diff options
Diffstat (limited to 'Documentation/crypto/crypto_engine.rst')
| -rw-r--r-- | Documentation/crypto/crypto_engine.rst | 111 |
1 files changed, 73 insertions, 38 deletions
diff --git a/Documentation/crypto/crypto_engine.rst b/Documentation/crypto/crypto_engine.rst index 1d56221dfe35..236c674d6897 100644 --- a/Documentation/crypto/crypto_engine.rst +++ b/Documentation/crypto/crypto_engine.rst @@ -1,50 +1,85 @@ -============= -CRYPTO ENGINE +.. SPDX-License-Identifier: GPL-2.0 +Crypto Engine ============= Overview -------- -The crypto engine API (CE), is a crypto queue manager. +The crypto engine (CE) API is a crypto queue manager. Requirement ----------- -You have to put at start of your tfm_ctx the struct crypto_engine_ctx:: +You must put, at the start of your transform context your_tfm_ctx, the structure +crypto_engine: + +:: - struct your_tfm_ctx { - struct crypto_engine_ctx enginectx; - ... - }; + struct your_tfm_ctx { + struct crypto_engine engine; + ... + }; -Why: Since CE manage only crypto_async_request, it cannot know the underlying -request_type and so have access only on the TFM. -So using container_of for accessing __ctx is impossible. -Furthermore, the crypto engine cannot know the "struct your_tfm_ctx", -so it must assume that crypto_engine_ctx is at start of it. +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 have to obtain a struct crypto_engine via crypto_engine_alloc_init(). -And start it via crypto_engine_start(). - -Before transferring any request, you have to fill the enginectx. -- prepare_request: (taking a function pointer) If you need to do some processing before doing the request -- unprepare_request: (taking a function pointer) Undoing what's done in prepare_request -- do_one_request: (taking a function pointer) Do encryption for current request - -Note: that those three functions get the crypto_async_request associated with the received request. -So your need to get the original request via container_of(areq, struct yourrequesttype_request, base); - -When your driver receive a crypto_request, you have to transfer it to -the cryptoengine via one of: -- crypto_transfer_ablkcipher_request_to_engine() -- crypto_transfer_aead_request_to_engine() -- crypto_transfer_akcipher_request_to_engine() -- crypto_transfer_hash_request_to_engine() -- crypto_transfer_skcipher_request_to_engine() - -At the end of the request process, a call to one of the following function is needed: -- crypto_finalize_ablkcipher_request -- crypto_finalize_aead_request -- crypto_finalize_akcipher_request -- crypto_finalize_hash_request -- crypto_finalize_skcipher_request +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_ablkcipher_request_to_engine() + +* crypto_transfer_aead_request_to_engine() + +* crypto_transfer_akcipher_request_to_engine() + +* crypto_transfer_hash_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_ablkcipher_request() + +* crypto_finalize_aead_request() + +* crypto_finalize_akcipher_request() + +* crypto_finalize_hash_request() + +* crypto_finalize_skcipher_request() |