[PATCH 1/3] 8xx: Analogue & Micro Adder875 board support.

[Scott Wood]

On Sun, Jan 13, 2008 at 02:26:12PM +0000, Bryan O'Donoghue wrote:
> I've applied your code against Linus' git v2.6.26-rc7 as at today.
> I have to apply 

It should apply against paulus's tree.

> make adder87x-uboot_defconfig
> 
> make uImage

make zImage, not uImage.

> cp arch/powerpc/boot/uImage /tftpboot - which is my tftpd root
> directory.

Use cuImage.8xx, not uImage.

> In U-Boot then.
> 
> => tftpboot 0x400000 uImage
> => bootm 0x400000

0x400000 is where u-boot is going to want to relocate the image to, so
loading the uImage there may not work.

> Which doesn't boot.
> 
> Attaching a BDI2000 to the target board I see that the kernel is
> panicing somewhere around line 104 of arch/powerpc/kernel/prom.c in
> of_scan_flat_dt - presumably because the kernel cannot find an
> OpenFirmware tree..

Yes, a uImage target will be expecting to be handed a device tree.  The
cuImage target has a device tree embedded and accepts the old-style bd_t.

> I admit not understanding everything I should about where the output
> of .dts & dtc "go" with respect to booting Linux.... but, didn't want to
> ask on the list - lest I display a "lack of knowledge" ...

Nothing wrong with asking...  doing so on the list just means a larger
pool of people to respond, and that others with the same question can see
the answer.

> /* pass open firmware flat tree */
> #define CONFIG_OF_LIBFDT      1
> #undef  CONFIG_OF_FLAT_TREE
> #define CONFIG_OF_BOARD_SETUP 1
> #define CONFIG_OF_HAS_BD_T    1
> #define CONFIG_OF_HAS_UBOOT_ENV       1
> 
> #define OF_CPU                        "PowerPC,875 at 0"
> #define OF_SOC                        "soc875 at ff000000"
> #define OF_TBCLK              (bd->bi_busfreq / 4)

You'll probably need some 8xx-specific code if you want to go this route. 
You'd also need to change the bootm command line to the three-argument
version, with the third argument being the address of the device tree
blob (the second argument can be - if there's no initrd).

If you're not comfortable with the device tree stuff, I recommend just
using cuImage for now.

-Scott