Message-ID: <20250625094028.758016-3-arnaud.pouliquen@foss.st.com>
Date: Wed, 25 Jun 2025 11:40:24 +0200
From: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
To: Bjorn Andersson <andersson@...nel.org>,
        Mathieu Poirier
	<mathieu.poirier@...aro.org>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        "Rob Herring" <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        "Conor Dooley" <conor+dt@...nel.org>
CC: <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <op-tee@...ts.trustedfirmware.org>, <devicetree@...r.kernel.org>,
        Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
Subject: [PATCH v19 2/6] remoteproc: Add TEE support

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@...s.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@...s.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*/
+
+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;
+}
+
+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 */
-- 
2.25.1

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