Dear Ilya Averyanov, > Dear Marek Vasut, > > Would you please explain, why do you want to initialize the sdram has been > in C code.
Ok, no problem: - You'll be able to call get_ram_size() to scan for ram size as any other board - SDRAM driver will fit properly into the driver model once it's in place (WIP, wanna volunteer for review process?) - It's much cleaner > If for provide this feature should be written assembly code. And it would > sometimes even harder than the initialization code sdram? What do you mean? Ah yes, just a remark, please don't top-post. Notice how other people don't do it -- I know gmail does it out-of-the-box, but that doesn't mean it's correct. > 2012/4/21 Marek Vasut <ma...@denx.de> > > > Dear Ilya Averyanov, > > > > > 2012/4/21 Vasily Khoruzhick <anars...@gmail.com> > > > > > > > 2012/4/21 Ilya Averyanov <averyanovin+ub...@gmail.com>: > > > > > No have problem. > > > > > Available only if you boot from NOR flash. > > > > > If you boot from the NAND 4kb of SRAM (steppingstone) not > > > > > available. > > > > > > > > For NAND boot it's mapped at 0x0 > > > > For NOR boot it's mapped at 0x40000000 > > > > > > > > NAND controller uses it for booting purpose, but anyway for SPL we > > > > should fit code into > > > > 4k (hardware limitation), so I think using assembly here for SDRAM > > > > init is OK. > > > > > > > > And how will you use the internal SRAM when you boot from NAND, if > > > > the SoC > > > > > > writes in the SDRAM read data from NAND, and your data will be > > > > overwritten. > > > > Why? You'll load SPL into SRAM, then in SPL you'll copy the rest of uboot > > from > > NAND to - then already inited - SDRAM and execute it. We even have > > ready-to-use > > NAND SPL. > > > > > > Regards > > > > Vasily > > > > Best regards, > > Marek Vasut Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
