SPL must contain the NAND Driver and UBIFS file system

[adityanagal]

Hi ,

If the SPL and uboot resides  in the NAND flash. Question is , does the SPL have the NAND FIash driver and the UBIFS file system. As per the below thread , I was suggested these should not , but per my understanding , when the SPL executes in SRAM , how will it loads the uboot  from NAND FLash unless it has the NAND Flash Driver and UBIFS file system. Please suggest.

https://community.nxp.com/thread/451729

Regards,

Aditya Nagal

[igorpadykov]

Hi Aditya

NAND Flash Driver and UBIFS file system are attributes of operating system,

while uboot is baremetal, just  executing instructions as binaries.

Best regards
igor
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[adityanagal]

Hi igor ,

Thank you for your response  , I have small disagreement with you on this point as though uboot  is a bare metal code , it has the layers of drivers and file system. Without these layers , how would SPL loads the uboot from Nand Flash and uboot loads the kernel from Nand Flash. In the uboot source, at path uboot/drivers , all drivers are  listed. Similarly at path uboot/fs , all supported file systems are listed. Now just the question is , how to configure u-boot with a particular file system UBIFS  . Also ,  how to configure SPL with MTD flash driver and UBIFS file system. Need your suggestion on this.

Regards,

Aditya Nagal

[igorpadykov]

Hi Aditya

please check

https://en.wikipedia.org/wiki/Das_U-Boot
U-Boot does not need to be able to read a filesystem in order for the kernel to use it
as a root filesystem or initial ramdisk; U-Boot simply provides an appropriate parameter to the
kernel, and/or copies the data to memory without understanding its contents.

regarding uboot ubifs support, seems this depends on architecture/version:
http://www.denx.de/wiki/publish/DULG/DULG-enbw_cmc.html#Section_5.9.3.6.
https://stackoverflow.com/questions/39582079/enabling-ubifs-in-u-boot

as for SPL, I am afraid it does not support ubifs, for more info one may post this on uboot mail list

U-Boot Info Page 

note, nxp uboot does not support spl.

Best regards
igor