[PATCH 1/4] arm: mvebu: limit OpenBlocks AX3-4 to 1 GB of RAM
From: Thomas Petazzoni <hidden>
Date: 2013-02-27 08:33:53
Dear Andrew Lunn, On Wed, 27 Feb 2013 08:03:33 +0100, Andrew Lunn wrote:
quoted
in U-Boot. Gr??gory and I are using OpenBlocks AX3 based on the A0 version of the silicon (so the message I copy/pasted above is *not* from our OpenBlocks, but a different Armada XP board). However, PlatHome has been shipping since some time B0 revisions. Maybe it could explain the difference we're seeing?Hi Thomas My machine is an A0.
Hum, ok, so that doesn't explain the problem.
I know you recently found some issue with windows. Could that explain something?
No, the issue with the window was only that devices can only access the first 32 bits of the physical address space, so if there is a DRAM CS configured with a base address higher than 4 GB, then devices shouldn't configure a window to access this part of the DRAM, because it creates two overlapping windows (both starting at base 0x0, since in the device address decoding window registers, the base only has 32 bits, while it has 35 bits for the SDRAM address decoding registers). And the issue with window was that the devices were really not working at all. What we're seeing with the OpenBlocks is some instability: sometimes it boots, sometimes not. We're going to discuss this issue further with PlatHome. Thanks for reporting! Best regards, Thomas -- Thomas Petazzoni, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com