Re: [PATCH] PCI/MSI: pci-xgene-msi: Enable MSI support in ACPI boot for X-Gene v1

[Duc Dang]

On Mon, Feb 22, 2016 at 8:03 AM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
>
> On Sat, Feb 20, 2016 at 1:47 PM, Duc Dang <dhdang@xxxxxxx> wrote:
> > On Tue, Feb 9, 2016 at 5:56 PM, Duc Dang <dhdang@xxxxxxx> wrote:
> >> This patch makes pci-xgene-msi driver ACPI-aware and provides
> >> MSI capability for X-Gene v1 PCIe controllers in ACPI boot mode.
> >
> > Hi Bjorn,
> >
> > Are you planning to take this patch into your tree?
>
> Sorry, I haven't had a chance to look at this yet.  I had a sick
> daughter last week, so I'm even farther behind than usual.
>
Hi Bjorn,

I hope your daughter is doing well.

> When I get to it, I'll be asking questions like:
>
>   - Does this correspond to some analogous x86 code?
I am not aware of any x86 code similar to this.

>   - Is there something unique about arm64 or X-Gene that means it
> needs special code?
The MSI controller on X-Gene v1 is a separate IP block. pci-xgene-msi
is a separate X-Gene v1 specific driver that provides MSI capability
for X-Gene v1 PCIe controllers. We already have device-tree version of
this driver. So the purpose of this patch is to make the driver can be
discovered and loaded when booting with ACPI mode.

Regards,
Duc Dang.

>
> I don't really understand the arm64/ACPI strategy yet, so I'll be
> looking first for generic solutions that work across x86/ia64/arm64,
> and justifications for the inevitable exceptions.
>
> >> Signed-off-by: Duc Dang <dhdang@xxxxxxx>
> >> ---
> >>  drivers/pci/host/pci-xgene-msi.c | 35 ++++++++++++++++++++++++++++++++---
> >>  1 file changed, 32 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/pci/host/pci-xgene-msi.c b/drivers/pci/host/pci-xgene-msi.c
> >> index a6456b5..466aa93 100644
> >> --- a/drivers/pci/host/pci-xgene-msi.c
> >> +++ b/drivers/pci/host/pci-xgene-msi.c
> >> @@ -24,6 +24,7 @@
> >>  #include <linux/pci.h>
> >>  #include <linux/platform_device.h>
> >>  #include <linux/of_pci.h>
> >> +#include <linux/acpi.h>
> >>
> >>  #define MSI_IR0                        0x000000
> >>  #define MSI_INT0               0x800000
> >> @@ -39,7 +40,7 @@ struct xgene_msi_group {
> >>  };
> >>
> >>  struct xgene_msi {
> >> -       struct device_node      *node;
> >> +       struct fwnode_handle    *fwnode;
> >>         struct irq_domain       *inner_domain;
> >>         struct irq_domain       *msi_domain;
> >>         u64                     msi_addr;
> >> @@ -249,6 +250,13 @@ static const struct irq_domain_ops msi_domain_ops = {
> >>         .free   = xgene_irq_domain_free,
> >>  };
> >>
> >> +#ifdef CONFIG_ACPI
> >> +static struct fwnode_handle *xgene_msi_get_fwnode(struct device *dev)
> >> +{
> >> +       return xgene_msi_ctrl.fwnode;
> >> +}
> >> +#endif
> >> +
> >>  static int xgene_allocate_domains(struct xgene_msi *msi)
> >>  {
> >>         msi->inner_domain = irq_domain_add_linear(NULL, NR_MSI_VEC,
> >> @@ -256,7 +264,7 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
> >>         if (!msi->inner_domain)
> >>                 return -ENOMEM;
> >>
> >> -       msi->msi_domain = pci_msi_create_irq_domain(of_node_to_fwnode(msi->node),
> >> +       msi->msi_domain = pci_msi_create_irq_domain(msi->fwnode,
> >>                                                     &xgene_msi_domain_info,
> >>                                                     msi->inner_domain);
> >>
> >> @@ -265,6 +273,9 @@ static int xgene_allocate_domains(struct xgene_msi *msi)
> >>                 return -ENOMEM;
> >>         }
> >>
> >> +#ifdef CONFIG_ACPI
> >> +       pci_msi_register_fwnode_provider(&xgene_msi_get_fwnode);
> >> +#endif
> >>         return 0;
> >>  }
> >>
> >> @@ -473,6 +484,13 @@ static const struct of_device_id xgene_msi_match_table[] = {
> >>         {},
> >>  };
> >>
> >> +#ifdef CONFIG_ACPI
> >> +static const struct acpi_device_id xgene_msi_acpi_ids[] = {
> >> +       {"APMC0D0E", 0},
> >> +       { },
> >> +};
> >> +#endif
> >> +
> >>  static int xgene_msi_probe(struct platform_device *pdev)
> >>  {
> >>         struct resource *res;
> >> @@ -494,7 +512,17 @@ static int xgene_msi_probe(struct platform_device *pdev)
> >>                 goto error;
> >>         }
> >>         xgene_msi->msi_addr = res->start;
> >> -       xgene_msi->node = pdev->dev.of_node;
> >> +
> >> +       xgene_msi->fwnode = of_node_to_fwnode(pdev->dev.of_node);
> >> +       if (!xgene_msi->fwnode) {
> >> +               xgene_msi->fwnode = irq_domain_alloc_fwnode(NULL);
> >> +               if (!xgene_msi->fwnode) {
> >> +                       dev_err(&pdev->dev, "Failed to create fwnode\n");
> >> +                       rc = ENOMEM;
> >> +                       goto error;
> >> +               }
> >> +       }
> >> +
> >>         xgene_msi->num_cpus = num_possible_cpus();
> >>
> >>         rc = xgene_msi_init_allocator(xgene_msi);
> >> @@ -571,6 +599,7 @@ static struct platform_driver xgene_msi_driver = {
> >>         .driver = {
> >>                 .name = "xgene-msi",
> >>                 .of_match_table = xgene_msi_match_table,
> >> +               .acpi_match_table = ACPI_PTR(xgene_msi_acpi_ids),
> >>         },
> >>         .probe = xgene_msi_probe,
> >>         .remove = xgene_msi_remove,
> >> --
> >> 1.9.1
> >>