Due to a lack of alignment in the data sent by requests, the actual DMA
support of the STM32 hash driver is only working with digest calls.
This patch, based on the algorithm used in the driver omap-sham.c,
allows for the usage of DMA in any situation.

It has been functionally tested on STM32MP15, STM32MP13 and STM32MP25.

By checking the performance of this new driver with OpenSSL, the
following results were found:

Performance:

(datasize: 4096, number of hashes performed in 10s)

|type   |no DMA    |DMA support|software  |
|-------|----------|-----------|----------|
|md5    |13873.56k |10958.03k  |71163.08k |
|sha1   |13796.15k |10729.47k  |39670.58k |
|sha224 |13737.98k |10775.76k  |22094.64k |
|sha256 |13655.65k |10872.01k  |22075.39k |

CPU Usage:

(algorithm used: sha256, computation time: 20s, measurement taken at
~10s)

|datasize  |no DMA |DMA  | software |
|----------|-------|-----|----------|
|  2048    | 56%   | 49% | 50%      |
|  4096    | 54%   | 46% | 50%      |
|  8192    | 53%   | 40% | 50%      |
| 16384    | 53%   | 33% | 50%      |

Note: this update doesn't change the driver performance without DMA.

As shown, performance with DMA is slightly lower than without, but in
most cases, it will save CPU time.
Signed-off-by: Maxime Méré <maxime.mere@foss.st.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>