Regarding MPC8540 IRQ Issue

From the PCI dump it looks like IRQ PIN register is 0. During enumeration

Hello All

I am working on MPC8540 board placing it in the PCI slot of the x86 system.
After system bootup , i could see the powerpc board detected and pci config space configured.
But i could not find any IRQ assigned for it.

SetUp:
Host: x86 System- Linux-2.6.9
HOST PCI Slot is 64-bit, 66MHz
Agent: MPC8540 Board.

Here is dump of "lspci -vx " for this device.

04:03.0 Power PC: Motorola MPC8540 (rev 20) (prog-if 01)

        Flags: bus master, 66Mhz, fast devsel, latency 64
        Memory at dee00000 (32-bit, non-prefetchable) [size=1M]
        Capabilities: [60] #00 [0000]

00: 57 10 08 00 46 01 b0 00 20 01 20 0b 00 40 00 00 10: 00 00 e0 de 00 00 00 00 00 00 00 00 00 00 00 00 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 30: 00 00 00 00 60 00 00 00 00 00 00 00 00 00 00 00

From the above dump - IRQ Pin & Line of config space shows zeroes.

I tried writing a small module and probing for IRQ generating a message interrupt. Though i could see in the 8540 message status register that interrupt is generated, i could not get any IRQ when i do the probe. For this trial, i have configured the PIC message enable register, message vector/priority and destination registers, processor current task priority register (CPTR).

Can anyone give me some suggestions to try out.

Thanks
Sudheer

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Hi Sudhir,

From the PCI dump it looks like IRQ PIN register is 0. During enumeration when BIOS sees that IRQ PIN register is 0, it would not allocate any interrupt for this card and that's why you are seeing IRQ Line register also as 0 value.

We need to do some work around for this.

IN the driver you need to register for all the pci vectors( INTA,B,C
and D). You would be called for any interrupt happening on the bus. you have to check if the interrupt is for you and then claim it otherwise return that interrupt is not for you.

Regards
Bhupi

On 6/16/07, *sudheer* <[email protected] <mailto:[email protected]>> wrote:

Hello All

I am working on MPC8540 board placing it in the PCI slot of the x86 system.
After system bootup , i could see the powerpc board detected and pci config space configured.
But i could not find any IRQ assigned for it.

SetUp:
Host: x86 System- Linux-2.6.9
HOST PCI Slot is 64-bit, 66MHz
Agent: MPC8540 Board.

Here is dump of "lspci -vx " for this device.

04:03.0 Power PC: Motorola MPC8540 (rev 20) (prog-if 01)
Flags: bus master, 66Mhz, fast devsel, latency 64 Memory at dee00000 (32-bit, non-prefetchable) [size=1M]
Capabilities: [60] #00 [0000]
00: 57 10 08 00 46 01 b0 00 20 01 20 0b 00 40 00 00 10: 00 00 e0 de 00 00 00 00 00 00 00 00 00 00 00 00 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 30: 00 00 00 00 60 00 00 00 00 00 00 00 00 00 00 00

From the above dump - IRQ Pin & Line of config space shows zeroes.

I tried writing a small module and probing for IRQ generating a message
interrupt. Though i could see in the 8540 message status register that interrupt is generated, i could not get any IRQ when i do the probe. For
this trial, i have configured the PIC message enable register, message
vector/priority and destination registers, processor current task priority register (CPTR).

Can anyone give me some suggestions to try out.

Thanks
Sudheer

_______________________________________________
Linuxppc-embedded mailing list [email protected] <mailto:[email protected]>
https://ozlabs.org/mailman/listinfo/linuxppc-embedded

Hi Bhupi
Thanks for the response.
I tried with all the free irqs as per /proc/interrupts in request_irq function one in each trial. But in none of them it jumped to interrupt handler.
Please let me know whether this is the one you said to try or anything else. ?

Thanks
Sudheer

Bhupender Saharan wrote:

Hi Sudhir,

Quoted 1 line

From the PCI dump it looks like IRQ PIN register is 0. During enumeration

when BIOS sees that IRQ PIN register is 0, it would not allocate any interrupt for this card and that's why you are seeing IRQ Line register also as 0 value.

We need to do some work around for this.

IN the driver you need to register for all the pci vectors( INTA,B,C and
D). You would be called for any interrupt happening on the bus. you have to check if the interrupt is for you and then claim it otherwise return that interrupt is not for you.

Regards
Bhupi

Quoted 45 lines · sudheer

Hello All

I am working on MPC8540 board placing it in the PCI slot of the x86 system.
After system bootup , i could see the powerpc board detected and pci config space configured.
But i could not find any IRQ assigned for it.

SetUp:
Host: x86 System- Linux-2.6.9
HOST PCI Slot is 64-bit, 66MHz
Agent: MPC8540 Board.

Here is dump of "lspci -vx " for this device.

04:03.0 Power PC: Motorola MPC8540 (rev 20) (prog-if 01)

        Flags: bus master, 66Mhz, fast devsel, latency 64
        Memory at dee00000 (32-bit, non-prefetchable) [size=1M]
        Capabilities: [60] #00 [0000]

00: 57 10 08 00 46 01 b0 00 20 01 20 0b 00 40 00 00 10: 00 00 e0 de 00 00 00 00 00 00 00 00 00 00 00 00 20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 30: 00 00 00 00 60 00 00 00 00 00 00 00 00 00 00 00

Quoted 1 line

From the above dump - IRQ Pin & Line of config space shows zeroes.

I tried writing a small module and probing for IRQ generating a message interrupt. Though i could see in the 8540 message status register that interrupt is generated, i could not get any IRQ when i do the probe. For

this trial, i have configured the PIC message enable register, message vector/priority and destination registers, processor current task priority register (CPTR).

Can anyone give me some suggestions to try out.

Thanks
Sudheer

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Linuxppc-embedded mailing list
[email protected]
https://ozlabs.org/mailman/listinfo/linuxppc-embedded