[PATCH] gpio: mvebu: Fix mask/unmask managment per irq chip type

[Linus Walleij]

On Thu, Apr 2, 2015 at 5:11 PM, Gregory CLEMENT
<gregory.clement at free-electrons.com> wrote:

> Level IRQ handlers and edge IRQ handler are managed by tow different
> sets of registers. But currently the driver uses the same mask for the
> both registers. It lead to issues with the following scenario:
>
> First, an IRQ is requested on a GPIO to be triggered on front. After,
> this an other IRQ is requested for a GPIO of the same bank but
> triggered on level. Then the first one will be also setup to be
> triggered on level. It leads to an interrupt storm.
>
> The different kind of handler are already associated with two
> different irq chip type. With this patch the driver uses a private
> mask for each one which solves this issue.
>
> It has been tested on an Armada XP based board and on an Armada 375
> board. For the both boards, with this patch is applied, there is no
> such interrupt storm when running the previous scenario.
>
> This bug was already fixed but in a different way in the legacy
> version of this driver by Evgeniy Dushistov:
> 9ece8839b1277fb9128ff6833411614ab6c88d68 "ARM: orion: Fix for certain
> sequence of request_irq can cause irq storm". The fact the new version
> of the gpio drive could be affected had been discussed there:
> http://thread.gmane.org/gmane.linux.ports.arm.kernel/344670/focus=364012
>
> Reported-by: Evgeniy A. Dushistov <dushistov at mail.ru>
> Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
> Cc: <stable at vger.kernel.org> # v3.7 +

Patch applied.

Yours,
Linus Walleij