ST_FAILURE;
+	}
+	if (!capability.tpm_present_flag) {
+		efi_st_error("TPM not present\n");
+		return EFI_ST_FAILURE;
+	}
+	efi_st_printf("TPM supports 0x%.8x event logs\n",
+		      capability.supported_event_logs);
+	return EFI_ST_SUCCESS;
+}
+
+EFI_UNIT_TEST(tcg2) = {
+	.name = "tcg2",
+	.phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
+	.execute = efi_st_tcg2_execute,
+	.setup = efi_st_tcg2_setup,
+};