Re: [PATCH v4 04/15] firmware: qcom: Add a PAS TEE service

[Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>]

On Mon, Apr 27, 2026 at 03:25:52PM +0530, Sumit Garg wrote:
> From: Sumit Garg <sumit.garg@oss.qualcomm.com>
> 
> Add support for Peripheral Authentication Service (PAS) driver based
> on TEE bus with OP-TEE providing the backend PAS service implementation.
> 
> The TEE PAS service ABI is designed to be extensible with additional API
> as PTA_QCOM_PAS_CAPABILITIES. This allows to accommodate any future
> extensions of the PAS service needed while still maintaining backwards
> compatibility.
> 
> Signed-off-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
> ---
>  drivers/firmware/qcom/Kconfig        |  10 +
>  drivers/firmware/qcom/Makefile       |   1 +
>  drivers/firmware/qcom/qcom_pas_tee.c | 479 +++++++++++++++++++++++++++
>  3 files changed, 490 insertions(+)
>  create mode 100644 drivers/firmware/qcom/qcom_pas_tee.c
> 
> diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig
> index 9a12ae2b639d..300b3a1bd178 100644
> --- a/drivers/firmware/qcom/Kconfig
> +++ b/drivers/firmware/qcom/Kconfig
> @@ -14,6 +14,16 @@ config QCOM_PAS
>  	  backends plugged in whether it's an SCM implementation or a proper
>  	  TEE bus based PAS service implementation.
>  
> +config QCOM_PAS_TEE
> +	tristate
> +	select QCOM_PAS
> +	depends on TEE
> +	depends on !CPU_BIG_ENDIAN
> +	default m if ARCH_QCOM
> +	help
> +	  Enable the generic Peripheral Authentication Service (PAS) provided
> +	  by the firmware TEE implementation as the backend.
> +
>  config QCOM_SCM
>  	select QCOM_PAS
>  	select QCOM_TZMEM
> diff --git a/drivers/firmware/qcom/Makefile b/drivers/firmware/qcom/Makefile
> index dc5ab45f906a..48801d18f37b 100644
> --- a/drivers/firmware/qcom/Makefile
> +++ b/drivers/firmware/qcom/Makefile
> @@ -9,3 +9,4 @@ obj-$(CONFIG_QCOM_TZMEM)	+= qcom_tzmem.o
>  obj-$(CONFIG_QCOM_QSEECOM)	+= qcom_qseecom.o
>  obj-$(CONFIG_QCOM_QSEECOM_UEFISECAPP) += qcom_qseecom_uefisecapp.o
>  obj-$(CONFIG_QCOM_PAS)		+= qcom_pas.o
> +obj-$(CONFIG_QCOM_PAS_TEE)	+= qcom_pas_tee.o
> diff --git a/drivers/firmware/qcom/qcom_pas_tee.c b/drivers/firmware/qcom/qcom_pas_tee.c
> new file mode 100644
> index 000000000000..af73d0a68525
> --- /dev/null
> +++ b/drivers/firmware/qcom/qcom_pas_tee.c
> @@ -0,0 +1,479 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/of.h>
> +#include <linux/firmware/qcom/qcom_pas.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/tee_drv.h>
> +#include <linux/uuid.h>
> +
> +#include "qcom_pas.h"
> +
> +/*
> + * Peripheral Authentication Service (PAS) supported.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + */
> +#define TA_QCOM_PAS_IS_SUPPORTED		1
> +
> +/*
> + * PAS capabilities.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + * [out] params[1].value.a:	PAS capability flags
> + */
> +#define TA_QCOM_PAS_CAPABILITIES		2
> +
> +/*
> + * PAS image initialization.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + * [in]  params[1].memref:	Loadable firmware metadata
> + */
> +#define TA_QCOM_PAS_INIT_IMAGE			3
> +
> +/*
> + * PAS memory setup.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + * [in]  params[0].value.b:	Relocatable firmware size
> + * [in]  params[1].value.a:	32bit LSB relocatable firmware memory address
> + * [in]  params[1].value.b:	32bit MSB relocatable firmware memory address
> + */
> +#define TA_QCOM_PAS_MEM_SETUP			4
> +
> +/*
> + * PAS get resource table.
> + *
> + * [in]     params[0].value.a:	Unique 32bit remote processor identifier
> + * [inout]  params[1].memref:	Resource table config
> + */
> +#define TA_QCOM_PAS_GET_RESOURCE_TABLE		5
> +
> +/*
> + * PAS image authentication and co-processor reset.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + * [in]  params[0].value.b:	Firmware size
> + * [in]  params[1].value.a:	32bit LSB firmware memory address
> + * [in]  params[1].value.b:	32bit MSB firmware memory address
> + * [in]  params[2].memref:	Optional fw memory space shared/lent
> + */
> +#define TA_QCOM_PAS_AUTH_AND_RESET		6
> +
> +/*
> + * PAS co-processor set suspend/resume state.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + * [in]  params[0].value.b:	Co-processor state identifier
> + */
> +#define TA_QCOM_PAS_SET_REMOTE_STATE		7
> +
> +/*
> + * PAS co-processor shutdown.
> + *
> + * [in]  params[0].value.a:	Unique 32bit remote processor identifier
> + */
> +#define TA_QCOM_PAS_SHUTDOWN			8
> +
> +#define TEE_NUM_PARAMS				4
> +
> +/**
> + * struct qcom_pas_tee_private - PAS service private data
> + * @dev:		PAS service device.
> + * @ctx:		TEE context handler.
> + * @session_id:		PAS TA session identifier.
> + */
> +struct qcom_pas_tee_private {
> +	struct device *dev;
> +	struct tee_context *ctx;
> +	u32 session_id;
> +};
> +
> +static bool qcom_pas_tee_supported(struct device *dev, u32 pas_id)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_IS_SUPPORTED,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = pas_id
> +		}
> +	};
> +	int ret;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS not supported, pas_id: %d, ret: %d, err: 0x%x\n",
> +			pas_id, ret, inv_arg.ret);
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
> +static int qcom_pas_tee_init_image(struct device *dev, u32 pas_id,
> +				   const void *metadata, size_t size,
> +				   struct qcom_pas_context *ctx)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_INIT_IMAGE,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = pas_id
> +		},
> +		[1] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
> +		}
> +	};
> +	struct tee_shm *mdata_shm;
> +	u8 *mdata_buf = NULL;
> +	int ret;
> +
> +	mdata_shm = tee_shm_alloc_kernel_buf(data->ctx, size);
> +	if (IS_ERR(mdata_shm)) {
> +		dev_err(dev, "mdata_shm allocation failed\n");
> +		return PTR_ERR(mdata_shm);
> +	}
> +
> +	mdata_buf = tee_shm_get_va(mdata_shm, 0);
> +	if (IS_ERR(mdata_buf)) {
> +		dev_err(dev, "mdata_buf get VA failed\n");
> +		tee_shm_free(mdata_shm);
> +		return PTR_ERR(mdata_buf);
> +	}
> +	memcpy(mdata_buf, metadata, size);
> +
> +	param[1].u.memref.shm = mdata_shm;
> +	param[1].u.memref.size = size;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS init image failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +			pas_id, ret, inv_arg.ret);
> +		tee_shm_free(mdata_shm);
> +		return ret ?: -EINVAL;
> +	}
> +
> +	if (ctx)
> +		ctx->ptr = (void *)mdata_shm;
> +	else
> +		tee_shm_free(mdata_shm);
> +
> +	return ret;
> +}
> +
> +static int qcom_pas_tee_mem_setup(struct device *dev, u32 pas_id,
> +				  phys_addr_t addr, phys_addr_t size)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_MEM_SETUP,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = pas_id,
> +			.u.value.b = size,
> +		},
> +		[1] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = lower_32_bits(addr),
> +			.u.value.b = upper_32_bits(addr),
> +		}
> +	};
> +	int ret;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS mem setup failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +			pas_id, ret, inv_arg.ret);
> +		return ret ?: -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +DEFINE_FREE(shm_free, struct tee_shm *, tee_shm_free(_T))
> +
> +static void *qcom_pas_tee_get_rsc_table(struct device *dev,
> +					struct qcom_pas_context *ctx,
> +					void *input_rt, size_t input_rt_size,
> +					size_t *output_rt_size)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_GET_RESOURCE_TABLE,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = ctx->pas_id,
> +		},
> +		[1] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT,
> +			.u.memref.size = input_rt_size,
> +		}
> +	};
> +	void *rt_buf = NULL;
> +	int ret;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS get RT failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +			ctx->pas_id, ret, inv_arg.ret);
> +		return ret ? ERR_PTR(ret) : ERR_PTR(-EINVAL);
> +	}
> +
> +	if (param[1].u.memref.size) {
> +		struct tee_shm *rt_shm __free(shm_free) =
> +			tee_shm_alloc_kernel_buf(data->ctx,
> +						 param[1].u.memref.size);
> +		void *rt_shm_va;
> +
> +		if (IS_ERR(rt_shm)) {
> +			dev_err(dev, "rt_shm allocation failed\n");
> +			return rt_shm;
> +		}
> +
> +		rt_shm_va = tee_shm_get_va(rt_shm, 0);
> +		if (IS_ERR(rt_shm_va)) {
> +			dev_err(dev, "rt_shm get VA failed\n");
> +			return ERR_CAST(rt_shm_va);
> +		}
> +		memcpy(rt_shm_va, input_rt, input_rt_size);

It is very obvious that every existing user will pass NULL as input_rt
and 0 as input_rt_size.

Are you not getting NULL pointer on this input_rt ? Ok, you may be not
getting because, input_rt_size == 0.

I hope, your backend implementation checks for this num == 0 and then
ignore input rt.

> +
> +		param[1].u.memref.shm = rt_shm;
> +		ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +		if (ret < 0 || inv_arg.ret != 0) {
> +			dev_err(dev, "PAS get RT failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +				ctx->pas_id, ret, inv_arg.ret);
> +			return ret ? ERR_PTR(ret) : ERR_PTR(-EINVAL);
> +		}
> +
> +		if (param[1].u.memref.size) {
> +			*output_rt_size = param[1].u.memref.size;
> +			rt_buf = kmemdup(rt_shm_va, *output_rt_size, GFP_KERNEL);
> +			if (!rt_buf)
> +				return ERR_PTR(-ENOMEM);
> +		}
> +	}
> +
> +	return rt_buf;
> +}
> +
> +static int __qcom_pas_tee_auth_and_reset(struct device *dev, u32 pas_id,
> +					 phys_addr_t mem_phys, size_t mem_size)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_AUTH_AND_RESET,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = pas_id,
> +			.u.value.b = mem_size,
> +		},
> +		[1] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = lower_32_bits(mem_phys),
> +			.u.value.b = upper_32_bits(mem_phys),
> +		},
> +		/* Reserved for fw memory space to be shared or lent */
> +		[2] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
> +		}
> +	};
> +	int ret;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS auth reset failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +			pas_id, ret, inv_arg.ret);
> +		return ret ?: -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int qcom_pas_tee_auth_and_reset(struct device *dev, u32 pas_id)
> +{
> +	return __qcom_pas_tee_auth_and_reset(dev, pas_id, 0, 0);
> +}
> +
> +static int qcom_pas_tee_prepare_and_auth_reset(struct device *dev,
> +					       struct qcom_pas_context *ctx)
> +{
> +	return __qcom_pas_tee_auth_and_reset(dev, ctx->pas_id, ctx->mem_phys,
> +					     ctx->mem_size);
> +}
> +
> +static int qcom_pas_tee_set_remote_state(struct device *dev, u32 state,
> +					 u32 pas_id)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_SET_REMOTE_STATE,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = pas_id,
> +			.u.value.b = state,
> +		}
> +	};
> +	int ret;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS shutdown failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +			pas_id, ret, inv_arg.ret);

should be "PAS set remote state failed .."

> +		return ret ?: -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int qcom_pas_tee_shutdown(struct device *dev, u32 pas_id)
> +{
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +	struct tee_ioctl_invoke_arg inv_arg = {
> +		.func = TA_QCOM_PAS_SHUTDOWN,
> +		.session = data->session_id,
> +		.num_params = TEE_NUM_PARAMS
> +	};
> +	struct tee_param param[4] = {
> +		[0] = {
> +			.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +			.u.value.a = pas_id
> +		}
> +	};
> +	int ret;
> +
> +	ret = tee_client_invoke_func(data->ctx, &inv_arg, param);
> +	if (ret < 0 || inv_arg.ret != 0) {
> +		dev_err(dev, "PAS shutdown failed, pas_id: %d, ret: %d, err: 0x%x\n",
> +			pas_id, ret, inv_arg.ret);
> +		return ret ?: -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static void qcom_pas_tee_metadata_release(struct device *dev,
> +					  struct qcom_pas_context *ctx)
> +{
> +	struct tee_shm *mdata_shm = ctx->ptr;
> +
> +	tee_shm_free(mdata_shm);
> +}
> +
> +static struct qcom_pas_ops qcom_pas_ops_tee = {
> +	.drv_name		= "qcom-pas-tee",
> +	.supported		= qcom_pas_tee_supported,
> +	.init_image		= qcom_pas_tee_init_image,
> +	.mem_setup		= qcom_pas_tee_mem_setup,
> +	.get_rsc_table		= qcom_pas_tee_get_rsc_table,
> +	.auth_and_reset		= qcom_pas_tee_auth_and_reset,
> +	.prepare_and_auth_reset	= qcom_pas_tee_prepare_and_auth_reset,
> +	.set_remote_state	= qcom_pas_tee_set_remote_state,
> +	.shutdown		= qcom_pas_tee_shutdown,
> +	.metadata_release	= qcom_pas_tee_metadata_release,
> +};
> +
> +static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
> +{
> +	return ver->impl_id == TEE_IMPL_ID_OPTEE;
> +}
> +
> +static int qcom_pas_tee_probe(struct tee_client_device *pas_dev)
> +{
> +	struct device *dev = &pas_dev->dev;
> +	struct qcom_pas_tee_private *data;
> +	struct tee_ioctl_open_session_arg sess_arg = {
> +		.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL
> +	};
> +	int ret, err = -ENODEV;

Most people prefer one line per variable..


> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->ctx = tee_client_open_context(NULL, optee_ctx_match, NULL, NULL);
> +	if (IS_ERR(data->ctx))
> +		return -ENODEV;
> +
> +	export_uuid(sess_arg.uuid, &pas_dev->id.uuid);
> +	ret = tee_client_open_session(data->ctx, &sess_arg, NULL);
> +	if (ret < 0 || sess_arg.ret != 0) {
> +		dev_err(dev, "tee_client_open_session failed, ret: %d, err: 0x%x\n",
> +			ret, sess_arg.ret);
> +		err = ret ?: -EINVAL;

Only user of goto,  we can close the context and return from here and
'err' not used.

		tee_client_close_context(data->ctx);
		return ret ?: -EINVAL;

> +		goto out_ctx;


> +	}
> +
> +	data->session_id = sess_arg.session;
> +	dev_set_drvdata(dev, data);
> +	qcom_pas_ops_tee.dev = dev;
> +	qcom_pas_ops_register(&qcom_pas_ops_tee);
> +
> +	return ret;
> +out_ctx:
> +	tee_client_close_context(data->ctx);

Return after two line does not look nice.

> +
> +	return err;
> +}
> +
> +static void qcom_pas_tee_remove(struct tee_client_device *pas_dev)
> +{
> +	struct device *dev = &pas_dev->dev;
> +	struct qcom_pas_tee_private *data = dev_get_drvdata(dev);
> +
> +	qcom_pas_ops_unregister();
> +	tee_client_close_session(data->ctx, data->session_id);
> +	tee_client_close_context(data->ctx);
> +}
> +
> +static const struct tee_client_device_id qcom_pas_tee_id_table[] = {
> +	{UUID_INIT(0xcff7d191, 0x7ca0, 0x4784,
> +		   0xaf, 0x13, 0x48, 0x22, 0x3b, 0x9a, 0x4f, 0xbe)},
> +	{}
> +};
> +MODULE_DEVICE_TABLE(tee, qcom_pas_tee_id_table);
> +
> +static struct tee_client_driver optee_pas_tee_driver = {
> +	.probe		= qcom_pas_tee_probe,
> +	.remove		= qcom_pas_tee_remove,
> +	.id_table	= qcom_pas_tee_id_table,
> +	.driver		= {
> +		.name		= "qcom-pas-tee",
> +	},
> +};
> +
> +module_tee_client_driver(optee_pas_tee_driver);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("Qualcomm PAS TEE driver");
> -- 
> 2.51.0
>


With above change,

Reviewed-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>

-- 
-Mukesh Ojha