Re: [PATCH v3 2/3] tpm: Introduce Qualcomm TPM driver

[Jarkko Sakkinen <jarkko@kernel.org>]

On Thu, Oct 15, 2026 at 12:07:47PM +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 | 413 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 423 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..0fe0104e8b5a
> --- /dev/null
> +++ b/drivers/char/tpm/tpm_qcom.c
> @@ -0,0 +1,413 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + *
> + */
> +
> +#include <linux/bitfield.h>
> +#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"
> +
> +#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 TPM_QCOM_MAX_COMMAND_SIZE	SZ_4K
> +#define TPM_QCOM_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_resp {
> +	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_resp {
> +	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_resp {
> +	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;
> +};
> +
> +/* 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 device *dev,
> +				       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) {
> +		dev_err(dev, "get client env obj failed: ret=%d, invoke_ret=0x%x\n",
> +			ret, inv_arg.ret);
> +		return -EINVAL;
> +	}
> +
> +	*client_env_obj = param[1].u.objref;
> +	return 0;
> +}
> +
> +static int tpm_qcom_get_svc_obj(struct device *dev,
> +				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) {
> +		dev_err(dev, "get TPM service obj failed: ret=%d, invoke_ret=0x%x\n",
> +			ret, inv_arg.ret);
> +		return -EINVAL;
> +	}
> +
> +	*tpm_svc_obj = param[1].u.objref;
> +	return 0;
> +}
> +
> +static int tpm_qcom_send_command(struct tpm_qcom_private *pvt_data,
> +				 void *req, size_t req_len, void *resp,
> +				 size_t *resp_len)
> +{
> +	struct tee_ioctl_object_invoke_arg inv_arg = {};
> +	struct tee_param param[3] = {};
> +	u8 locality_arg = 0;
> +	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 = resp, .size = *resp_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 ?: -EINVAL;
> +	}
> +
> +	*resp_len = param[2].u.ubuf.size;
> +
> +	return 0;
> +}
> +
> +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_resp ver_resp;
> +	size_t resp_len = sizeof(ver_resp);
> +	struct tpm_qcom_type_req type_req = {
> +		.command_id = QCOMTEE_TPM_TYPE_ID,
> +	};
> +	struct tpm_qcom_type_resp type_resp;
> +	int ret;
> +
> +	ret = tpm_qcom_send_command(pvt_data, &ver_req, sizeof(ver_req),
> +				    &ver_resp, &resp_len);
> +	if (ret < 0 || resp_len < sizeof(ver_resp) || ver_resp.status != 0)
> +		return ret ?: -EIO;
> +
> +	dev_info(pvt_data->dev, "TPM TA version %u.%u\n",
> +		 FIELD_GET(QCOMTEE_TPM_TA_VERSION_MAJOR, ver_resp.version_num),
> +		 FIELD_GET(QCOMTEE_TPM_TA_VERSION_MINOR, ver_resp.version_num));
> +
> +	resp_len = sizeof(type_resp);
> +	ret = tpm_qcom_send_command(pvt_data, &type_req, sizeof(type_req),
> +				    &type_resp, &resp_len);
> +	if (ret < 0 || resp_len < sizeof(type_resp) || type_resp.status != 0)
> +		return ret ?: -EIO;
> +
> +	switch (type_resp.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_resp.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_resp resp;
> +	size_t resp_len = sizeof(resp);
> +
> +	tpm_qcom_send_command(pvt_data, &req, sizeof(req), &resp, &resp_len);
> +}
> +
> +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);
> +	struct tpm_header *header = (struct tpm_header *)buf;
> +	size_t resp_len = PAGE_ALIGN(TPM_QCOM_MAX_RESPONSE_SIZE);
> +	size_t copy_len;
> +	int ret;
> +
> +	if (cmd_len > TPM_QCOM_MAX_COMMAND_SIZE) {
> +		dev_err(&chip->dev, "len=%zd exceeds TPM_QCOM_MAX_COMMAND_SIZE\n",
> +			cmd_len);
> +		return -EIO;
> +	}
> +
> +	u8 *response __free(kfree) = kzalloc(resp_len, GFP_KERNEL);
> +	if (!response)
> +		return -ENOMEM;
> +
> +	ret = tpm_qcom_send_command(pvt_data, buf, cmd_len, response, &resp_len);
> +	if (ret < 0) {
> +		dev_err(&chip->dev, "TPM command failed: cmd_len=%zu, tpm_cc=0x%08x, ret:%d\n",
> +			cmd_len, be32_to_cpu(header->ordinal), ret);
> +		return ret;
> +	}
> +
> +	copy_len = min_t(size_t, bufsiz, resp_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 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;
> +
> +	err = tpm_qcom_get_client_env_obj(dev, pvt_data->ctx, &client_env_obj);
> +	if (err)
> +		goto out_ctx;
> +
> +	err = tpm_qcom_get_svc_obj(dev, pvt_data->ctx, client_env_obj, &tpm_svc_obj);
> +	/* Release client_env object irrespective of service obj return status */
> +	tpm_qcom_release_object(pvt_data->ctx, client_env_obj);
> +	if (err)
> +		goto out_ctx;
> +
> +	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 = tpmm_chip_alloc(dev, &tpm_qcom_ops);
> +	if (IS_ERR(chip)) {
> +		dev_err(dev, "tpmm_chip_alloc failed\n");
> +		err = PTR_ERR(chip);
> +		goto out_svc_obj;
> +	}
> +
> +	pvt_data->chip = chip;
> +	dev_set_drvdata(dev, pvt_data);
> +	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_svc_obj;
> +	}
> +
> +	return 0;
> +
> +out_svc_obj:
> +	tpm_qcom_release_object(pvt_data->ctx, tpm_svc_obj);

This is very cleanly laid out driver. This goes perhaps unhealthy
levels of nitpicking but we usually tend to have newline before
the next label.

I'm sorry but it distracted me and I do hate myself for sending
this response...

> +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);
> +	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");
> 
> -- 
> 2.34.1
> 

Br, Jarkko