[U-Boot] testing x86 builds on the fly
Graeme Russ
graeme.russ at gmail.com
Sun Aug 7 12:21:21 CEST 2011
Hi Mike, Marek,
On 07/08/11 10:54, Graeme Russ wrote:
> Hi Mike, Marek,
>
> On 07/08/11 09:43, Mike Frysinger wrote:
>> On Sat, Aug 6, 2011 at 05:49, Marek Vasut wrote:
>>> On Saturday, August 06, 2011 01:22:38 PM Mike Frysinger wrote:
>>>> disclaimer: i have like 0 u-boot experience on x86. but i cant find
>>>> README's in the src to answer my questions.
>>>>
>>>> the PIC support on x86 is finished right ? so does that mean we can
>>>> take a u-boot.bin, tftp it to a running system into external memory,
>>>> and then boot that on the fly purely for testing purposes ?
A little more explanation...
I did once have full PIC support for x86 when loaded with SDRAM already
initialised - It would figure out were it was loaded in relation to
TEXT_BASE and perform the required adjustments during the relocation
phase). But this functionality was removed when the Cache-As-RAM
implementation was introduced.
[snip]
> Now it would be fairly trivial to add a parameter passed by the 'go'
> command which sets a flag in global data that would tell board_init_f to
> not perform SDRAM init which is on my todo list (see below)
Well I just looked at the code and the warm reset entry point sets
GD_FLG_WARM_BOOT in gd->flags so you could easily bypass SDRAM
initialisation by doing a test in the arch specific dram_init_f()
int dram_init_f(void)
{
if (gd->flags | GD_FLG_WARM_BOOT)
return 0;
...
}
Regards,
Graeme
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