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From:   Sergei Shtylyov <sergei.shtylyov@gmail.com>
Subject: Re: [PATCH 2/3] i2c: sh_mobile: Use platform_get_irq_optional() to
 get the interrupt
To:     Arnd Bergmann <arnd@arndb.de>
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        Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
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Date:   Wed, 9 Feb 2022 18:48:24 +0300
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On 2/9/22 6:18 PM, Arnd Bergmann wrote:
> On Wed, Feb 9, 2022 at 4:11 PM Sergei Shtylyov
> <sergei.shtylyov@gmail.com> wrote:
>>
>> On 2/8/22 3:31 PM, Arnd Bergmann wrote:
>>
>> [...]
>>>>> I might have missed something, but it seems the only user of IRQ 0 on
>>>>> SuperH is smsc911x Ethernet in arch/sh/boards/board-apsh4a3a.c and
>>>>> arch/sh/boards/board-apsh4ad0a.c, which use evt2irq(0x200).
>>>>> These should have been seeing the "0 is an invalid IRQ number"
>>>>> warning splat since it was introduced in commit a85a6c86c25be2d2
>>>>> ("driver core: platform: Clarify that IRQ 0 is invalid"). Or not:
>>>>
>>>>     Warning or no warning, 0 is still returned. :-/
>>>>     My attempt to put an end to this has stuck waiting a review from the IRQ
>>>> people...
>>>
>>> I had another look at this after you asked about it on IRC. I don't
>>> know much SH assembly, but I suspect IRQ 0 has not been delivered

   Neither do I, sigh...
   I do know the instuctions are 16-bit and so there are no immediate
opperands... :-)

>>> since 2009 after 1e1030dccb10 ("sh: nmi_debug support."). On a
>>
>>    Mhm... this commit changes the SH3 code while SH778x are SH4A, no?
> 
> This code is shared between both:
> 
> arch/sh/kernel/cpu/sh4/Makefile:common-y        += $(addprefix
> ../sh3/, entry.o ex.o)

   Ah, quite convoluted! :-)
   So you mean thet broke the delivery of EVT 0x200 when mucking with NMI?

>        Arnd

MBR, Sergey