Re: [loongson-dev] Fuloong liberated

[Vladimir 'φ-coder/phcoder' Serbinenko]

On 16.05.2011 18:05, Roman Mamedov wrote:
> On Mon, 16 May 2011 11:12:42 +0200
> Vladimir 'φ-coder/phcoder' Serbinenko <address@hidden> wrote:
>
>> Hello all. As you all probably know the Floong as shipped by lemote uses
>> a 64K binary blob to initialize the video which makes it non-free.
>> Fortunately now there is an alternative: GRUB2.
> Hello,
>
> So you are replacing PMON with GRUB2, but are you sure the video BIOS is also
> removed by this operation?
I believe so. I couldn't find any other flash chip which could contain
it. The video chip is soldered on the board and has no flash nearby. The
Video BIOS I reverse engineered was recovered from pmon source tree. So
I suppose it is eradicated.
>  And then, is it GRUB2 that initializes the video
> chip instead of SiS BIOS, setting up VRAM timings, the video output, screen
> mode, etc? Does it actually have special code for bringing up the SiS 315E?
>
Yes. It wasn't easy to figure out the right sequence to bring CR
(controller) up. Currently the only supported resolution is 640x480x8
and the parameters are precomputed. While not the nicest resolution it
should work with any monitor and is enough to show console (or menu).
Linux is able to change to any mode afterwards.
>> To generate firmware
>> image do:
>> bzr branch http://bzr.savannah.gnu.org/r/grub/trunk/grub
>> cd grub
>> ./configure --target=mipsel --with-platform=loongson
>> make
>> ./grub-mkimage -C xz -O mipsel-fuloong-flash -o grub.img -d grub-core/
>> normal linux ata usb_keyboard ohci part_msdos ext2 xfs part_gpt ls halt
>> reboot usbms gzio
> Can you perhaps post a compiled firmware somewhere.
>
Sorry but I'm on my way now and I don't have fuloong under my hand. I
could post the latest image that worked for me but it has no support for
compressed kernel (I didn't include gzio module)
>> The resulting grub.img can be flashed using flashrom
>> http://flashrom.org/Flashrom. Be sure to have backup chip before
>> flashing.
> Also I believe it should be possible to chain-load this image from PMON for
> testing, via the "load <filename>" command, and then "g".
>
Not this image. Image generated with -O mipsel-fuloong-flash has to be
flashed (it can start only from ROM and at fixed address). To generate
loadable image replace -O mipsel-fuloong-flash with -O
mipsel-fuloong-elf. It will create an image which is the same as ROM
image but in ELF format and without fwstart.S part.


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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