Re: [PATCH v8 06/10] PCI: dwc: Handle MSIs routed to multiple GIC interrupts

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On Fri, 13 May 2022 at 14:52, Johan Hovold <johan@kernel.org> wrote:
>
> On Thu, May 12, 2022 at 01:45:41PM +0300, Dmitry Baryshkov wrote:
> > On some of Qualcomm platforms each group of 32 MSI vectors is routed to the
> > separate GIC interrupt. Implement support for such configuraions by
> > parsing "msi0" ... "msi7" interrupts and attaching them to the chained
> > handler.
> >
> > Note, that if DT doesn't list an array of MSI interrupts and uses single
> > "msi" IRQ, the driver will limit the amount of supported MSI vectors
> > accordingly (to 32).
> >
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > ---
> >  .../pci/controller/dwc/pcie-designware-host.c | 33 ++++++++++++++++++-
> >  drivers/pci/controller/dwc/pcie-designware.h  |  1 +
> >  2 files changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> > index 6b0c7b75391f..258bafa306dc 100644
> > --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> > @@ -291,7 +291,8 @@ static void dw_pcie_msi_init(struct pcie_port *pp)
> >  static int dw_pcie_msi_host_init(struct pcie_port *pp)
> >  {
> >       struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> > -     struct platform_device *pdev = to_platform_device(pci->dev);
> > +     struct device *dev = pci->dev;
> > +     struct platform_device *pdev = to_platform_device(dev);
> >       int ret;
> >       u32 ctrl, num_ctrls;
> >
> > @@ -299,6 +300,36 @@ static int dw_pcie_msi_host_init(struct pcie_port *pp)
> >       for (ctrl = 0; ctrl < num_ctrls; ctrl++)
> >               pp->irq_mask[ctrl] = ~0;
> >
> > +     if (pp->has_split_msi_irq) {
> > +             char irq_name[] = "msiXX";
> > +             int irq;
> > +
> > +             if (!pp->msi_irq[0]) {
> > +                     irq = platform_get_irq_byname_optional(pdev, irq_name);
>
> This looks broken; you're requesting "msiXX", not "msi0".

Yes, I'm preparing the updated patch.

>
> > +                     if (irq == -ENXIO) {
> > +                             num_ctrls = 1;
> > +                             pp->num_vectors = min((u32)MAX_MSI_IRQS_PER_CTRL, pp->num_vectors);
> > +                             dev_warn(dev, "No additional MSI IRQs, limiting amount of MSI vectors to %d\n",
> > +                                      pp->num_vectors);
> > +                     } else {
> > +                             pp->msi_irq[0] = irq;
> > +                     }
> > +             }
> > +
> > +             /* If we fallback to the single MSI ctrl IRQ, this loop will be skipped as num_ctrls is 1 */
> > +             for (ctrl = 1; ctrl < num_ctrls; ctrl++) {
> > +                     if (pp->msi_irq[ctrl])
> > +                             continue;
> > +
> > +                     snprintf(irq_name, sizeof(irq_name), "msi%d", ctrl);
> > +                     irq = platform_get_irq_byname(pdev, irq_name);
> > +                     if (irq < 0)
> > +                             return irq;
> > +
> > +                     pp->msi_irq[ctrl] = irq;
> > +             }
> > +     }
> > +
> >       if (!pp->msi_irq[0]) {
> >               int irq = platform_get_irq_byname_optional(pdev, "msi");
>
> Johan



-- 
With best wishes
Dmitry