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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Driver for Qualcomm Secure Execution Environment (SEE) interface (QSEECOM).
* Responsible for setting up and managing QSEECOM client devices.
*
* Copyright (C) 2023 Maximilian Luz <luzmaximilian@gmail.com>
*/
#ifndef __QCOM_QSEECOM_H
#define __QCOM_QSEECOM_H
#include <linux/auxiliary_bus.h>
#include <linux/dma-mapping.h>
#include <linux/types.h>
#include <linux/firmware/qcom/qcom_scm.h>
/**
* struct qseecom_client - QSEECOM client device.
* @aux_dev: Underlying auxiliary device.
* @app_id: ID of the loaded application.
*/
struct qseecom_client {
struct auxiliary_device aux_dev;
u32 app_id;
};
/**
* qseecom_scm_dev() - Get the SCM device associated with the QSEECOM client.
* @client: The QSEECOM client device.
*
* Returns the SCM device under which the provided QSEECOM client device
* operates. This function is intended to be used for DMA allocations.
*/
static inline struct device *qseecom_scm_dev(struct qseecom_client *client)
{
return client->aux_dev.dev.parent->parent;
}
/**
* qseecom_dma_alloc() - Allocate DMA memory for a QSEECOM client.
* @client: The QSEECOM client to allocate the memory for.
* @size: The number of bytes to allocate.
* @dma_handle: Pointer to where the DMA address should be stored.
* @gfp: Allocation flags.
*
* Wrapper function for dma_alloc_coherent(), allocating DMA memory usable for
* TZ/QSEECOM communication. Refer to dma_alloc_coherent() for details.
*/
static inline void *qseecom_dma_alloc(struct qseecom_client *client, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
return dma_alloc_coherent(qseecom_scm_dev(client), size, dma_handle, gfp);
}
/**
* dma_free_coherent() - Free QSEECOM DMA memory.
* @client: The QSEECOM client for which the memory has been allocated.
* @size: The number of bytes allocated.
* @cpu_addr: Virtual memory address to free.
* @dma_handle: DMA memory address to free.
*
* Wrapper function for dma_free_coherent(), freeing memory previously
* allocated with qseecom_dma_alloc(). Refer to dma_free_coherent() for
* details.
*/
static inline void qseecom_dma_free(struct qseecom_client *client, size_t size,
void *cpu_addr, dma_addr_t dma_handle)
{
return dma_free_coherent(qseecom_scm_dev(client), size, cpu_addr, dma_handle);
}
/**
* qcom_qseecom_app_send() - Send to and receive data from a given QSEE app.
* @client: The QSEECOM client associated with the target app.
* @req: Request buffer sent to the app (must be TZ memory).
* @req_size: Size of the request buffer.
* @rsp: Response buffer, written to by the app (must be TZ memory).
* @rsp_size: Size of the response buffer.
*
* Sends a request to the QSEE app associated with the given client and read
* back its response. The caller must provide two DMA memory regions, one for
* the request and one for the response, and fill out the @req region with the
* respective (app-specific) request data. The QSEE app reads this and returns
* its response in the @rsp region.
*
* Note: This is a convenience wrapper around qcom_scm_qseecom_app_send().
* Clients should prefer to use this wrapper.
*
* Return: Zero on success, nonzero on failure.
*/
static inline int qcom_qseecom_app_send(struct qseecom_client *client,
void *req, size_t req_size,
void *rsp, size_t rsp_size)
{
return qcom_scm_qseecom_app_send(client->app_id, req, req_size, rsp, rsp_size);
}
#endif /* __QCOM_QSEECOM_H */
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