crypto: doc - Fix formatting of new crypto engine content

Tidy up the formatting/grammar in crypto_engine.rst. Use bulleted lists
where appropriate.

Signed-off-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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;
-        ...
-  };
+::
 
-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.
+	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 have to obtain a struct crypto_engine via crypto_engine_alloc_init().
-And start it via crypto_engine_start().
+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 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
+Before transferring any request, you have to fill the context enginectx by
+providing functions for the following:
 
-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);
+* ``prepare_crypt_hardware``: Called once before any prepare functions are
+  called.
 
-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()
+* ``unprepare_crypt_hardware``: Called once after all unprepare functions have
+  been called.
 
-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
+* ``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()