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author | Daniel Thompson <daniel.thompson@linaro.org> | 2018-06-05 09:55:20 +0100 |
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committer | Nico Huber <nico.h@gmx.de> | 2018-08-17 21:16:57 +0000 |
commit | 455a6fc86e833d1165c68d9dbaef8b0188875bc5 (patch) | |
tree | d362e9f7fe5096e83b1c3df9d3ee0d4c225017fc /flashchips.c | |
parent | b623f403a00a6ce796fe632d4c1ff3fc4f5a5e40 (diff) | |
download | flashrom-455a6fc86e833d1165c68d9dbaef8b0188875bc5.tar.gz flashrom-455a6fc86e833d1165c68d9dbaef8b0188875bc5.tar.bz2 flashrom-455a6fc86e833d1165c68d9dbaef8b0188875bc5.zip |
bitbang_spi: Add half-duplex optimizations
Currently, the core of bitbang_spi is a full-duplex SPI loop but in
practice this code is only ever used half-duplex. Spliting this code
into two half duplex loops allows us to optimize performance by reducing
communications and/or CPU pipeline stalls.
The speed up varies depending on how much the overhead of
getting/setting pins dominates execution time. For a USB bit bang driver
running on a 7th generation Core i5, the time to probe drops from ~7.7
seconds to ~6.7 seconds when this patch is applied.
Change-Id: I33b9f363716f651146c09113bda5fffe53b16738
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-on: https://review.coreboot.org/26947
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Diffstat (limited to 'flashchips.c')
0 files changed, 0 insertions, 0 deletions