ARM cortex A8 serial kernel

wade456 · Post by **wade456** » Wed Mar 21, 2012 9:30 pm

Is anyone know a good kernel for contex A8 serial like beagleboard (except linux and BSD*)?
I need study contex A8 so i want to write a contex A8 serial kernel.
Has anyone write a open source kernel for contex a8 (mmu is need)?
thx a lot~

JamesM · Post by **JamesM** » Thu Mar 22, 2012 12:20 pm

Hi,

wade456 wrote:Is anyone know a good kernel for contex A8 serial like beagleboard (except linux and BSD*)?
I need study contex A8 so i want to write a contex A8 serial kernel.
Has anyone write a open source kernel for contex a8 (mmu is need)?
thx a lot~

The CPU on a board is unrelated to the serial controller. Whether a board has a Cortex-A8, Cortex-A9, A15, R4 or M3 doesn't matter - the serial controller is a separate piece of RTL.

If you're interested in the serial controller on the Beagleboard, have you looked at the technical documentation for the Beagleboard on its website? That details the register mapping and protocol for using the serial port.

That is, if you want to write a serial port driver. If you don't, why not use Linux or FreeBSD?

Cheers,

James

bluemoon · Post by **bluemoon** » Thu Mar 22, 2012 2:17 pm

Since "serial kernel" has no match on google, I suppose that is something alien technology or not exist in our universe

Well, perhaps he meant kernel for A8 series processor?

xenos · Post by **xenos** » Thu Mar 22, 2012 2:28 pm

berkus wrote:Serial controller on Beagleboard is standard 16650 compatible, you can get the MMIO addresses in the Linux sources, for example.

...or the Technical Reference Manual.

But um "serial kernel", what's that supposed to mean?

I guess the OP wants to get some "Hello World" (or whatever) output from the serial console.

mutex · Post by **mutex** » Thu Mar 22, 2012 2:43 pm

I may be wrong, but my interpretation of this "Cortex A8 serial kernel" is that he means a "mainstream, normal A8 core" and no specialized ARM A8 compatible SoC like Samsung's etc..

Ubuntu have toolchain for ARM in its package repository and writing a kernel for ARM is basically not much more different than doing it for x86 etc..

You need to do some lowlevel boilerplate initialization (like for x86 etc) but when you get that up and running its pretty straight forward. I recommend creating a C - code stub doing while(1) and creating some boilerplate code in ASM and get that up and running first anyway.

I have ported my kernel to ARM and it was done very easily. Using the Beagleboard xm.. Booting is easy with the internal bootloader.

regards
Thomas

JamesM · Post by **JamesM** » Thu Mar 22, 2012 2:48 pm

"mainstream, normal A8 core"

I don't think you're quite "getting" it. ARM chips are not sold themselves. Instead, the IP is sold to semiconductor manufacturers who add their own IP and put that on a chip as a SoC.

The Cortex-A8 processor is a processor. It doesn't contain a UART. Most SoCs with one in however will. There's no such thing as a "normal" A8 SoC because all semi companies put their own fabric on them!

So you need to know for which SoC you're designing in order to know how to access the peripherals.

mutex · Post by **mutex** » Thu Mar 22, 2012 3:40 pm

Of course i know.....

I just told what I thought he meant (I think I stated that clearly, but understand why I might have made you missunderstand) (Samsung part...) ..? Sorry if I did not make it clear enough.

If he means serial in like rs232 there is the hardware manual for that specific chip/SoC.

Anyway rest of my post is still vaild and can be recommended by myself based on my experience with my kernel

wade456 · Post by **wade456** » Thu Mar 22, 2012 7:55 pm

ha ~sorry to all
My means want using ARMv7 architecture CPU (like beagleboard) develop OS.
I think ARMv7 is very universal and powerful in embedded system.

As far as I know has no open source micro kernel is porting to ARMv7 architecture so i want find it.
minix on ARM seems dead.

OSwhatever · Post by **OSwhatever** » Fri Mar 23, 2012 2:51 am

wade456 wrote:ha ~sorry to all
My means want using ARMv7 architecture CPU (like beagleboard) develop OS.
I think ARMv7 is very universal and powerful in embedded system.

As far as I know has no open source micro kernel is porting to ARMv7 architecture so i want find it.
minix on ARM seems dead.

BeagleBoard is based on Ti OMAP and Linux supports this board for example. Probably you'll find more OS support for this board once you start looking.

OSwhatever · Post by **OSwhatever** » Fri Mar 23, 2012 3:41 am

berkus wrote:I guess what he's fixed on is _micro-kernels_.

Ok. According to beagleboard.org on the main page you can find that

RISC OS
Symbian
QNX Neutrino

Supports beagleboard. Symbian and QNX are supposed to be microkernels.

OSDev.org

ARM cortex A8 serial kernel

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