From: Sergei Shtylyov <sshtylyov@ru•mvista.com>
To: Charles Krinke <ckrinke@istor•com>
Cc: Randy Brown <rbrown@istor•com>,
Chris Carlson <ccarlson@istor•com>,
Kevin Smith <ksmith@istor•com>,
linuxppc-embedded@ozlabs•org
Subject: Re: How do external irq's get mapped?
Date: Fri, 27 Apr 2007 21:46:08 +0400 [thread overview]
Message-ID: <463236E0.8070409@ru.mvista.com> (raw)
In-Reply-To: <9F3F0A752CAEBE4FA7E906CC2FBFF57C06A1EF@MERCURY.inside.istor.com>
Charles Krinke wrote:
>>Let me try a more simplified IRQ question a different way by only
>>referring to the 8541.
>>There are 12 external interrupt sources, irq[0..11] and as I understand
>>it, they all go through one vector, ExternalInput set in
>>head_fsl_booke.S and this vector resolves to "do_IRQ()", which I believe
>>is in arch/powerpc/kernel/irq.c (not arch/ppc/kernel/...).
>>I am striving to understand how mapping of these external pins
>>irq[0..11] gets to IRQ numbers as shown with "cat /proc/interrupts".
> IIUC, the external IRQ #'s should follow those occupied by 32
> internal IRQs.
> But those shown in that file are "virtual" numbers, i.e. they got
> re-mapped by the kernel as it sees fit (basically, it tries to assign
> the same # to IRQs above 15 and remaps those below)
>>Could someone point me at some references I can read to understand this
>>nuance of the 8541 in a linux-2.6.17.11 kernel, please.
> I'm not sure arch/powerpc/ in 2.6.17 had the complete MPC8541
> support...
> So would this mean that the external IRQ0 pin would map to irq #32 and
> not irq #16 and the external IRQ11 pin would map to irq #43 and not irq
Where from is that #16?
> #27? So that if I want IRQ0, I would set my irq member of the pci_dev
> struct to 32?
Yeah, unless MPC8541 has some complications like CPM. And also note that I'm assuming 32 internal IRQs based on what MPC8540 has, not having MPC8541 specs...
> Charles
WBR, Sergei
next prev parent reply other threads:[~2007-04-27 17:44 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-26 16:10 gcj & PPC405 Patrick Olinet
2007-04-26 18:36 ` IRQ questions & puzzles Charles Krinke
2007-04-27 15:17 ` Charles Krinke
2007-04-27 15:41 ` Jon Loeliger
2007-04-27 16:55 ` How do external irq's get mapped? Charles Krinke
2007-04-27 17:03 ` Sergei Shtylyov
2007-04-27 17:35 ` Jon Loeliger
2007-04-27 17:38 ` Charles Krinke
2007-04-27 17:46 ` Sergei Shtylyov [this message]
2007-04-27 18:05 ` Charles Krinke
2007-04-27 18:42 ` Sergei Shtylyov
2007-04-27 19:34 ` Charles Krinke
2007-04-27 20:58 ` Charles Krinke
2007-04-27 21:23 ` Andy Fleming
2007-04-27 22:51 ` Charles Krinke
2007-04-28 2:30 ` Zhang Wei-r63237
2007-04-30 16:25 ` I2C support for 8541 Charles Krinke
2007-05-02 10:43 ` Clemens Koller
2007-10-13 13:52 ` Vitaly Bordug
2007-04-30 14:32 ` How do external irq's get mapped? Charles Krinke
2007-05-01 0:22 ` Andy Fleming
2007-05-01 23:11 ` Charles Krinke
2007-05-02 18:42 ` Andy Fleming
2007-05-02 22:11 ` Charles Krinke
2007-05-02 22:43 ` Andy Fleming
2007-05-03 20:19 ` Charles Krinke
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