MPIC ISU

MPIC ISU

[vb]

Greetings,

I am trying to write a BSP for an 8245 based device. One thing which
really gets me puzzled is the 'ISU' facility in
arch/powerpc/sysdev/mpic.c, there is also a notion of ISU-less
platforms, etc. I looked through the chip's programmer's reference,
even read the original AMD/Cypress OpenPIC specification - not a clue.

What is it, at the very least - what does ISU stand for?

I would really appreciate any hints,

thank you in advance,
/vb

Re: MPIC ISU

[Kumar Gala]

On Jan 16, 2008, at 12:03 AM, vb wrote:

> Greetings,
>
> I am trying to write a BSP for an 8245 based device. One thing which
> really gets me puzzled is the 'ISU' facility in
> arch/powerpc/sysdev/mpic.c, there is also a notion of ISU-less
> platforms, etc. I looked through the chip's programmer's reference,
> even read the original AMD/Cypress OpenPIC specification - not a clue.
>
> What is it, at the very least - what does ISU stand for?
>
> I would really appreciate any hints,

Interrupt service unit.  I believe its an IBM concept.

For 8245 can you look at what the linkstation port is doing and mimic  
that.  I believe its an 8245 or 8241 so it should be close to what you  
need.

         mpic = mpic_alloc(dnp, paddr, MPIC_PRIMARY |  
MPIC_WANTS_RESET, 4, 32, " EPIC     ");
         BUG_ON(mpic == NULL);

         /* PCI IRQs */
         mpic_assign_isu(mpic, 0, paddr + 0x10200);

         /* I2C */
         mpic_assign_isu(mpic, 1, paddr + 0x11000);

         /* ttyS0, ttyS1 */
         mpic_assign_isu(mpic, 2, paddr + 0x11100);

         mpic_init(mpic);

- k

Re: MPIC ISU

[vb]

Kumar,

thank you for your reply!

On Jan 18, 2008 7:54 AM, Kumar Gala <galak@kernel.crashing.org> wrote:
>
> >
> > What is it, at the very least - what does ISU stand for?
> >
> > I would really appreciate any hints,
>
> Interrupt service unit.  I believe its an IBM concept.
>
> For 8245 can you look at what the linkstation port is doing and mimic
> that.  I believe its an 8245 or 8241 so it should be close to what you
> need.
>

what platform is linkstation and what kernel version can I find it in?


TIA,
/vb

>          mpic = mpic_alloc(dnp, paddr, MPIC_PRIMARY |
> MPIC_WANTS_RESET, 4, 32, " EPIC     ");
>          BUG_ON(mpic == NULL);
>
>          /* PCI IRQs */
>          mpic_assign_isu(mpic, 0, paddr + 0x10200);
>
>          /* I2C */
>          mpic_assign_isu(mpic, 1, paddr + 0x11000);
>
>          /* ttyS0, ttyS1 */
>          mpic_assign_isu(mpic, 2, paddr + 0x11100);
>
>          mpic_init(mpic);
>
> - k
>

Re: MPIC ISU

[Kumar Gala]

On Jan 18, 2008, at 12:44 PM, vb wrote:

> Kumar,
>
> thank you for your reply!
>
> On Jan 18, 2008 7:54 AM, Kumar Gala <galak@kernel.crashing.org> wrote:
>>
>>>
>>> What is it, at the very least - what does ISU stand for?
>>>
>>> I would really appreciate any hints,
>>
>> Interrupt service unit.  I believe its an IBM concept.
>>
>> For 8245 can you look at what the linkstation port is doing and mimic
>> that.  I believe its an 8245 or 8241 so it should be close to what  
>> you
>> need.
>>
>
> what platform is linkstation and what kernel version can I find it in?

arch/powerpc/platforms/embedded6xx/linkstation.c

you should be able to find it 2.6.23 or newer.

- k

Fwd: MPIC ISU

[vb]

[add linuxppc-embedded@ozlabs.org,]

On Jan 19, 2008 8:19 AM, Kumar Gala <galak@kernel.crashing.org> wrote:
>

> >
> > what platform is linkstation and what kernel version can I find it in?
>
> arch/powerpc/platforms/embedded6xx/linkstation.c
>
> you should be able to find it 2.6.23 or newer.
>

Kumar, thank you for this clarification, I see this file in the latest kernel.

One more question, just out of curiosity - why is it in
platforms/embedded6xx and not in platforms/82xx - is there any
explicit reason for this distinction?

TIA,
/vb

> - k
>
>