[coreboot-gerrit] Patch merged into coreboot/master: spi: Get rid of SPI_ATOMIC_SEQUENCING
gerrit at coreboot.org
gerrit at coreboot.org
Fri Dec 23 04:55:02 CET 2016
the following patch was just integrated into master:
commit c2973d196d1224a1253478dc29d5f8fa004eaab8
Author: Furquan Shaikh <furquan at chromium.org>
Date: Tue Nov 29 22:07:42 2016 -0800
spi: Get rid of SPI_ATOMIC_SEQUENCING
SPI_ATOMIC_SEQUENCING was added to accomodate spi flash controllers with
the ability to perform tx and rx of flash command and response at the
same time. Instead of introducing this notion at SPI flash driver layer,
clean up the interface to SPI used by flash.
Flash uses a command-response kind of communication. Thus, even though
SPI is duplex, flash command needs to be sent out on SPI bus and then
flash response should be received on the bus. Some specialized x86
flash controllers are capable of handling command and response in a
single transaction.
In order to support all the varied cases:
1. Add spi_xfer_vector that takes as input a vector of SPI operations
and calls back into SPI controller driver to process these operations.
2. In order to accomodate flash command-response model, use two vectors
while calling into spi_xfer_vector -- one with dout set to
non-NULL(command) and other with din set to non-NULL(response).
3. For specialized SPI flash controllers combine two successive vectors
if the transactions look like a command-response pair.
4. Provide helper functions for common cases like supporting only 2
vectors at a time, supporting n vectors at a time, default vector
operation to cycle through all SPI op vectors one by one.
BUG=chrome-os-partner:59832
BRANCH=None
TEST=Compiles successfully
Change-Id: I4c9e78c585ad95c40c0d5af078ff8251da286236
Signed-off-by: Furquan Shaikh <furquan at chromium.org>
Reviewed-on: https://review.coreboot.org/17681
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin at chromium.org>
See https://review.coreboot.org/17681 for details.
-gerrit
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