Commits
Michael Trimarchi committed ddd69302153
sunxi: dram_sun8i: Fix A33 memory initialization While the exact problem is not known, based on discussion between Philipp Tomsich and André Przywara it is guessed that exit self-refresh timing is not set with correct value. There may be implicit enter or exit Self-Refresh anywhere as part of some training phase. In ZynqMP register guide [1], which is close to the various Allwinner DRAM controllers, tXSDLL is bits [14:8], while the non-DLL tXS is bits [6:0]: Self refresh exit delay. So it could be safely increased and it only affects the time after the self-refresh “exit”, which happens only after (re-)initialisation. There was no document for cpu in question so based on oscilloscope readings [2][3] and observed result by comparing allwinner architecture. So set it same as Allwinner H5 silicon. Before this patch, failure rate of was 7%. This was tested on A33 allwinner cpu, dual rank connection connected with two MT41K512M16HA-125:A memory model. Memory is configured as DDR3 1.5V And also this is tested in A33-OLinuXino dev board. [1] https://www.xilinx.com/html_docs/registers/ug1087/ddrc___dramtmg8.html [2] https://ibb.co/R70zmyS [3] https://ibb.co/HVVCGQ8 Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com> Signed-off-by: Shyam Saini <shyam.saini@amarulasolutions.com> Acked-by: Jagan Teki <jagan@openedev.com>