linux-kernel - Re: MPC85xx External/Internal Interrupts

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 6 Sep 2009 13:06:41 +0200
From:	Sebastian Andrzej Siewior <sebastian@...akpoint.cc>
To:	Alemao <xcarandiru@...il.com>
Cc:	linux-kernel@...r.kernel.org, linuxppc-dev@...abs.org
Subject: Re: MPC85xx External/Internal Interrupts

* Alemao | 2009-09-04 16:29:15 [-0300]:

>On Fri, Sep 4, 2009 at 4:28 PM, Alemao<xcarandiru@...il.com> wrote:
>> I've read some posts in the list, and about:
>>
>> irq_of_parse_and_map()
>> irq_create_map()
>>
>> But Im still trying to understand MPC85xx TSEC1 dts.
>>
>> Gianfar driver is using request_irq(), and request_irq() uses virtual
>> irq, right?
Yes. request_irq() expects a linux-irq-number. irq_of_parse_and_map()
provides such a number.

>>
>> Thats why in dts all irqs for TSEC1 are "offseted" of 16?
>>
>> Manual ?| ?DTS
>> ----------------------
>> 13 ? ? ? ? 29
>> 14 ? ? ? ? 30
>> 18 ? ? ? ? 34
>>
>
>This makes no sense.
>
>CPM2-PIC, in MPC8555ERM, its on 30. In DTS is on 46. Offset of 16.
>But my platform code use irq_of_parse_and_map()!
>
>So why this offset?!?!
irq_of_parse_and_map() creates a mapping between the hardware irq number
as specified in the device tree and the linux number (virq) which is
used within the linux api in request_irq() for instance.
irq_of_parse_and_map() is essential to create a mapping between those
two. The interrupt controller on the MPC8555 (mpic) specifies the first
few interrupt numbers as external sources followed by internal sources. 
Now, during the init sequenze of the mpic every interrupt source
(internal and external) becomes its uniqe vector number which identifies
the source by a number. This number is the hardware interrupt number
i.e. that thing in the device tree. The init sequence is a for loop
which starts at 0 for the first interrupt source which happens to be
external interrupt 0, 1 for external interrupt 1 and so on. At the time
it reaches the first internal interrupt source the vector number is 16.
That's why you always have an offset of 16 between every internal
interupt source number in the MPC855ERM document and those weired
numbers in the device tree :)

>Alemao
Sebastian
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/