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Xiaolei Li 42d13a09ef mtd: rawnand: mtk: Improve data sampling timing for read cycle
Currently, we expand RE# low level time by choosing the max value
between RE# pulse width and RE# access time, and sample data at the
rising edge of RE#.

Then, if RE# access time is bigger than RE# pulse width, the real
read cycle time may be more than NAND SPEC required. This makes
read performance be worse than that expected.

This patch improves data sampling timing by calculating RE# low level
time according to RE# pulse width. If RE# access time is bigger than
RE# pulse width, then delay sampling data timing.

The result of contrast test base on MT2712 evaluat board is as follow.

nand: Micron MT29F16G08ADBCAH4
nand: 2048 MiB, SLC, erase size: 256 KiB, page size: 4096, OOB size: 224
NFI 2x clock rate: 124800000 HZ.

Read speed without this patch:
mtd_speedtest: page read speed is 14012 KiB/s
mtd_speedtest: 2 page read speed is 14860 KiB/s

Read speed with this patch:
mtd_speedtest: page read speed is 18724 KiB/s
mtd_speedtest: 2 page read speed is 18713 KiB/s

Signed-off-by: Xiaolei Li <xiaolei.li@mediatek.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
2019-06-27 20:05:24 +02:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-06-02 11:10:01 -07:00
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Documentation mm, memcg: consider subtrees in memory.events 2019-06-01 15:51:31 -07:00
drivers mtd: rawnand: mtk: Improve data sampling timing for read cycle 2019-06-27 20:05:24 +02:00
fs for-linus-20190601 2019-06-02 09:27:44 -07:00
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Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.