Hello Albert,
Albert ARIBAUD wrote:
Le 02/11/2010 07:29, Heiko Schocher a écrit :
- preloader copies first page of nand (nand_spl code) to 0xbb000000 (some cpu internal mem) and jumps to this address
- nand_spl does lowlevelinit, relocate itself to TEXT_BASE (nand_spl
code)
- from there, it copies u-boot code from nand to
CONFIG_SYS_NAND_U_BOOT_DST and jumps to CONFIG_SYS_NAND_U_BOOT_START
- u-boot run into board_init_f, calculates new relocation address and relocates ...
But there is a possibility to prevent one copy, if TEXT_BASE = relocation address = CONFIG_SYS_NAND_U_BOOT_DST
In this case nand_spl code copies u-boot from nand to CONFIG_SYS_NAND_U_BOOT_DST. As this is equal to the relocation address, no need to copy code in relocate_code().
But as codesize changes (and with it relocation address) this is not a perfect solution.
bye, Heiko
Heiko,
Since SPL is loaded in internal RAM, and since U-BOOT itself is loaded only in DRAM, why does SPL need to relocate itself? Can it not run entirely from IRAM and then jump to U-BOOT?
Good question. This was the old behaviour. Check this, if we can prevent it.
If SPL needs to relocate, then why does it run only the copy loop but not the fixups loop?
in nand_spl//nand_boot_fsl_nfc.c:
void board_init_f (ulong bootflag) { relocate_code (CONFIG_SYS_TEXT_BASE - TOTAL_MALLOC_LEN, NULL, CONFIG_SYS_TEXT_BASE); }
-> nand_spl code gets copied where it is compiled for ... no need for fixups.
bye, Heiko