[U-Boot] [PATCH] sunxi: improve throughput in the sunxi_mmc driver

[Maxime Ripard]

On Fri, Apr 06, 2018 at 07:54:47AM +0200, Maxime Ripard wrote:
> Hi Jaehoon,
> 
> On Wed, Mar 21, 2018 at 12:18:58PM +0100, Maxime Ripard wrote:
> > From: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> > 
> > Throughput tests have shown the sunxi_mmc driver to take over 10s to
> > read 10MB from a fast eMMC device due to excessive delays in polling
> > loops.
> > 
> > This commit restructures the main polling loops to use get_timer(...)
> > to determine whether a (millisecond) timeout has expired.  We choose
> > not to use the wait_bit function, as we don't need interruptability
> > with ctrl-c and have at least one case where two bits (one for an
> > error condition and another one for completion) need to be read and
> > using wait_bit would have not added to the clarity.
> > 
> > The observed speedup in testing on a A31 is greater than 10x (e.g. a
> > 10MB write decreases from 9.302s to 0.884s).
> > 
> > Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> > Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
> 
> Any chance we can merge this for the next release?

Ping?

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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