I have the eval board as well as our custom board based on the at91sam9g45-ekes and i'm trying to get linux using all of the 256 megs of ddr2.

I've patched uboot with a posting i've seen here which basically adds the following lines to dram_init.

gd->bd->bi_dram[1].start = 0x20000000;
gd->bd->bi_dram[1].size = 0x08000000;

When u-boot loads, it says it has 256 megs available but when I run a mtest 0x20000000 it goes very slow on my eval board and fails on my custom board. My custom board has no data flash installed.

I've seen references (http://blog.linuxconsulting.ro/2010/05/ ... -with.html) saying I need to patch at91bootstrap to initialize the second bank of ram but the patch he supplies will not go anywhere near the at91bootstrap versions i've been trying (ftp://www.at91.com/pub/at91bootstrap). I tried old versions and new versions.

Does anybody have any ideas?

Well you're going to have to initialize the SDRAM/DDR controllers within AT91Bootstrap for the memory devices you are using. It sets up the memories for the downstream code like uBoot and Linux.

The code you added to uBoot just tells it where the regions of memory are, and it dutifully adds up the numbers in your list and prints it out, nothing else.

You will need to read the datasheet for the memories you are using, and add the appropriate timing and structural details into the controllers, and initialize them suitably for your bus speed and widths, and refresh.