On Fri, Jun 17, 2022 at 10:38:08AM +0200, Mark Kettenis wrote:
> > Date: Fri, 17 Jun 2022 17:22:58 +1000
> > From: Jonathan Gray <[email protected]>
> >
> > On Fri, Jun 17, 2022 at 12:33:47AM +0200, Mark Kettenis wrote:
> > > On the Ampere Altra machines, some PCIe devices show up 32 times; once
> > > for each possible PCI device number. This is a hardware bug, since a
> > > downstream switch port (or root port) is supposed to terminate
> > > configuration request targeted at device numbers 1-31. But it is a
> > > somewhat common bug since I have seen this before on other hardware.
> > > Linux and FreeBSD both have code that only scans device 0 on
> > > downstream switch ports. So let's do that in OpenBSD as well.
> > >
> > > ok?
> > >
> >
> > ok jsg@
> >
> > Linux and NetBSD also handle additional types as downstream.
> > Referred to in the pcie base spec as:
> >
> > 0100b Root Port of PCI Express Root Complex*
> > 1000b PCI/PCI-X to PCI Express Bridge*
> >
> > *This value is only valid for Functions that implement a Type
> > 01h PCI Configuration Space header.
> >
> > FreeBSD also checks for Root Port but not the bridge.
>
> Ah, I missed that Linux also checks for the root port. That's
> probably a good idea. The PCI-PCIe bridge is probably rare enough not
> to matter, but lets align with Linux and NetBSD here.
>
> How about this?
sure, still ok with this version
>
>
> Index: dev/pci/pci.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/pci.c,v
> retrieving revision 1.124
> diff -u -p -r1.124 pci.c
> --- dev/pci/pci.c 11 Mar 2022 18:00:51 -0000 1.124
> +++ dev/pci/pci.c 17 Jun 2022 08:34:30 -0000
> @@ -807,11 +807,31 @@ pci_enumerate_bus(struct pci_softc *sc,
> {
> pci_chipset_tag_t pc = sc->sc_pc;
> int device, function, nfunctions, ret;
> + int maxndevs = sc->sc_maxndevs;
> const struct pci_quirkdata *qd;
> - pcireg_t id, bhlcr;
> + pcireg_t id, bhlcr, cap;
> pcitag_t tag;
>
> - for (device = 0; device < sc->sc_maxndevs; device++) {
> + /*
> + * PCIe downstream ports and root ports should only forward
> + * configuration requests for device number 0. However, not
> + * all hardware implements this correctly, and some devices
> + * will respond to other device numbers making the device show
> + * up 32 times. Prevent this by only scanning a single
> + * device.
> + */
> + if (sc->sc_bridgetag && pci_get_capability(pc, *sc->sc_bridgetag,
> + PCI_CAP_PCIEXPRESS, NULL, &cap)) {
> + switch (PCI_PCIE_XCAP_TYPE(cap)) {
> + case PCI_PCIE_XCAP_TYPE_RP:
> + case PCI_PCIE_XCAP_TYPE_DOWN:
> + case PCI_PCIE_XCAP_TYPE_PCI2PCIE:
> + maxndevs = 1;
> + break;
> + }
> + }
> +
> + for (device = 0; device < maxndevs; device++) {
> tag = pci_make_tag(pc, sc->sc_bus, device, 0);
>
> bhlcr = pci_conf_read(pc, tag, PCI_BHLC_REG);
> Index: dev/pci/pcireg.h
> ===================================================================
> RCS file: /cvs/src/sys/dev/pci/pcireg.h,v
> retrieving revision 1.60
> diff -u -p -r1.60 pcireg.h
> --- dev/pci/pcireg.h 31 Dec 2021 11:24:24 -0000 1.60
> +++ dev/pci/pcireg.h 17 Jun 2022 08:34:30 -0000
> @@ -563,6 +563,10 @@ typedef u_int8_t pci_revision_t;
> #define PCI_PCIE_XCAP 0x00
> #define PCI_PCIE_XCAP_SI 0x01000000
> #define PCI_PCIE_XCAP_VER(x) (((x) >> 16) & 0x0f)
> +#define PCI_PCIE_XCAP_TYPE(x) (((x) >> 20) & 0x0f)
> +#define PCI_PCIE_XCAP_TYPE_RP 0x4
> +#define PCI_PCIE_XCAP_TYPE_DOWN 0x6
> +#define PCI_PCIE_XCAP_TYPE_PCI2PCIE 0x8
> #define PCI_PCIE_DCAP 0x04
> #define PCI_PCIE_DCSR 0x08
> #define PCI_PCIE_DCSR_ERO 0x00000010
>
