Subject: [PATCH 00/10] crypto: omap-aes: DMA and PIO mode improvements

From: [email-masked] (Joel Fernandes)
Date: Wed, 14 Aug 2013 18:30:47 -0500

On 08/14/2013 06:12 PM, Joel Fernandes wrote:
> This patch series is a rewrite of the DMA portion of omap-aes driver
> and also adds support for PIO mode. Both these modes, give better
> performance than before.
> 
> Earlier, only a single SG was used for DMA purpose, and the SG-list
> passed from the crypto layer was being copied and DMA'd one entry at
> a time. This turns out to be quite inefficient, so we replace it with
> much simpler code that directly passes the SG-list from crypto to the
> DMA layer.
> 
> We also add PIO mode support to the driver, and switch to PIO mode
> whenever the DMA channel allocation is not available. This is only for
> OMAP4 platform will work on any platform on which IRQ information is
> populated.
> 
> Tests performed on am33xx and omap4 SoCs , notice the 50% perf improvement

Just correcting, this is more like 35% not 50% when using DMA.

Thanks,

-Joel

> for large 8K blocks:
> 
> Sample run on am33xx (beaglebone):
> With DMA rewrite:
> [   26.410052] test 0 (128 bit key, 16 byte blocks): 4318 operations in 1 seconds (69088 bytes)
> [   27.414314] test 1 (128 bit key, 64 byte blocks): 4360 operations in 1 seconds (279040 bytes)
> [   28.414406] test 2 (128 bit key, 256 byte blocks): 3609 operations in 1 seconds (923904 bytes)
> [   29.414410] test 3 (128 bit key, 1024 byte blocks): 3418 operations in 1 seconds (3500032 bytes)
> [   30.414510] test 4 (128 bit key, 8192 byte blocks): 1766 operations in 1 seconds (14467072 bytes)
> 
> Without DMA rewrite:
> [   31.920519] test 0 (128 bit key, 16 byte blocks): 4417 operations in 1 seconds (70672 bytes)
> [   32.925997] test 1 (128 bit key, 64 byte blocks): 4221 operations in 1 seconds (270144 bytes)
> [   33.926194] test 2 (128 bit key, 256 byte blocks): 3528 operations in 1 seconds (903168 bytes)
> [   34.926225] test 3 (128 bit key, 1024 byte blocks): 3281 operations in 1 seconds (3359744 bytes)
> [   35.926385] test 4 (128 bit key, 8192 byte blocks): 1460 operations in 1 seconds (11960320 bytes)
> 
> With PIO mode, note the tremndous boost in performance for small blocks there:
> [   27.294905] test 0 (128 bit key, 16 byte blocks): 20585 operations in 1 seconds (329360 bytes)
> [   28.302282] test 1 (128 bit key, 64 byte blocks): 8106 operations in 1 seconds (518784 bytes)
> [   29.302374] test 2 (128 bit key, 256 byte blocks): 2359 operations in 1 seconds (603904 bytes)
> [   30.302575] test 3 (128 bit key, 1024 byte blocks): 605 operations in 1 seconds (619520 bytes)
> [   31.303781] test 4 (128 bit key, 8192 byte blocks): 79 operations in 1 seconds (647168 bytes)
> 
> Future work in this direction would be to dynamically change between
> PIO/DMA mode based on the block size.
> 
> Joel Fernandes (10):
>   crypto: scatterwalk:  Add support for calculating number of SG
>     elements
>   crypto: omap-aes: Add useful debug macros
>   crypto: omap-aes: Populate number of SG elements
>   crypto: omap-aes: Simplify DMA usage by using direct SGs
>   crypto: omap-aes: Sync SG before DMA operation
>   crypto: omap-aes: Remove previously used intermediate buffers
>   crypto: omap-aes: Add IRQ info and helper macros
>   crypto: omap-aes: PIO mode: Add IRQ handler and walk SGs
>   crypto: omap-aes: PIO mode: platform data for OMAP4 and trigger it
>   crypto: omap-aes: Switch to PIO mode in probe function
> 
>  crypto/scatterwalk.c         |   22 +++
>  drivers/crypto/omap-aes.c    |  400 ++++++++++++++++++++----------------------
>  include/crypto/scatterwalk.h |    2 +
>  3 files changed, 217 insertions(+), 207 deletions(-)
>