Device tree and IRQ for chip on PCI

I have a chip connected on the PCI bus on an MPC512x, but if I get the IRQ property from the PCI chip, it is not set up by Linux.
The IRQ line goes directly from the chip to the MPC512x uc, so I don't know if I should create a separate node just to get the interrupt, or I should expect the pci functions to assign it an interrupt based on the PCI bus.

The description for the PCI bus is like this:
       pci: pci@80008500 {
               interrupt-map-mask = <0xf800 0x0 0x0 0x7>;
               interrupt-map = <
                               // IDSEL 0x15 - Slot PCI
                                0xa800 0x0 0x0 0x1 &ipic 0x0 0x8
                                0xa800 0x0 0x0 0x2 &ipic 0x1 0x8
                                0xa800 0x0 0x0 0x3 &ipic 0x2 0x8
                                0xa800 0x0 0x0 0x4 &ipic 0x3 0x8

                               >;
               interrupt-parent = < &ipic >;
               interrupts = <17 0x8>;
               bus-range = <0 0>;
               ranges = <0x42000000 0x0 0xa0000000 0xa0000000 0x0 0x10000000
                         0x02000000 0x0 0xb0000000 0xb0000000 0x0 0x10000000
                         0x01000000 0x0 0x00000000 0x84000000 0x0 0x01000000>;
               clock-frequency = <66000000>;
               #interrupt-cells = <1>;
               #size-cells = <2>;
               #address-cells = <3>;
               reg = <0x80008500 0x100>;
               compatible = "fsl,mpc5121-pci";
               device_type = "pci";
       };


Thanks,
Matteo

Hi Matteo,

I have a chip connected on the PCI bus on an MPC512x, but if I get the
IRQ property from the PCI chip, it is not set up by Linux.

It's not clear to me what you mean by this. 
Do you see an interrupt assigned to your pci device's PCI_INTERRUPT_LINE 
register? Check lspci output.

The IRQ line goes directly from the chip to the MPC512x uc, so I don't
know if I should create a separate node just to get the interrupt, or I

No. The pci node in  the DT should be ok.
Because you posted to an embedded list, I need to ask this: are you using a 
custom hardware? Does the DT fit to your board's interrupt / IDSEL routing?

Matthias

should expect the pci functions to assign it an interrupt based on the
PCI bus.

The description for the PCI bus is like this:
        pci: pci@80008500 {
                interrupt-map-mask = <0xf800 0x0 0x0 0x7>;
                interrupt-map = <
                                // IDSEL 0x15 - Slot PCI
                                 0xa800 0x0 0x0 0x1 &ipic 0x0 0x8
                                 0xa800 0x0 0x0 0x2 &ipic 0x1 0x8
                                 0xa800 0x0 0x0 0x3 &ipic 0x2 0x8
                                 0xa800 0x0 0x0 0x4 &ipic 0x3 0x8

                                >;

                interrupt-parent = < &ipic >;
                interrupts = <17 0x8>;
                bus-range = <0 0>;
                ranges = <0x42000000 0x0 0xa0000000 0xa0000000 0x0
0x10000000
                          0x02000000 0x0 0xb0000000 0xb0000000 0x0
0x10000000
                          0x01000000 0x0 0x00000000 0x84000000 0x0
0x01000000>;
                clock-frequency = <66000000>;
                #interrupt-cells = <1>;
                #size-cells = <2>;
                #address-cells = <3>;
                reg = <0x80008500 0x100>;
                compatible = "fsl,mpc5121-pci";
                device_type = "pci";
        };

The lspci output gives me the same IRQ for both the PCI bus and the peripheral attached to it. I don't know why the pci_get_config_byte call was returning me 0x00, I'll check into it.

Regarding the DT, it should be ok, at least the IDSEL is 0x15, but if you have any specific documentation I can take a look at, I will recheck it.

Thanks,
Matteo

Matthias Fuchs ha scritto:

Hi Matteo,

  

quoted

I have a chip connected on the PCI bus on an MPC512x, but if I get the
IRQ property from the PCI chip, it is not set up by Linux.
    

It's not clear to me what you mean by this. Do you see an interrupt assigned to your pci device's PCI_INTERRUPT_LINE register? Check lspci output.

  

quoted

The IRQ line goes directly from the chip to the MPC512x uc, so I don't
know if I should create a separate node just to get the interrupt, or I
    

No. The pci node in  the DT should be ok.
Because you posted to an embedded list, I need to ask this: are you using a custom hardware? Does the DT fit to your board's interrupt / IDSEL routing?

Matthias

  

quoted

should expect the pci functions to assign it an interrupt based on the
PCI bus.

The description for the PCI bus is like this:
        pci: pci@80008500 {
                interrupt-map-mask = <0xf800 0x0 0x0 0x7>;
                interrupt-map = <
                                // IDSEL 0x15 - Slot PCI
                                 0xa800 0x0 0x0 0x1 &ipic 0x0 0x8
                                 0xa800 0x0 0x0 0x2 &ipic 0x1 0x8
                                 0xa800 0x0 0x0 0x3 &ipic 0x2 0x8
                                 0xa800 0x0 0x0 0x4 &ipic 0x3 0x8

                                >;

                interrupt-parent = < &ipic >;
                interrupts = <17 0x8>;
                bus-range = <0 0>;
                ranges = <0x42000000 0x0 0xa0000000 0xa0000000 0x0
0x10000000
                          0x02000000 0x0 0xb0000000 0xb0000000 0x0
0x10000000

18 more quoted lines

-- 
Ing. Matteo Fortini, PhD
Digitek spa
Embedded Linux specialist
V. Romagnoli, 24
41033 Concordia (MO)
Italy

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