drivers/tpm: Move PPI stub

As preparation to a full PPI implementation move the acpi code out
of the pc80/tpm/tis driver into the generic tpm driver folder.

This doesn't change any functionality.

Change-Id: I7818d0344d4a08926195bd4804565502717c48fa
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/45567
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

3 files changed, 193 insertions, 0 deletions

diff --git a/src/drivers/tpm/Makefile.inc b/src/drivers/tpm/Makefile.inc
index 4e80600ddf..5fc4632912 100644
--- a/src/drivers/tpm/Makefile.inc
+++ b/src/drivers/tpm/Makefile.inc
@@ -1 +1,3 @@
 ramstage-$(CONFIG_TPM_INIT) += tpm.c
+
+ramstage-$(CONFIG_HAVE_ACPI_TABLES) += ppi_stub.c
diff --git a/src/drivers/tpm/ppi_stub.c b/src/drivers/tpm/ppi_stub.c
new file mode 100644
index 0000000000..11bd07e10a
--- /dev/null
+++ b/src/drivers/tpm/ppi_stub.c
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <types.h>
+#include <stddef.h>
+#include <acpi/acpi.h>
+#include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
+
+#include "tpm_ppi.h"
+
+static void tpm_ppi_func0_cb(void *arg)
+{
+	/* Functions 1-8. */
+	u8 buf[] = {0xff, 0x01};
+	acpigen_write_return_byte_buffer(buf, sizeof(buf));
+}
+
+static void tpm_ppi_func1_cb(void *arg)
+{
+	if (CONFIG(TPM2))
+		/* Interface version: 2.0 */
+		acpigen_write_return_string("2.0");
+	else
+		/* Interface version: 1.2 */
+		acpigen_write_return_string("1.2");
+}
+
+static void tpm_ppi_func2_cb(void *arg)
+{
+	/* Submit operations: drop on the floor and return success. */
+	acpigen_write_return_byte(PPI2_RET_SUCCESS);
+}
+
+static void tpm_ppi_func3_cb(void *arg)
+{
+	/* Pending operation: none. */
+	acpigen_emit_byte(RETURN_OP);
+	acpigen_write_package(2);
+	acpigen_write_byte(0);
+	acpigen_write_byte(0);
+	acpigen_pop_len();
+}
+
+static void tpm_ppi_func4_cb(void *arg)
+{
+	/* Pre-OS transition method: reboot. */
+	acpigen_write_return_byte(2);
+}
+
+static void tpm_ppi_func5_cb(void *arg)
+{
+	/* Operation response: no operation executed. */
+	acpigen_emit_byte(RETURN_OP);
+	acpigen_write_package(3);
+	acpigen_write_byte(0);
+	acpigen_write_byte(0);
+	acpigen_write_byte(0);
+	acpigen_pop_len();
+}
+
+static void tpm_ppi_func6_cb(void *arg)
+{
+	/*
+	 * Set preferred user language: deprecated and must return 3 AKA
+	 * "not implemented".
+	 */
+	acpigen_write_return_byte(PPI6_RET_NOT_IMPLEMENTED);
+}
+
+static void tpm_ppi_func7_cb(void *arg)
+{
+	/* Submit operations: deny. */
+	acpigen_write_return_byte(PPI7_RET_BLOCKED_BY_FIRMWARE);
+}
+
+static void tpm_ppi_func8_cb(void *arg)
+{
+	/* All actions are forbidden. */
+	acpigen_write_return_byte(PPI8_RET_FIRMWARE_ONLY);
+}
+
+static void (*tpm_ppi_callbacks[])(void *) = {
+	tpm_ppi_func0_cb,
+	tpm_ppi_func1_cb,
+	tpm_ppi_func2_cb,
+	tpm_ppi_func3_cb,
+	tpm_ppi_func4_cb,
+	tpm_ppi_func5_cb,
+	tpm_ppi_func6_cb,
+	tpm_ppi_func7_cb,
+	tpm_ppi_func8_cb,
+};
+
+static void tpm_mci_func0_cb(void *arg)
+{
+	/* Function 1. */
+	acpigen_write_return_singleton_buffer(0x3);
+}
+static void tpm_mci_func1_cb(void *arg)
+{
+	/* Just return success. */
+	acpigen_write_return_byte(0);
+}
+
+static void (*tpm_mci_callbacks[])(void *) = {
+	tpm_mci_func0_cb,
+	tpm_mci_func1_cb,
+};
+
+void tpm_ppi_acpi_fill_ssdt(const struct device *dev)
+{
+	/*
+	 * _DSM method
+	 */
+	struct dsm_uuid ids[] = {
+		/* Physical presence interface.
+		 * This is used to submit commands like "Clear TPM" to
+		 * be run at next reboot provided that user confirms
+		 * them. Spec allows user to cancel all commands and/or
+		 * configure BIOS to reject commands. So we pretend that
+		 * user did just this: cancelled everything. If user
+		 * really wants to clear TPM the only option now is to
+		 * do it manually in payload.
+		 */
+		DSM_UUID(TPM_PPI_UUID, tpm_ppi_callbacks,
+			ARRAY_SIZE(tpm_ppi_callbacks), NULL),
+		/* Memory clearing on boot: just a dummy. */
+		DSM_UUID(TPM_MCI_UUID, tpm_mci_callbacks,
+			ARRAY_SIZE(tpm_mci_callbacks), NULL),
+	};
+
+	acpigen_write_dsm_uuid_arr(ids, ARRAY_SIZE(ids));
+}
diff --git a/src/drivers/tpm/tpm_ppi.h b/src/drivers/tpm/tpm_ppi.h
new file mode 100644
index 0000000000..7662386575
--- /dev/null
+++ b/src/drivers/tpm/tpm_ppi.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _TPM_PPI_H_
+#define _TPM_PPI_H_
+
+#include <device/device.h>
+
+#if CONFIG(HAVE_ACPI_TABLES)
+void tpm_ppi_acpi_fill_ssdt(const struct device *dev);
+#else
+static inline void tpm_ppi_acpi_fill_ssdt(const struct device *dev)
+{
+}
+#endif
+
+
+/* Return codes */
+/* Function 2 */
+#define PPI2_RET_SUCCESS 0
+#define PPI2_RET_NOT_SUPPORTED 1
+#define PPI2_RET_GENERAL_FAILURE 2
+
+/* Function 3 */
+#define PPI3_RET_SUCCESS 0
+#define PPI3_RET_GENERAL_FAILURE 1
+
+/* Function 4 */
+#define PPI4_RET_NONE 0
+#define PPI4_RET_SHUTDOWN 1
+#define PPI4_RET_REBOOT 2
+#define PPI4_RET_OS_VENDOR_SPECIFIC 3
+
+/* Function 5 */
+#define PPI5_RET_SUCCESS 0
+#define PPI5_RET_GENERAL_FAILURE 1
+
+/* Function 6 */
+#define PPI6_RET_NOT_IMPLEMENTED 3
+
+/* Function 7 */
+#define PPI7_RET_SUCCESS 0
+#define PPI7_RET_NOT_IMPLEMENTED 1
+#define PPI7_RET_GENERAL_FAILURE 2
+#define PPI7_RET_BLOCKED_BY_FIRMWARE 3
+
+/* Function 8 */
+#define PPI8_RET_NOT_IMPLEMENTED 0
+#define PPI8_RET_FIRMWARE_ONLY 1
+#define PPI8_RET_BLOCKED_FOR_OS_BY_FW 2
+#define PPI8_RET_ALLOWED_WITH_PP 3
+#define PPI8_RET_ALLOWED 4
+
+/* TCG Physical Presence Interface */
+#define TPM_PPI_UUID   "3dddfaa6-361b-4eb4-a424-8d10089d1653"
+/* TCG Memory Clear Interface */
+#define TPM_MCI_UUID   "376054ed-cc13-4675-901c-4756d7f2d45d"
+
+#endif /* _TPM_PPI_H_ */