tree 0291863f57ddf0220596ad9382dcfe8e33bc268b
parent 59fc8005a6391146c3df65684df15c8aed4775ce
author Ionela Voinescu <ionela.voinescu@imgtec.com> 1423134009 +0000
committer ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> 1423170193 +0000

depthcharge: spi-nand: Remove "wait until ready" in the write path

The "wait until ready" call reads the STATUS (0xC0) register, and waits
until the OIP (Operation-In-Progress) flag is cleared.
Currently, it is used after page program and block erase commands are sent,
to check they are completed and the device is idle.

The call is also used between the cache programand the page program
commands. However, the GD5F specification does not mention it as part
of the write sequence. Instead, the write sequence is specified as:

1) Program Load (cache program)
2) Write Enable
3) Program Execute (page program)
4) Read Status register and wait until ready

Intensive testing shows it's actually problematic, causing pages to not get
properly written. Remove it.

BUG=chrome-os-partner:31438
TEST=tested on Pistachio bring up board; works as expected;
BRANCH=none

Author: Ezequiel Garcia <ezequiel.garcia@imgtec.com>
Change-Id: I6dc5a34222f486f17fc0f94b84748a2f25d17346
Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
Reviewed-on: https://chromium-review.googlesource.com/246482
Reviewed-by: Daniel Ehrenberg <dehrenberg@chromium.org>