Am Mittwoch, den 26.04.2017, 14:11 -0700 schrieb Tim Harvey:
> On Wed, Apr 26, 2017 at 11:15 AM, Lucas Stach <l.stach@xxxxxxxxxxxxxx> wrote:
> > The DWC host does not support legacy PCI IRQs and MSIs at the same time,
> > so we need to fall back to using only legacy IRQs if there is a chance
> > that multiple devices with differing MSI capabilities are connected to
> > the host. The only configuration where MSIs can be safely used is when
> > the device below the host bridge is not a bridge, i.e. the only device
> > connected to this host.
> >
> > By disallowing MSI allocation when multiple devices might be attached
> > we get those configurations in a working state. The only configurations
> > that depend on MSIs being available, that I am aware of, are some
> > embedded devices with a PCIe attached FPGA, that is incapable of
> > generating PCI legacy IRQs. Those are kept working by allowing MSIs
> > when only a single device is attached to the host.
> >
> > Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> > ---
> > drivers/pci/dwc/pcie-designware-host.c | 24 ++++++++++++++++++++++--
> > drivers/pci/dwc/pcie-designware.h | 1 +
> > 2 files changed, 23 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/pci/dwc/pcie-designware-host.c b/drivers/pci/dwc/pcie-designware-host.c
> > index 5ba334938b52..be2b2762c944 100644
> > --- a/drivers/pci/dwc/pcie-designware-host.c
> > +++ b/drivers/pci/dwc/pcie-designware-host.c
> > @@ -92,6 +92,8 @@ void dw_pcie_msi_init(struct pcie_port *pp)
> > (u32)(msi_target & 0xffffffff));
> > dw_pcie_wr_own_conf(pp, PCIE_MSI_ADDR_HI, 4,
> > (u32)(msi_target >> 32 & 0xffffffff));
> > +
> > + pp->msi_disabled = false;
> > }
> >
> > static void dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq)
> > @@ -136,9 +138,11 @@ static void dw_pcie_msi_set_irq(struct pcie_port *pp, int irq)
> > static int assign_irq(int no_irqs, struct msi_desc *desc, int *pos)
> > {
> > int irq, pos0, i;
> > - struct pcie_port *pp;
> > + struct pcie_port *pp = (struct pcie_port *)msi_desc_to_pci_sysdata(desc);
> > +
> > + if (pp->msi_disabled)
> > + return -EINVAL;
> >
> > - pp = (struct pcie_port *)msi_desc_to_pci_sysdata(desc);
> > pos0 = bitmap_find_free_region(pp->msi_irq_in_use, MAX_MSI_IRQS,
> > order_base_2(no_irqs));
> > if (pos0 < 0)
> > @@ -410,6 +414,22 @@ int dw_pcie_host_init(struct pcie_port *pp)
> > goto error;
> > }
> >
> > + /*
> > + * The DWC host does not support legacy PCI IRQs and MSIs at the same
> > + * time, so we need to fall back to using only legacy IRQs if there is
> > + * a chance that multiple devices with differing MSI capabilities are
> > + * connected to the host. The only configuration where MSIs can be
> > + * safely used is when the device below the host bridge is not a bridge,
> > + * i.e. the only device connected to this host.
> > + */
> > + child = list_first_entry(&bus->children, struct pci_bus, node);
> > + if (!list_empty(&child->devices)) {
> > + struct pci_dev *dev = list_first_entry(&child->devices,
> > + struct pci_dev, bus_list);
> > + if (pci_is_bridge(dev))
> > + pp->msi_disabled = true;
> > + }
> > +
> > if (pp->ops->scan_bus)
> > pp->ops->scan_bus(pp);
> >
> > diff --git a/drivers/pci/dwc/pcie-designware.h b/drivers/pci/dwc/pcie-designware.h
> > index cd3b8713fe50..741bc31f8947 100644
> > --- a/drivers/pci/dwc/pcie-designware.h
> > +++ b/drivers/pci/dwc/pcie-designware.h
> > @@ -140,6 +140,7 @@ struct pcie_port {
> > struct irq_domain *irq_domain;
> > unsigned long msi_data;
> > DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
> > + bool msi_disabled;
> > };
> >
> > struct dw_pcie_ops {
> > --
> > 2.11.0
> >
>
> Lucas,
>
> Legacy interrupts are still not firing with this.
Can you provide me the output of "cat /proc/interrupts" and "lspci -t"
on your system? I've tested this change on the GW54xx and legacy IRQs
seemed to work there.
Regards,
Lucas
