In message 1101030722.6343.6.camel@localhost you wrote:
Instead of doing all this which is really non-trivial and also ineffficient you could just boot from flash. I've just checked in the necessary patches for the AT91RM9200DK and CMC_PU2 boards ...
What do you mean by booting from flash? Since I've got only an SPI flash
I mean booting from the NOR flash attached to any halfway sane design.
connected, U-boot has to be taken apart, since the AT91 internal boot loader can only load 16KB of code from the flash into the internal processor SRAM. So what is needed is some code for the SPI flash, which
No - you are not restricted to booting from SPI DataFlash, and it's not 16 kB. The AT91RM9200 supports 3 boot methods:
1) Pulling the first 12 kilobytes of a SPI DataFlash memory part into internal SRAM and executing it.
2) If #1 fails, pulling the first 12 kilobytes of a serial I2C EEPROM into internal SRAM and executing it.
3) If #2 fails, executing code from an attached NOR flash device.
What we use is 3) as there is NOR flash on both the AT91RM9200DK and the CMC_PU2 boards, so this is the fastest way to boot a system.
If you don't have any nor flash, you should (1) complain at your hardware designers and (2) make sure that CONFIG_BOOTBINFUNC is _not_ defned in your board config file.
boots the processor, and reads the rest of u-boot from the SPI flash into the initialized SDRAM.
Does booting from flash solve the SDRAM initialization problem? (I mean
Yes, of course, because you can include regular initialization code for the memory controller.
Best regards,
Wolfgang Denk