From: broonie@opensource.wolfsonmicro.com (Mark Brown)
To: linux-arm-kernel@lists.infradead.org
Subject: Regarding hw irq to Linux irq mapping on ARM
Date: Wed, 22 Sep 2010 11:51:11 +0100 [thread overview]
Message-ID: <20100922105111.GA20986@sirena.org.uk> (raw)
In-Reply-To: <AANLkTinrfJkK85v2epOY95YWaVyMBcxSF2xakHqsM7vh@mail.gmail.com>
On Wed, Sep 22, 2010 at 12:08:17AM -0300, Grant Likely wrote:
> On Tue, Sep 21, 2010 at 6:45 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > Add all the I2C, SPI based irq extenders to that list. They seem to
> > pop up all over the place in rapid speed even in x86. We are happy
> > citizens of the embedded horror^Wuniverse now.
> *shudder*
> What's the irq handling latency on those? Glad I haven't had to deal
> with any of them yet.
Milisecondish, but depends on bus congestion and bus type. You need to
schedule a thread which then does one but typically more register I/O
operations on the device (read one or more IRQ status registers, and
typically write back to acknowledge the interrupts as well). These tend
for obvious reasons to be for low volume interrupts like jack detection.
WARNING: multiple messages have this Message-ID (diff)
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Grant Likely <grant.likely@secretlab.ca>
Cc: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
devicetree-discuss <devicetree-discuss@lists.ozlabs.org>,
linux-arm-kernel@lists.infradead.org,
Jeremy Kerr <jeremy.kerr@canonical.com>,
Eric Miao <eric.miao@canonical.com>,
Thomas Gleixner <tglx@linutronix.de>,
Shaju Abraham <shaju.abraham@linaro.org>
Subject: Re: Regarding hw irq to Linux irq mapping on ARM
Date: Wed, 22 Sep 2010 11:51:11 +0100 [thread overview]
Message-ID: <20100922105111.GA20986@sirena.org.uk> (raw)
In-Reply-To: <AANLkTinrfJkK85v2epOY95YWaVyMBcxSF2xakHqsM7vh@mail.gmail.com>
On Wed, Sep 22, 2010 at 12:08:17AM -0300, Grant Likely wrote:
> On Tue, Sep 21, 2010 at 6:45 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > Add all the I2C, SPI based irq extenders to that list. They seem to
> > pop up all over the place in rapid speed even in x86. We are happy
> > citizens of the embedded horror^Wuniverse now.
> *shudder*
> What's the irq handling latency on those? Glad I haven't had to deal
> with any of them yet.
Milisecondish, but depends on bus congestion and bus type. You need to
schedule a thread which then does one but typically more register I/O
operations on the device (read one or more IRQ status registers, and
typically write back to acknowledge the interrupts as well). These tend
for obvious reasons to be for low volume interrupts like jack detection.
next prev parent reply other threads:[~2010-09-22 10:51 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <AANLkTi=6nCJnfLB1uc0uLGOvOm0CX_R=j-8GQWTzmmep@mail.gmail.com>
2010-09-21 19:57 ` Regarding hw irq to Linux irq mapping on ARM Grant Likely
2010-09-21 19:57 ` Grant Likely
2010-09-21 21:45 ` Thomas Gleixner
2010-09-21 21:45 ` Thomas Gleixner
2010-09-22 3:08 ` Grant Likely
2010-09-22 3:08 ` Grant Likely
2010-09-22 5:31 ` Benjamin Herrenschmidt
2010-09-22 5:31 ` Benjamin Herrenschmidt
2010-09-22 8:59 ` Eric Miao
2010-09-22 8:59 ` Eric Miao
2010-09-23 23:45 ` Ben Dooks
2010-09-24 15:06 ` Mark Brown
2010-09-25 23:08 ` Ben Dooks
2010-09-27 17:15 ` Mark Brown
2010-09-22 10:51 ` Mark Brown [this message]
2010-09-22 10:51 ` Mark Brown
2010-09-22 10:54 ` Mark Brown
2010-09-22 10:54 ` Mark Brown
2010-09-21 22:02 ` Benjamin Herrenschmidt
2010-09-21 22:02 ` Benjamin Herrenschmidt
2010-09-22 3:06 ` Grant Likely
2010-09-22 3:06 ` Grant Likely
2010-09-22 11:00 ` Shaju Abraham
2010-09-22 11:00 ` Shaju Abraham
2010-09-22 11:52 ` Grant Likely
2010-09-22 11:52 ` Grant Likely
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100922105111.GA20986@sirena.org.uk \
--to=broonie@opensource.wolfsonmicro.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.