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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 21:03:32 +0400	[thread overview]
Message-ID: <46322CE4.1060004@ru.mvista.com> (raw)
In-Reply-To: <9F3F0A752CAEBE4FA7E906CC2FBFF57C06A1EE@MERCURY.inside.istor.com>

Hello.

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...

WBR, Sergei

  reply	other threads:[~2007-04-27 17:01 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 [this message]
2007-04-27 17:35         ` Jon Loeliger
2007-04-27 17:38         ` Charles Krinke
2007-04-27 17:46           ` Sergei Shtylyov
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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