Re: [PATCH v2 2/3] tpm: Introduce Qualcomm TPM driver

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, Sep 07, 2026 at 02:58:42PM +0530, Kuldeep Singh wrote:
> 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@oss.qualcomm.com>
> ---
>  drivers/char/tpm/Kconfig    |   9 ++
>  drivers/char/tpm/Makefile   |   1 +
>  drivers/char/tpm/tpm_qcom.c | 354 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/char/tpm/tpm_qcom.h |  83 +++++++++++
>  4 files changed, 447 insertions(+)
> 
> 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..ef29c66f18ae
> --- /dev/null
> +++ b/drivers/char/tpm/tpm_qcom.c
> @@ -0,0 +1,354 @@
> +// 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 = {};
> +
> +	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)
> +{
> +	struct tee_ioctl_object_invoke_arg inv_arg = {};
> +	struct tee_param param[2] = {};
> +	int ret;
> +
> +	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)
> +{
> +	struct tee_ioctl_object_invoke_arg inv_arg = {};
> +	struct tee_param param[2] = {};
> +	u32 tpm_uid = QCOMTEE_TPM_UID;
> +	int ret;
> +
> +	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,
> +				 u32 locality, void *req, size_t req_len,
> +				 void *rsp, size_t *rsp_len)
> +{
> +	struct tee_ioctl_object_invoke_arg inv_arg = {};
> +	struct tee_param param[3] = {};
> +	u8 locality_arg = locality;
> +	int ret;
> +
> +	inv_arg.id = pvt_data->tpm_svc_obj.id;
> +	inv_arg.op = QCOMTEE_TPM_OP_SEND_COMMAND;
> +	inv_arg.num_params = 3;
> +
> +	param[0].attr = TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT;
> +	param[0].u.ubuf = (struct tee_param_ubuf){ .addr = &locality_arg,
> +						   .size = sizeof(locality_arg) };
> +	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT;
> +	param[1].u.ubuf = (struct tee_param_ubuf){ .addr = req, .size = req_len };
> +	param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT;
> +	param[2].u.ubuf = (struct tee_param_ubuf){ .addr = rsp, .size = *rsp_len };
> +
> +	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[2].u.ubuf.size;
> +
> +	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, 0, &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 %lu.%lu\n",
> +		 FIELD_GET(QCOMTEE_TPM_TA_VERSION_MAJOR, ver_rsp.version_num),
> +		 FIELD_GET(QCOMTEE_TPM_TA_VERSION_MINOR, ver_rsp.version_num));
> +
> +	ret = tpm_qcom_send_command(pvt_data, 0, &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 and to be invoked via 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, 0, &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, "len=%zd exceeds MAX_COMMAND_SIZE\n", cmd_len);
> +		return -EIO;
> +	}
> +
> +	u8 *response __free(kfree) = kzalloc(rsp_len, GFP_KERNEL);
> +	if (!response)
> +		return -ENOMEM;
> +
> +	ret = tpm_qcom_send_command(pvt_data, 0, buf, cmd_len, response,
> +				    &rsp_len);
> +	if (ret < 0) {
> +		dev_err(&chip->dev, "send_command failed: ret=%d\n", 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, "tpm_chip_alloc failed\n");
> +		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, "tpm_chip_register failed with rc=%d\n", 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@oss.qualcomm.com>");
> +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..3945b12643b7
> --- /dev/null
> +++ b/drivers/char/tpm/tpm_qcom.h
> @@ -0,0 +1,83 @@
> +/* 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			81
> +
> +/* 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_MAJOR	GENMASK(31, 16)
> +#define QCOMTEE_TPM_TA_VERSION_MINOR	GENMASK(15, 0)
> +
> +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
> 


Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko