[PATCH 2/2] firmware: tpm: Introduce tpm-qcom driver

[Kuldeep Singh]

Add a TPM chip driver for platforms where a TPM 2.0 instance is
implemented by a Trusted Application (TA) running in Qualcomm's Trusted
Execution Environment (QTEE), reachable over the QCOMTEE object-IPC
transport.

The driver discovers the qcom.tz.tpm TEE-bus device, opens a session
with the TPM TA, and register with tpm interface. This exposes the TA
through the standard /dev/tpm interface and the existing tpm2 command
layer. OS need not be aware underlying TPM instance is dTPM or fTPM.

Signed-off-by: Kuldeep Singh <kuldeep.singh@xxxxxxxxxxxxxxxx>
---
 MAINTAINERS                 |   7 +
 drivers/char/tpm/Kconfig    |   9 ++
 drivers/char/tpm/Makefile   |   1 +
 drivers/char/tpm/tpm_qcom.c | 371 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/char/tpm/tpm_qcom.h |  82 ++++++++++
 5 files changed, 470 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 47b04968e79a..cfa5b66823c7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22636,6 +22636,13 @@ S:	Maintained
 F:	Documentation/tee/qtee.rst
 F:	drivers/tee/qcomtee/
 
+QUALCOMM TPM DRIVER
+M:	Kuldeep Singh <kuldeep.singh@xxxxxxxxxxxxxxxx>
+L:	linux-arm-msm@xxxxxxxxxxxxxxx
+S:	Maintained
+F:	drivers/char/tpm/tpm_qcom.c
+F:	drivers/char/tpm/tpm_qcom.h
+
 QUALCOMM TRUST ZONE MEMORY ALLOCATOR
 M:	Bartosz Golaszewski <brgl@xxxxxxxxxx>
 L:	linux-arm-msm@xxxxxxxxxxxxxxx
diff --git a/drivers/char/tpm/Kconfig b/drivers/char/tpm/Kconfig
index 5f672f2c01b0..05d704ed3632 100644
--- a/drivers/char/tpm/Kconfig
+++ b/drivers/char/tpm/Kconfig
@@ -243,6 +243,15 @@ config TCG_FTPM_TEE
 	help
 	  This driver proxies for firmware TPM running in TEE.
 
+config TCG_QCOM
+	tristate "Qualcomm TEE based TPM Interface"
+	depends on QCOMTEE
+	help
+	  This driver provides interface to run TPM instances with Trustzone
+	  having Qualcomm TPM TA running in Qualcomm TEE.
+	  The mechanism uses the object-IPC based transport provided by
+	  QCOMTEE.
+
 config TCG_SVSM
 	tristate "SNP SVSM vTPM interface"
 	depends on AMD_MEM_ENCRYPT
diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
index 5b5cdc0d32e4..471cbf49afd2 100644
--- a/drivers/char/tpm/Makefile
+++ b/drivers/char/tpm/Makefile
@@ -45,5 +45,6 @@ obj-$(CONFIG_TCG_CRB) += tpm_crb.o
 obj-$(CONFIG_TCG_ARM_CRB_FFA) += tpm_crb_ffa.o
 obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o
 obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o
+obj-$(CONFIG_TCG_QCOM) += tpm_qcom.o
 obj-$(CONFIG_TCG_SVSM) += tpm_svsm.o
 obj-$(CONFIG_TCG_LOONGSON) += tpm_loongson.o
diff --git a/drivers/char/tpm/tpm_qcom.c b/drivers/char/tpm/tpm_qcom.c
new file mode 100644
index 000000000000..00ee61204056
--- /dev/null
+++ b/drivers/char/tpm/tpm_qcom.c
@@ -0,0 +1,371 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ *
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/tee.h>
+#include <linux/tee_drv.h>
+#include <linux/tpm.h>
+#include <linux/uuid.h>
+
+#include "tpm.h"
+#include "tpm_qcom.h"
+
+/* UUID of the QTEE-bus device representing the TPM TA. */
+static const uuid_t tpm_qcom_uuid =
+	UUID_INIT(0xaabcb593, 0x7083, 0x5536,
+		  0xac, 0x27, 0x3d, 0x2d, 0x89, 0x41, 0x9d, 0xdb);
+
+static void tpm_qcom_release_object(struct tee_context *ctx,
+				    struct tee_param_objref object)
+{
+	struct tee_ioctl_object_invoke_arg inv_arg;
+
+	memset(&inv_arg, 0, sizeof(inv_arg));
+	inv_arg.id = object.id;
+	inv_arg.op = QCOMTEE_MSG_OBJECT_OP_RELEASE;
+	inv_arg.num_params = 0;
+
+	tee_client_object_invoke_func(ctx, &inv_arg, NULL);
+}
+
+static int tpm_qcom_get_client_env_obj(struct tee_context *ctx,
+				       struct tee_param_objref *client_env_obj)
+{
+	int ret;
+	struct tee_ioctl_object_invoke_arg inv_arg;
+	struct tee_param param[2];
+
+	memset(&inv_arg, 0, sizeof(inv_arg));
+	memset(&param, 0, sizeof(param));
+
+	inv_arg.id = TEE_OBJREF_NULL;
+	inv_arg.op = QCOMTEE_ROOT_OP_REG_WITH_CREDENTIALS;
+	inv_arg.num_params = 2;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT;
+	param[0].u.objref.id = TEE_OBJREF_NULL;
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT;
+
+	ret = tee_client_object_invoke_func(ctx, &inv_arg, param);
+	if (ret < 0 || inv_arg.ret != 0)
+		return ret ?: inv_arg.ret;
+
+	*client_env_obj = param[1].u.objref;
+	return ret;
+}
+
+static int tpm_qcom_get_svc_obj(struct tee_context *ctx,
+				struct tee_param_objref client_env_obj,
+				struct tee_param_objref *tpm_svc_obj)
+{
+	int ret;
+	struct tee_ioctl_object_invoke_arg inv_arg;
+	struct tee_param param[2];
+	u32 tpm_uid = QCOMTEE_TPM_UID;
+
+	memset(&inv_arg, 0, sizeof(inv_arg));
+	memset(&param, 0, sizeof(param));
+
+	inv_arg.id = client_env_obj.id;
+	inv_arg.op = QCOMTEE_OP_CLIENT_ENV_OPEN;
+	inv_arg.num_params = 2;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT;
+	param[0].u.ubuf = (struct tee_param_ubuf){ .addr = &tpm_uid,
+						    .size = sizeof(tpm_uid) };
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT;
+
+	ret = tee_client_object_invoke_func(ctx, &inv_arg, param);
+	if (ret < 0 || inv_arg.ret != 0)
+		return ret ?: inv_arg.ret;
+
+	*tpm_svc_obj = param[1].u.objref;
+	return ret;
+}
+
+static int tpm_qcom_send_command(struct tpm_qcom_private *pvt_data,
+				 void *req, size_t req_len,
+				 void *rsp, size_t *rsp_len)
+{
+	int ret;
+	struct tee_ioctl_object_invoke_arg inv_arg;
+	struct tee_param param[2];
+
+	memset(&inv_arg, 0, sizeof(inv_arg));
+	memset(&param, 0, sizeof(param));
+
+	inv_arg.id = pvt_data->tpm_svc_obj.id;
+	inv_arg.op = QCOMTEE_TPM_OP_SEND_COMMAND;
+	inv_arg.num_params = 2;
+
+	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT;
+	param[0].u.ubuf = (struct tee_param_ubuf){ .addr = req, .size = req_len };
+	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT;
+	param[1].u.ubuf = (struct tee_param_ubuf){ .addr = rsp, .size = *rsp_len };
+
+	print_hex_dump_debug("tpm_qcom req: ", DUMP_PREFIX_OFFSET,
+			     16, 1, req, req_len, true);
+
+	ret = tee_client_object_invoke_func(pvt_data->ctx, &inv_arg, param);
+	if (ret < 0 || inv_arg.ret != 0) {
+		dev_err(pvt_data->dev,
+			"send_command invoke ret: %d, err: 0x%x\n",
+			ret, inv_arg.ret);
+		return ret ?: inv_arg.ret;
+	}
+
+	*rsp_len = param[1].u.ubuf.size;
+
+	print_hex_dump_debug("tpm_qcom rsp: ", DUMP_PREFIX_OFFSET,
+			     16, 1, rsp, *rsp_len, true);
+
+	return ret;
+}
+
+static int tpm_qcom_get_ta_details(struct tpm_qcom_private *pvt_data)
+{
+	struct tpm_qcom_ta_version_req ver_req = {
+		.command_id = QCOMTEE_TPM_GET_TA_VERSION_ID,
+	};
+	struct tpm_qcom_ta_version_rsp ver_rsp;
+	size_t ver_rsp_len = sizeof(ver_rsp);
+	struct tpm_qcom_type_req type_req = {
+		.command_id = QCOMTEE_TPM_TYPE_ID,
+	};
+	struct tpm_qcom_type_rsp type_rsp;
+	size_t type_rsp_len = sizeof(type_rsp);
+	int ret;
+
+	ret = tpm_qcom_send_command(pvt_data, &ver_req, sizeof(ver_req),
+				    &ver_rsp, &ver_rsp_len);
+	if (ret || ver_rsp_len < sizeof(ver_rsp) || ver_rsp.status != 0) {
+		dev_err(pvt_data->dev,
+			"failed to query TA version: ret=%d, status=%u\n",
+			ret, ret ? 0 : ver_rsp.status);
+		return ret ?: -EIO;
+	}
+
+	dev_info(pvt_data->dev, "TPM TA version %u.%u\n",
+		 QCOMTEE_TPM_TA_VERSION_GET_MAJOR(ver_rsp.version_num),
+		 QCOMTEE_TPM_TA_VERSION_GET_MINOR(ver_rsp.version_num));
+
+	ret = tpm_qcom_send_command(pvt_data, &type_req, sizeof(type_req),
+				    &type_rsp, &type_rsp_len);
+	if (ret || type_rsp_len < sizeof(type_rsp) || type_rsp.status != 0) {
+		dev_err(pvt_data->dev,
+			"failed to query TPM type: ret=%d, status=%u\n",
+			ret, ret ? 0 : type_rsp.status);
+		return ret ?: -EIO;
+	}
+
+	switch (type_rsp.tpm_type) {
+	case QCOMTEE_TPM_TYPE_FTPM:
+		dev_info(pvt_data->dev, "TPM type: fTPM\n");
+		pvt_data->is_dtpm = false;
+		break;
+	case QCOMTEE_TPM_TYPE_DTPM:
+		dev_info(pvt_data->dev, "TPM type: dTPM\n");
+		pvt_data->is_dtpm = true;
+		break;
+	default:
+		dev_err(pvt_data->dev, "unsupported TPM type: 0x%08x\n",
+			type_rsp.tpm_type);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/*
+ * fTPM does not implement this command, so this is only ever called in case of
+ * dtpm only.
+ */
+static void tpm_qcom_transfer(struct tpm_qcom_private *pvt_data,
+			      u32 transfer_state)
+{
+	struct tpm_qcom_transfer_req req = {
+		.command_id = QCOMTEE_TPM_TRANSFER_ID,
+		.transfer_state = transfer_state,
+	};
+	struct tpm_qcom_transfer_rsp rsp;
+	size_t rsp_len = sizeof(rsp);
+	int ret;
+
+	ret = tpm_qcom_send_command(pvt_data, &req, sizeof(req), &rsp, &rsp_len);
+	if (ret || rsp_len < sizeof(rsp) || rsp.status != 0)
+		dev_warn(pvt_data->dev,
+			 "transfer state=%u hint failed: ret=%d, status=%u\n",
+			 transfer_state, ret, ret ? 0 : rsp.status);
+}
+
+static int tpm_qcom_cmd_ready(struct tpm_chip *chip)
+{
+	struct tpm_qcom_private *pvt_data = dev_get_drvdata(chip->dev.parent);
+
+	if (pvt_data->is_dtpm)
+		tpm_qcom_transfer(pvt_data, QCOMTEE_TPM_TRANSFER_START);
+
+	return 0;
+}
+
+static int tpm_qcom_go_idle(struct tpm_chip *chip)
+{
+	struct tpm_qcom_private *pvt_data = dev_get_drvdata(chip->dev.parent);
+
+	if (pvt_data->is_dtpm)
+		tpm_qcom_transfer(pvt_data, QCOMTEE_TPM_TRANSFER_END);
+
+	return 0;
+}
+
+/*
+ * The raw TPM2 command in @buf is sent directly as send_command's UBUF-in
+ * param and the raw TPM2 response is read back from its UBUF-out param.
+ */
+static int tpm_qcom_send(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
+			 size_t cmd_len)
+{
+	struct tpm_qcom_private *pvt_data = dev_get_drvdata(chip->dev.parent);
+	size_t rsp_len = PAGE_ALIGN(MAX_RESPONSE_SIZE);
+	size_t copy_len;
+	int ret;
+
+	if (cmd_len > MAX_COMMAND_SIZE) {
+		dev_err(&chip->dev,
+			"%s: len=%zd exceeds MAX_COMMAND_SIZE\n",
+			__func__, cmd_len);
+		return -EIO;
+	}
+
+	u8 *response __free(kfree) = kzalloc(rsp_len, GFP_KERNEL);
+	if (!response)
+		return -ENOMEM;
+
+	ret = tpm_qcom_send_command(pvt_data, buf, cmd_len, response, &rsp_len);
+	if (ret < 0) {
+		dev_err(&chip->dev, "%s: failed: ret=%d\n", __func__, ret);
+		return ret;
+	}
+
+	copy_len = min_t(size_t, bufsiz, rsp_len);
+	memcpy(buf, response, copy_len);
+
+	return copy_len;
+}
+
+static const struct tpm_class_ops tpm_qcom_ops = {
+	.flags = TPM_OPS_AUTO_STARTUP,
+	.send = tpm_qcom_send,
+	.cmd_ready = tpm_qcom_cmd_ready,
+	.go_idle = tpm_qcom_go_idle,
+};
+
+static int tpm_qcom_ctx_match(struct tee_ioctl_version_data *ver,
+			      const void *data)
+{
+	return (ver->impl_id == TEE_IMPL_ID_QTEE);
+}
+
+static int tpm_qcom_probe(struct tee_client_device *tee_dev)
+{
+	struct device *dev = &tee_dev->dev;
+	struct tpm_qcom_private *pvt_data;
+	struct tee_param_objref client_env_obj;
+	struct tee_param_objref tpm_svc_obj;
+	struct tpm_chip *chip;
+	int rc, err;
+
+	pvt_data = devm_kzalloc(dev, sizeof(*pvt_data), GFP_KERNEL);
+	if (!pvt_data)
+		return -ENOMEM;
+
+	dev_set_drvdata(dev, pvt_data);
+
+	pvt_data->ctx = tee_client_open_context(NULL, tpm_qcom_ctx_match, NULL,
+						NULL);
+	if (IS_ERR(pvt_data->ctx))
+		return -ENODEV;
+
+	rc = tpm_qcom_get_client_env_obj(pvt_data->ctx, &client_env_obj);
+	if (rc) {
+		err = -EINVAL;
+		goto out_ctx;
+	}
+
+	rc = tpm_qcom_get_svc_obj(pvt_data->ctx, client_env_obj, &tpm_svc_obj);
+	if (rc) {
+		err = -EINVAL;
+		goto out_client_env;
+	}
+	pvt_data->tpm_svc_obj = tpm_svc_obj;
+	pvt_data->dev = dev;
+
+	err = tpm_qcom_get_ta_details(pvt_data);
+	if (err)
+		goto out_svc_obj;
+
+	chip = tpm_chip_alloc(dev, &tpm_qcom_ops);
+	if (IS_ERR(chip)) {
+		dev_err(dev, "%s: tpm_chip_alloc failed\n", __func__);
+		err = PTR_ERR(chip);
+		goto out_svc_obj;
+	}
+
+	pvt_data->chip = chip;
+	pvt_data->chip->flags |= TPM_CHIP_FLAG_TPM2 | TPM_CHIP_FLAG_SYNC;
+
+	err = tpm_chip_register(pvt_data->chip);
+	if (err) {
+		dev_err(dev, "%s: tpm_chip_register failed with rc=%d\n",
+			__func__, err);
+		goto out_chip;
+	}
+
+	tpm_qcom_release_object(pvt_data->ctx, client_env_obj);
+	return 0;
+
+out_chip:
+	put_device(&pvt_data->chip->dev);
+out_svc_obj:
+	tpm_qcom_release_object(pvt_data->ctx, tpm_svc_obj);
+out_client_env:
+	tpm_qcom_release_object(pvt_data->ctx, client_env_obj);
+out_ctx:
+	tee_client_close_context(pvt_data->ctx);
+	return err;
+}
+
+static void tpm_qcom_remove(struct tee_client_device *tee_dev)
+{
+	struct tpm_qcom_private *pvt_data = dev_get_drvdata(&tee_dev->dev);
+
+	tpm_chip_unregister(pvt_data->chip);
+	put_device(&pvt_data->chip->dev);
+	tpm_qcom_release_object(pvt_data->ctx, pvt_data->tpm_svc_obj);
+	tee_client_close_context(pvt_data->ctx);
+}
+
+static const struct tee_client_device_id tpm_qcom_id_table[] = {
+	{ tpm_qcom_uuid },
+	{}
+};
+MODULE_DEVICE_TABLE(tee, tpm_qcom_id_table);
+
+static struct tee_client_driver tpm_qcom_driver = {
+	.id_table	= tpm_qcom_id_table,
+	.probe		= tpm_qcom_probe,
+	.remove		= tpm_qcom_remove,
+	.driver		= {
+		.name	= "tpm-qcom",
+	},
+};
+
+module_tee_client_driver(tpm_qcom_driver);
+
+MODULE_DESCRIPTION("TPM driver for Qualcomm TPM TA");
+MODULE_AUTHOR("Kuldeep Singh <kuldeep.singh@xxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/char/tpm/tpm_qcom.h b/drivers/char/tpm/tpm_qcom.h
new file mode 100644
index 000000000000..0f3756944768
--- /dev/null
+++ b/drivers/char/tpm/tpm_qcom.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ */
+
+#ifndef __TPM_QCOM_H__
+#define __TPM_QCOM_H__
+
+#include <linux/bitfield.h>
+#include <linux/tee_drv.h>
+#include <linux/tpm.h>
+#include <linux/uuid.h>
+
+#define QCOMTEE_ROOT_OP_REG_WITH_CREDENTIALS	5
+#define QCOMTEE_OP_CLIENT_ENV_OPEN		0
+#define QCOMTEE_MSG_OBJECT_OP_MASK		GENMASK(15, 0)
+#define QCOMTEE_MSG_OBJECT_OP_RELEASE		(QCOMTEE_MSG_OBJECT_OP_MASK - 0)
+
+#define QCOMTEE_TPM_OP_SEND_COMMAND		0
+
+/* UID of the "qcom.tz.tpm" service */
+#define QCOMTEE_TPM_UID			489
+
+/* Max buffer size supported by TPM TA */
+#define MAX_COMMAND_SIZE	SZ_4K
+#define MAX_RESPONSE_SIZE	SZ_4K
+
+#define QCOMTEE_TPM_GET_TA_VERSION_ID		0x0001000
+#define QCOMTEE_TPM_TA_VERSION_GET_MAJOR(ver)	((u32)(ver) >> 16)
+#define QCOMTEE_TPM_TA_VERSION_GET_MINOR(ver)	((u32)(ver) & 0x0000ffffU)
+
+struct tpm_qcom_ta_version_req {
+	u32 command_id;
+} __packed;
+
+struct tpm_qcom_ta_version_rsp {
+	u32 status;
+	u32 command_id;
+	u32 version_num;
+} __packed;
+
+#define QCOMTEE_TPM_TYPE_ID		0x0080000
+#define QCOMTEE_TPM_TYPE_DTPM		0x6454504dU
+#define QCOMTEE_TPM_TYPE_FTPM		0x6654504dU
+#define QCOMTEE_TPM_TYPE_NONE		0x4e6f6e65U
+
+struct tpm_qcom_type_req {
+	u32 command_id;
+} __packed;
+
+struct tpm_qcom_type_rsp {
+	u32 command_id;
+	u32 status;
+	u32 tpm_type;
+} __packed;
+
+/* dTPM SPI transfer optimization:
+ * TRANSFER_START before a burst of commands, TRANSFER_END once done.
+ */
+#define QCOMTEE_TPM_TRANSFER_ID		0x0000002
+#define QCOMTEE_TPM_TRANSFER_END	0
+#define QCOMTEE_TPM_TRANSFER_START	1
+
+struct tpm_qcom_transfer_req {
+	u32 command_id;
+	u32 transfer_state;
+} __packed;
+
+struct tpm_qcom_transfer_rsp {
+	u32 command_id;
+	u32 status;
+} __packed;
+
+struct tpm_qcom_private {
+	struct tpm_chip *chip;
+	struct device *dev;
+	struct tee_context *ctx;
+	struct tee_param_objref tpm_svc_obj;
+	bool is_dtpm;
+};
+
+#endif /* __TPM_QCOM_H__ */

-- 
2.34.1