Re: [RFC Patch v1 00/31] Synopsys ARC Linux kernel Port

From: Arnd Bergmann
Date: Wed Nov 07 2012 - 09:36:55 EST


On Wednesday 07 November 2012, Vineet Gupta wrote:
> This patchset based off-of 3.7-rc3, introduces the Linux kernel port to
> ARC700 processor family (750D and 770D) from Synopsys.
>
> ARC700 is highly configurable and power efficient 32-bit RISC core with MMU.
> It is embedded in SoCs deployed in TV Set Top boxes, Digital Media Players,
> all the way to Network-on-Chips.

Hi Vineet,

I'm largely quite happy with how the series has turned out, having looked
at earlier versions of the ARC kernel a couple of years ago. I've commented
already on individual patches, but overall, I see two main issues that
need to be resolved in order to merge the port:

* You have to use the generic syscall interface, and that means not using
any of the legacy system calls that have since been replaced by newer
versions of the same.

* You are missing dynamic hardware detection. Rather than building a kernel
with everything known about the hardware at compile time, new ports these
days are normally able to run on all kinds of hardware and detect the
differences by looking at configuration registers (e.g. PCI), asking
firmware (Open Firmware, ACPI, ...) or by interpreting a device tree
that is passed by the boot loader (most embedded systems).
I assume that device tree is the right solution for you because a lot of
the hardware you use is likely shared with ARM, PowerPC or MIPS based
SoCs and they are all using (or getting migrated to) DT now instead of
static platform devices,

Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/