Hi,
I'm working on a custom board based on P1011. There are 2 board flavours, with either 128MB or 256MB of soldered DDR2 SDRAM. Having u-boot image per board works fine, but I'd like to have a single image and use get_ram_size() to detect memory size at runtime. So far I had no luck.
The only significant difference between memory devices on these boards is the number of banks: 4 banks on 128MB board and 8 banks on 256MB board.
The memory size detection logic is loosely based on the code in boards/tqc/tqm85xx/sdram.c, but I use fsl_ddr_set_memctl_regs() to configure DDR controller registers and enable the controller. The sequence is:
1. Configure TLBs for 2GB DDR 2. Configure LAWs for 2GB DDR 3. Configure DDR controller registers and enable DDR controller, CS0_BNDS is set to 256MB. 4. Iterate over possible memory sizes starting from the largest. Each iteration configures CS0_CONFIG (sets number of banks, rows and columns) and runs get_ram_size()
What I observe on 128MB board, is that only 32KB of RAM is detected in both first and second iteration. So it seems that setting number of banks to 8 on 4-bank devices is fatal, and cannot be changed even if CS0_CONFIG is modified.
I've tried to rerun DDR controller initialization sequence with new CS0_CONFIG value, but that just hangs the board. I've also tried to disable DDR controller via RORDEVDISR register and then enable it and reconfigure DDR. That also leads to hang.
I hope Freescale gurus on the list can help me to find a solution.
Thanks in advance.
Felix.