Re: [RESEND PATCH v16 2/6] remoteproc: Add TEE support

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Good morning,

On Tue, Jun 03, 2025 at 12:08:04PM +0200, Arnaud Pouliquen wrote:
> Add a remoteproc TEE (Trusted Execution Environment) driver that will be
> probed by the TEE bus. If the associated Trusted application is supported
> on the secure part, this driver offers a client interface to load firmware
> by the secure part.
> This firmware could be authenticated by the secure trusted application.
> 
> A specificity of the implementation is that the firmware has to be
> authenticated and optionally decrypted to access the resource table.
> 
> Consequently, the boot sequence is:
> 
> 1) rproc_parse_fw --> rproc_tee_parse_fw
>    remoteproc TEE:
>    - Requests the TEE application to authenticate and load the firmware
>      in the remote processor memories.
>    - Requests the TEE application for the address of the resource table.
>    - Creates a copy of the resource table stored in rproc->cached_table.
> 
> 2) rproc_load_segments --> rproc_tee_load_fw
>    remoteproc TEE:
>    - Requests the TEE application to load the firmware. Nothing is done
>      at the TEE application as the firmware is already loaded.
>    - In case of recovery, the TEE application has to reload the firmware.
> 
> 3) rproc_tee_get_loaded_rsc_table
>    remoteproc TEE requests the TEE application for the address of the
>    resource table.
> 
> 4) rproc_start --> rproc_tee_start
>    - Requests the TEE application to start the remote processor.
> 
> 
> The shutdown sequence is:
> 
> 5) rproc_stop --> rproc_tee_stop
>    - Requests the TEE application to stop the remote processor.
> 
> 6) rproc_tee_release_fw
>    This function is used to request the TEE application to perform actions
>    to return to the initial state on stop or on error during the boot
>    sequence.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> Updates vs previous version:
> - Come back to v13 managing a load in rproc_tee_parse_fw().
> - Replace IS_REACHABLE with IS_ENABLED in remoteproc_tee.h, remoteproc_tee
>   is not supported as module
> - update REMOTEPROC_TEE config description in Kconfig
> - manage unbind sequence of the consumer rproc drivers using devlink
> - remove TA_RPROC_FW_CMD_GET_COREDUMP as not use ( to be treated in a
>   separate thread)
> - define a static `rproc_tee_ctx` variable instead of allocating it
> - add spinlock to protect `rproc_tee_ctx` accesses.
> - add exported function doumentation
> ---
>  drivers/remoteproc/Kconfig          |  10 +
>  drivers/remoteproc/Makefile         |   1 +
>  drivers/remoteproc/remoteproc_tee.c | 619 ++++++++++++++++++++++++++++
>  include/linux/remoteproc_tee.h      |  90 ++++
>  4 files changed, 720 insertions(+)
>  create mode 100644 drivers/remoteproc/remoteproc_tee.c
>  create mode 100644 include/linux/remoteproc_tee.h
> 
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index 83962a114dc9..e39265d249d9 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -23,6 +23,16 @@ config REMOTEPROC_CDEV
>  
>  	  It's safe to say N if you don't want to use this interface.
>  
> +config REMOTEPROC_TEE
> +	bool "Remoteproc support by a TEE application"
> +	depends on OPTEE
> +	help
> +	  Support a remote processor that is managed by an application running in a Trusted
> +	  Execution Environment (TEE). This application is responsible for loading the remote
> +	  processor firmware image and managing its lifecycle.
> +

This is a much better help message than it used to be.

> +	  It's safe to say N if the remote processor is not managed by a TEE.
> +
>  config IMX_REMOTEPROC
>  	tristate "i.MX remoteproc support"
>  	depends on ARCH_MXC
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index 5ff4e2fee4ab..f77e0abe8349 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -11,6 +11,7 @@ remoteproc-y				+= remoteproc_sysfs.o
>  remoteproc-y				+= remoteproc_virtio.o
>  remoteproc-y				+= remoteproc_elf_loader.o
>  obj-$(CONFIG_REMOTEPROC_CDEV)		+= remoteproc_cdev.o
> +obj-$(CONFIG_REMOTEPROC_TEE)		+= remoteproc_tee.o
>  obj-$(CONFIG_IMX_REMOTEPROC)		+= imx_rproc.o
>  obj-$(CONFIG_IMX_DSP_REMOTEPROC)	+= imx_dsp_rproc.o
>  obj-$(CONFIG_INGENIC_VPU_RPROC)		+= ingenic_rproc.o
> diff --git a/drivers/remoteproc/remoteproc_tee.c b/drivers/remoteproc/remoteproc_tee.c
> new file mode 100644
> index 000000000000..cf50de7eb952
> --- /dev/null
> +++ b/drivers/remoteproc/remoteproc_tee.c
> @@ -0,0 +1,619 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) STMicroelectronics 2024
> + * Author: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> + */
> +
> +#include <linux/firmware.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/remoteproc.h>
> +#include <linux/remoteproc_tee.h>
> +#include <linux/slab.h>
> +#include <linux/tee_drv.h>
> +
> +#define MAX_TEE_PARAM_ARRAY_MEMBER	4
> +
> +/*
> + * Authentication and load of the firmware image in the remote processor memories by the TEE.
> + * After this step the firmware is loaded in destination memories, which can then be locked to
> + * prevent access by Linux.
> + *
> + * [in]  params[0].value.a:	remote processor identifier
> + * [in]	 params[1].memref:	buffer containing a temporary copy of the signed image to load.
> + */
> +#define TA_RPROC_FW_CMD_LOAD_FW		1
> +
> +/*
> + * Start the remote processor by the TEE
> + *
> + * [in]  params[0].value.a:	remote processor identifier
> + */
> +#define TA_RPROC_FW_CMD_START		2
> +
> +/*
> + * Stop the remote processor by the TEE
> + *
> + * [in]  params[0].value.a:	remote processor identifier
> + */
> +#define TA_RPROC_FW_CMD_STOP		3
> +
> +/*
> + * Return the address of the resource table, or 0 if not found.
> + *
> + * [in]  params[0].value.a:	remote processor identifier
> + * [out]  params[1].value.a:	32bit LSB resource table memory address
> + * [out]  params[1].value.b:	32bit MSB resource table memory address
> + * [out]  params[2].value.a:	32bit LSB resource table memory size
> + * [out]  params[2].value.b:	32bit MSB resource table memory size
> + */
> +#define TA_RPROC_FW_CMD_GET_RSC_TABLE	4
> +
> +/*
> + * Release remote processor firmware images and associated resources.
> + * This command should be used in case an error occurs between the loading of
> + * the firmware images (TA_RPROC_CMD_LOAD_FW) and the starting of the remote
> + * processor (TA_RPROC_CMD_START_FW) or after stopping the remote processor
> + * to release associated resources (TA_RPROC_CMD_STOP_FW).
> + *
> + * [in]  params[0].value.a: Unique 32-bit remote processor identifier
> + */
> +#define TA_RPROC_CMD_RELEASE_FW		6
> +
> +struct rproc_tee_context {
> +	struct list_head	sessions;
> +	struct tee_context	*tee_ctx;
> +	struct device		*dev;
> +};
> +
> +/**
> + * struct rproc_tee - TEE remoteproc structure
> + * @node:		Reference in list
> + * @rproc:		Remoteproc reference
> + * @rproc_id:		Identifier of the target firmware
> + * @session_id:		TEE session identifier
> + */
> +struct rproc_tee {
> +	struct list_head node;
> +	struct rproc *rproc;
> +	u32 rproc_id;
> +	u32 session_id;
> +};
> +
> +static struct rproc_tee_context rproc_tee_ctx;
> +static DEFINE_SPINLOCK(ctx_lock);
> +
> +static struct rproc_tee *rproc_to_trproc(struct rproc *rproc)
> +{
> +	struct rproc_tee *trproc;
> +
> +	list_for_each_entry(trproc, &rproc_tee_ctx.sessions, node)
> +		if (trproc->rproc == rproc)
> +			return trproc;
> +
> +	return NULL;
> +}
> +
> +static void rproc_tee_prepare_args(struct rproc_tee *trproc, int cmd,
> +				   struct tee_ioctl_invoke_arg *arg,
> +				   struct tee_param *param,
> +				   unsigned int num_params)
> +{
> +	memset(arg, 0, sizeof(*arg));
> +	memset(param, 0, MAX_TEE_PARAM_ARRAY_MEMBER * sizeof(*param));
> +
> +	arg->func = cmd;
> +	arg->session = trproc->session_id;
> +	arg->num_params = num_params + 1;
> +
> +	param[0] = (struct tee_param) {
> +		.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +		.u.value.a = trproc->rproc_id,
> +	};
> +}
> +
> +/**
> + * rproc_tee_release_fw - Release the firmware for a TEE-based remote processor
> + *
> + * This function invokes the TA_RPROC_CMD_RELEASE_FW TEE client function to release the firmware.
> + * It should only be called when the remoteproc state is RPROC_OFFLINE or RPROC_DETACHED.
> + * The function requests the TEE remoteproc application to release the firmware loaded by
> + * rproc_tee_load_fw(). The request is ignored if the rproc state is RPROC_DETACHED as the
> + * remote processor is still running.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + */
> +void rproc_tee_release_fw(struct rproc *rproc)
> +{
> +	struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> +	struct rproc_tee *trproc = rproc_to_trproc(rproc);
> +	struct tee_ioctl_invoke_arg arg;
> +	int ret;
> +
> +	if (!rproc_tee_ctx.dev)
> +		return;
> +
> +	if (!trproc)
> +		return;
> +
> +	/*
> +	 * If the remote processor state is RPROC_DETACHED, just ignore the
> +	 * request, as the remote processor is still running.
> +	 */
> +	if (rproc->state == RPROC_DETACHED)
> +		return;
> +
> +	if (rproc->state != RPROC_OFFLINE) {
> +		dev_err(rproc_tee_ctx.dev, "unexpected rproc state: %d\n", rproc->state);
> +		return;
> +	}
> +
> +	rproc_tee_prepare_args(trproc, TA_RPROC_CMD_RELEASE_FW, &arg, param, 0);
> +
> +	ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> +	if (ret < 0 || arg.ret != 0) {
> +		dev_err(rproc_tee_ctx.dev,
> +			"TA_RPROC_CMD_RELEASE_FW invoke failed TEE err: %#x, ret:%d\n",
> +			arg.ret, ret);
> +		ret = -EIO;
> +	}
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_release_fw);
> +
> +/**
> + * rproc_tee_load_fw - Load firmware from TEE application
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and size
> + *
> + * This function invokes the TA_RPROC_FW_CMD_LOAD_FW TEE client function to load the firmware.
> + * It registers the fw->data as a shared memory region with the TEE, and request the TEE to load
> + * the firmware. This function can be called twice during the remote processor boot, considering
> + * that the TEE application ignores the command if the firmware is already loaded.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and size
> + *
> + * Return: 0 on success, or an error code on failure
> + */
> +int rproc_tee_load_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> +	struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> +	struct rproc_tee *trproc = rproc_to_trproc(rproc);
> +	struct tee_ioctl_invoke_arg arg;
> +	struct tee_shm *fw_shm;
> +	int ret;
> +
> +	if (!rproc_tee_ctx.dev)
> +		return -ENODEV;
> +
> +	if (!trproc)
> +		return -EINVAL;
> +
> +	fw_shm = tee_shm_register_kernel_buf(rproc_tee_ctx.tee_ctx, (void *)fw->data, fw->size);
> +	if (IS_ERR(fw_shm))
> +		return PTR_ERR(fw_shm);
> +
> +	rproc_tee_prepare_args(trproc, TA_RPROC_FW_CMD_LOAD_FW, &arg, param, 1);
> +
> +	/* Provide the address of the firmware image */
> +	param[1] = (struct tee_param) {
> +		.attr = TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT,
> +		.u.memref = {
> +			.shm = fw_shm,
> +			.size = fw->size,
> +			.shm_offs = 0,
> +		},
> +	};
> +
> +	ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> +	if (ret < 0 || arg.ret != 0) {
> +		dev_err(rproc_tee_ctx.dev,
> +			"TA_RPROC_FW_CMD_LOAD_FW invoke failed TEE err: %#x, ret:%d\n",
> +			arg.ret, ret);
> +		if (!ret)
> +			ret = -EIO;
> +	}
> +
> +	tee_shm_free(fw_shm);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_load_fw);
> +
> +static int rproc_tee_get_loaded_rsc_table(struct rproc *rproc, phys_addr_t *rsc_pa,
> +					  size_t *table_sz)
> +{
> +	struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> +	struct rproc_tee *trproc = rproc_to_trproc(rproc);
> +	struct tee_ioctl_invoke_arg arg;
> +	int ret;
> +
> +	if (!rproc_tee_ctx.dev)
> +		return -ENODEV;
> +
> +	if (!trproc)
> +		return -EINVAL;
> +
> +	rproc_tee_prepare_args(trproc, TA_RPROC_FW_CMD_GET_RSC_TABLE, &arg, param, 2);
> +
> +	param[1].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
> +	param[2].attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT;
> +
> +	ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> +	if (ret < 0 || arg.ret != 0) {
> +		dev_err(rproc_tee_ctx.dev,
> +			"TA_RPROC_FW_CMD_GET_RSC_TABLE invoke failed TEE err: %#x, ret:%d\n",
> +			arg.ret, ret);
> +		return -EIO;
> +	}
> +
> +	*table_sz = param[2].u.value.a;
> +
> +	if (*table_sz)
> +		*rsc_pa = param[1].u.value.a;
> +	else
> +		*rsc_pa  = 0;
> +
> +	return 0;
> +}
> +
> +/**
> + * rproc_tee_parse_fw - Get the resource table from TEE application
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and size
> + *
> + * This function retrieves the loaded resource table and creates a cached_table copy. Since the
> + * firmware image is signed and potentially encrypted, the firmware must be loaded first to
> + * access the loaded resource table.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and size
> + *
> + * Return: 0 on success, or an error code on failure
> + */
> +int rproc_tee_parse_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> +	phys_addr_t rsc_table;
> +	void __iomem *rsc_va;
> +	size_t table_sz;
> +	int ret;
> +
> +	if (!rproc)
> +		return -EINVAL;
> +
> +	/* We need first to Load the firmware, to be able to get the resource table. */
> +	ret = rproc_tee_load_fw(rproc, fw);
> +	if (ret)
> +		return ret;
> +
> +	ret = rproc_tee_get_loaded_rsc_table(rproc, &rsc_table, &table_sz);
> +	if (ret)
> +		goto release_fw;
> +
> +	/*
> +	 * We assume here that the memory mapping is the same between the TEE and Linux kernel
> +	 * contexts. Else a new TEE remoteproc service could be needed to get a copy of the
> +	 * resource table
> +	 */
> +	rsc_va = ioremap_wc(rsc_table, table_sz);
> +	if (!rsc_va) {
> +		dev_err(rproc_tee_ctx.dev, "Unable to map memory region: %pa+%zx\n",
> +			&rsc_table, table_sz);
> +		ret = -ENOMEM;
> +		goto release_fw;
> +	}
> +
> +	/*
> +	 * Create a copy of the resource table to have the same behavior as the ELF loader.
> +	 * This cached table will be used by the remoteproc core after the remoteproc stops
> +	 * to free resources and for crash recovery to reapply the settings.
> +	 * The cached table will be freed by the remoteproc core.
> +	 */
> +	rproc->cached_table = kmemdup((__force void *)rsc_va, table_sz, GFP_KERNEL);
> +	iounmap(rsc_va);
> +
> +	if (!rproc->cached_table) {
> +		ret = -ENOMEM;
> +		goto release_fw;
> +	}
> +
> +	rproc->table_ptr = rproc->cached_table;
> +	rproc->table_sz = table_sz;
> +
> +	return 0;
> +
> +release_fw:
> +	rproc_tee_release_fw(rproc);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_parse_fw);
> +
> +/**
> + * rproc_tee_find_loaded_rsc_table - Find the loaded resource table loaded by the TEE application
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and size
> + *
> + * This function retrieves the physical address and size of the resource table loaded by the TEE
> + * application.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @fw: Pointer to the firmware structure containing the firmware data and size
> + *
> + * Return:  pointer to the resource table if found, or NULL if not found or size is 0
> + */
> +struct resource_table *rproc_tee_find_loaded_rsc_table(struct rproc *rproc,
> +						       const struct firmware *fw)
> +{
> +	phys_addr_t rsc_table;
> +	size_t table_sz;
> +	int ret;
> +
> +	ret = rproc_tee_get_loaded_rsc_table(rproc, &rsc_table, &table_sz);
> +	if (ret)
> +		return NULL;
> +
> +	rproc->table_sz = table_sz;
> +	if (!table_sz)
> +		return NULL;
> +
> +	/*
> +	 * At this step the memory area that contains the resource table should have been registered
> +	 * by the remote proc platform driver and allocated by rproc_alloc_registered_carveouts().
> +	 */
> +	return (struct resource_table *)rproc_pa_to_va(rproc, rsc_table, table_sz, NULL);
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_find_loaded_rsc_table);
> +
> +/**
> + * rproc_tee_start - Request the TEE application to start the remote processor
> + *
> + * This function invokes the TA_RPROC_FW_CMD_START command to start the remote processor.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + *
> + * Return: Returns 0 on success, -EINVAL or -EIO on failure
> + */
> +int rproc_tee_start(struct rproc *rproc)
> +{
> +	struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> +	struct rproc_tee *trproc = rproc_to_trproc(rproc);
> +	struct tee_ioctl_invoke_arg arg;
> +	int ret = 0;
> +
> +	if (!trproc)
> +		return -EINVAL;
> +
> +	rproc_tee_prepare_args(trproc, TA_RPROC_FW_CMD_START, &arg, param, 0);
> +
> +	ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> +	if (ret < 0 || arg.ret != 0) {
> +		dev_err(rproc_tee_ctx.dev,
> +			"TA_RPROC_FW_CMD_START invoke failed TEE err: %#x, ret:%d\n", arg.ret, ret);
> +		if (!ret)
> +			return  -EIO;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_start);
> +
> +/**
> + * rproc_tee_stop - Request the TEE application to start the remote processor
> + *
> + * This function invokes the TA_RPROC_FW_CMD_STOP command to stop the remote processor.
> + *
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + *
> + * Return: Returns 0 on success, -EINVAL or -EIO on failure
> + */
> +int rproc_tee_stop(struct rproc *rproc)
> +{
> +	struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> +	struct rproc_tee *trproc = rproc_to_trproc(rproc);
> +	struct tee_ioctl_invoke_arg arg;
> +	int ret;
> +
> +	if (!trproc)
> +		return -EINVAL;
> +
> +	rproc_tee_prepare_args(trproc, TA_RPROC_FW_CMD_STOP, &arg, param, 0);
> +
> +	ret = tee_client_invoke_func(rproc_tee_ctx.tee_ctx, &arg, param);
> +	if (ret < 0 || arg.ret != 0) {
> +		dev_err(rproc_tee_ctx.dev,
> +			"TA_RPROC_FW_CMD_STOP invoke failed TEE err: %#x, ret:%d\n", arg.ret, ret);
> +		if (!ret)
> +			ret = -EIO;
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_stop);
> +
> +static const struct tee_client_device_id rproc_tee_id_table[] = {
> +	{UUID_INIT(0x80a4c275, 0x0a47, 0x4905, 0x82, 0x85, 0x14, 0x86, 0xa9, 0x77, 0x1a, 0x08)},
> +	{}
> +};
> +
> +/**
> + * rproc_tee_register - Register a remote processor controlled by a TEE application.
> + *
> + * This function registers a remote processor that will be managed by a TEE application,by opening
> + * a session with the TEE client.
> + *
> + * @dev: Pointer to client rproc device
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + * @rproc_id: ID of the remote processor
> + *
> + * Return: Returns 0 on success, or an error code on failure
> + */
> +int rproc_tee_register(struct device *dev, struct rproc *rproc, unsigned int rproc_id)
> +{
> +	struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
> +	struct tee_ioctl_open_session_arg sess_arg;
> +	struct tee_client_device *tee_device;
> +	struct rproc_tee *trproc;
> +	struct device_link *link;
> +	int ret;
> +
> +	spin_lock(&ctx_lock);
> +	/*
> +	 * Test if the device has been probed by the TEE bus. In case of failure, we ignore the
> +	 * reason. The bus could be not yet probed or the service not available in the secure
> +	 * firmware.The assumption in such a case is that the TEE remoteproc is not probed.
> +	 */
> +	if (!rproc_tee_ctx.dev) {
> +		ret =  -EPROBE_DEFER;
> +		goto out;
> +	}
> +
> +	trproc =  kzalloc(sizeof(*trproc), GFP_KERNEL);
> +	if (!trproc) {
> +		ret =  -ENOMEM;

Extra space between '=' and "-ENOMEM".  More comments to come over the next few
days.

Thanks,
Mathieu

> +		goto out;
> +	}
> +
> +	tee_device = to_tee_client_device(rproc_tee_ctx.dev);
> +	memset(&sess_arg, 0, sizeof(sess_arg));
> +
> +	memcpy(sess_arg.uuid, tee_device->id.uuid.b, TEE_IOCTL_UUID_LEN);
> +
> +	sess_arg.clnt_login = TEE_IOCTL_LOGIN_REE_KERNEL;
> +	sess_arg.num_params = 1;
> +
> +	param[0] = (struct tee_param) {
> +		.attr = TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT,
> +		.u.value.a = rproc_id,
> +	};
> +
> +	ret = tee_client_open_session(rproc_tee_ctx.tee_ctx, &sess_arg, param);
> +	if (ret < 0 || sess_arg.ret != 0) {
> +		dev_err(dev, "tee_client_open_session failed, err: %#x\n", sess_arg.ret);
> +		ret = -EINVAL;
> +		goto free_tproc;
> +	}
> +
> +	trproc->rproc_id = rproc_id;
> +	trproc->session_id = sess_arg.session;
> +
> +	trproc->rproc = rproc;
> +
> +	/* Create device link between the rproc device and the TEE device */
> +	link = device_link_add(dev, rproc_tee_ctx.dev, DL_FLAG_AUTOREMOVE_CONSUMER);
> +	if (!link) {
> +		ret = -ENOMEM;
> +		goto close_tee;
> +	}
> +	list_add_tail(&trproc->node, &rproc_tee_ctx.sessions);
> +
> +	goto out;
> +
> +close_tee:
> +	if (tee_client_close_session(rproc_tee_ctx.tee_ctx, trproc->session_id))
> +		dev_err(rproc_tee_ctx.dev, "tee_client_close_session failed\n");
> +free_tproc:
> +	kfree(trproc);
> +out:
> +	spin_unlock(&ctx_lock);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_register);
> +
> +/**
> + * rproc_tee_unregister - Register a remote processor controlled by a TEE application.
> + *
> + * This function unregisters a remote processor previously registered by the rproc_tee_register()
> + * function.
> + *
> + * @dev: Pointer to client rproc device
> + * @rproc: Pointer to the struct rproc representing the remote processor
> + *
> + * Return: Returns 0 on success, or an error code on failure
> + */
> +int rproc_tee_unregister(struct device *dev, struct rproc *rproc)
> +{
> +	struct rproc_tee *trproc = rproc_to_trproc(rproc);
> +	int ret;
> +
> +	if (!trproc)
> +		return -EINVAL;
> +
> +	spin_lock(&ctx_lock);
> +
> +	ret = tee_client_close_session(rproc_tee_ctx.tee_ctx, trproc->session_id);
> +	if (ret < 0)
> +		dev_err(rproc_tee_ctx.dev, "tee_client_close_session failed, err: %#x\n", ret);
> +
> +	spin_unlock(&ctx_lock);
> +
> +	list_del(&trproc->node);
> +	kfree(trproc);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(rproc_tee_unregister);
> +
> +static int rproc_tee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
> +{
> +	/* Today we support only the OP-TEE, could be extend to other tees */
> +	return (ver->impl_id == TEE_IMPL_ID_OPTEE);
> +}
> +
> +static int rproc_tee_probe(struct device *dev)
> +{
> +	struct tee_context *tee_ctx;
> +
> +	/* Open context with TEE driver */
> +	tee_ctx = tee_client_open_context(NULL, rproc_tee_ctx_match, NULL, NULL);
> +	if (IS_ERR(tee_ctx))
> +		return PTR_ERR(tee_ctx);
> +
> +	spin_lock(&ctx_lock);
> +	rproc_tee_ctx.dev = dev;
> +	rproc_tee_ctx.tee_ctx = tee_ctx;
> +	INIT_LIST_HEAD(&rproc_tee_ctx.sessions);
> +	spin_unlock(&ctx_lock);
> +
> +	return 0;
> +}
> +
> +static int rproc_tee_remove(struct device *dev)
> +{
> +	spin_lock(&ctx_lock);
> +	tee_client_close_context(rproc_tee_ctx.tee_ctx);
> +	rproc_tee_ctx.dev = NULL;
> +	rproc_tee_ctx.tee_ctx = NULL;
> +	spin_unlock(&ctx_lock);
> +
> +	return 0;
> +}
> +
> +MODULE_DEVICE_TABLE(tee, rproc_tee_id_table);
> +
> +static struct tee_client_driver rproc_tee_fw_driver = {
> +	.id_table	= rproc_tee_id_table,
> +	.driver		= {
> +		.name		= KBUILD_MODNAME,
> +		.bus		= &tee_bus_type,
> +		.probe		= rproc_tee_probe,
> +		.remove		= rproc_tee_remove,
> +	},
> +};
> +
> +static int __init rproc_tee_fw_mod_init(void)
> +{
> +	return driver_register(&rproc_tee_fw_driver.driver);
> +}
> +
> +static void __exit rproc_tee_fw_mod_exit(void)
> +{
> +	driver_unregister(&rproc_tee_fw_driver.driver);
> +}
> +
> +module_init(rproc_tee_fw_mod_init);
> +module_exit(rproc_tee_fw_mod_exit);
> +
> +MODULE_DESCRIPTION(" remote processor TEE module");
> +MODULE_LICENSE("GPL");
> diff --git a/include/linux/remoteproc_tee.h b/include/linux/remoteproc_tee.h
> new file mode 100644
> index 000000000000..659bd77a4f12
> --- /dev/null
> +++ b/include/linux/remoteproc_tee.h
> @@ -0,0 +1,90 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * Copyright(c) 2024 STMicroelectronics
> + */
> +
> +#ifndef REMOTEPROC_TEE_H
> +#define REMOTEPROC_TEE_H
> +
> +#include <linux/tee_drv.h>
> +#include <linux/firmware.h>
> +#include <linux/remoteproc.h>
> +
> +struct rproc;
> +struct rproc_tee;
> +
> +#if IS_ENABLED(CONFIG_REMOTEPROC_TEE)
> +
> +int rproc_tee_register(struct device *dev, struct rproc *rproc, unsigned int rproc_id);
> +int rproc_tee_unregister(struct device *dev, struct rproc *rproc);
> +int rproc_tee_parse_fw(struct rproc *rproc, const struct firmware *fw);
> +int rproc_tee_load_fw(struct rproc *rproc, const struct firmware *fw);
> +void rproc_tee_release_fw(struct rproc *rproc);
> +struct resource_table *rproc_tee_find_loaded_rsc_table(struct rproc *rproc,
> +						       const struct firmware *fw);
> +int rproc_tee_start(struct rproc *rproc);
> +int rproc_tee_stop(struct rproc *rproc);
> +
> +#else
> +
> +static inline int rproc_tee_register(struct device *dev, struct rproc *rproc, unsigned int rproc_id)
> +{
> +	return -ENODEV;
> +}
> +
> +static inline int rproc_tee_parse_fw(struct rproc *rproc, const struct firmware *fw)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return 0;
> +}
> +
> +static inline int rproc_tee_unregister(struct device *dev, struct rproc *rproc)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return 0;
> +}
> +
> +static inline int rproc_tee_load_fw(struct rproc *rproc,  const struct firmware *fw)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return 0;
> +}
> +
> +static inline int rproc_tee_start(struct rproc *rproc)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return 0;
> +}
> +
> +static inline int rproc_tee_stop(struct rproc *rproc)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return 0;
> +}
> +
> +static inline void rproc_tee_release_fw(struct rproc *rproc)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +}
> +
> +static inline struct resource_table *
> +rproc_tee_find_loaded_rsc_table(struct rproc *rproc, const struct firmware *fw)
> +{
> +	/* This shouldn't be possible */
> +	WARN_ON(1);
> +
> +	return NULL;
> +}
> +#endif /* CONFIG_REMOTEPROC_TEE */
> +#endif /* REMOTEPROC_TEE_H */
> -- 
> 2.25.1
>