> -----Original Message----- > From: Sun York-R58495 > Sent: Saturday, March 08, 2014 12:31 AM > To: Bansal Aneesh-B39320 > Cc: Wood Scott-B07421; Wolfgang Denk; u-boot@lists.denx.de; Gupta > Ruchika-R66431 > Subject: Re: [U-Boot] [PATCH 1/3] powerpc/p1010rdb: SECURE BOOT- > define CONFIG_SYS_RAMBOOT for NAND boot > > On 03/07/2014 10:57 AM, Scott Wood wrote: > > On Thu, 2014-03-06 at 03:24 -0600, Bansal Aneesh-B39320 wrote: > >>> -----Original Message----- > >>> From: Wood Scott-B07421 > >>> Sent: Wednesday, March 05, 2014 11:30 PM > >>> To: Bansal Aneesh-B39320 > >>> Cc: Sun York-R58495; Wolfgang Denk; u-boot@lists.denx.de; Gupta > >>> Ruchika-R66431 > >>> Subject: Re: [U-Boot] [PATCH 1/3] powerpc/p1010rdb: SECURE BOOT- > >>> define CONFIG_SYS_RAMBOOT for NAND boot > >>> > >>> On Tue, 2014-03-04 at 23:30 -0600, Bansal Aneesh-B39320 wrote: > >>>> Yes, in case of secure boot from NAND, the DRAM is initialized by > >>> the > >>>> BootROM and complete u-boot image is copied from NAND to DRAM by > >>>> the > >>> BootROM. > >>>> So, it should be called RAMBOOT. > >>> > >>> DRAM or SRAM? Having ROM initialize DDR is a bit scary. > >>> > >>> -Scott > >>> > >> It can be either DDR or SRAM. It is not hardcoded in BootROM to > initialize DDR. > >> This depends on the config words (CF_WORDS) in the CF_HEADER. > >> The Boot ROM code parses the config words and programs the > addresses > >> with data values accordingly. The user may opt to initialize DDR > and > >> get the image copied onto DDR or configure CPC as SRAM and get the > Image copied onto SRAM. > >> On 1010, > > > > P1010? LS1010? Something else? > > > >> the CPC size is not big enough to accommodate the U-boot image. > >> So, currently the CF_WORDS are for DDR to be initialized and copy > the image on DDR. > > > > Generally if SPD is present, it should be used to init DDR rather > than > > using hardcoded values. If U-Boot doesn't fit in SRAM, you can use > > SPL instead of hardcoded init. > > I agree with Scott on this point. Using hardcoded values totally skip > DDR driver. You don't only lose the flexibility of various speeds, you > also skip all workarounds implemented in DDR driver. > > York Currently we are following the same approach which was there for SPI and SD on P1010 i.e hardcoded initialization of DDR in platforms like P1010, 9131/9132 using config words.
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