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authorFurquan Shaikh <furquan@chromium.org>2016-11-29 22:07:42 -0800
committerFurquan Shaikh <furquan@google.com>2016-12-23 04:54:55 +0100
commitc2973d196d1224a1253478dc29d5f8fa004eaab8 (patch)
tree2377f357ee09f147b3f413949057306ca1839bab /src/soc/broadcom/cygnus
parent42cfdf5184b3e94805958a3368f2e049c09119ac (diff)
downloadcoreboot-c2973d196d1224a1253478dc29d5f8fa004eaab8.tar.xz
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@chromium.org> Reviewed-on: https://review.coreboot.org/17681 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src/soc/broadcom/cygnus')
-rw-r--r--src/soc/broadcom/cygnus/spi.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/src/soc/broadcom/cygnus/spi.c b/src/soc/broadcom/cygnus/spi.c
index e597efced9..f03d453307 100644
--- a/src/soc/broadcom/cygnus/spi.c
+++ b/src/soc/broadcom/cygnus/spi.c
@@ -279,6 +279,7 @@ static const struct spi_ctrlr spi_ctrlr = {
.claim_bus = spi_ctrlr_claim_bus,
.release_bus = spi_ctrlr_release_bus,
.xfer = spi_ctrlr_xfer,
+ .xfer_vector = spi_xfer_two_vectors,
};
int spi_setup_slave(unsigned int bus, unsigned int cs, struct spi_slave *slave)