[U-Boot] [PATCH v4 1/2] blackfin: convert blackfin board_f and board_r to use generic board init functions

Michal Simek monstr at monstr.eu
Mon Sep 1 13:01:38 CEST 2014


On 09/01/2014 04:52 AM, Sonic Zhang wrote:
> Hi Michael,
> 
> On Fri, Aug 29, 2014 at 8:20 PM, Michal Simek <monstr at monstr.eu> wrote:
>> Hi Sonic
>>
>> On 08/07/2014 09:08 AM, Sonic Zhang wrote:
>>> From: Sonic Zhang <sonic.zhang at analog.com>
>>>
>>> - move blackfin specific cpu init code from blackfin board.c to cpu.c
>>> - remove blackfin specific board init code and invoke generic board_f fron cpu init entry
>>> - rename section name bss_vma to bss_start in order to match the generic board init code
>>> - add a fake relocate_code function to set up the new stack only
>>
>> I would like get more information about this change.
>> I have spent some time on Microblaze to move to generic board
>> and I need to use sort of the same approach.
>> I will play with full reloc but as I see there will be a lot of additional
>> code generated which increase u-boot footprint and brings nothing.
>>
>> That's why I would like to know why you have decided to use fake relocate_code
>> function and what setup you are using before and "after" relocation (location of stack, gd, malloc
>> areas, etc).
> 
> The Blackfin u-boot start code has already done the relocation before
> the generic board_init_f() is invoked. But, the new stack pointer can
> not be set until all functions in init_sequence_f[] are done. So, the
> last function in init_sequence_f[] relocate_code() is used to update
> the stack point and jump to the generic board_init_f(). Blackfin
> architecture defines global static gd and bd data and set the init
> stack point to (CONFIG_SYS_MALLOC_BASE - 4).

Ah ok.

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform



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