From mboxrd@z Thu Jan  1 00:00:00 1970
From: santosh.shilimkar@oracle.com (santosh.shilimkar at oracle.com)
Date: Mon, 19 Jan 2015 11:05:17 -0800
Subject: [PATCH 1/1] gpio: omap: Fix bad device access with setup_irq()
In-Reply-To: <20150117010003.GP18552@atomide.com>
References: <1421448650-15904-1-git-send-email-tony@atomide.com>
 <54B9AA9D.7080300@oracle.com> <20150117010003.GP18552@atomide.com>
Message-ID: <54BD556D.3080206@oracle.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On 1/16/15 5:00 PM, Tony Lindgren wrote:
> * santosh shilimkar <santosh.shilimkar@oracle.com> [150116 16:23]:
>> On 1/16/2015 2:50 PM, Tony Lindgren wrote:
>>> Similar to omap_gpio_irq_type() let's make sure that the GPIO
>>> is usable as an interrupt if the platform init code did not
>>> call gpio_request(). Otherwise we can get invalid device access
>>> after setup_irq():
>>>
>> I let Linus W comment on it but IIRC we chewed this issue last
>> time and the conclusion was the gpio_request() must have to be called
>> directly or indirectly in case of irq line.
>
> This is a corner case where the error is triggered by a wrong,
> non-GPIO IRQ so gpio_request() will never be called before setup_irq()
> unlike for any legacy platform code.
>
> The legacy and DT cases we're already handling in the gpio-omap.c
> driver a while back with:
>
> 2f56e0a57ff1 ("gpio/omap: use gpiolib API to mark a GPIO used as an IRQ")
> fac7fa162a19 ("gpio/omap: auto-setup a GPIO when used as an IRQ")
> fa365e4d7290 ("gpio/omap: maintain GPIO and IRQ usage separately")
>
> And most of that the bank specific hacks we can get rid of by making
> the driver multple instances as that allows replacing BANK_USED
> with just runtime PM.
>
Right. Thanks for expanding it.

Regards,
Santosh