1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3 * Driver for Qualcomm Secure Execution Environment (SEE) interface (QSEECOM).
4 * Responsible for setting up and managing QSEECOM client devices.
5 *
6 * Copyright (C) 2023 Maximilian Luz <luzmaximilian@gmail.com>
7 */
8
9 #ifndef __QCOM_QSEECOM_H
10 #define __QCOM_QSEECOM_H
11
12 #include <linux/auxiliary_bus.h>
13 #include <linux/dma-mapping.h>
14 #include <linux/types.h>
15
16 #include <linux/firmware/qcom/qcom_scm.h>
17
18 /**
19 * struct qseecom_client - QSEECOM client device.
20 * @aux_dev: Underlying auxiliary device.
21 * @app_id: ID of the loaded application.
22 */
23 struct qseecom_client {
24 struct auxiliary_device aux_dev;
25 u32 app_id;
26 };
27
28 /**
29 * qseecom_scm_dev() - Get the SCM device associated with the QSEECOM client.
30 * @client: The QSEECOM client device.
31 *
32 * Returns the SCM device under which the provided QSEECOM client device
33 * operates. This function is intended to be used for DMA allocations.
34 */
35 static inline struct device *qseecom_scm_dev(struct qseecom_client *client)
36 {
37 return client->aux_dev.dev.parent->parent;
38 }
39
40 /**
41 * qseecom_dma_alloc() - Allocate DMA memory for a QSEECOM client.
42 * @client: The QSEECOM client to allocate the memory for.
43 * @size: The number of bytes to allocate.
44 * @dma_handle: Pointer to where the DMA address should be stored.
45 * @gfp: Allocation flags.
46 *
47 * Wrapper function for dma_alloc_coherent(), allocating DMA memory usable for
48 * TZ/QSEECOM communication. Refer to dma_alloc_coherent() for details.
49 */
50 static inline void *qseecom_dma_alloc(struct qseecom_client *client, size_t size,
51 dma_addr_t *dma_handle, gfp_t gfp)
52 {
53 return dma_alloc_coherent(qseecom_scm_dev(client), size, dma_handle, gfp);
54 }
55
56 /**
57 * dma_free_coherent() - Free QSEECOM DMA memory.
58 * @client: The QSEECOM client for which the memory has been allocated.
59 * @size: The number of bytes allocated.
60 * @cpu_addr: Virtual memory address to free.
61 * @dma_handle: DMA memory address to free.
62 *
63 * Wrapper function for dma_free_coherent(), freeing memory previously
64 * allocated with qseecom_dma_alloc(). Refer to dma_free_coherent() for
65 * details.
66 */
67 static inline void qseecom_dma_free(struct qseecom_client *client, size_t size,
68 void *cpu_addr, dma_addr_t dma_handle)
69 {
70 return dma_free_coherent(qseecom_scm_dev(client), size, cpu_addr, dma_handle);
71 }
72
73 /**
74 * qcom_qseecom_app_send() - Send to and receive data from a given QSEE app.
75 * @client: The QSEECOM client associated with the target app.
76 * @req: Request buffer sent to the app (must be TZ memory).
77 * @req_size: Size of the request buffer.
78 * @rsp: Response buffer, written to by the app (must be TZ memory).
79 * @rsp_size: Size of the response buffer.
80 *
81 * Sends a request to the QSEE app associated with the given client and read
82 * back its response. The caller must provide two DMA memory regions, one for
83 * the request and one for the response, and fill out the @req region with the
84 * respective (app-specific) request data. The QSEE app reads this and returns
85 * its response in the @rsp region.
86 *
87 * Note: This is a convenience wrapper around qcom_scm_qseecom_app_send().
88 * Clients should prefer to use this wrapper.
89 *
90 * Return: Zero on success, nonzero on failure.
91 */
92 static inline int qcom_qseecom_app_send(struct qseecom_client *client,
93 void *req, size_t req_size,
94 void *rsp, size_t rsp_size)
95 {
96 return qcom_scm_qseecom_app_send(client->app_id, req, req_size, rsp, rsp_size);
97 }
98
99 #endif /* __QCOM_QSEECOM_H */
100
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