Re: [PATCH v19 2/6] remoteproc: Add TEE support

Harshal Dev
2025-08-04T09:26:40Z

Hi Arnaud,

On 8/1/2025 12:53 PM, Arnaud POULIQUEN wrote:
> Hello Harshal,
>
>
> On 7/31/25 12:25, Harshal Dev wrote:
>> Hello Arnaud,
>>
>> On 6/25/2025 3:10 PM, 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 version [18]:
>>> - rework/fix function headers
>>> - use memremap instead of ioremap for the resource table.
>>> - realign comments to 80 chars limit, with few exceptions for readability
>>> - replace spinlock by mutex and and protect APIs from concurrent access
>>> - add support of 64-bit address in rproc_tee_get_loaded_rsc_table()
>>> - Generalize teston rproc_tee_ctx.dev to prevent an unbind
>>> - update copyright year
>>>
>>> Updates vs version [17]:
>>> Fix warning:
>>> warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
>>> ---
>>> drivers/remoteproc/Kconfig | 10 +
>>> drivers/remoteproc/Makefile | 1 +
>>> drivers/remoteproc/remoteproc_tee.c | 708 ++++++++++++++++++++++++++++
>>> include/linux/remoteproc_tee.h | 87 ++++
>>> 4 files changed, 806 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.
>>> +
>>> + 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 1c7598b8475d..a1a5201982d4 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..b9da911b8a83
>>> --- /dev/null
>>> +++ b/drivers/remoteproc/remoteproc_tee.c
>>> @@ -0,0 +1,708 @@
>>> +// SPDX-License-Identifier: GPL-2.0-or-later
>>> +/*
>>> + * Copyright (C) STMicroelectronics 2025
>>> + * Author: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>>> + */
>>> +
>>> +#include <linux/export.h>
>>> +#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 installed 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: 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: remote processor identifier
>>> + * @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 struct mutex (ctx_lock); /* Protects concurrent manipulations of the rproc_tee_ctx*/
>>> +
>>
>> Since ctx_lock is protecting struct rproc_tee_ctx, can we place it within the struct?
>>
>>> +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
>>> + * @rproc: Pointer to the struct rproc representing the 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.
>>> + */
>>> +void rproc_tee_release_fw(struct rproc *rproc)
>>> +{
>>> + struct tee_param param[MAX_TEE_PARAM_ARRAY_MEMBER];
>>> + struct rproc_tee *trproc;
>>> + struct tee_ioctl_invoke_arg arg;
>>> + int ret;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return;
>>> +
>>> + if (!rproc_tee_ctx.dev)
>>> + goto out;
>>> +
>>> + trproc = rproc_to_trproc(rproc);
>>> + if (!trproc)
>>> + goto out;
>>> +
>>> + /*
>>> + * If the remote processor state is RPROC_DETACHED, just ignore the
>>> + * request, as the remote processor is still running.
>>> + */
>>> + if (rproc->state == RPROC_DETACHED)
>>> + goto out;
>>> +
>>> + if (rproc->state != RPROC_OFFLINE) {
>>> + dev_err(rproc_tee_ctx.dev, "unexpected rproc state: %d\n", rproc->state);
>>> + goto out;
>>> + }
>>> +
>>> + 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);
>>> + }
>>> +
>>> +out:
>>> + mutex_unlock(&ctx_lock);
>>> +}
>>> +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, a first by rproc_tee_parse_fw() to
>>> + * parse the resource table , and a second time by rproc_tee_load_fw().
>>> + * The TEE application should ignores the command if the firmware
>>> + * is already loaded by rproc_tee_parse_fw().
>>> + *
>>> + * 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;
>>> + struct tee_ioctl_invoke_arg arg;
>>> + struct tee_shm *fw_shm;
>>> + int ret;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + if (!rproc_tee_ctx.dev) {
>>> + ret = -ENODEV;
>>> + goto out;
>>> + }
>>> +
>>> + trproc = rproc_to_trproc(rproc);
>>> + if (!trproc) {
>>> + ret = -EINVAL;
>>> + goto out;
>>> + }
>>> +
>>> + fw_shm = tee_shm_register_kernel_buf(rproc_tee_ctx.tee_ctx, (void *)fw->data, fw->size);
>>> + if (IS_ERR(fw_shm)) {
>>> + ret = PTR_ERR(fw_shm);
>>> + goto out;
>>> + }
>>> +
>>> + 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);
>>> +
>>> +out:
>>> + mutex_unlock(&ctx_lock);
>>> + 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;
>>> + struct tee_ioctl_invoke_arg arg;
>>> + int ret;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + if (!rproc_tee_ctx.dev) {
>>> + ret = -ENODEV;
>>> + goto out;
>>> + }
>>> +
>>> + trproc = rproc_to_trproc(rproc);
>>> + if (!trproc) {
>>> + ret = -EINVAL;
>>> + goto out;
>>> + }
>>> +
>>> + 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);
>>> + ret = -EIO;
>>> + goto out;
>>> + }
>>> +
>>> + *table_sz = param[2].u.value.a;
>>> + if (sizeof(phys_addr_t) == sizeof(u64))
>>> + *table_sz |= param[2].u.value.b << 32;
>>> +
>>> + if (*table_sz) {
>>> + *rsc_pa = param[1].u.value.a;
>>> + if (sizeof(phys_addr_t) == sizeof(u64))
>>> + *rsc_pa |= param[1].u.value.b << 32;
>>> + } else {
>>> + *rsc_pa = 0;
>>> + }
>>> +
>>> +out:
>>> + mutex_unlock(&ctx_lock);
>>> + return ret;
>>> +}
>>> +
>>> +/**
>>> + * 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.
>>> + *
>>> + * 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 *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 = memremap(rsc_table, table_sz, MEMREMAP_WC);
>>> + 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(rsc_va, table_sz, GFP_KERNEL);
>>> + memunmap(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.
>>> + *
>>> + * 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 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
>>> + * @rproc: Pointer to the struct rproc representing the remote processor
>>> + *
>>> + * This function invokes the TA_RPROC_FW_CMD_START command to start 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;
>>> + struct tee_ioctl_invoke_arg arg;
>>> + int ret;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + if (!rproc_tee_ctx.dev) {
>>> + ret = -ENODEV;
>>> + goto out;
>>> + }
>>> +
>>> + trproc = rproc_to_trproc(rproc);
>>> + if (!trproc) {
>>> + ret = -EINVAL;
>>> + goto out;
>>> + }
>>> +
>>> + 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)
>>> + ret = -EIO;
>>> + }
>>> +
>>> +out:
>>> + mutex_unlock(&ctx_lock);
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(rproc_tee_start);
>>> +
>>> +/**
>>> + * rproc_tee_stop() - Request the TEE application to start the remote processor
>>> + * @rproc: Pointer to the struct rproc representing the remote processor
>>> + *
>>> + * This function invokes the TA_RPROC_FW_CMD_STOP command to stop 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;
>>> + struct tee_ioctl_invoke_arg arg;
>>> + int ret;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + if (!rproc_tee_ctx.dev) {
>>> + ret = -ENODEV;
>>> + goto out;
>>> + }
>>> +
>>> + trproc = rproc_to_trproc(rproc);
>>> + if (!trproc) {
>>> + ret = -EINVAL;
>>> + goto out;
>>> + }
>>> +
>>> + 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;
>>> + }
>>> +
>>> +out:
>>> + mutex_unlock(&ctx_lock);
>>> + 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 the TEE application.
>>> + * @dev: Pointer to client rproc device
>>> + * @rproc: Pointer to the struct rproc representing the remote processor
>>> + * @rproc_id: ID of the remote processor
>>> + *
>>> + * This function registers a remote processor that will be managed by a TEE
>>> + * application,by opening a session with the TEE client.
>>> + *
>>> + * 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;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + /*
>>> + * 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;
>>> + 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 to
>>> + * ensure that the rproc device is removed accordingly to a remove of
>>> + * the remoteproc 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);
>>> +
>>> + mutex_unlock(&ctx_lock);
>>> +
>>> + return 0;
>>> +
>>> +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:
>>> + mutex_unlock(&ctx_lock);
>>> +
>>> + return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(rproc_tee_register);
>>> +
>>> +/**
>>> + * rproc_tee_unregister - Register a remote processor controlled by the TEE application.
>>> + * @dev: Pointer to client rproc device
>>> + * @rproc: Pointer to the struct rproc representing the remote processor
>>> + *
>>> + * This function unregisters a remote processor previously registered by the
>>> + * rproc_tee_register() function.
>>> + *
>>> + * 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;
>>> + int ret;
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + if (!rproc_tee_ctx.dev) {
>>> + ret = -EPROBE_DEFER;
>>> + goto out;
>>> + }
>>> +
>>> + trproc = rproc_to_trproc(rproc);
>>> + if (!trproc) {
>>> + ret = -EINVAL;
>>> + goto out;
>>> + }
>>> +
>>> + 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);
>>> +
>>> + list_del(&trproc->node);
>>> + kfree(trproc);
>>> +
>>> +out:
>>> + mutex_unlock(&ctx_lock);
>>> + 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;
>>> + int ret;
>>> +
>>> + /* 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);
>>> +
>>> + ret = mutex_lock_interruptible(&ctx_lock);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + rproc_tee_ctx.dev = dev;
>>> + rproc_tee_ctx.tee_ctx = tee_ctx;
>>> + INIT_LIST_HEAD(&rproc_tee_ctx.sessions);
>>> + mutex_unlock(&ctx_lock);
>>> +
>>> + return 0;
>>> +}
>>
>> As you mentioned above, this could be extended to other TEEs. If so, is it possible for probe
>> to be called multiple times if we we have other TEE devices exposing the firmware authentication
>> service? In that case, I think rproc_tee_ctx should be dynamically initializated instead of being
>> static. And since we are creating a link between the Rproc device and TEE device, a call to a
>> function like rproc_tee_start() could retreive the associated TEE device, and then the associated
>> rproc_tee? :)
>
> I have never seen a use case that requires multiple instances, but perhaps you
> have some?
>
> We can expect only one TEE, which could be OP-TEE, Trusty, or another.
> The device is associated with a unique UUID, so only one instance is expected.
>
> That said, making this driver support multiple instances seems like a valid
> future enhancement. However, I would suggest implementing it as a second step
> when there is a concrete need.
>

My thought process on this stems from 1) the recent ARM FF-A developments and 2) from the current
implementation of the TEE subsystem which allows multiple back-end drivers to register themselves
via the tee_device_register() API. This means, that it's possible to have a configuration
where a platform supports multiple TEEs running as Secure Partitions via FF-A, and each of those
TEEs register their services as PTA devices on the TEE bus.

However, I do not really know if it's possible to have a UUID collision in such a case, which
would lead to rproc_tee_probe() being called twice above, which is why I raised this question. :)

All of this aside, I realize now that other TEE client drivers are also implemented with a static
private data similar to how you are doing it. So perhaps we can think of this as a later
enhancement if we believe that the scenario I am describing is not possible in the near future..

Thanks,
Harshal
> Thanks,
> Arnaud
>
>>
>> Thanks,
>> Harshal
>>> +
>>> +static int rproc_tee_remove(struct device *dev)
>>> +{
>>> + mutex_lock(&ctx_lock);
>>> + tee_client_close_context(rproc_tee_ctx.tee_ctx);
>>> + rproc_tee_ctx.dev = NULL;
>>> + rproc_tee_ctx.tee_ctx = NULL;
>>> + mutex_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)
>>> +{
>>> + mutex_init(&ctx_lock);
>>> +
>>> + 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..a5fdc1627774
>>> --- /dev/null
>>> +++ b/include/linux/remoteproc_tee.h
>>> @@ -0,0 +1,87 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>>> +/*
>>> + * Copyright(c) 2025 STMicroelectronics
>>> + */
>>> +
>>> +#ifndef REMOTEPROC_TEE_H
>>> +#define REMOTEPROC_TEE_H
>>> +
>>> +#include <linux/tee_drv.h>
>>> +#include <linux/firmware.h>
>>> +#include <linux/remoteproc.h>
>>> +
>>> +#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 */
>>