On Sun, 2020-11-01 at 11:43 +0000, Marc Zyngier wrote:
> On Sun, 01 Nov 2020 09:25:04 +0000,
> Frank Wunderlich <frank-w@xxxxxxxxxxxxxxx> wrote:
> >
> > Am 31. Oktober 2020 22:49:14 MEZ schrieb Thomas Gleixner <tglx@xxxxxxxxxxxxx>:
> >
> > >That's not a fix. It's just supressing the warning.
> >
> > Ok sorry
> >
> > >So it needs to be figured out why the domain association is not there.
> >
> > It looks like for mt7623 there is no msi domain setup (done via
> > mtk_pcie_setup_irq callback + mtk_pcie_init_irq_domain) in mtk pcie
> > driver.
>
> Does this mean that this SoC never handled MSIs the first place? Which
> would explain the warning, as there is no MSI domain registered for
> the device, and we end-up falling back to arch_setup_msi_irqs().
>
> If this system truly is unable to handle MSIs, one potential
> workaround would be to register a PCI-MSI domain that would always
> fail its allocation with -ENOSPC. It is really ugly, but would keep
> the horror localised. See the patchlet below, which I can't test.
>
> If this situation is more common than we expect, we may need something
> in core code instead.
>
> M.
>
Yea, mt7623 (mtk_pcie_soc_v1) does not support MSI, so that's a way to
handle it.
@Frank, could you help to test it?
Ryder
> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index cf4c18f0c25a..52758b546d40 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
> @@ -151,6 +151,7 @@ struct mtk_pcie_port;
> struct mtk_pcie_soc {
> bool need_fix_class_id;
> bool need_fix_device_id;
> + bool no_msi;
> unsigned int device_id;
> struct pci_ops *ops;
> int (*startup)(struct mtk_pcie_port *port);
> @@ -435,6 +436,9 @@ static int mtk_pcie_irq_domain_alloc(struct irq_domain *domain, unsigned int vir
> struct mtk_pcie_port *port = domain->host_data;
> unsigned long bit;
>
> + if (port->pcie->soc->no_msi)
> + return -ENOSPC;
> +
> WARN_ON(nr_irqs != 1);
> mutex_lock(&port->lock);
>
> @@ -966,11 +970,13 @@ static int mtk_pcie_parse_port(struct mtk_pcie *pcie,
> port->slot = slot;
> port->pcie = pcie;
>
> - if (pcie->soc->setup_irq) {
> + if (pcie->soc->setup_irq)
> err = pcie->soc->setup_irq(port, node);
> - if (err)
> - return err;
> - }
> + else
> + err = mtk_pcie_allocate_msi_domains(port);
> +
> + if (err)
> + return err;
>
> INIT_LIST_HEAD(&port->list);
> list_add_tail(&port->list, &pcie->ports);
> @@ -1173,6 +1179,7 @@ static const struct dev_pm_ops mtk_pcie_pm_ops = {
> };
>
> static const struct mtk_pcie_soc mtk_pcie_soc_v1 = {
> + .no_msi = true,
> .ops = &mtk_pcie_ops,
> .startup = mtk_pcie_startup_port,
> };
>
