kernel-ark/Documentation/crypto/crypto_engine.rst
Prabhjot Khurana 1730c5aa3b crypto: engine - Add KPP Support to Crypto Engine
Add KPP support to the crypto engine queue manager, so that it can be
used to simplify the logic of KPP device drivers as done for other
crypto drivers.

Signed-off-by: Prabhjot Khurana <prabhjot.khurana@intel.com>
Signed-off-by: Daniele Alessandrelli <daniele.alessandrelli@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-10-29 21:04:03 +08:00

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.. SPDX-License-Identifier: GPL-2.0
Crypto Engine
=============
Overview
--------
The crypto engine (CE) API is a crypto queue manager.
Requirement
-----------
You must put, at the start of your transform context your_tfm_ctx, the structure
crypto_engine:
::
struct your_tfm_ctx {
struct crypto_engine engine;
...
};
The crypto engine only manages asynchronous requests in the form of
crypto_async_request. It cannot know the underlying request type and thus only
has access to the transform structure. It is not possible to access the context
using container_of. In addition, the engine knows nothing about your
structure "``struct your_tfm_ctx``". The engine assumes (requires) the placement
of the known member ``struct crypto_engine`` at the beginning.
Order of operations
-------------------
You are required to obtain a struct crypto_engine via ``crypto_engine_alloc_init()``.
Start it via ``crypto_engine_start()``. When finished with your work, shut down the
engine using ``crypto_engine_stop()`` and destroy the engine with
``crypto_engine_exit()``.
Before transferring any request, you have to fill the context enginectx by
providing functions for the following:
* ``prepare_crypt_hardware``: Called once before any prepare functions are
called.
* ``unprepare_crypt_hardware``: Called once after all unprepare functions have
been called.
* ``prepare_cipher_request``/``prepare_hash_request``: Called before each
corresponding request is performed. If some processing or other preparatory
work is required, do it here.
* ``unprepare_cipher_request``/``unprepare_hash_request``: Called after each
request is handled. Clean up / undo what was done in the prepare function.
* ``cipher_one_request``/``hash_one_request``: Handle the current request by
performing the operation.
Note that these functions access the crypto_async_request structure
associated with the received request. You are able to retrieve the original
request by using:
::
container_of(areq, struct yourrequesttype_request, base);
When your driver receives a crypto_request, you must to transfer it to
the crypto engine via one of:
* crypto_transfer_aead_request_to_engine()
* crypto_transfer_akcipher_request_to_engine()
* crypto_transfer_hash_request_to_engine()
* crypto_transfer_kpp_request_to_engine()
* crypto_transfer_skcipher_request_to_engine()
At the end of the request process, a call to one of the following functions is needed:
* crypto_finalize_aead_request()
* crypto_finalize_akcipher_request()
* crypto_finalize_hash_request()
* crypto_finalize_kpp_request()
* crypto_finalize_skcipher_request()