On Thu, Feb 28, 2013 at 7:19 PM, Bill Gatliff <[email protected]> wrote:
> I'm not insisting that we have to bring all this stuff into Linux too. > In fact, keeping some of these details hidden away inside a true > bootloader is often a good idea because some low-level hardware > details Linux just doesn't care about, or they have to be addressed > before the hardware can deal with the large memory footprint that > Linux requires. if you're familiar with the allwinner a10 3-stage initialisation process, they have a 16k bit of assembly code which conveniently fits into the 1st level cache of the Cortex A8 processor. i say "conveniently" but actually i mean "you have no option but to follow this 3-stage initialisation". it carries out the low-level initialisation i mentioned earlier [such as bringing up the DDR3 RAM interface]. this assembly code has been added into a separate subdirectory of the u-boot sunxi source code tree... .... but it's actually a completely independent application. this application, its authors have modified it so that it can do reading from the SD/MMC card, providing greatly-enhanced functionality over what allwinner originally provided. there is absolutely no reason why this application should not read a linux kernel + initrd and execute that instead of u-boot. the point i'm making is: the exact same technique could be deployed on any other hardware, again making it completely unnecessary to make a dog's dinner out of u-boot or pollute the linux kernel itself with yet more low-level initialisation. l. -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/CAPweEDxdTHyPBqBCdd5=u8wuwiuwrcr-vxck91gyjq9vndy...@mail.gmail.com
