Dear Marek Vasut, Would you please explain, why do you want to initialize the sdram has been in C code. If for provide this feature should be written assembly code. And it would sometimes even harder than the initialization code sdram?
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 >
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