Hi York, On 05/05/2011 04:29 PM, York Sun wrote: > Felix, > > On Thu, 2011-05-05 at 16:17 +0300, Felix Radensky wrote: >> 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. >> > I don't think get_ram_size works for your case. If you want to test the > DDR to find the correct size, you have to initialize the DDR first. But > you cannot do this correctly without knowing the number of banks. You > may be able to blindly set the bank number and test the DDR to catch the > error if there is any, but you have to run this code somewhere else, for > example, in the flash (before relocation). > > There might be another way. Do you have any board ID to distinguish > these two kinds? > > York > >
Thanks a lot for a prompt reply, I appreciate it very much. I suspected this might be the case. The tqm boards I've used as a reference all have 4-bank memory devices, so that's why it get_ram_size() works for them. We'll have to keep board ID on EEPROM to distinguish between boards with different RAM sizes. Thanks a lot for your help. Felix. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
