Mainline android fiq_glue patch in Linux kernel

; Summary: Mainline android fiq_glue patch in Linux kernel

; Proposer: Tim Bird, Sony Network Entertainment

== Description ==
Android includes some patches to support serial-line debugging via the ARM FIQ (Fast IRQ).
This support includes some wrappers (fiq_glue) for managing the interrupt handling for FIQs
in C, as well as the actual debug code itself. This code is present in the
Android common kernel repository, and Tim Bird has a broken-out patch for this feature, which
includes the

It would be handy to have this FIQ glue code available for other embedded devices
(whether the FIQ is used for debugging or some other thing). At Sony, we've used FIQ in
some products as a way to generate process stack dumps. Maybe it should be tied as
a wakeup mechanism to KDB?

This project consists of merely getting the FIQ glue code integrated, so that it
is easier to install an FIQ handler. The current Android code only supports a single
FIQ handler at a time. It might be nice to investigate supporting multiple handlers
(that is, sharing the FIQ).

== Related work ==
* It looks like the glue code was added to OLPC
** See https://github.com/andreiw/andreiw-wip/blob/master/linux/3.2/olpc/fiq/0002-ARM-Add-Google-FIQ-glue-code.patch
* The current kernel appears to support some way to claim the FIQ
** See <kernel-src>/arch/arm/kernel/fiq.c
** Need to investigate more to see why this API is not sufficient (which is fiq_glue.c needed?)

== Scope ==
3 to 4 person-weeks?

== Contractor Candidates ==
None currently.

== Comments ==

[[Category:Project proposals 2012]]

On 05/24/2012 04:19 PM, Tim Bird wrote:

== Description ==
Android includes some patches to support serial-line debugging via the ARM FIQ (Fast IRQ).
This support includes some wrappers (fiq_glue) for managing the interrupt handling for FIQs
in C, as well as the actual debug code itself. This code is present in the
Android common kernel repository, and Tim Bird has a broken-out patch for this feature, which
includes the

[I should finish my sentences. This should read:]
"which includes the code for both the glue portion and the debugger portion of this
feature."

-- Tim

=============================
Tim Bird
Architecture Group Chair, CE Workgroup of the Linux Foundation
Senior Staff Engineer, Sony Network Entertainment
=============================