Re: [PATCH 7/7] powerpc: Added PCI MSI support using the HSTA module

Arnd Bergmann
2014-02-21T14:33:58Z

On Friday 21 February 2014 17:31:33 Alistair Popple wrote:
>
> + HSTA0: hsta@310000e0000 {
> + compatible = "ibm,476gtr-hsta-msi", "ibm,hsta-msi";
> + reg = <0x310 0x000e0000 0x0 0xf0>;
> + interrupt-parent = <&MPIC>;
> + interrupts = <108 0
> + 109 0
> + 110 0
> + 111 0
> + 112 0
> + 113 0
> + 114 0
> + 115 0
> + 116 0
> + 117 0
> + 118 0
> + 119 0
> + 120 0
> + 121 0
> + 122 0
> + 123 0>;
> + };

Please add a binding to Documentation/devicetree for this device.

> @@ -242,8 +264,10 @@
> ranges = <0x02000000 0x00000000 0x80000000 0x00000110 0x80000000 0x0 0x80000000
> 0x01000000 0x0 0x0 0x00000140 0x0 0x0 0x00010000>;
>
> - /* Inbound starting at 0 to memsize filled in by zImage */
> - dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x0 0x0>;
> + /* Inbound starting at 0x0 to 0x40000000000. In order to use MSI
> + * PCI devices must be able to write to the HSTA module.
> + */
> + dma-ranges = <0x42000000 0x0 0x0 0x0 0x0 0x400 0x0>;
>
> /* This drives busses 0 to 0xf */
> bus-range = <0x0 0xf>;

Ah, I first only saw the line you are removing and was about
to suggest what you do anyway. Great!

> diff --git a/arch/powerpc/sysdev/ppc4xx_pci.c b/arch/powerpc/sysdev/ppc4xx_pci.c
> index 54ec1d5..7cc3acc 100644
> --- a/arch/powerpc/sysdev/ppc4xx_pci.c
> +++ b/arch/powerpc/sysdev/ppc4xx_pci.c
> @@ -176,8 +176,12 @@ static int __init ppc4xx_parse_dma_ranges(struct pci_controller *hose,
> return -ENXIO;
> }
>
> - /* Check that we are fully contained within 32 bits space */
> - if (res->end > 0xffffffff) {
> + /* Check that we are fully contained within 32 bits space if we are not
> + * running on a 460sx or 476fpe which have 64 bit bus addresses.
> + */
> + if (res->end > 0xffffffff &&
> + !(of_device_is_compatible(hose->dn, "ibm,plb-pciex-460sx")
> + || of_device_is_compatible(hose->dn, "ibm,plb-pciex-476fpe"))) {
> printk(KERN_ERR "%s: dma-ranges outside of 32 bits space\n",
> hose->dn->full_name);
> return -ENXIO;

A more general question for BenH: Apparently this PCI implementation is
getting reused on arm64 for APM X-Gene. Do you see any value in trying to
share host controller drivers like this one across powerpc and arm64?

It's possible we are going to see the same situation with fsl_pci in the
future, if arm and powerpc qoriq chips use the same peripherals. My
plan for arm64 right now is to make PCI work without any code in arch/,
just using new helper functions in drivers/pci and sticking the host
drivers into drivers/pci/host as we started doing for arm32, but it
can require significant work to make those drivers compatible with
the powerpc pci-common.c.

Arnd
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