1.. SPDX-License-Identifier: GPL-2.0
2Crypto Engine
3=============
4
5Overview
6--------
7The crypto engine (CE) API is a crypto queue manager.
8
9Requirement
10-----------
11You must put, at the start of your transform context your_tfm_ctx, the structure
12crypto_engine:
13
14::
15
16	struct your_tfm_ctx {
17		struct crypto_engine engine;
18		...
19	};
20
21The crypto engine only manages asynchronous requests in the form of
22crypto_async_request. It cannot know the underlying request type and thus only
23has access to the transform structure. It is not possible to access the context
24using container_of. In addition, the engine knows nothing about your
25structure "``struct your_tfm_ctx``". The engine assumes (requires) the placement
26of the known member ``struct crypto_engine`` at the beginning.
27
28Order of operations
29-------------------
30You are required to obtain a struct crypto_engine via ``crypto_engine_alloc_init()``.
31Start it via ``crypto_engine_start()``. When finished with your work, shut down the
32engine using ``crypto_engine_stop()`` and destroy the engine with
33``crypto_engine_exit()``.
34
35Before transferring any request, you have to fill the context enginectx by
36providing functions for the following:
37
38* ``prepare_crypt_hardware``: Called once before any prepare functions are
39  called.
40
41* ``unprepare_crypt_hardware``: Called once after all unprepare functions have
42  been called.
43
44* ``prepare_cipher_request``/``prepare_hash_request``: Called before each
45  corresponding request is performed. If some processing or other preparatory
46  work is required, do it here.
47
48* ``unprepare_cipher_request``/``unprepare_hash_request``: Called after each
49  request is handled. Clean up / undo what was done in the prepare function.
50
51* ``cipher_one_request``/``hash_one_request``: Handle the current request by
52  performing the operation.
53
54Note that these functions access the crypto_async_request structure
55associated with the received request. You are able to retrieve the original
56request by using:
57
58::
59
60	container_of(areq, struct yourrequesttype_request, base);
61
62When your driver receives a crypto_request, you must to transfer it to
63the crypto engine via one of:
64
65* crypto_transfer_ablkcipher_request_to_engine()
66
67* crypto_transfer_aead_request_to_engine()
68
69* crypto_transfer_akcipher_request_to_engine()
70
71* crypto_transfer_hash_request_to_engine()
72
73* crypto_transfer_skcipher_request_to_engine()
74
75At the end of the request process, a call to one of the following functions is needed:
76
77* crypto_finalize_ablkcipher_request()
78
79* crypto_finalize_aead_request()
80
81* crypto_finalize_akcipher_request()
82
83* crypto_finalize_hash_request()
84
85* crypto_finalize_skcipher_request()
86