Re: [PATCH v2 1/4] remoteproc: Add TEE support

[Mathieu Poirier]

On Fri, Jan 26, 2024 at 02:39:33PM +0100, Arnaud POULIQUEN wrote:
> Hi Mathieu,
> 
> On 1/25/24 19:55, Mathieu Poirier wrote:
> > Hi Arnaud,
> > 
> > On Thu, Jan 18, 2024 at 11:04:30AM +0100, Arnaud Pouliquen wrote:
> >> From: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>
> >>
> >> Add a remoteproc TEE (Trusted Execution Environment) device
> > 
> > Device or driver?  Seems to be the latter...
> 
> Right, driver is better
> 
> > 
> >> that will be probed by the TEE bus. If the associated Trusted
> >> application is supported on secure part this device offers a client
> >> interface to load a firmware in the secure part.
> >> This firmware could be authenticated and decrypted by the secure
> >> trusted application.
> >>
> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>
> >> ---
> >>  drivers/remoteproc/Kconfig          |   9 +
> >>  drivers/remoteproc/Makefile         |   1 +
> >>  drivers/remoteproc/tee_remoteproc.c | 393 ++++++++++++++++++++++++++++
> >>  include/linux/tee_remoteproc.h      |  99 +++++++
> >>  4 files changed, 502 insertions(+)
> >>  create mode 100644 drivers/remoteproc/tee_remoteproc.c
> >>  create mode 100644 include/linux/tee_remoteproc.h
> >>
> >> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> >> index 48845dc8fa85..85299606806c 100644
> >> --- a/drivers/remoteproc/Kconfig
> >> +++ b/drivers/remoteproc/Kconfig
> >> @@ -365,6 +365,15 @@ config XLNX_R5_REMOTEPROC
> >>  
> >>  	  It's safe to say N if not interested in using RPU r5f cores.
> >>  
> >> +
> >> +config TEE_REMOTEPROC
> >> +	tristate "trusted firmware support by a TEE application"
> >> +	depends on OPTEE
> >> +	help
> >> +	  Support for trusted remote processors firmware. The firmware
> >> +	  authentication and/or decryption are managed by a trusted application.
> >> +	  This can be either built-in or a loadable module.
> >> +
> >>  endif # REMOTEPROC
> >>  
> >>  endmenu
> >> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> >> index 91314a9b43ce..fa8daebce277 100644
> >> --- a/drivers/remoteproc/Makefile
> >> +++ b/drivers/remoteproc/Makefile
> >> @@ -36,6 +36,7 @@ obj-$(CONFIG_RCAR_REMOTEPROC)		+= rcar_rproc.o
> >>  obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
> >>  obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
> >>  obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o
> >> +obj-$(CONFIG_TEE_REMOTEPROC)		+= tee_remoteproc.o
> >>  obj-$(CONFIG_TI_K3_DSP_REMOTEPROC)	+= ti_k3_dsp_remoteproc.o
> >>  obj-$(CONFIG_TI_K3_R5_REMOTEPROC)	+= ti_k3_r5_remoteproc.o
> >>  obj-$(CONFIG_XLNX_R5_REMOTEPROC)	+= xlnx_r5_remoteproc.o
> >> diff --git a/drivers/remoteproc/tee_remoteproc.c b/drivers/remoteproc/tee_remoteproc.c
> >> new file mode 100644
> >> index 000000000000..49e1e0caf889
> >> --- /dev/null
> >> +++ b/drivers/remoteproc/tee_remoteproc.c
> >> @@ -0,0 +1,393 @@
> >> +// SPDX-License-Identifier: GPL-2.0-or-later
> >> +/*
> >> + * Copyright (C) STMicroelectronics 2023 - All Rights Reserved
> >> + * Author: Arnaud Pouliquen <arnaud.pouliquen@xxxxxx>
> >> + */
> >> +
> >> +#include <linux/firmware.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/io.h>
> >> +#include <linux/module.h>
> >> +#include <linux/of_address.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/of_reserved_mem.h>
> >> +#include <linux/remoteproc.h>
> >> +#include <linux/slab.h>
> >> +#include <linux/tee_drv.h>
> >> +#include <linux/tee_remoteproc.h>
> >> +
> >> +#include "remoteproc_internal.h"
> >> +
> >> +#define MAX_TEE_PARAM_ARRY_MEMBER	4
> >> +
> >> +/*
> >> + * Authentication of the firmware and load in the remote processor memory
> >> + *
> >> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
> >> + * [in]	 params[1].memref:	buffer containing the image of the buffer
> >> + */
> >> +#define TA_RPROC_FW_CMD_LOAD_FW		1
> >> +
> >> +/*
> >> + * Start the remote processor
> >> + *
> >> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
> >> + */
> >> +#define TA_RPROC_FW_CMD_START_FW	2
> >> +
> >> +/*
> >> + * Stop the remote processor
> >> + *
> >> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
> >> + */
> >> +#define TA_RPROC_FW_CMD_STOP_FW		3
> >> +
> >> +/*
> >> + * Return the address of the resource table, or 0 if not found
> >> + * No check is done to verify that the address returned is accessible by
> >> + * the non secure context. If the resource table is loaded in a protected
> >> + * memory the access by the non secure context will lead to a data abort.
> >> + *
> >> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
> >> + * [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
> >> +
> >> +/*
> >> + * Return the address of the core dump
> >> + *
> >> + * [in]  params[0].value.a:	unique 32bit identifier of the remote processor
> >> + * [out] params[1].memref:	address of the core dump image if exist,
> >> + *				else return Null
> >> + */
> >> +#define TA_RPROC_FW_CMD_GET_COREDUMP	5
> >> +
> >> +struct tee_rproc_mem {
> >> +	char name[20];
> >> +	void __iomem *cpu_addr;
> >> +	phys_addr_t bus_addr;
> >> +	u32 dev_addr;
> >> +	size_t size;
> >> +};
> >> +
> >> +struct tee_rproc_context {
> >> +	struct list_head sessions;
> >> +	struct tee_context *tee_ctx;
> >> +	struct device *dev;
> >> +};
> >> +
> >> +static struct tee_rproc_context *tee_rproc_ctx;
> >> +
> >> +static void prepare_args(struct tee_rproc *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_ARRY_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,
> >> +	};
> >> +}
> >> +
> >> +int tee_rproc_load_fw(struct tee_rproc *trproc, const struct firmware *fw)
> >> +{
> >> +	struct tee_ioctl_invoke_arg arg;
> >> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >> +	struct tee_shm *fw_shm;
> >> +	int ret;
> >> +
> >> +	fw_shm = tee_shm_register_kernel_buf(tee_rproc_ctx->tee_ctx, (void *)fw->data, fw->size);
> >> +	if (IS_ERR(fw_shm))
> >> +		return PTR_ERR(fw_shm);
> >> +
> >> +	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(tee_rproc_ctx->tee_ctx, &arg, param);
> >> +	if (ret < 0 || arg.ret != 0) {
> >> +		dev_err(tee_rproc_ctx->dev,
> >> +			"TA_RPROC_FW_CMD_LOAD_FW invoke failed TEE err: %x, ret:%x\n",
> >> +			arg.ret, ret);
> >> +		if (!ret)
> >> +			ret = -EIO;
> >> +	}
> >> +
> >> +	tee_shm_free(fw_shm);
> >> +
> >> +	return ret;
> >> +}
> >> +EXPORT_SYMBOL_GPL(tee_rproc_load_fw);
> >> +
> >> +int rproc_tee_get_rsc_table(struct tee_rproc *trproc)
> >> +{
> >> +	struct tee_ioctl_invoke_arg arg;
> >> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >> +	struct rproc *rproc = trproc->rproc;
> >> +	size_t rsc_size;
> >> +	int ret;
> >> +
> >> +	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(tee_rproc_ctx->tee_ctx, &arg, param);
> >> +	if (ret < 0 || arg.ret != 0) {
> >> +		dev_err(tee_rproc_ctx->dev,
> >> +			"TA_RPROC_FW_CMD_GET_RSC_TABLE invoke failed TEE err: %x, ret:%x\n",
> >> +			arg.ret, ret);
> >> +		return -EIO;
> >> +	}
> >> +
> >> +	rsc_size = param[2].u.value.a;
> >> +
> >> +	/* If the size is null no resource table defined in the image */
> >> +	if (!rsc_size)
> >> +		return 0;
> >> +
> >> +	/* Store the resource table address that would be updated by the remote core . */
> >> +	trproc->rsc_va = ioremap_wc(param[1].u.value.a, rsc_size);
> >> +	if (IS_ERR_OR_NULL(trproc->rsc_va)) {
> >> +		dev_err(tee_rproc_ctx->dev, "Unable to map memory region: %lld+%zx\n",
> >> +			param[1].u.value.a, rsc_size);
> >> +		trproc->rsc_va = NULL;
> >> +		return -ENOMEM;
> >> +	}
> >> +
> >> +	/*
> >> +	 * A cached table is requested as the physical address is not mapped yet
> >> +	 * but remoteproc needs to parse the table for resources.
> >> +	 */
> >> +	rproc->cached_table = kmemdup((__force void *)trproc->rsc_va, rsc_size, GFP_KERNEL);
> >> +	if (!rproc->cached_table)
> >> +		return -ENOMEM;
> >> +
> >> +	rproc->table_ptr = rproc->cached_table;
> >> +	rproc->table_sz = rsc_size;
> >> +
> >> +	return 0;
> >> +}
> >> +EXPORT_SYMBOL_GPL(rproc_tee_get_rsc_table);
> >> +
> >> +struct resource_table *tee_rproc_get_loaded_rsc_table(struct tee_rproc *trproc)
> >> +{
> >> +	return (__force struct resource_table *)trproc->rsc_va;
> >> +}
> >> +EXPORT_SYMBOL_GPL(tee_rproc_get_loaded_rsc_table);
> >> +
> >> +int tee_rproc_start(struct tee_rproc *trproc)
> >> +{
> >> +	struct tee_ioctl_invoke_arg arg;
> >> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >> +	int ret;
> >> +
> >> +	prepare_args(trproc, TA_RPROC_FW_CMD_START_FW, &arg, param, 0);
> >> +
> >> +	ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
> >> +	if (ret < 0 || arg.ret != 0) {
> >> +		dev_err(tee_rproc_ctx->dev,
> >> +			"TA_RPROC_FW_CMD_START_FW invoke failed TEE err: %x, ret:%x\n",
> >> +			arg.ret, ret);
> >> +		if (!ret)
> >> +			ret = -EIO;
> >> +	}
> >> +
> >> +	return ret;
> >> +}
> >> +EXPORT_SYMBOL_GPL(tee_rproc_start);
> >> +
> >> +int tee_rproc_stop(struct tee_rproc *trproc)
> >> +{
> >> +	struct tee_ioctl_invoke_arg arg;
> >> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >> +	int ret;
> >> +
> >> +	prepare_args(trproc, TA_RPROC_FW_CMD_STOP_FW, &arg, param, 0);
> >> +
> >> +	ret = tee_client_invoke_func(tee_rproc_ctx->tee_ctx, &arg, param);
> >> +	if (ret < 0 || arg.ret != 0) {
> >> +		dev_err(tee_rproc_ctx->dev,
> >> +			"TA_RPROC_FW_CMD_STOP_FW invoke failed TEE err: %x, ret:%x\n",
> >> +			arg.ret, ret);
> >> +		if (!ret)
> >> +			ret = -EIO;
> >> +	}
> >> +	if (trproc->rsc_va)
> >> +		iounmap(trproc->rsc_va);
> >> +	trproc->rsc_va = NULL;
> >> +
> >> +	return ret;
> >> +}
> >> +EXPORT_SYMBOL_GPL(tee_rproc_stop);
> >> +
> >> +static const struct tee_client_device_id stm32_tee_rproc_id_table[] = {
> >> +	{UUID_INIT(0x80a4c275, 0x0a47, 0x4905,
> >> +		   0x82, 0x85, 0x14, 0x86, 0xa9, 0x77, 0x1a, 0x08)},
> >> +	{}
> >> +};
> >> +
> >> +struct tee_rproc *tee_rproc_register(struct device *dev, unsigned int rproc_id)
> >> +{
> >> +	struct tee_client_device *rproc_tee_device;
> >> +	struct tee_ioctl_open_session_arg sess_arg;
> >> +	struct tee_param param[MAX_TEE_PARAM_ARRY_MEMBER];
> >> +	struct tee_rproc *trproc;
> >> +	int ret;
> >> +
> >> +	/*
> >> +	 * The device is not probed by the TEE bus. We ignore the reason (bus could be not yet
> >> +	 * probed or service not available in the secure firmware)
> >> +	 * Assumption here is that the TEE bus is not probed.
> >> +	 */
> >> +	if (!tee_rproc_ctx)
> >> +		return ERR_PTR(-EPROBE_DEFER);
> >> +
> >> +	trproc =  devm_kzalloc(dev, sizeof(*trproc), GFP_KERNEL);
> >> +	if (!trproc)
> >> +		return ERR_PTR(-ENOMEM);
> >> +
> >> +	rproc_tee_device = to_tee_client_device(tee_rproc_ctx->dev);
> >> +	memset(&sess_arg, 0, sizeof(sess_arg));
> >> +
> >> +	/* Open session with rproc_tee load the OP-TEE Trusted Application */
> >> +	memcpy(sess_arg.uuid, rproc_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(tee_rproc_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);
> >> +		return ERR_PTR(-EINVAL);
> >> +	}
> >> +
> >> +	trproc->parent =  dev;
> >> +	trproc->rproc_id = rproc_id;
> >> +	trproc->session_id = sess_arg.session;
> >> +
> >> +	list_add_tail(&trproc->node, &tee_rproc_ctx->sessions);
> >> +
> >> +	return trproc;
> >> +}
> >> +EXPORT_SYMBOL_GPL(tee_rproc_register);
> >> +
> >> +int tee_rproc_unregister(struct tee_rproc *trproc)
> >> +{
> >> +	int ret;
> >> +
> >> +	if (!tee_rproc_ctx)
> >> +		return -ENODEV;
> >> +
> >> +	ret = tee_client_close_session(tee_rproc_ctx->tee_ctx, trproc->session_id);
> >> +	if (ret < 0)
> >> +		dev_err(trproc->parent,	"tee_client_close_session failed, err: %x\n", ret);
> >> +
> >> +	list_del(&trproc->node);
> >> +
> >> +	return ret;
> >> +}
> >> +EXPORT_SYMBOL_GPL(tee_rproc_unregister);
> >> +
> >> +static int 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 tee_rproc_probe(struct device *dev)
> >> +{
> >> +	struct tee_context *tee_ctx;
> >> +	int ret;
> >> +
> >> +	/* Only one RPROC OP-TEE device allowed */
> >> +	if (tee_rproc_ctx) {
> >> +		dev_err(dev, "An RPROC OP-TEE device was already initialized: only one allowed\n");
> >> +		return -EBUSY;
> >> +	}
> >> +
> >> +	/* Open context with TEE driver */
> >> +	tee_ctx = tee_client_open_context(NULL, tee_ctx_match, NULL, NULL);
> >> +	if (IS_ERR(tee_ctx))
> >> +		return PTR_ERR(tee_ctx);
> >> +
> >> +	tee_rproc_ctx = devm_kzalloc(dev, sizeof(*tee_ctx), GFP_KERNEL);
> >> +	if (!tee_ctx) {
> >> +		ret = -ENOMEM;
> >> +		goto err;
> >> +	}
> >> +
> >> +	tee_rproc_ctx->dev = dev;
> >> +	tee_rproc_ctx->tee_ctx = tee_ctx;
> >> +	INIT_LIST_HEAD(&tee_rproc_ctx->sessions);
> >> +
> >> +	return 0;
> >> +err:
> >> +	tee_client_close_context(tee_ctx);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static int tee_rproc_remove(struct device *dev)
> >> +{
> >> +	struct tee_rproc *entry, *tmp;
> >> +
> >> +	list_for_each_entry_safe(entry, tmp, &tee_rproc_ctx->sessions, node) {
> >> +		tee_client_close_session(tee_rproc_ctx->tee_ctx, entry->session_id);
> >> +		list_del(&entry->node);
> >> +		kfree(entry);
> >> +	}
> >> +
> >> +	tee_client_close_context(tee_rproc_ctx->tee_ctx);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +MODULE_DEVICE_TABLE(tee, stm32_tee_rproc_id_table);
> >> +
> >> +static struct tee_client_driver tee_rproc_fw_driver = {
> >> +	.id_table	= stm32_tee_rproc_id_table,
> >> +	.driver		= {
> >> +		.name		= KBUILD_MODNAME,
> >> +		.bus		= &tee_bus_type,
> >> +		.probe		= tee_rproc_probe,
> >> +		.remove		= tee_rproc_remove,
> >> +	},
> >> +};
> >> +
> >> +static int __init tee_rproc_fw_mod_init(void)
> >> +{
> >> +	return driver_register(&tee_rproc_fw_driver.driver);
> >> +}
> >> +
> >> +static void __exit tee_rproc_fw_mod_exit(void)
> >> +{
> >> +	driver_unregister(&tee_rproc_fw_driver.driver);
> >> +}
> >> +
> >> +module_init(tee_rproc_fw_mod_init);
> >> +module_exit(tee_rproc_fw_mod_exit);
> >> +
> >> +MODULE_DESCRIPTION(" TEE remote processor control driver");
> >> +MODULE_LICENSE("GPL");
> >> diff --git a/include/linux/tee_remoteproc.h b/include/linux/tee_remoteproc.h
> >> new file mode 100644
> >> index 000000000000..537d6dc3b858
> >> --- /dev/null
> >> +++ b/include/linux/tee_remoteproc.h
> >> @@ -0,0 +1,99 @@
> >> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> >> +/*
> >> + * Copyright(c) 2023 STMicroelectronics - All Rights Reserved
> >> + */
> >> +
> >> +#ifndef TEE_REMOTEPROC_H
> >> +#define TEE_REMOTEPROC_H
> >> +
> >> +#include <linux/remoteproc.h>
> >> +#include <linux/tee_drv.h>
> >> +
> >> +/**
> >> + * struct tee_rproc - TEE remoteproc structure
> >> + * @node:		Reference in list
> >> + * @rproc:		Remoteproc reference
> >> + * @parent:		Parent device
> >> + * @rproc_id:		Identifier of the target firmware
> >> + * @session_id:		TEE session identifier
> >> + * @rsc_va:		Resource table virtual address.
> >> + */
> >> +struct tee_rproc {
> >> +	struct list_head node;
> >> +	struct rproc *rproc;
> >> +	struct device *parent;
> >> +	u32 rproc_id;
> >> +	u32 session_id;
> >> +	void __iomem *rsc_va;
> >> +};
> >> +
> >> +#if IS_ENABLED(CONFIG_TEE_REMOTEPROC)
> >> +
> >> +struct tee_rproc *tee_rproc_register(struct device *dev, unsigned int rproc_id);
> >> +int tee_rproc_unregister(struct tee_rproc *trproc);
> >> +
> >> +int tee_rproc_load_fw(struct tee_rproc *trproc, const struct firmware *fw);
> >> +int rproc_tee_get_rsc_table(struct tee_rproc *trproc);
> > 
> > Shouldn't this be tee_rproc_get_rsc_table()?  Why the exception?
> 
> No reason, just a miss during concatenation of patches to prepare the series.
> I will change this.
> 
> > 
> >> +struct resource_table *tee_rproc_get_loaded_rsc_table(struct tee_rproc *trproc);
> >> +int tee_rproc_start(struct tee_rproc *trproc);
> >> +int tee_rproc_stop(struct tee_rproc *trproc);
> >> +
> >> +#else
> >> +
> >> +static inline struct tee_rproc *tee_rproc_register(struct device *dev, unsigned int rproc_id)
> >> +{
> >> +	return ERR_PTR(-ENODEV);
> >> +}
> >> +
> >> +static inline int tee_rproc_unregister(struct tee_rproc *trproc)
> >> +{
> >> +	/* This shouldn't be possible */
> > 
> > Why can't this be possible?  Looking at the Kconfig file it seems entirely
> > plausible to compile stm32_rproc without TEE_REMOTEPROC...
> 
> This sentence is copied from rpmsg.h [1]. It is not possible to call the API if
> the TEE_REMOTEPROC is not set, as an error is returned by tee_rproc_register.

Yes, I see.  I agree with your assessment.

> Therefore, we should not fall into a state where we call this API or another one.
> 
> [1]https://elixir.bootlin.com/linux/v6.7.1/source/include/linux/rpmsg.h#L218
> 
> Thanks,
> Arnaud
> 
> > 
> > More comments to come tomorrow or on Monday.
> > 
> > Thanks,
> > Mathieu
> > 
> >> +	WARN_ON(1);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static inline int tee_rproc_load_fw(struct tee_rproc *trproc,
> >> +				    const struct firmware *fw)
> >> +{
> >> +	/* This shouldn't be possible */
> >> +	WARN_ON(1);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static inline int tee_rproc_start(struct tee_rproc *trproc)
> >> +{
> >> +	/* This shouldn't be possible */
> >> +	WARN_ON(1);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static inline int tee_rproc_stop(struct tee_rproc *trproc)
> >> +{
> >> +	/* This shouldn't be possible */
> >> +	WARN_ON(1);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static inline int rproc_tee_get_rsc_table(struct tee_rproc *trproc)
> >> +{
> >> +	/* This shouldn't be possible */
> >> +	WARN_ON(1);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static inline struct resource_table *
> >> +	tee_rproc_get_loaded_rsc_table(struct tee_rproc *trproc)
> >> +{
> >> +	/* This shouldn't be possible */
> >> +	WARN_ON(1);
> >> +
> >> +	return NULL;
> >> +}
> >> +
> >> +#endif /* CONFIG_TEE_REMOTEPROC */
> >> +#endif /* TEE_REMOTEPROC_H */
> >> -- 
> >> 2.25.1
> >>