On 03/10/2014 02:14 AM, Bansal Aneesh-B39320 wrote:
-----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.
Understood.
York