the following patch was just integrated into master: commit 44f465d21cad78c87c32b916f72e1bff2ef532a0 Author: Aaron Durbin adurbin@chromium.org Date: Mon Jul 21 22:11:29 2014 -0500
tegra132: fix Rx FIFO underruns with slower SPI clock
The SPI controller operates on packets which can be variable length up to 32-bit packets. It also has the ability to be put in packed or unpacked mode w.r.t each packet. i.e. does a single fifo register hold >= 1 packet. The current programming uses 8-bit packets in unpacked mode which means 4 fifo slots are used for a 32-bit DMA transfter. As the AHB can only operate on a minimum of 32-bit bursts the triggers need to be programmed correctly so that there is room for a full 32-bit DMA transaction.
Previously faster SPI clocks just made things magically work.
BUG=chrome-os-partner:30779 BRANCH=None TEST=Built and booted through coreboot with 20MHz SPI clock.
Original-Change-Id: I3f1cd4dddcea9514327b2363ed450a527db7e1fe Original-Signed-off-by: Aaron Durbin adurbin@chromium.org Original-Reviewed-on: https://chromium-review.googlesource.com/208862 Original-Reviewed-by: Tom Warren twarren@nvidia.com Original-Reviewed-by: Furquan Shaikh furquan@chromium.org Original-Commit-Queue: Furquan Shaikh furquan@chromium.org (cherry picked from commit d9864228a2479e412d7e0d2221fe536f78329acd) Signed-off-by: Marc Jones marc.jones@se-eng.com
Change-Id: I61c145f35e1f889d4f83f3dfea049bfd347c1196 Reviewed-on: http://review.coreboot.org/8649 Tested-by: build bot (Jenkins) Reviewed-by: Furquan Shaikh furquan@google.com
See http://review.coreboot.org/8649 for details.
-gerrit