From: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
To: Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>
Cc: Sebastian Hesselbarth
<sebastian.hesselbarth-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org,
grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org,
Michael Walle <michael-QKn5cuLxLXY@public.gmane.org>,
linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Subject: Re: [PATCH v2 01/12] ARM: Orion: DT support for IRQ and GPIO Controllers
Date: Fri, 6 Jul 2012 20:08:23 +0000 [thread overview]
Message-ID: <201207062008.23952.arnd@arndb.de> (raw)
In-Reply-To: <20120705161600.GA28860-g2DYL2Zd6BY@public.gmane.org>
On Thursday 05 July 2012, Andrew Lunn wrote:
> > I think the latter one needs to be
> >
> > +static int __initdata gpio1_irqs[4] = {
> > + IRQ_DOVE_HIGH_GPIO,
> > + IRQ_DOVE_HIGH_GPIO,
> > + IRQ_DOVE_HIGH_GPIO,
> > + IRQ_DOVE_HIGH_GPIO,
> > +};
> >
> > so we register all four parts to the same primary IRQ. The
> > same is true for the devicetree representation.
>
> Nope, does not work like that.
>
> It does not matter which IRQ of a GPIO chip fires. It looks at the IRQ
> cause bits for all lines and fires off the secondary ISR as needed for
> the whole chip. So in effect, there is a mapping IRQ->GPIO chip, not
> IRQ->1/4 of GPIO chip. With what you suggest above, you would end up
> with four chained interrupt handlers, all being handled by the same
> interrupt handler for one chio, and the last three in the chain would
> never do anything since the first one does all the work.
Does it really?
The handler function I'm looking at is
static void gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
{
int irqoff;
BUG_ON(irq < IRQ_DOVE_GPIO_0_7 || irq > IRQ_DOVE_HIGH_GPIO);
irqoff = irq <= IRQ_DOVE_GPIO_16_23 ? irq - IRQ_DOVE_GPIO_0_7 :
3 + irq - IRQ_DOVE_GPIO_24_31;
orion_gpio_irq_handler(irqoff << 3);
if (irq == IRQ_DOVE_HIGH_GPIO) {
orion_gpio_irq_handler(40);
orion_gpio_irq_handler(48);
orion_gpio_irq_handler(56);
}
}
My reading of this is a manual hardwired implementation of a
primary handler that triggers the secondary handler four times
when it's called with a specific argument.
If you want to keep that behavior, this handler cannot be
generic across all mvebu socs, whereas registering four
chained handlers for the same primary interrupt would have
the same effect at a very small runtime overhead without the
need for any special case.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 01/12] ARM: Orion: DT support for IRQ and GPIO Controllers
Date: Fri, 6 Jul 2012 20:08:23 +0000 [thread overview]
Message-ID: <201207062008.23952.arnd@arndb.de> (raw)
In-Reply-To: <20120705161600.GA28860@lunn.ch>
On Thursday 05 July 2012, Andrew Lunn wrote:
> > I think the latter one needs to be
> >
> > +static int __initdata gpio1_irqs[4] = {
> > + IRQ_DOVE_HIGH_GPIO,
> > + IRQ_DOVE_HIGH_GPIO,
> > + IRQ_DOVE_HIGH_GPIO,
> > + IRQ_DOVE_HIGH_GPIO,
> > +};
> >
> > so we register all four parts to the same primary IRQ. The
> > same is true for the devicetree representation.
>
> Nope, does not work like that.
>
> It does not matter which IRQ of a GPIO chip fires. It looks at the IRQ
> cause bits for all lines and fires off the secondary ISR as needed for
> the whole chip. So in effect, there is a mapping IRQ->GPIO chip, not
> IRQ->1/4 of GPIO chip. With what you suggest above, you would end up
> with four chained interrupt handlers, all being handled by the same
> interrupt handler for one chio, and the last three in the chain would
> never do anything since the first one does all the work.
Does it really?
The handler function I'm looking at is
static void gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
{
int irqoff;
BUG_ON(irq < IRQ_DOVE_GPIO_0_7 || irq > IRQ_DOVE_HIGH_GPIO);
irqoff = irq <= IRQ_DOVE_GPIO_16_23 ? irq - IRQ_DOVE_GPIO_0_7 :
3 + irq - IRQ_DOVE_GPIO_24_31;
orion_gpio_irq_handler(irqoff << 3);
if (irq == IRQ_DOVE_HIGH_GPIO) {
orion_gpio_irq_handler(40);
orion_gpio_irq_handler(48);
orion_gpio_irq_handler(56);
}
}
My reading of this is a manual hardwired implementation of a
primary handler that triggers the secondary handler four times
when it's called with a specific argument.
If you want to keep that behavior, this handler cannot be
generic across all mvebu socs, whereas registering four
chained handlers for the same primary interrupt would have
the same effect@a very small runtime overhead without the
need for any special case.
Arnd
next prev parent reply other threads:[~2012-07-06 20:08 UTC|newest]
Thread overview: 130+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-03 14:22 [PATCH v2 00/12] IRQ, GPIO SPI, I2C, etc DTC support Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
[not found] ` <1341325365-21393-1-git-send-email-andrew-g2DYL2Zd6BY@public.gmane.org>
2012-07-03 14:22 ` [PATCH v2 01/12] ARM: Orion: DT support for IRQ and GPIO Controllers Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-05 8:15 ` Andrew Lunn
[not found] ` <1341325365-21393-2-git-send-email-andrew-g2DYL2Zd6BY@public.gmane.org>
2012-07-05 9:02 ` Thomas Petazzoni
2012-07-05 9:02 ` Thomas Petazzoni
2012-07-05 9:48 ` Andrew Lunn
2012-07-05 9:48 ` Andrew Lunn
2012-07-05 10:11 ` Arnaud Patard
2012-07-05 10:11 ` Arnaud Patard (Rtp)
[not found] ` <87sjd6ikkj.fsf-0gaJ4kiyQU6khWr4QmshqB2eb7JE58TQ@public.gmane.org>
2012-07-05 10:20 ` Thomas Petazzoni
2012-07-05 10:20 ` Thomas Petazzoni
2012-07-05 10:38 ` Arnaud Patard
2012-07-05 10:38 ` Arnaud Patard (Rtp)
[not found] ` <87liiyijb8.fsf-0gaJ4kiyQU6khWr4QmshqB2eb7JE58TQ@public.gmane.org>
2012-07-05 11:42 ` Thomas Petazzoni
2012-07-05 11:42 ` Thomas Petazzoni
2012-07-05 11:48 ` Andrew Lunn
2012-07-05 11:48 ` Andrew Lunn
[not found] ` <20120705114815.GT17534-g2DYL2Zd6BY@public.gmane.org>
2012-07-05 12:09 ` Sebastian Hesselbarth
2012-07-05 12:09 ` Sebastian Hesselbarth
[not found] ` <20120705094824.GO17534-g2DYL2Zd6BY@public.gmane.org>
2012-07-05 10:10 ` Thomas Petazzoni
2012-07-05 10:10 ` Thomas Petazzoni
2012-07-05 10:25 ` Andrew Lunn
2012-07-05 10:25 ` Andrew Lunn
2012-07-05 12:58 ` Thomas Petazzoni
2012-07-05 12:58 ` Thomas Petazzoni
2012-07-05 13:15 ` Andrew Lunn
2012-07-05 13:15 ` Andrew Lunn
[not found] ` <20120705131522.GW17534-g2DYL2Zd6BY@public.gmane.org>
2012-07-05 13:28 ` Thomas Petazzoni
2012-07-05 13:28 ` Thomas Petazzoni
2012-07-05 13:33 ` Andrew Lunn
2012-07-05 13:36 ` Thomas Petazzoni
2012-07-05 12:25 ` Arnd Bergmann
2012-07-05 12:25 ` Arnd Bergmann
[not found] ` <201207051225.55390.arnd-r2nGTMty4D4@public.gmane.org>
2012-07-05 13:08 ` Andrew Lunn
2012-07-05 13:08 ` Andrew Lunn
[not found] ` <20120705130819.GV17534-g2DYL2Zd6BY@public.gmane.org>
2012-07-05 13:47 ` Arnd Bergmann
2012-07-05 13:47 ` Arnd Bergmann
[not found] ` <201207051347.38887.arnd-r2nGTMty4D4@public.gmane.org>
2012-07-05 13:54 ` Andrew Lunn
2012-07-05 13:54 ` Andrew Lunn
[not found] ` <20120705135449.GZ17534-g2DYL2Zd6BY@public.gmane.org>
2012-07-05 15:47 ` Arnd Bergmann
2012-07-05 15:47 ` Arnd Bergmann
2012-07-05 14:14 ` Sebastian Hesselbarth
2012-07-05 14:14 ` Sebastian Hesselbarth
[not found] ` <4FF5A15A.8070309-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
2012-07-05 14:43 ` Andrew Lunn
2012-07-05 14:43 ` Andrew Lunn
2012-07-05 14:54 ` Arnd Bergmann
2012-07-05 14:54 ` Arnd Bergmann
[not found] ` <201207051454.24475.arnd-r2nGTMty4D4@public.gmane.org>
2012-07-05 15:51 ` Sebastian Hesselbarth
2012-07-05 15:51 ` Sebastian Hesselbarth
[not found] ` <4FF5B7F9.9020507-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org>
2012-07-05 16:30 ` Arnaud Patard
2012-07-05 16:30 ` Arnaud Patard (Rtp)
2012-07-05 16:16 ` Andrew Lunn
2012-07-05 16:16 ` Andrew Lunn
[not found] ` <20120705161600.GA28860-g2DYL2Zd6BY@public.gmane.org>
2012-07-06 20:08 ` Arnd Bergmann [this message]
2012-07-06 20:08 ` Arnd Bergmann
[not found] ` <201207062008.23952.arnd-r2nGTMty4D4@public.gmane.org>
2012-07-06 21:00 ` Andrew Lunn
2012-07-06 21:00 ` Andrew Lunn
[not found] ` <20120706210009.GC11470-g2DYL2Zd6BY@public.gmane.org>
2012-07-07 0:24 ` Where to put a large bootloader-supplied device tree on ARM ? Mitch Bradley
2012-07-07 0:24 ` Mitch Bradley
[not found] ` <4FF781D8.3040206-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org>
2012-07-07 1:23 ` David VomLehn (dvomlehn)
2012-07-07 1:23 ` David VomLehn (dvomlehn)
[not found] ` <2966DB01BC317A4DA23684BA0F653415013701-WE/xwOPrfQKHONfmNwMhBaBKnGwkPULj@public.gmane.org>
2012-07-07 1:59 ` Mitch Bradley
2012-07-07 1:59 ` Mitch Bradley
[not found] ` <4FF7980E.7050705-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org>
2012-07-09 4:30 ` Nicolas Pitre
2012-07-09 4:30 ` Nicolas Pitre
[not found] ` <alpine.LFD.2.02.1207090015270.31100-QuJgVwGFrdf/9pzu0YdTqQ@public.gmane.org>
2012-07-12 6:52 ` Mitch Bradley
2012-07-12 6:52 ` Mitch Bradley
[not found] ` <4FFE743B.6080504-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org>
2012-07-12 18:16 ` Nicolas Pitre
2012-07-12 18:16 ` Nicolas Pitre
2012-07-12 20:34 ` Rob Herring
2012-07-12 20:34 ` [U-Boot] " Rob Herring
2012-07-12 20:34 ` Rob Herring
2012-07-12 21:38 ` Albert ARIBAUD
2012-07-12 21:38 ` [U-Boot] " Albert ARIBAUD
2012-07-12 21:38 ` Albert ARIBAUD
2012-07-12 21:47 ` Wolfgang Denk
2012-07-12 21:47 ` [U-Boot] " Wolfgang Denk
2012-07-12 21:47 ` Wolfgang Denk
2012-07-13 1:28 ` Rob Herring
2012-07-13 1:28 ` [U-Boot] " Rob Herring
2012-07-13 1:28 ` Rob Herring
[not found] ` <4FFF79B6.6040508-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2012-07-13 6:45 ` Albert ARIBAUD
2012-07-13 6:45 ` Albert ARIBAUD
2012-07-13 6:45 ` Albert ARIBAUD
2012-07-05 18:36 ` [PATCH v2 01/12] ARM: Orion: DT support for IRQ and GPIO Controllers Mitch Bradley
2012-07-05 18:36 ` Mitch Bradley
2012-07-03 14:22 ` [PATCH v2 02/12] SPI: Refactor spi-orion to use SPI framework queue Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 03/12] spi-orion: remove uneeded spi_info Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 04/12] spi-orion: add device tree binding Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 05/12] ARM: kirkwood: use devicetree for orion-spi Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 06/12] ARM: kirkwood: use devicetree for SPI on dreamplug Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 07/12] I2C: MV64XXX: Add Device Tree support Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
[not found] ` <1341325365-21393-8-git-send-email-andrew-g2DYL2Zd6BY@public.gmane.org>
2012-07-03 15:59 ` Florian Fainelli
2012-07-03 15:59 ` Florian Fainelli
2012-07-03 16:58 ` Andrew Lunn
2012-07-03 16:58 ` Andrew Lunn
[not found] ` <20120703165839.GA1519-g2DYL2Zd6BY@public.gmane.org>
2012-07-04 19:49 ` Florian Fainelli
2012-07-04 19:49 ` Florian Fainelli
2012-07-05 6:52 ` Andrew Lunn
2012-07-05 6:52 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 08/12] Kirkwood: Add basic device tree support for QNAP TS219 Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
[not found] ` <1341325365-21393-9-git-send-email-andrew-g2DYL2Zd6BY@public.gmane.org>
2012-07-03 15:47 ` Florian Fainelli
2012-07-03 15:47 ` Florian Fainelli
2012-07-03 17:09 ` Andrew Lunn
2012-07-03 17:09 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 09/12] ARM: Kirkwood: DTify the watchdog timer Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 10/12] ATA: sata_mv: Add device tree support Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 11/12] ARM: Kirkwood: Use DT to configure SATA device Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
[not found] ` <1341325365-21393-12-git-send-email-andrew-g2DYL2Zd6BY@public.gmane.org>
2012-07-03 14:52 ` Josh Coombs
2012-07-03 14:52 ` Josh Coombs
[not found] ` <CAMW5Ufa2bsYs9VD2g9hJWKpcQNcZt+WXCA1ohYoHeLk9SambSg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-07-03 15:32 ` Andrew Lunn
2012-07-03 15:32 ` Andrew Lunn
2012-07-03 14:22 ` [PATCH v2 12/12] Crypto: CESA: Add support for DT based instantiation Andrew Lunn
2012-07-03 14:22 ` Andrew Lunn
[not found] ` <1341325365-21393-13-git-send-email-andrew-g2DYL2Zd6BY@public.gmane.org>
2012-07-03 15:50 ` Florian Fainelli
2012-07-03 15:50 ` Florian Fainelli
2012-07-03 17:03 ` Andrew Lunn
2012-07-03 17:03 ` Andrew Lunn
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