1.. SPDX-License-Identifier: GPL-2.0
2
3Crypto Engine
4=============
5
6Overview
7--------
8The crypto engine (CE) API is a crypto queue manager.
9
10Requirement
11-----------
12You must put, at the start of your transform context your_tfm_ctx, the structure
13crypto_engine:
14
15::
16
17	struct your_tfm_ctx {
18		struct crypto_engine engine;
19		...
20	};
21
22The crypto engine only manages asynchronous requests in the form of
23crypto_async_request. It cannot know the underlying request type and thus only
24has access to the transform structure. It is not possible to access the context
25using container_of. In addition, the engine knows nothing about your
26structure "``struct your_tfm_ctx``". The engine assumes (requires) the placement
27of the known member ``struct crypto_engine`` at the beginning.
28
29Order of operations
30-------------------
31You are required to obtain a struct crypto_engine via ``crypto_engine_alloc_init()``.
32Start it via ``crypto_engine_start()``. When finished with your work, shut down the
33engine using ``crypto_engine_stop()`` and destroy the engine with
34``crypto_engine_exit()``.
35
36Before transferring any request, you have to fill the context enginectx by
37providing functions for the following:
38
39* ``prepare_crypt_hardware``: Called once before any prepare functions are
40  called.
41
42* ``unprepare_crypt_hardware``: Called once after all unprepare functions have
43  been called.
44
45* ``prepare_cipher_request``/``prepare_hash_request``: Called before each
46  corresponding request is performed. If some processing or other preparatory
47  work is required, do it here.
48
49* ``unprepare_cipher_request``/``unprepare_hash_request``: Called after each
50  request is handled. Clean up / undo what was done in the prepare function.
51
52* ``cipher_one_request``/``hash_one_request``: Handle the current request by
53  performing the operation.
54
55Note that these functions access the crypto_async_request structure
56associated with the received request. You are able to retrieve the original
57request by using:
58
59::
60
61	container_of(areq, struct yourrequesttype_request, base);
62
63When your driver receives a crypto_request, you must to transfer it to
64the crypto engine via one of:
65
66* crypto_transfer_aead_request_to_engine()
67
68* crypto_transfer_akcipher_request_to_engine()
69
70* crypto_transfer_hash_request_to_engine()
71
72* crypto_transfer_skcipher_request_to_engine()
73
74At the end of the request process, a call to one of the following functions is needed:
75
76* crypto_finalize_aead_request()
77
78* crypto_finalize_akcipher_request()
79
80* crypto_finalize_hash_request()
81
82* crypto_finalize_skcipher_request()
83