[ARMedslack] A quick primer for the PI

[Davide]

>>I got a friend to lend me a PI  for a week ...

>>I had a quick look at the community links for slackware on the PI but none really tell me what i want to know:
>>what does the GPU  look  for in the SD ? (as fas as I know it's the GPU that loads stuff from SD into memory and then passes control to it)
>>does it look for a second stage boot loader like a uboot image or does it load kernel and initrd ? (bootcode.bin)
>>I'm supposing that the first partition (the dos one) is where this stuff should be put ?
>>The content in there looks about right:

>>root at darkstar:/tmp# fdisk  -l slackwarearm-14.0-8GB-20130623.img 

>>Disk slackwarearm-14.0-8GB-20130623.img: 2558 MB, 2558967808 bytes
>>4 heads, 32 sectors/track, 39046 cylinders, total 4997984 sectors
>>Units = sectors of
 1 * 512 = 512 bytes
>>Sector size (logical/physical): 512 bytes / 512 bytes
>>I/O size (minimum/optimal): 512 bytes / 512 bytes
>>Disk identifier: 0x00007091

>>                            Device Boot      Start         End      Blocks   Id  System
>>slackwarearm-14.0-8GB-20130623.img1              32       97663       48816    c  W95 FAT32 (LBA)
>>slackwarearm-14.0-8GB-20130623.img2           97664      878847      390592   82  Linux
 swap
>>slackwarearm-14.0-8GB-20130623.img3          878848    15751167     7436160   83  Linux
>>root at darkstar:/tmp# echo $((32 * 512))
>>16384
>>root at darkstar:/tmp# losetup -o 16384 /dev/loop0  slackwarearm-14.0-8GB-20130623.img
>>root at darkstar:/tmp# modprobe vfat
>>root at darkstar:/tmp# mount /dev/loop0 /mnt/floppy/
>>root at darkstar:/tmp# ls /mnt/floppy/
>>COPYING.linux*                  config-raspberrypi-3.2.27*  start.elf*
>>LICENCE.broadcom*               config.txt*                 start_cd.elf*
>>System.map-raspberrypi-3.2.27* 
 fixup.dat*                  zImage-raspberrypi-3.2.27*
>>bootcode.bin*                   fixup_cd.dat*
>>cmdline.txt*                    initrd-raspberrypi.img*
>root at darkstar:/tmp#


>>I plan to play a little with a miniroot so I won't need an 8Gb SD :)

>Hi David,
Hi Dave ;)
 
>The GPU looks for
 bootcode.bin, which looks for and loads loader.bin. Loader.bin reads in
 config.txt (to configure the hardware) and loads start.elf (the GPU 
binary blob). Once it has configured the hardware, it then >loads 
kernel.img, and feeds it the contents of cmdline.txt.

But on the readymade image from http://stanleygarvey.com/slackwarearm_rpi/index.php there is no loader.bin in the dos partition !
Is there something wrong with this image or is loader.bin optional ?

>So you have
 to have bootcode.bin, loader.bin, config.txt, start.elf, kernel.img, 
and cmdline.txt, then if you load a ramdisk image in the cmdline.txt 
file you need the ramdisk image file.

Is the initrd loading governed by config.txt ?
I see in there ramfsfile=initrd-raspberrypi.img
Can I change that manualy with vi and load a different initrd ? or comment it out to not load an initrd at all ?

When is the HDMI output initiated ?

ATB
David
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