IRQS on 6 Slot Macs

IRQS on 6 Slot Macs

[Robert E Brose II]

In trying to get OpenGL working on a YDL 3.0 system with kernel 2.4.22-ben2
and XFree86-4.3.0-2.1e,  I get a warning on X initialization:

(II) R128(0): [drm] failure adding irq handler, there is a device already using
that irq

Digging into it more, I'm having a hard time understanding why there is a
problem and how the interrupts are allocated on a S900 (w/G3 card).


With the folowing configuration:
Slot 1:
00:0d.0 VGA compatible controller: ATI Technologies Inc Rage 128 RE/SG (prog-if 00 [VGA])
        Flags: bus master, stepping, medium devsel, latency 32, IRQ 23
Slot 2:
00:0e.0 Ethernet controller: Digital Equipment Corporation DECchip 21142/43 (rev 21)
        Flags: bus master, medium devsel, latency 32, IRQ 24
Slot 3:
01:00.0 SCSI storage controller: LSI Logic / Symbios Logic 53c875 (rev 04)
        Flags: bus master, medium devsel, latency 32, IRQ 25
Slot 4:
01:01.0 Communication controller: Comtrol Corporation RocketPort 8 Intf (rev 02)
        Flags: medium devsel, IRQ 25
Slot 5:
01:02.0 FireWire (IEEE 1394): Texas Instruments FireWire Controller (rev 01) (pr
og-if 10 [OHCI])
        Flags: bus master, medium devsel, latency 32, IRQ 25
Slot 6:
01:03.0 USB Controller: Lucent Microelectronics USS-312 USB Controller (rev 10)
(prog-if 10 [OHCI])
        Flags: bus master, medium devsel, latency 32, IRQ 25

and /proc/interrupts

  2:          0   PMAC-PIC  Edge      MACE-txdma
  3:      77087   PMAC-PIC  Edge      MACE-rxdma
  8:        345   PMAC-PIC  Edge      Built-in Sound out
  9:          0   PMAC-PIC  Edge      Built-in Sound in
 13:         71   PMAC-PIC  Edge      MESH
 14:      77840   PMAC-PIC  Edge      MACE
 17:          0   PMAC-PIC  Edge      Built-in Sound misc
 18:       4352   PMAC-PIC  Edge      ADB
 19:          0   PMAC-PIC  Edge      SWIM3
 24:      21259   PMAC-PIC  Level     eth0
 25:   72922493   PMAC-PIC  Level     sym53c8xx, usb-ohci, ohci1394



A couple of things right off, the rage128 appears to be the only thing on
irq 23 however 23 doesn't show up in /proc/interrupts meaning, I suppose,
that it's not using the interrupt. So why does the drm complain?

How come everything from slots 3-6 says it's on the same interrupt (25)?

Bob
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Re: IRQS on 6 Slot Macs

[Benjamin Herrenschmidt]

On Mon, 2003-11-03 at 14:35, Robert E Brose II wrote:

> A couple of things right off, the rage128 appears to be the only thing on
> irq 23 however 23 doesn't show up in /proc/interrupts meaning, I suppose,
> that it's not using the interrupt. So why does the drm complain?
>
> How come everything from slots 3-6 says it's on the same interrupt (25)?

I don't know what's up with the DRM not liking your interrupt. I can
answer for the sharing of USB, symbios and firewire interrupts: all 3
slots share one interrupt because of bad motherboard design :)
Basicallly, what they did when designing that machine was to use a
standard powersurge design with 3 slots and replace one of them
with a PCI<->PCI bridge. Since they didn't "know" how to get more
interrupt lines out of Grand Central, they just also stuffed all
interrupt lines together for those 4 slots (I'm pretty sure GC do
have spare lines they could have used, but that would have meant
updating Open Firmware to understand the layout, I doubt the people
who designed that machine wanted to dive into that).

Ben.


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Re: IRQS on 6 Slot Macs

[Bob Brose]

User Benjamin Herrenschmidt says:
> On Mon, 2003-11-03 at 14:35, Robert E Brose II wrote:
>
> > A couple of things right off, the rage128 appears to be the only thing on
> > irq 23 however 23 doesn't show up in /proc/interrupts meaning, I suppose,
> > that it's not using the interrupt. So why does the drm complain?
> >
> > How come everything from slots 3-6 says it's on the same interrupt (25)?
>
> I don't know what's up with the DRM not liking your interrupt. I can
> answer for the sharing of USB, symbios and firewire interrupts: all 3
> slots share one interrupt because of bad motherboard design :)
> Basicallly, what they did when designing that machine was to use a
> standard powersurge design with 3 slots and replace one of them
> with a PCI<->PCI bridge. Since they didn't "know" how to get more
> interrupt lines out of Grand Central, they just also stuffed all
> interrupt lines together for those 4 slots (I'm pretty sure GC do
> have spare lines they could have used, but that would have meant
> updating Open Firmware to understand the layout, I doubt the people
> who designed that machine wanted to dive into that).
>
> Ben.

I suppose then that I should reorder the cards so that the ones generating
the most interrupts would be in the first 2 slots? It's pretty funny
having the possibility of the use of lots of irqs then ending up with
x86 style sharing. :(

Bob
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Re: IRQS on 6 Slot Macs

[Geert Uytterhoeven]

On Mon, 3 Nov 2003, Bob Brose wrote:
> User Benjamin Herrenschmidt says:
> > On Mon, 2003-11-03 at 14:35, Robert E Brose II wrote:
> > > A couple of things right off, the rage128 appears to be the only thing on
> > > irq 23 however 23 doesn't show up in /proc/interrupts meaning, I suppose,
> > > that it's not using the interrupt. So why does the drm complain?
> > >
> > > How come everything from slots 3-6 says it's on the same interrupt (25)?
> >
> > I don't know what's up with the DRM not liking your interrupt. I can
> > answer for the sharing of USB, symbios and firewire interrupts: all 3
> > slots share one interrupt because of bad motherboard design :)
> > Basicallly, what they did when designing that machine was to use a
> > standard powersurge design with 3 slots and replace one of them
> > with a PCI<->PCI bridge. Since they didn't "know" how to get more
> > interrupt lines out of Grand Central, they just also stuffed all
> > interrupt lines together for those 4 slots (I'm pretty sure GC do

Tsss... They could at least have `swizzled' the lines...

> > have spare lines they could have used, but that would have meant
> > updating Open Firmware to understand the layout, I doubt the people
> > who designed that machine wanted to dive into that).
> >
> > Ben.
>
> I suppose then that I should reorder the cards so that the ones generating
> the most interrupts would be in the first 2 slots? It's pretty funny
> having the possibility of the use of lots of irqs then ending up with
> x86 style sharing. :(

Yes, try to spread out interrupts evenly across interrupt lines.
Furthermore the presence of the bridge will probably incur a slight slowdown
for the last 3 slots, too. Don't know whether it's significant (should reread
PCI specs first).

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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Re: IRQS on 6 Slot Macs

[Benjamin Herrenschmidt]

> I suppose then that I should reorder the cards so that the ones generating
> the most interrupts would be in the first 2 slots? It's pretty funny
> having the possibility of the use of lots of irqs then ending up with
> x86 style sharing. :(

Yup :(

Ben.


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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 17:54 +1100 11/03/2003, Benjamin Herrenschmidt wrote:
>On Mon, 2003-11-03 at 14:35, Robert E Brose II wrote:
>
>>  A couple of things right off, the rage128 appears to be the only thing on
>>  irq 23 however 23 doesn't show up in /proc/interrupts meaning, I suppose,
>>  that it's not using the interrupt. So why does the drm complain?
>>
>>  How come everything from slots 3-6 says it's on the same interrupt (25)?
>
>I don't know what's up with the DRM not liking your interrupt. I can
>answer for the sharing of USB, symbios and firewire interrupts: all 3
>slots share one interrupt because of bad motherboard design :)

I'm not sure it was bad motherboard design--at least, not unless
following specifications leads to bad motherboard design.   I can't
find the reference now, but I could swear that I read that the proper
procedure when implementing a PCI-PCI Bridge is to tie the
subordinate slot's interrupts into the interrupt for the host slot.
The firmware for the host machine is supposed to be able to sort this
out, if written properly.

After all, one can, in theory, add 1024 PCI slots to a machine using
PPBs.   There aren't going to be 1024 interrupts available.   The
specification for PCI-PCI Bridges had to have some more general
method of handling interrupts for slots behind a PPB, and tieing them
to the host slot interrupt makes the most sense.

All that said, the firmware for the x500 and x600 Macs is not written
properly, at least with respect to implementing PCI-PCI Bridges.

>Basicallly, what they did when designing that machine was to use a
>standard powersurge design with 3 slots and replace one of them
>with a PCI<->PCI bridge. Since they didn't "know" how to get more
>interrupt lines out of Grand Central, they just also stuffed all
>interrupt lines together for those 4 slots (I'm pretty sure GC do
>have spare lines they could have used,

The interrupts for the slots (in the 9500/9600) go to the following pins on GC:

Slot #      GC pin #
1                193
2	     194
3	     189
4	     188
5	      173
6	      174

On the S900 (and J700) the interrupts for slots 3 through 6 are tied
to pin 189.

Slots 1 through 3 are also correct for all other PowerSurge machines.
I would love to know if there are other unused interrupts available,
as the PowerSurge architecture supposedly can support up to four
Bandit chips, but as far as I know, if one constructed such a beast,
there'd be no interrupts available for any PCI slots beyond six.

This seems to be born out (limited interrupts available) by the
gymnastics they went through to arrange the interrupts in the Apple
Network Server, which has six PCI slots, but also four built-in PCI
devices (including Grand Central) on the motherboard.  They didn't
use any previously unused interrupts on GC in the ANS, they just
rearranged and combined the interrupts used in the 9500.

However, I can't help but wonder if all that lovely video circuitry
on the 7500 and 8500 requires any interrupts and if so, where they
come from.  Do they recycle the interrupts for slots 4 -6 or are
there other interrupts available on GC besides the ones for the six
slots?

>but that would have meant
>updating Open Firmware to understand the layout, I doubt the people
>who designed that machine wanted to dive into that).

At 14:16 +1100 11/04/2003, Benjamin Herrenschmidt wrote:
>Probably because updating Apple's 1.0.5 OF code to assign them properly
>with the P2P setup was beyond their ability to deal with crappy code :)

What is P2P setup?

The cloners just soldered Apple ROMs down in their machines.  The
ROM/firmware used in the PowerComputing and Umax machines (except
PowerBase and C series) was the same ROM/firmware used in the x500
series of machines--the $77D.28F2.   This ROM was used in the 7200,
7500, 8500, 9500, all of PCC's Catalyst clones, PowerWave, PowerTower
Pro, S900 and the J700.

I'm not sure if the cloner's license even allowed them to modify the
ROM.  The chips are labeled with Apple part numbers and Apple
markings, so I think they really did purchase them from Apple, rather
than licensing their production.

Anyway, the point being that even if Umax had wanted to go that route
(rewrite/modify/fix OF 1.05), I'm not sure it was technically
feasible under the licensing agreement.   Is hacking the interrupt
assignment for the PCI slots the kind of thing one could squeeze into
the NVRAMrc?

Jeff Walther


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Re: IRQS on 6 Slot Macs

[Benjamin Herrenschmidt]

> I'm not sure it was bad motherboard design--at least, not unless
> following specifications leads to bad motherboard design.   I can't
> find the reference now, but I could swear that I read that the proper
> procedure when implementing a PCI-PCI Bridge is to tie the
> subordinate slot's interrupts into the interrupt for the host slot.
> The firmware for the host machine is supposed to be able to sort this
> out, if written properly.

Hrm... nah nah nah :) If you tie them together, you get one
interrupt shared for all in the end... what you can do on
platforms with an irq router like x86 is to make use of the
4 different irq lines of the bridge and route them to the
sub-slots, but on macs, like on lots of othre platforms, the
4 lines are just or-ed together.

Anyway, such a rule really only apply when you design a PCI
card with a P2P bridge on it. As long as you are on the
motherboard, you do what you want.

> After all, one can, in theory, add 1024 PCI slots to a machine using
> PPBs.   There aren't going to be 1024 interrupts available.

Why ? Some iSeries have up to 2048 irq lines afaik ;)

> The
> specification for PCI-PCI Bridges had to have some more general
> method of handling interrupts for slots behind a PPB, and tieing them
> to the host slot interrupt makes the most sense.

No. The P2P specification provides nothing for interrupts, just
a generic "guideline" that you may or may not follow depending on
what you are designing. The way you route a motherboard interrupt
line (regardless of it beeing on a bridge or not) is a matter
of commen sense rather.

> All that said, the firmware for the x500 and x600 Macs is not written
> properly, at least with respect to implementing PCI-PCI Bridges.

Well... Again, do not mix what happens on the mobo and what happens
in slots. Indeed, the x500 and x600 machines have an OF bug that
cause it to not properly assign the shared irq line to the child
devices, but that's really only a concern for _slots_.

> >Basicallly, what they did when designing that machine was to use a
> >standard powersurge design with 3 slots and replace one of them
> >with a PCI<->PCI bridge. Since they didn't "know" how to get more
> >interrupt lines out of Grand Central, they just also stuffed all
> >interrupt lines together for those 4 slots (I'm pretty sure GC do
> >have spare lines they could have used,
>
> The interrupts for the slots (in the 9500/9600) go to the following pins on GC:
>
> Slot #      GC pin #
> 1                193
> 2	     194
> 3	     189
> 4	     188
> 5	      173
> 6	      174
>
> On the S900 (and J700) the interrupts for slots 3 through 6 are tied
> to pin 189.

Yup. My point is that those could have been dispatched to the GC pins

> Slots 1 through 3 are also correct for all other PowerSurge machines.
> I would love to know if there are other unused interrupts available,
> as the PowerSurge architecture supposedly can support up to four
> Bandit chips, but as far as I know, if one constructed such a beast,
> there'd be no interrupts available for any PCI slots beyond six.

I don't know how much exactly GC provides. It has a single mask
register of 32 interrupts, so if you count all the GC internal ones,
that still leaves a few of them I beleive... You'd need the pinout
of GC, I don't have it (maybe you do ? :) I'm interested in any spec
for these old chipsets...)

> This seems to be born out (limited interrupts available) by the
> gymnastics they went through to arrange the interrupts in the Apple
> Network Server, which has six PCI slots, but also four built-in PCI
> devices (including Grand Central) on the motherboard.  They didn't
> use any previously unused interrupts on GC in the ANS, they just
> rearranged and combined the interrupts used in the 9500.

Yup. Still... it would have made a lot of sense for the S900 designers
to actually route the additional slot interrupts to separate GC
interrupt pins. The main problem with that would have been the need to
"teach" Apple's OF about the binding, which of course would have been
a total mess....

> However, I can't help but wonder if all that lovely video circuitry
> on the 7500 and 8500 requires any interrupts and if so, where they
> come from.  Do they recycle the interrupts for slots 4 -6 or are
> there other interrupts available on GC besides the ones for the six
> slots?

Maybe compare the interrupt numbers ? I don't have my datas at hand
but that should give you an idea of who goes where. IIRC, some Mklinux
source (or maybe it's early darwin source) had a map of all the irqs
of GC as well.

> >but that would have meant
> >updating Open Firmware to understand the layout, I doubt the people
> >who designed that machine wanted to dive into that).
>
> At 14:16 +1100 11/04/2003, Benjamin Herrenschmidt wrote:
> >Probably because updating Apple's 1.0.5 OF code to assign them properly
> >with the P2P setup was beyond their ability to deal with crappy code :)
>
> What is P2P setup?

PCI 2 PCI bridge setup.

> The cloners just soldered Apple ROMs down in their machines.  The
> ROM/firmware used in the PowerComputing and Umax machines (except
> PowerBase and C series) was the same ROM/firmware used in the x500
> series of machines--the $77D.28F2.   This ROM was used in the 7200,
> 7500, 8500, 9500, all of PCC's Catalyst clones, PowerWave, PowerTower
> Pro, S900 and the J700.

Yup. That is part of the problem.

> I'm not sure if the cloner's license even allowed them to modify the
> ROM.  The chips are labeled with Apple part numbers and Apple
> markings, so I think they really did purchase them from Apple, rather
> than licensing their production.

Yah, though they probably could have dealt some small change to OF
to deal with that issue, or have an nvramrc patch (ugh !) at worst.

> Anyway, the point being that even if Umax had wanted to go that route
> (rewrite/modify/fix OF 1.05), I'm not sure it was technically
> feasible under the licensing agreement.   Is hacking the interrupt
> assignment for the PCI slots the kind of thing one could squeeze into
> the NVRAMrc?

Yes, that's doable. A bit more tricky, they could have put a routing
circuit optionally or'ing them all together. By default, the machine
boots with them all or'ed. If the nvramrc script (or whatever other
possible software patch) doesn't load, they stay that way. The software
patch ticks an IO disabling that OR'ing after patching either the
device-tree  (nvramrc patch) or whatever MacOS used for routing.

Probably doable with a few gates, or bits of a PLD if any was already
there.

Ben.


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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 09:32 +1100 11/05/2003, Benjamin Herrenschmidt wrote:
>>  By iSeries, do you mean iBook and iMac?   Or is that something else?
>>  I'm still kind of living in the PowerSurge world, with occasional
>>  forays up to Beige G3.  :-)
>
>Nah ;) iSeries are IBM big boxes :) Though a G5 has about 256 interrupt
>sources on his 2 openpics, but I doubt they are all used.

How do they handle that physically?   Surely there are not 256
separate wires?   Do they use an 8 wire bus and signal interrupts as
if they were addresses?

>Isn't MESH an IBM part ? I may be confused... Also, I would have
>expected MESH to be actually _inside_ GC, it isn't ?

It is an Apple part.  I do not know for certain where it came from
originally.  However, following the evolution of Apple design
suggests that it's based on the NCR 53CF96.   The previous generation
of machines, the PPC NuBus machines, included the PMac 8100 and 9100
which used exactly the same CURIO chip as the x500 machines to
provide the slow (5 MB/s) ethernet and used the NCR 53CF96 to provide
the Fast SCSI bus.   Earlier machines (the Quadras) used the NCR
53C96 to handle their SCSI bus.   And, of course, the earlier
machines used the NCR 53C80.

Additionally, the 53CF96 chip in the 8100 is in a 100 pin, 20 X 30
quad flat pack.   MESH is in exactly the same package.    This is not
definitive, but suggests to me that MESH is simply a licensed 53CF96.


MESH is a separate chip and is not contained in GC.   It would be
kind of cool if MESH was in GC, because then one could implement the
Fast SCSI bus on 7200s and the PCC Catalyst clones, but that's not
the way it is....

In my queue of projects (massive and ever lengthening) is to install
a 53CF96 in place of a MESH and/or vice versa and see what happens.
However, I wonder if a similar test could be done with software.   I
assume that Linux implements some kind of driver to support MESH.
Is there a driver for the 53CF96 which could be substituted or
compared as an experiment.

As an aside, it's too bad that CURIO's pinout is not available from
AMD.   They have datasheets for several related chips on their site.
I guess CURIO was a custom job for Apple or something.

>>  There is no PLD between the PCI interrupt pins and GC on the S900
>>  board.  But, since Umax designed the board, they certainly could have
>>  added one.   They already did that quirky E100 hack to PCI slot 1.
>>  I haven't dug into that, but I'd like to know how they made that
>>  work.  Does an Enet card require an interrupt?  Does it ever master
>>  the PCI bus?
>
>Yes, especially recent ones, they need both.

Thank you.

Jeff Walther


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Re: IRQS on 6 Slot Macs

[Benjamin Herrenschmidt]

On Wed, 2003-11-05 at 13:11, Jeff Walther wrote:
> At 09:32 +1100 11/05/2003, Benjamin Herrenschmidt wrote:
> >>  By iSeries, do you mean iBook and iMac?   Or is that something else?
> >>  I'm still kind of living in the PowerSurge world, with occasional
> >>  forays up to Beige G3.  :-)
> >
> >Nah ;) iSeries are IBM big boxes :) Though a G5 has about 256 interrupt
> >sources on his 2 openpics, but I doubt they are all used.
>
> How do they handle that physically?   Surely there are not 256
> separate wires?   Do they use an 8 wire bus and signal interrupts as
> if they were addresses?

Lots of them are internal to the K2 & U3 ASICs and the link between
those is over HyperTransport (though in the current setup, I don't
think they use HT interrupt facilities, they just wire U3 output
to one K2 output, possibly a GPIO, so you deal with them as cascaded
controllers, which prevents anything like interrupt affinity on SMP,
though it's not that bad as U3 IRQs so far only concern the i2c
controller in there.

They do have quite a bunch of lines going out though, some to slots,
other on GPIOs that can be used as IRQ inputs.

> >Isn't MESH an IBM part ? I may be confused... Also, I would have
> >expected MESH to be actually _inside_ GC, it isn't ?
>
> It is an Apple part.  I do not know for certain where it came from
> originally.  However, following the evolution of Apple design
> suggests that it's based on the NCR 53CF96.

8500 class machines also have a 53c94 (Curio) and I remember
seeing a document about an IBM "MESH" scsi controller, I suspect though
that both IBM and Apple may have picked the same original cell. I do
still think the MESH cell is actually inside GC though, as it is
inside later revs of Apple "mac-io" ASIC until paddington.

> The previous generation
> of machines, the PPC NuBus machines, included the PMac 8100 and 9100
> which used exactly the same CURIO chip as the x500 machines to
> provide the slow (5 MB/s) ethernet and used the NCR 53CF96 to provide
> the Fast SCSI bus.   Earlier machines (the Quadras) used the NCR
> 53C96 to handle their SCSI bus.   And, of course, the earlier
> machines used the NCR 53C80.

Ok. I need to look at the 53C96 specs to see if it's really similar
to MESH.

> Additionally, the 53CF96 chip in the 8100 is in a 100 pin, 20 X 30
> quad flat pack.   MESH is in exactly the same package.    This is not
> definitive, but suggests to me that MESH is simply a licensed 53CF96.
>
>
> MESH is a separate chip and is not contained in GC.   It would be
> kind of cool if MESH was in GC, because then one could implement the
> Fast SCSI bus on 7200s and the PCC Catalyst clones, but that's not
> the way it is....

Ok. Strange then. I was sure it was internal. It is internal to
Hydra (the "CHRP" MacIO chip).

> In my queue of projects (massive and ever lengthening) is to install
> a 53CF96 in place of a MESH and/or vice versa and see what happens.
> However, I wonder if a similar test could be done with software.   I
> assume that Linux implements some kind of driver to support MESH.
> Is there a driver for the 53CF96 which could be substituted or
> compared as an experiment.

Maybe, but one important thing with MESH is that it's behind a DBDMA
controller, which completely changes the way you actually use it.

> As an aside, it's too bad that CURIO's pinout is not available from
> AMD.   They have datasheets for several related chips on their site.
> I guess CURIO was a custom job for Apple or something.

It's a 53c94 afaik. We do have a driver for it. And Apple released
both their MESH and Curio drivers in darwin.

It would be interesting if someone acutally had time to review those
and find out which of the HW bugs they work around in darwin for which
we would need equivalent fixes in linux :)

Ben.


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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 13:46 +1100 11/05/2003, Benjamin Herrenschmidt wrote:

>Ok. I need to look at the 53C96 specs to see if it's really similar
>to MESH.

Nitpick:  53CF96.  The 53C96 is an earlier chip which does not
support Fast SCSI.  The 53C96 was used in the Quadras to provide the
only SCSI bus in those machines.  The 53CF96 was used in the 8100 and
9100 to provide the Fast SCSI bus.

The MESH is marked 343S1146.

>Ok. Strange then. I was sure it was internal. It is internal to
>Hydra (the "CHRP" MacIO chip).

It went internal after the PowerSurge machines.   The Beige G3 lacks
a Fast SCSI bus and SCSI isn't built in after that.  However,
according to an Apple Tech note, one of the Blue & White chips has an
internal MESH cell because some part of the OS or firmware expects to
find a MESH.   However, the MESH connections are not carried to the
exterior of the chip.

>>  As an aside, it's too bad that CURIO's pinout is not available from
>>  AMD.   They have datasheets for several related chips on their site.
>>  I guess CURIO was a custom job for Apple or something.
>
>It's a 53c94 afaik. We do have a driver for it. And Apple released
>both their MESH and Curio drivers in darwin.

The SCSI cell in CURIO is a 53C94, but CURIO provides SCSI, ethernet
and serial port support all in one chip.   So the pinout of the 53C94
doesn't tell one about the pinout of CURIO, except it does identify
some of the pins which must be present on CURIO somewhere.

In fact, a great deal of the pinout of GC would be revealed if one
had a pinout for CURIO, because much of what GC does is connect to
CURIO.

It's interesting that the drivers are available in Darwin.  Thank
you.  I'm going to have to brush off those programming skills, I
think.   That's such a huge learning curve in my case, though.

CURIO was used from the NuBus power macs (or was it first in the AV
Quadras?) through the x500 series.   It had quite a long life.   It
is marked AM79C950KC.

>It would be interesting if someone acutally had time to review those
>and find out which of the HW bugs they work around in darwin for which
>we would need equivalent fixes in linux :)

Yes, it would.

Jeff Walther


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Re: IRQS on 6 Slot Macs

[Benjamin Herrenschmidt]

> It went internal after the PowerSurge machines.   The Beige G3 lacks
> a Fast SCSI bus and SCSI isn't built in after that.  However,
> according to an Apple Tech note, one of the Blue & White chips has an
> internal MESH cell because some part of the OS or firmware expects to
> find a MESH.   However, the MESH connections are not carried to the
> exterior of the chip.

Well, it's not that the OS/firm expect a MESH... It's that the B&W G3
and the early Yikes G4 used the Paddington ASIC which contain a MESH...
Apple didn't produce a entire new ASIC line just to strip it from there.

Next MacIO chip is KeyLargo (coming with UniNorth that is AGP machines)
and this one doesn't have MESH anymore.

> The SCSI cell in CURIO is a 53C94, but CURIO provides SCSI, ethernet
> and serial port support all in one chip.   So the pinout of the 53C94
> doesn't tell one about the pinout of CURIO, except it does identify
> some of the pins which must be present on CURIO somewhere.

Ah ? Interesting. I though like for MESH that the ESCC and MACE were
also part of GC. They do appear as cells of GC in the OF device
tree, so it may be that they just "split" the ASIC for production
reasons.

> In fact, a great deal of the pinout of GC would be revealed if one
> had a pinout for CURIO, because much of what GC does is connect to
> CURIO.
>
> It's interesting that the drivers are available in Darwin.  Thank
> you.  I'm going to have to brush off those programming skills, I
> think.   That's such a huge learning curve in my case, though.
>
> CURIO was used from the NuBus power macs (or was it first in the AV
> Quadras?) through the x500 series.   It had quite a long life.   It
> is marked AM79C950KC.
>
> >It would be interesting if someone acutally had time to review those
> >and find out which of the HW bugs they work around in darwin for which
> >we would need equivalent fixes in linux :)
>
> Yes, it would.
>
> Jeff Walther
>
>
--
Benjamin Herrenschmidt <benh@kernel.crashing.org>


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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 18:18 +1100 11/05/2003, Benjamin Herrenschmidt wrote:

>Well, it's not that the OS/firm expect a MESH... It's that the B&W G3
>and the early Yikes G4 used the Paddington ASIC which contain a MESH...
>Apple didn't produce a entire new ASIC line just to strip it from there.
>
>Next MacIO chip is KeyLargo (coming with UniNorth that is AGP machines)
>and this one doesn't have MESH anymore.

Ah, thanks.

>>  The SCSI cell in CURIO is a 53C94, but CURIO provides SCSI, ethernet
>>  and serial port support all in one chip.   So the pinout of the 53C94
>>  doesn't tell one about the pinout of CURIO, except it does identify
>>  some of the pins which must be present on CURIO somewhere.
>
>Ah ? Interesting. I though like for MESH that the ESCC and MACE were
>also part of GC. They do appear as cells of GC in the OF device
>tree, so it may be that they just "split" the ASIC for production
>reasons.

CURIO is an interesting chip.   It has the unenhanced SCSI (53C94),
MACE and ESCC all on one chip.   It's an AMD chip and has no Apple
markings on it at all, which implies that it is a generally available
AMD product.   Checking their listings of datasheets, one finds
several similar chips and a part number series that would include the
79C950 but no listing for the datasheet for the CURIO/79C950.
Usually when Apple has a chip made just for Apple it has Apple
markings on it somewhere.   So I'm uncertain what the deal is with
CURIO.

Ah, I went and checked Freetradezone.com and they have a datasheet
available.  Unfortunately, as of Oct. 31 they require a subscription.
They were my best source of obscure datasheets.  Grrr.   Hard to
blame them though.   Googling on the 79C950 shows many vendors have
it available, so I guess it was generally available, so I don't
understand why AMD doesn't have the datasheet up.

Anyway, it wasn't a case of splitting an ASIC.   As closely as GC and
CURIO work together that's a reasonable conclusion.   But CURIO was
used in the x100 NuBus PowerMacs before they put it in the x500
series.   So CURIO had a couple of years of history before GC showed
up.

Jeff Walther

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Re: IRQS on 6 Slot Macs

[Brad Boyer]

On Wed, Nov 05, 2003 at 11:39:33AM -0600, Jeff Walther wrote:
> At 18:18 +1100 11/05/2003, Benjamin Herrenschmidt wrote:
> >> The SCSI cell in CURIO is a 53C94, but CURIO provides SCSI, ethernet
> >> and serial port support all in one chip.   So the pinout of the 53C94
> >> doesn't tell one about the pinout of CURIO, except it does identify
> >> some of the pins which must be present on CURIO somewhere.
>
> CURIO is an interesting chip.   It has the unenhanced SCSI (53C94),
> MACE and ESCC all on one chip.   It's an AMD chip and has no Apple
> markings on it at all, which implies that it is a generally available
> AMD product.   Checking their listings of datasheets, one finds
> several similar chips and a part number series that would include the
> 79C950 but no listing for the datasheet for the CURIO/79C950.
> Usually when Apple has a chip made just for Apple it has Apple
> markings on it somewhere.   So I'm uncertain what the deal is with
> CURIO.
>
> Anyway, it wasn't a case of splitting an ASIC.   As closely as GC and
> CURIO work together that's a reasonable conclusion.   But CURIO was
> used in the x100 NuBus PowerMacs before they put it in the x500
> series.   So CURIO had a couple of years of history before GC showed
> up.

I just looked, and the Quadra 840AV has a chip on the motherboard with
an AMD logo and the part number AM79C950KC. And as a noteworthy fact,
the AV models were the only 68k models to have a number of features,
including using the MACE ethernet and having DMA on the serial ports.
All the other 68k Macs with onboard Ethernet use the sonic driver.
Supposedly the AV models also had an AMD chip controlling the floppy
drive, but this is the only AMD labelled chip. Perhaps it has more
features than SCSI, Ethernet, and serial? There are several very
large Apple ASICs, tho...

	Brad Boyer
	flar@allandria.com


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Re: IRQS on 6 Slot Macs

[Michael R. Zucca]

On Thursday, November 6, 2003, at 02:07  AM, Brad Boyer wrote:

Sorry to butt-in but I've done a little work on the AV's for NetBSD.

> And as a noteworthy fact,
> the AV models were the only 68k models to have a number of features,
> including using the MACE ethernet and having DMA on the serial ports.

Most of the I/O on the AV's had DMA. Unfortunately, the DMA engine is a
bit brain dead. It's not descriptor based. Each I/O item has a channel
and two sets of registers that indicate physical start address and
transfer length. I think each channel has a "done" interrupt so I
suppose it's possible to fake descriptor DMA in software.

> All the other 68k Macs with onboard Ethernet use the sonic driver.
> Supposedly the AV models also had an AMD chip controlling the floppy
> drive, but this is the only AMD labelled chip.

The floppy on the AV's is controlled by the NEC uPD72070. The only
surviving documentation I could find was in Japanese! After a little
translation it seems the chip is pretty much the same as a typical PC
floppy controller but some of the commands to the chip take an extra
byte or two. I think this is because the chip can handle both GCR and
MFM.

>  Perhaps it has more
> features than SCSI, Ethernet, and serial? There are several very
> large Apple ASICs, tho...

The video on those machines is very complex. In fact, I think it's the
same video subsystem (Civic) that is on the HPV card of the x100
PowerMacs. There's also DMA sound, a NuBus bridge, and, of course,
there's the DSP.

All in all it's an interesting little machine. If I had more time I'd
be writing drivers for it :-)

--
----------------------------------------------
  Michael Zucca - mrz5149@acm.org
----------------------------------------------
  "I'm too old to use Emacs." -- Rod MacDonald
----------------------------------------------


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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 23:07 -0800 11/05/2003, Brad Boyer wrote:

>I just looked, and the Quadra 840AV has a chip on the motherboard with
>an AMD logo and the part number AM79C950KC. And as a noteworthy fact,
>the AV models were the only 68k models to have a number of features,
>including using the MACE ethernet and having DMA on the serial ports.
>All the other 68k Macs with onboard Ethernet use the sonic driver.
>Supposedly the AV models also had an AMD chip controlling the floppy
>drive, but this is the only AMD labelled chip. Perhaps it has more
>features than SCSI, Ethernet, and serial? There are several very
>large Apple ASICs, tho...

Thank you.  So CURIO goes all the way back to the AV Quadras.    I
thought I had read that but wasn't certain.   I know it doesn't go
any further back because I have examples of the Q650/800  and Q700
boards handy and they definitely don't use it.

According to Apple's Developer Note for the AV Quadras,
"Centris_660AV_Quadra_840AV.pdf" the floppy controller is a separate
chip called "New Age".    I would expect it to be relatively small,
probably 40 or 44 pins in a PLCC package, but that's a guess based on
Apple's other floppy controllers.

I think CURIO is limited to the three features listed.

The SWIM is a separate chip in the x100 Macs, but I think it's
integrated into GC in the x500 Macs.    Let's see, from
"PPC_9500.pdf":

"The Grand Central IC performs the following functions:
     support for the Cuda IC (the VIA registers)
     central system interrupt collection
     support for descriptor-based DMA for I/O devices
     floppy disk interface (SWIM III)

"The Grand Central IC contains a DMA controller. It provides DBDMA
support for all I/O transfers, including transfers through its
internal I/O controllers as well as transfers through the Curio IC
for other I/O devices."

Jeff Walther

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Re: IRQS on 6 Slot Macs

[Geert Uytterhoeven]

On Tue, 4 Nov 2003, Jeff Walther wrote:
> At 09:32 +1100 11/05/2003, Benjamin Herrenschmidt wrote:
> >Isn't MESH an IBM part ? I may be confused... Also, I would have
> >expected MESH to be actually _inside_ GC, it isn't ?
>
> It is an Apple part.  I do not know for certain where it came from
> originally.  However, following the evolution of Apple design
> suggests that it's based on the NCR 53CF96.   The previous generation
> of machines, the PPC NuBus machines, included the PMac 8100 and 9100
> which used exactly the same CURIO chip as the x500 machines to
> provide the slow (5 MB/s) ethernet and used the NCR 53CF96 to provide
> the Fast SCSI bus.   Earlier machines (the Quadras) used the NCR
> 53C96 to handle their SCSI bus.   And, of course, the earlier
> machines used the NCR 53C80.
>
> Additionally, the 53CF96 chip in the 8100 is in a 100 pin, 20 X 30
> quad flat pack.   MESH is in exactly the same package.    This is not
> definitive, but suggests to me that MESH is simply a licensed 53CF96.
>
>
> MESH is a separate chip and is not contained in GC.   It would be
> kind of cool if MESH was in GC, because then one could implement the
> Fast SCSI bus on 7200s and the PCC Catalyst clones, but that's not
> the way it is....
>
> In my queue of projects (massive and ever lengthening) is to install
> a 53CF96 in place of a MESH and/or vice versa and see what happens.
> However, I wonder if a similar test could be done with software.   I
> assume that Linux implements some kind of driver to support MESH.
> Is there a driver for the 53CF96 which could be substituted or
> compared as an experiment.

There's a driver for the 53C96 in the Quadra (mac_esp.c and NCR53C9x.c).

The NCR53C9x.c core supports various 53C9x chips, including (53CF9x and FAS*),
and is used on various platforms.  It's very similar to the esp.c core for
SPARC, but Dave didn't like us to merge non-SPARC support in his driver.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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Re: IRQS on 6 Slot Macs

[Michael Schmitz]

> > In my queue of projects (massive and ever lengthening) is to install
> > a 53CF96 in place of a MESH and/or vice versa and see what happens.
> > However, I wonder if a similar test could be done with software.   I
> > assume that Linux implements some kind of driver to support MESH.
> > Is there a driver for the 53CF96 which could be substituted or
> > compared as an experiment.
>
> There's a driver for the 53C96 in the Quadra (mac_esp.c and NCR53C9x.c).
>
> The NCR53C9x.c core supports various 53C9x chips, including (53CF9x and FAS*),
> and is used on various platforms.  It's very similar to the esp.c core for
> SPARC, but Dave didn't like us to merge non-SPARC support in his driver.

The Quadra 53C96 driver is a strange beast since we don't know how to use
DMA on those boxes (in case they have DMA) so it implements PIO.
Plus we had trouble with reselection interrupt races there. Better
look at the Amiga ESP code.

	Michael


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Re: IRQS on 6 Slot Macs

[Etsushi Kato]

On 2003.11.5, at 07:38  PM, Michael Schmitz wrote:

>
>>> In my queue of projects (massive and ever lengthening) is to install
>>> a 53CF96 in place of a MESH and/or vice versa and see what happens.
>>> However, I wonder if a similar test could be done with software.   I
>>> assume that Linux implements some kind of driver to support MESH.
>>> Is there a driver for the 53CF96 which could be substituted or
>>> compared as an experiment.
>>
>> There's a driver for the 53C96 in the Quadra (mac_esp.c and
>> NCR53C9x.c).
>>
>> The NCR53C9x.c core supports various 53C9x chips, including (53CF9x
>> and FAS*),
>> and is used on various platforms.  It's very similar to the esp.c
>> core for
>> SPARC, but Dave didn't like us to merge non-SPARC support in his
>> driver.
>
> The Quadra 53C96 driver is a strange beast since we don't know how to
> use
> DMA on those boxes (in case they have DMA) so it implements PIO.
> Plus we had trouble with reselection interrupt races there. Better
> look at the Amiga ESP code.

I once modified NCR53C9x.c to make it work with DMA for NuBus PowerMac.
  It works with both 53C94 (on PowerMac 6/7/8100) and 53CF94 (PowerMac
8100) behind AMIC DMA (see NCR53C9x.c and nbpmac_esp.c at
http://nubus-pmac.bkbits.net:8080/linuxppc_2_4_nubus/src/drivers/scsi).

--
Etsushi Kato
ekato@ees.hokudai.ac.jp


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Re: IRQS on 6 Slot Macs

[Michel Dänzer]

On Mon, 2003-11-03 at 04:35, Robert E Brose II wrote:
> In trying to get OpenGL working on a YDL 3.0 system with kernel 2.4.22-ben2
> and XFree86-4.3.0-2.1e,  I get a warning on X initialization:
>
> (II) R128(0): [drm] failure adding irq handler, there is a device already using
> that irq

Not sure what's up with that (depending on how old the DRM is, the error
could be misleading though), but this shouldn't prevent the DRI from
working.


--
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Software libre enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer


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Re: IRQS on 6 Slot Macs

[Robert E. Brose II]

Michel Dänzer wrote:
> On Mon, 2003-11-03 at 04:35, Robert E Brose II wrote:
>
>>In trying to get OpenGL working on a YDL 3.0 system with kernel 2.4.22-ben2
>>and XFree86-4.3.0-2.1e,  I get a warning on X initialization:
>>
>>(II) R128(0): [drm] failure adding irq handler, there is a device already using
>>that irq
>
>
> Not sure what's up with that (depending on how old the DRM is, the error
> could be misleading though), but this shouldn't prevent the DRI from
> working.

The reason I was wondering about the IRQ is I've been trying to get 3d
stuff (like tuxracer) to run and I get the error message:


*** tuxracer error: Couldn't initialize video: X11 driver not configured
with OpenGL (Success)

Now the glxgears programs runs with about 400 fps (1024x768x24 400 mhz g3)

I can't run tuxracer compiled by me or the stock ydl3.0 one. Other 3d
stuff I compile fails as well with the same message. I'm pretty sure I
have the X and kernel configuration right. (similar settings work on an
  x86 box with a 3dfx card).

	Load    "GLcore"
         Load    "dbe"
         Load    "extmod"
         Load    "fbdevhw"
         Load    "dri"
         Load    "glx"
         Load    "record"
         Load    "freetype"
         Load    "type1"

And I'm building the kernel with 4.1 rage 128 drm support and the r128
module is loaded and there are no errors on X startup other than that
IRQ error (which is also noted in the dmesg when the r128 kernel module
loads)

also glxinfo looks ok to me so I'm having a hard time figuring out the
problem.

root# glxinfo

name of display: :0.0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: SGI
server glx version string: 1.2
server glx extensions:
     GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_EXT_import_context
client glx vendor string: SGI
client glx version string: 1.2
client glx extensions:
     GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_EXT_import_context
GLX extensions:
     GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_EXT_import_context
OpenGL vendor string: VA Linux Systems, Inc.
OpenGL renderer string: Mesa DRI Rage128 20020221 AGP 1x
OpenGL version string: 1.2 Mesa 4.0.4
OpenGL extensions:
     GL_ARB_imaging, GL_ARB_multitexture, GL_ARB_texture_env_add,
     GL_ARB_transpose_matrix, GL_EXT_abgr, GL_EXT_bgra, GL_EXT_blend_color,
     GL_EXT_blend_minmax, GL_EXT_blend_subtract, GL_EXT_clip_volume_hint,
     GL_EXT_convolution, GL_EXT_compiled_vertex_array, GL_EXT_histogram,
     GL_EXT_packed_pixels, GL_EXT_polygon_offset, GL_EXT_rescale_normal,
     GL_EXT_texture3D, GL_EXT_texture_env_add, GL_EXT_texture_object,
     GL_EXT_vertex_array, GL_IBM_rasterpos_clip, GL_MESA_window_pos,
     GL_NV_texgen_reflection, GL_SGI_color_matrix, GL_SGI_color_table
glu version: 1.3
glu extensions:
     GLU_EXT_nurbs_tessellator, GLU_EXT_object_space_tess

Any more suggestions are appreciated!

Thanks,
Bob


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Re: IRQS on 6 Slot Macs

[Michel Dänzer]

On Mon, 2003-11-03 at 15:40, Robert E. Brose II wrote:
>
> *** tuxracer error: Couldn't initialize video: X11 driver not configured
> with OpenGL (Success)

Sounds like an SDL error?


--
Earthling Michel Dänzer      |     Debian (powerpc), X and DRI developer
Software libre enthusiast    |   http://svcs.affero.net/rm.php?r=daenzer


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Re: IRQS on 6 Slot Macs

[Mich Lanners]

On   3 Nov, this message from Geert Uytterhoeven echoed through
cyberspace:
>> > I don't know what's up with the DRM not liking your interrupt. I
>> > can answer for the sharing of USB, symbios and firewire interrupts:
>> > all 3 slots share one interrupt because of bad motherboard design
>> > :) Basicallly, what they did when designing that machine was to use
>> > a standard powersurge design with 3 slots and replace one of them
>> > with a PCI<->PCI bridge. Since they didn't "know" how to get more
>> > interrupt lines out of Grand Central, they just also stuffed all
>> > interrupt lines together for those 4 slots (I'm pretty sure GC do
>
> Tsss... They could at least have `swizzled' the lines...

Sure, but it's indeed totally not understandable why they didn't use the
other lines on GrandCentral, since the 9500/9600 design includes six PCI
slots with each a dedicated IRQ line. Weird...

Michel

-------------------------------------------------------------------------
Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
L-1710 Luxembourg              |
email   mlan@cpu.lu            |
http://www.cpu.lu/~mlan        |                     Learn Always. "

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Re: IRQS on 6 Slot Macs

[Benjamin Herrenschmidt]

> Sure, but it's indeed totally not understandable why they didn't use the
> other lines on GrandCentral, since the 9500/9600 design includes six PCI
> slots with each a dedicated IRQ line. Weird...

Probably because updating Apple's 1.0.5 OF code to assign them properly
with the P2P setup was beyond their ability to deal with crappy code :)

Ben.


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Re: IRQS on 6 Slot Macs

[Mich Lanners]

On   4 Nov, this message from Jeff Walther echoed through cyberspace:
> I'm not sure it was bad motherboard design--at least, not unless
> following specifications leads to bad motherboard design.   I can't
> find the reference now, but I could swear that I read that the proper
> procedure when implementing a PCI-PCI Bridge is to tie the
> subordinate slot's interrupts into the interrupt for the host slot.
> The firmware for the host machine is supposed to be able to sort this
> out, if written properly.
>
> After all, one can, in theory, add 1024 PCI slots to a machine using
> PPBs.   There aren't going to be 1024 interrupts available.   The
> specification for PCI-PCI Bridges had to have some more general
> method of handling interrupts for slots behind a PPB, and tieing them
> to the host slot interrupt makes the most sense.
>
> All that said, the firmware for the x500 and x600 Macs is not written
> properly, at least with respect to implementing PCI-PCI Bridges.
>
>>Basicallly, what they did when designing that machine was to use a
>>standard powersurge design with 3 slots and replace one of them
>>with a PCI<->PCI bridge. Since they didn't "know" how to get more
>>interrupt lines out of Grand Central, they just also stuffed all
>>interrupt lines together for those 4 slots (I'm pretty sure GC do
>>have spare lines they could have used,
>
> The interrupts for the slots (in the 9500/9600) go to the following
> pins on GC:
>
> Slot #      GC pin #
> 1                193
> 2	     194
> 3	     189
> 4	     188
> 5	      173
> 6	      174
>
> On the S900 (and J700) the interrupts for slots 3 through 6 are tied
> to pin 189.
>
> Slots 1 through 3 are also correct for all other PowerSurge machines.
> I would love to know if there are other unused interrupts available,
> as the PowerSurge architecture supposedly can support up to four
> Bandit chips, but as far as I know, if one constructed such a beast,
> there'd be no interrupts available for any PCI slots beyond six.
>
> This seems to be born out (limited interrupts available) by the
> gymnastics they went through to arrange the interrupts in the Apple
> Network Server, which has six PCI slots, but also four built-in PCI
> devices (including Grand Central) on the motherboard.  They didn't
> use any previously unused interrupts on GC in the ANS, they just
> rearranged and combined the interrupts used in the 9500.
>
> However, I can't help but wonder if all that lovely video circuitry
> on the 7500 and 8500 requires any interrupts and if so, where they
> come from.  Do they recycle the interrupts for slots 4 -6 or are
> there other interrupts available on GC besides the ones for the six
> slots?

Here is my all-slots-filled config on a 7600:

00:0b.0 Host bridge: Apple Computer Inc. Bandit PowerPC host bridge (rev 03)
        Flags: bus master, medium devsel, latency 32, IRQ 22
00:0d.0 Unknown mass storage controller: Promise Technology, Inc. 20262 (rev 01)
        Flags: bus master, medium devsel, latency 32, IRQ 23
00:0e.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139 (rev 10)
        Flags: bus master, medium devsel, latency 32, IRQ 24
00:0f.0 VGA compatible controller: Matrox Graphics, Inc. MGA 2064W [Millennium] (rev 01) (prog-if 00 [VGA])
        Flags: stepping, medium devsel, IRQ 25
00:10.0 Class ff00: Apple Computer Inc. Grand Central I/O (rev 02)
        Flags: bus master, medium devsel, latency 32, IRQ 22
01:0b.0 Non-VGA unclassified device: Apple Computer Inc. Control Video
        Flags: fast devsel, IRQ 26
01:0d.0 Class ff00: Apple Computer Inc. PlanB Video-In (rev 01)
        Flags: bus master, medium devsel, latency 32, IRQ 28

So yes, video-in and graphics have separate interrupts. But those could
be the same IRQ's as used on slots 4-6 on 9x00 machines. AFAIK, there
have been no machines with video circuitry _and_ 6 PCI slots.

I have no info about video-in; but I think I remember some site
somewhere with all possible device trees online. You might find more
info there...

Cheers

Michel

-------------------------------------------------------------------------
Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
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http://www.cpu.lu/~mlan        |                     Learn Always. "

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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 21:27 +0100 11/04/2003, Mich Lanners wrote:

>>  However, I can't help but wonder if all that lovely video circuitry
>>  on the 7500 and 8500 requires any interrupts and if so, where they
>>  come from.  Do they recycle the interrupts for slots 4 -6 or are
>>  there other interrupts available on GC besides the ones for the six
>>  slots?
>
>Here is my all-slots-filled config on a 7600:
>
>00:0b.0 Host bridge: Apple Computer Inc. Bandit PowerPC host bridge (rev 03)
>         Flags: bus master, medium devsel, latency 32, IRQ 22
>00:0d.0 Unknown mass storage controller: Promise Technology, Inc.
>20262 (rev 01)
>         Flags: bus master, medium devsel, latency 32, IRQ 23
>00:0e.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139 (rev 10)
>         Flags: bus master, medium devsel, latency 32, IRQ 24
>00:0f.0 VGA compatible controller: Matrox Graphics, Inc. MGA 2064W
>[Millennium] (rev 01) (prog-if 00 [VGA])
>         Flags: stepping, medium devsel, IRQ 25
>00:10.0 Class ff00: Apple Computer Inc. Grand Central I/O (rev 02)
>         Flags: bus master, medium devsel, latency 32, IRQ 22
>01:0b.0 Non-VGA unclassified device: Apple Computer Inc. Control Video
>         Flags: fast devsel, IRQ 26
>01:0d.0 Class ff00: Apple Computer Inc. PlanB Video-In (rev 01)
>         Flags: bus master, medium devsel, latency 32, IRQ 28
>
>So yes, video-in and graphics have separate interrupts. But those could
>be the same IRQ's as used on slots 4-6 on 9x00 machines. AFAIK, there
>have been no machines with video circuitry _and_ 6 PCI slots.

Thank you, michel.  That will get me quite a ways along on that inquiry.

>I have no info about video-in; but I think I remember some site
>somewhere with all possible device trees online. You might find more
>info there...

I have that site bookmarked somewhere--at least I think it's the same
site.   I just haven't checked it in a while.  However, I think that
the device tree only generates a listing if there is a PCI card
installed in the slot, and as I recall, most of the machines listed
only had one or two PCI cards installed.  Still, it's worth a look to
me.

I have a hardware project in mind, but am not actively working on it.
So, when discussion that touches on it comes up, I'll pop up for a
bit to gather/share what info I can, but until I move this to the
front of my hobby queue I won't make a lot of progress.

The thing I'm interested in is building a PowerSurge with three or
four Bandits.   The architecture supports it, according to Apple
docs, but the big question is whether the actual implementation of
chips supports the full architecture or just a subset.   For example,
one would need twelve interrupts for PCI slots (at least) with four
Bandits.  Are there six more external interrupts available on GC?
And how could we ever figure that one out, unless someone sneaks into
a vault at Apple?  (Or one could build that hypothetical machine with
6 PCI slots and built-in video which you mentioned above.)

Another essential question is whether there are sufficient
arbitration lines on Hammerhead to support three or four Bandits.

And the thing that usually kills my ambition to make this my primary
hobby at the moment is the firmware mods it would take.   I'm into
hardware and not much of a programmer.

As to how I would build such a machine, if Apple's chips supported
it, the S900 has a second CPU slot on the motherboard.   However,
that slot could be used for a CPU Bus expansion card, because almost
all the required signals are available there.    So, one could put
two or three Bandits on a daughter card, install the card in the
secondary CPU slot on the S900 and run cables from the daughter card
to the PCI backplanes for the additional Bandits.   Actually, it
would be fairly trivial to build a daughter card with a single Bandit
on it for the S900, adding three PCI slots....One need only copy
connections from the 9500 in order to do that.

Jeff Walther

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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 20:14 +1100 11/04/2003, Benjamin Herrenschmidt wrote:
>>  I can't
>>  find the reference now, but I could swear that I read that the proper
>>  procedure when implementing a PCI-PCI Bridge is to tie the
>>  subordinate slot's interrupts into the interrupt for the host slot.

>Hrm... nah nah nah :) If you tie them together, you get one
>interrupt shared for all in the end... what you can do on
>platforms with an irq router like x86 is to make use of the
>4 different irq lines of the bridge and route them to the
>sub-slots, but on macs, like on lots of othre platforms, the
>4 lines are just or-ed together.

Ah, my memory is working this morning (okay, afternoon).   The
reference I couldn't find was Apple's Tech Note TN_1135, which is an
Apple reference, not a PCI specification reference.   My apologies
for any confusion I may have caused anyone.

>Anyway, such a rule really only apply when you design a PCI
>card with a P2P bridge on it. As long as you are on the
>motherboard, you do what you want.

Right, because with a card, one only has access to what's in the slot
but on the motherboard one can wire to anything present.   Thank you.
Brain is feeling much more limber now.

>>  After all, one can, in theory, add 1024 PCI slots to a machine using
>>  PPBs.   There aren't going to be 1024 interrupts available.
>
>Why ? Some iSeries have up to 2048 irq lines afaik ;)

By iSeries, do you mean iBook and iMac?   Or is that something else?
I'm still kind of living in the PowerSurge world, with occasional
forays up to Beige G3.  :-)

>>  The
>>  specification for PCI-PCI Bridges had to have some more general
>>  method of handling interrupts for slots behind a PPB, and tieing them
>>  to the host slot interrupt makes the most sense.
>
>No. The P2P specification provides nothing for interrupts, just
>a generic "guideline" that you may or may not follow depending on
>what you are designing. The way you route a motherboard interrupt
>line (regardless of it beeing on a bridge or not) is a matter
>of commen sense rather.

Right.   My mistake for misremembering an Apple note as part of the PCI spec.

>>  All that said, the firmware for the x500 and x600 Macs is not written
>>  properly, at least with respect to implementing PCI-PCI Bridges.
>
>Well... Again, do not mix what happens on the mobo and what happens
>in slots. Indeed, the x500 and x600 machines have an OF bug that
>cause it to not properly assign the shared irq line to the child
>devices, but that's really only a concern for _slots_.

The bug I've observed, I first became aware of because of the S900.
The PowerSurge machines have a problem with more than one level of
PPB.  If you put a PPB bearing card in the lower four slots of the
S900, you've created two layers of PPBs.   With a few exceptions
(like leaving all the other lower slots empty) this causes the
machine to freeze during initialization at the gray screen.

>>  >Basicallly, what they did when designing that machine was to use a
>>  >standard powersurge design with 3 slots and replace one of them
>>  >with a PCI<->PCI bridge. Since they didn't "know" how to get more
>>  >interrupt lines out of Grand Central, they just also stuffed all
>>  >interrupt lines together for those 4 slots (I'm pretty sure GC do
>>  >have spare lines they could have used,

>I don't know how much exactly GC provides. It has a single mask
>register of 32 interrupts, so if you count all the GC internal ones,
>that still leaves a few of them I beleive... You'd need the pinout
>of GC, I don't have it (maybe you do ? :) I'm interested in any spec
>for these old chipsets...)

Unfortunately, no, I don't have the GC pinout.  All the pinout
information I have on the PowerSurge chipset, I've gotten by starting
with the PCI slot pinout and the PPC601 pinout and working backwards
to the various chips.  I wish, wish, wish that I had access to
Apple's documents on that chipset.  Oh, and the CPU slot listing in
the ANS Hardware Developer Notes helped too, because the ANS used the
same chipset, so some of the pin IDs can be found by working
backwards to Hammerhead on the ANS.

Anyway, the listing of slot interrupt pins on GC was all I have
except that pin 61 is GNT and pin 62 is REQ for Grand Central's
arbitration as a device on the PCI bus.    It will be fairly easy to
identify the PCI bus pins on GC.  I just haven't done it yet and
that's probably the least interesting component of GC's pinout.

I think I can find GC's connection to MESH as well, but I'm
uncertain.   I believe that MESH is just a licensed NEC (now LSI
Logic) 53CF96 and I have the pinout for the 53CF96 so tracing
backwards from that wouldn't be tough, if that's true.   I need to
solder a 53CF96 in place of a MESH some time and see if it works....

I do have the complete CPU slot pinout and a mostly complete Bandit
pinout (two or three pins uncertain).   But I think I've emailed
those to the list before, so you probably have them.   If not, let me
know and I'll shoot you a copy.

>>  This seems to be born out (limited interrupts available) by the
>>  gymnastics they went through to arrange the interrupts in the Apple
>>  Network Server, which has six PCI slots, but also four built-in PCI
>>  devices (including Grand Central) on the motherboard.  They didn't
>>  use any previously unused interrupts on GC in the ANS, they just
>>  rearranged and combined the interrupts used in the 9500.
>
>Yup. Still... it would have made a lot of sense for the S900 designers
>to actually route the additional slot interrupts to separate GC
>interrupt pins. The main problem with that would have been the need to
>"teach" Apple's OF about the binding, which of course would have been
>a total mess....

You've convinced me.   I agree that would have been better.    It's
kind of sad, because I worked with a fellow who interned at Umax's
Mac cloning hardware group, and he said they were engaging in a
pretty intricate firmware development effort for PREP (or was it
CHRP?) before things got shut down.  If they put that much effort
into the next generation, they were willing to spend the same type of
resources it would have taken to hack the earlier OF.   But it was a
different deal as far as the licensing issues go.

>>  However, I can't help but wonder if all that lovely video circuitry
>>  on the 7500 and 8500 requires any interrupts and if so, where they
>>  come from.  Do they recycle the interrupts for slots 4 -6 or are
>>  there other interrupts available on GC besides the ones for the six
>>  slots?
>
>Maybe compare the interrupt numbers ? I don't have my datas at hand
>but that should give you an idea of who goes where. IIRC, some Mklinux
>source (or maybe it's early darwin source) had a map of all the irqs
>of GC as well.

Now that's interesting.   I wonder how they figured them out.  I
wonder how hard it's going to be to find...

>  A bit more tricky, they could have put a routing
>circuit optionally or'ing them all together. By default, the machine
>boots with them all or'ed. If the nvramrc script (or whatever other
>possible software patch) doesn't load, they stay that way. The software
>patch ticks an IO disabling that OR'ing after patching either the
>device-tree  (nvramrc patch) or whatever MacOS used for routing.
>
>Probably doable with a few gates, or bits of a PLD if any was already
>there.

There is no PLD between the PCI interrupt pins and GC on the S900
board.  But, since Umax designed the board, they certainly could have
added one.   They already did that quirky E100 hack to PCI slot 1.
I haven't dug into that, but I'd like to know how they made that
work.  Does an Enet card require an interrupt?  Does it ever master
the PCI bus?

Somehow they convinced the machine that there's another PCI slot
there when the E100 (Mercury) card is installed.   It's a combined UW
SCSI and 10/100 Enet for those not familiar with it and slot 1 on the
S900 has an extender to provide additional signals to the E100 card.

The E100 gets dual fuctionality without a PPB.   I haven't traced the
connections, but my assumption is that the two chipsets on the card
are sharing the common PCI bus lines in the slot, and that the
extender on slot 1 provides the slot specific PCI signals to one of
the two chipsets on the card.   But that might include an additional
interrupt and additional bus arbitration (does Enet bus master?).
And somehow the extension for the E100 card tells the S900 firmware
that there's an extra PCI slot called E100.

I read something about a legacy device left in the firmware called
E100, and I think Umax took advantage of that somehow, but I never
really understood what I read, and my memory is vague.

Jeff Walther

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Re: IRQS on 6 Slot Macs

[Geert Uytterhoeven]

On Tue, 4 Nov 2003, Jeff Walther wrote:
> At 20:14 +1100 11/04/2003, Benjamin Herrenschmidt wrote:
> >>  After all, one can, in theory, add 1024 PCI slots to a machine using
> >>  PPBs.   There aren't going to be 1024 interrupts available.
> >
> >Why ? Some iSeries have up to 2048 irq lines afaik ;)
>
> By iSeries, do you mean iBook and iMac?   Or is that something else?

iSeries are the big IBM boxes formerly known as AS/400.

> I think I can find GC's connection to MESH as well, but I'm
> uncertain.   I believe that MESH is just a licensed NEC (now LSI
                                                      ^^^
> Logic) 53CF96 and I have the pinout for the 53CF96 so tracing

NCR, I assume?

> I haven't dug into that, but I'd like to know how they made that
> work.  Does an Enet card require an interrupt?  Does it ever master
> the PCI bus?

Ethernet prefers to have an interrupt, else it becomes quite slow :-)
Most modern Ethernet interfaces do bus mastering. Old NE2000 clones don't.

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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Re: IRQS on 6 Slot Macs

[Jeff Walther]

At 23:30 +0100 11/04/2003, Geert Uytterhoeven wrote:

>On Tue, 4 Nov 2003, Jeff Walther wrote:
>>  At 20:14 +1100 11/04/2003, Benjamin Herrenschmidt wrote:
>>  >>  After all, one can, in theory, add 1024 PCI slots to a machine using
>>  >>  PPBs.   There aren't going to be 1024 interrupts available.
>>  >
>>  >Why ? Some iSeries have up to 2048 irq lines afaik ;)
>>
>>  By iSeries, do you mean iBook and iMac?   Or is that something else?
>
>iSeries are the big IBM boxes formerly known as AS/400.

How do they provide that many IRQ lines?  I'm assuming that there
can't be one wire/pin per IRQ because of the routing/packaging
problems for the traces and chips.   Do they do something like an
address bus for IRQs?
>
>>  I think I can find GC's connection to MESH as well, but I'm
>>  uncertain.   I believe that MESH is just a licensed NEC (now LSI
>                                                       ^^^
>>  Logic) 53CF96 and I have the pinout for the 53CF96 so tracing
>
>NCR, I assume?

Derrrrrrr.  Yes.   Must.  Find.  New.  Brain.

NCR spun off their semiconductor business as SYMBIOS which was later
acquired by LSI Logic.

>>  I haven't dug into that, but I'd like to know how they made that
>>  work.  Does an Enet card require an interrupt?  Does it ever master
>>  the PCI bus?
>
>Ethernet prefers to have an interrupt, else it becomes quite slow :-)
>Most modern Ethernet interfaces do bus mastering. Old NE2000 clones don't.

Thank you.  Then one would expect to find an interrupt and PCI bus
arbitration lines in the extender on PCI slot 1 of the S900.   The
PCI bus arbitration lines are simple.  The arbiter that Apple used
has something like six GNT and REQ lines available, so there are
spares of those, but I wonder where Umax got the interrupt, unless
it's sharing one with the UW SCSI portion of the card and the drivers
take that into account.

Jeff Walther

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