kernel-aes67/drivers/dma
Dan Williams b2f46fd8ef async_tx: add support for asynchronous GF multiplication
[ Based on an original patch by Yuri Tikhonov ]

This adds support for doing asynchronous GF multiplication by adding
two additional functions to the async_tx API:

 async_gen_syndrome() does simultaneous XOR and Galois field
    multiplication of sources.

 async_syndrome_val() validates the given source buffers against known P
    and Q values.

When a request is made to run async_pq against more than the hardware
maximum number of supported sources we need to reuse the previous
generated P and Q values as sources into the next operation.  Care must
be taken to remove Q from P' and P from Q'.  For example to perform a 5
source pq op with hardware that only supports 4 sources at a time the
following approach is taken:

p, q = PQ(src0, src1, src2, src3, COEF({01}, {02}, {04}, {08}))
p', q' = PQ(p, q, q, src4, COEF({00}, {01}, {00}, {10}))

p' = p + q + q + src4 = p + src4
q' = {00}*p + {01}*q + {00}*q + {10}*src4 = q + {10}*src4

Note: 4 is the minimum acceptable maxpq otherwise we punt to
synchronous-software path.

The DMA_PREP_CONTINUE flag indicates to the driver to reuse p and q as
sources (in the above manner) and fill the remaining slots up to maxpq
with the new sources/coefficients.

Note1: Some devices have native support for P+Q continuation and can skip
this extra work.  Devices with this capability can advertise it with
dma_set_maxpq.  It is up to each driver how to handle the
DMA_PREP_CONTINUE flag.

Note2: The api supports disabling the generation of P when generating Q,
this is ignored by the synchronous path but is implemented by some dma
devices to save unnecessary writes.  In this case the continuation
algorithm is simplified to only reuse Q as a source.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Ilya Yanok <yanok@emcraft.com>
Reviewed-by: Andre Noll <maan@systemlinux.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-08-29 19:09:27 -07:00
..
ipu dma: Add SoF and EoF debugging to ipu_idmac.c, minor cleanup 2009-04-02 16:59:10 -07:00
dmaengine.c async_tx: add support for asynchronous GF multiplication 2009-08-29 19:09:27 -07:00
dmatest.c dmatest: add dma interrupts and callbacks 2009-03-25 09:13:25 -07:00
dw_dmac_regs.h dw_dmac: add cyclic API to DW DMA driver 2009-04-01 15:42:34 -07:00
dw_dmac.c dw_dmac: add cyclic API to DW DMA driver 2009-04-01 15:42:34 -07:00
fsldma.c dmaengine: initialize tx_list in dma_async_tx_descriptor_init 2009-03-25 09:13:24 -07:00
fsldma.h fsldma: allow Freescale Elo DMA driver to be compiled as a module 2008-09-26 17:00:11 -07:00
ioat_dca.c I/OAT: update driver version and copyright dates 2009-03-04 16:04:40 -07:00
ioat_dma.c dmaengine: initialize tx_list in dma_async_tx_descriptor_init 2009-03-25 09:13:24 -07:00
ioat.c I/OAT: update driver version and copyright dates 2009-03-04 16:04:40 -07:00
ioatdma_hw.h I/OAT: update driver version and copyright dates 2009-03-04 16:04:40 -07:00
ioatdma_registers.h I/OAT: update driver version and copyright dates 2009-03-04 16:04:40 -07:00
ioatdma.h I/OAT: update driver version and copyright dates 2009-03-04 16:04:40 -07:00
iop-adma.c async_tx: add support for asynchronous GF multiplication 2009-08-29 19:09:27 -07:00
iovlock.c [2/4] I/OAT: fix dma_pin_iovec_pages() error handling 2008-11-10 15:00:56 -08:00
Kconfig async_xor: permit callers to pass in a 'dma/page scribble' region 2009-06-03 14:22:28 -07:00
Makefile i.MX31: Image Processing Unit DMA and IRQ drivers 2009-01-19 15:36:21 -07:00
mv_xor.c dmaengine: initialize tx_list in dma_async_tx_descriptor_init 2009-03-25 09:13:24 -07:00
mv_xor.h dmaengine: DMA engine driver for Marvell XOR engine 2008-07-08 11:58:36 -07:00