Re: [PATCH 0/2] crypto: add new driver for Marvell CESA

[Sebastian Hesselbarth]

On 09.04.2015 16:58, Boris Brezillon wrote:
> This is an attempt to replace the mv_cesa driver by a new one to address
> some limitations of the existing driver.
>  From a performance and CPU load point of view the most important
> limitation is the lack of DMA support, thus preventing us from chaining
> crypto operations.
>
> I know we usually try to adapt existing drivers instead of replacing them
> by new ones, but after trying to refactor the mv_cesa driver I realized it
> would take longer than writing an new one from scratch.

Boris,

if you include a bunch of performance measurements, I guess it will help
you to get an agreement of replacing the driver instead of reworking it.

> Here are the main features brought by this new driver:
> - support for armada SoCs (up to 38x) while keeping support for older ones
>    (Orion and Kirkwood)

Unfortunately, the list above is missing Dove SoCs which also have a
CESA engine with TDMA support. I checked the registers _very_ quickly
but it seems that they are compatible with Kirkwood's CESA.

> - DMA mode to offload the CPU in case of intensive crypto usage
> - new algorithms: SHA256, DES and 3DES
[...]
> Boris Brezillon (2):
>    crypto: add new driver for Marvell CESA
>    crypto: marvell/CESA: update DT bindings documentation

IMHO, the patch set should be split up in:
- new core driver
- add support for TDMA on platforms that support it
- new cipher algorithms
- removal of old mv_cesa

I'd love to test on Dove, but time still is very limited. I guess the
patches will receive another round anyway, maybe I find some until the
final version.

Sebastian

>   .../devicetree/bindings/crypto/mv_cesa.txt         |   50 +-
>   drivers/crypto/Kconfig                             |    2 +
>   drivers/crypto/Makefile                            |    2 +-
>   drivers/crypto/marvell/Makefile                    |    1 +
>   drivers/crypto/marvell/cesa.c                      |  539 ++++++++
>   drivers/crypto/marvell/cesa.h                      |  802 ++++++++++++
>   drivers/crypto/marvell/cipher.c                    |  761 +++++++++++
>   drivers/crypto/marvell/hash.c                      | 1349 ++++++++++++++++++++
>   drivers/crypto/marvell/tdma.c                      |  223 ++++
>   drivers/crypto/mv_cesa.c                           | 1193 -----------------
>   drivers/crypto/mv_cesa.h                           |  150 ---
>   11 files changed, 3716 insertions(+), 1356 deletions(-)
>   create mode 100644 drivers/crypto/marvell/Makefile
>   create mode 100644 drivers/crypto/marvell/cesa.c
>   create mode 100644 drivers/crypto/marvell/cesa.h
>   create mode 100644 drivers/crypto/marvell/cipher.c
>   create mode 100644 drivers/crypto/marvell/hash.c
>   create mode 100644 drivers/crypto/marvell/tdma.c
>   delete mode 100644 drivers/crypto/mv_cesa.c
>   delete mode 100644 drivers/crypto/mv_cesa.h

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