Re: understanding Debian support on ARM architecture
On 8/10/2014 2:39 AM, Reco wrote:
> Hi.
>
> On Sun, 10 Aug 2014 04:40:05 +0300
> Martin T <m4rtntns@gmail.com> wrote:
>
>> Hi,
>>
>> according to wiki, Debian is supported on little-endian ARM
>> architecture. However, then wiki lists some sub-architectures which
>> are supported. For example iop32x, ixp4xx, kirkwood and orion5x. Does
>> this mean that Debian ARM port works on fairly limited number of
>> sub-architectures? For example all the ARM-based embedded boards would
>> probably not work with Debian ARM port?
>
> There's a difference between x86 and ARM, and that difference is
> hardware enumeration. x86 provides OS with one, ARM does not.
>
> To boot any Linux on ARM and to work with any hardware, one does need
> so called 'device tree' ([1]) compiled into the kernel.
>
> So, to answer your question - you have 100% guarantee that booting any
> of armel Debian kernel won't be successful and will end with kernel
> panic in the best case for any of those ARM-based embedded boards.
>
> Now, if you manage to build a working kernel for that specific board
> and boot it - sure you can use any part of Debian with the board short
> of the stock kernel(s).
>
> [1] http://lwn.net/Articles/448502/
>
> PS I'm happy user of kirkwood family Debian kernel :)
>
> Reco
>
>
I don't think the x86 architecture provides ANY hardware enumeration.
The processor couldn't care less. It's all about ports and interrupts.
It's the kernel which provides the actual enumeration.
However, there is a difference in the instruction set for each type of
processor. The same binary machine code means one thing in the x86
architecture, and something completely different in the ARM
architecture. *Most* C programs can be compiled for both, but much of
the hardware-dependent code (i.e. kernel, device drivers) will be
device-dependent and will need modifications.
Jerry
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