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

[Joel Fernandes]

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
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(-)

-- 
1.7.9.5