From: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-arm-kernel@lists.infradead.org,
linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org,
Wim Van Sebroeck <wim@iguana.be>,
Gregory Clement <gregory.clement@free-electrons.com>,
Lior Amsalem <alior@marvell.com>,
Tawfik Bayouk <tawfik@marvell.com>,
Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
Jason Cooper <jason@lakedaemon.net>,
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
Andrew Lunn <andrew@lunn.ch>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Fabio Estevam <festevam@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 04/15] watchdog: orion: Handle IRQ
Date: Mon, 27 Jan 2014 04:18:59 -0300 [thread overview]
Message-ID: <20140127071858.GB17506@localhost> (raw)
In-Reply-To: <52E5FFCB.5000802@roeck-us.net>
On Sun, Jan 26, 2014 at 10:42:19PM -0800, Guenter Roeck wrote:
> On 01/26/2014 10:30 PM, Ezequiel Garcia wrote:
> > Hi Guenter,
> >
> > On Tue, Jan 21, 2014 at 06:31:02AM -0800, Guenter Roeck wrote:
> > [..]
> >>> @@ -131,6 +138,19 @@ static int orion_wdt_probe(struct platform_device *pdev)
> >>> if (!wdt_reg)
> >>> return -ENOMEM;
> >>>
> >>> + irq = platform_get_irq(pdev, 0);
> >>> + if (irq > 0) {
> >>
> >> 0 is a valid interrupt number, and platform_get_irq returns an error code on errors.
> >> Should be >= 0.
> >>
> >
> > I'm revisiting this one. I believe this is not the hardware interrupt
> > number, but the one mapped into virq space. So, 0 is not a valid
> > interrupt number.
> >
> > Right?
> >
>
> If so, the entire interrupt numbering scheme appears broken. Conceptually it should
> not make a difference where the interrupt is coming from. If the virq system
> returns 0 for invalid (non-configured) interrupts, and non-configured 'real'
> interrupts are reported as -ENXIO, all bets are off. How would a driver know
> what to expect ? And how would one be expected to review such non-deterministic
> code ?
>
I wouldn't know that much. I'm just pointing out that '0' doesn't seem
to be a valid IRQ number in this context (i.e. virq space).
> FWIW, platform_get_irq() does return -ENXIO for invalid interrupts. If there
> is an independent notion of "0 is an invalid interrupt", it is well hidden.
>
Yes, AFAICS platform_get_irq() returns a negative error or a positive
irq number. I fail to see how it's able return '0' (of course, I can be
wrong).
> Anyway, if you think the driver should treat 0 as invalid interrupt, go ahead.
> Who am I to know. Just please don't use my Reviewed-by in this case.
>
Quite frankly not sure how to handle this best. A quick grep through the
code doesn't help either: lots of drivers treat 0 as a valid interrupt
and lots treat it as invalid. So I guess it doesn't really matter...
Can someone shed a light on this?
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com
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next prev parent reply other threads:[~2014-01-27 7:18 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-21 13:25 [PATCH v3 00/15] Armada 370/XP watchdog support Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 01/15] ARM: Introduce atomic MMIO modify Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 02/15] clocksource: orion: Use atomic access for shared registers Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 03/15] watchdog: " Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 04/15] watchdog: orion: Handle IRQ Ezequiel Garcia
2014-01-21 14:31 ` Guenter Roeck
2014-01-21 14:35 ` Ezequiel Garcia
2014-01-27 6:30 ` Ezequiel Garcia
2014-01-27 6:42 ` Guenter Roeck
2014-01-27 7:18 ` Ezequiel Garcia [this message]
2014-01-21 13:26 ` [PATCH v3 05/15] watchdog: orion: Make RSTOUT register a separate resource Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 06/15] watchdog: orion: Remove unneeded BRIDGE_CAUSE clear Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 07/15] watchdog: orion: Introduce an orion_watchdog device structure Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 08/15] watchdog: orion: Introduce per-compatible of_device_id data Ezequiel Garcia
2014-01-21 16:35 ` Guenter Roeck
2014-01-22 17:06 ` Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 09/15] watchdog: orion: Add per-compatible clock initialization Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 10/15] watchdog: orion: Add per-compatible watchdog start implementation Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 11/15] watchdog: orion: Add support for Armada 370 and Armada XP SoC Ezequiel Garcia
2014-01-21 16:41 ` Guenter Roeck
2014-01-21 13:26 ` [PATCH v3 12/15] ARM: mvebu: Enable Armada 370/XP watchdog in the devicetree Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 13/15] ARM: kirkwood: Add RSTOUT 'reg' entry to devicetree Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 14/15] watchdog: orion: Enable the build on ARCH_MVEBU Ezequiel Garcia
2014-01-21 13:26 ` [PATCH v3 15/15] ARM: mvebu: Enable watchdog support in defconfig Ezequiel Garcia
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