Messages in this thread | | | Date | Wed, 31 Aug 2022 11:20:28 +0100 | From | Jonathan Cameron <> | Subject | Re: [PATCH 07/15] cxl/acpi: Check RCH's PCIe Host Bridge ACPI ID |
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On Wed, 31 Aug 2022 10:15:55 +0200 Robert Richter <rrichter@amd.com> wrote:
> An RCH is a root bridge and has "PNP0A08" or "ACPI0016" ACPI ID set. > Check this. > > Signed-off-by: Robert Richter <rrichter@amd.com>
Hi Robert,
I'm a little uncomfortable with repurposing acpi_device_id as you have done here. Might be better to do the same as in pci_root.c where the matches are done more directly.
> --- > drivers/cxl/acpi.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > index a19e3154dd44..ffdf439adb87 100644 > --- a/drivers/cxl/acpi.c > +++ b/drivers/cxl/acpi.c > @@ -312,9 +312,16 @@ static int add_root_nvdimm_bridge(struct device *match, void *data) > return 1; > } > > +static const struct acpi_device_id cxl_host_ids[] = { > + { "ACPI0016", 0 }, > + { "PNP0A08", 0 }, > + { },
Trivial but no comma after a null terminator. Always good to make it harder for people to add things where they really shouldn't!
pci_root.c avoids using an acpi_device_id table for similar matching. I think the point being to separate probe type use of this table from cases where we aren't using a normal device probe. So to remain consistent with that, I would just grab the hid and match it directly in this code.
I don't feel that strongly about this if the ACPI maintainers are fine with reusing this infrastructure as you have it here.
> +}; > + > struct pci_host_bridge *cxl_find_next_rch(struct pci_host_bridge *host) > { > struct pci_bus *bus = host ? host->bus : NULL; > + struct acpi_device *adev; > > while ((bus = pci_find_next_bus(bus)) != NULL) { > host = bus ? to_pci_host_bridge(bus->bridge) : NULL; > @@ -323,6 +330,19 @@ struct pci_host_bridge *cxl_find_next_rch(struct pci_host_bridge *host) > > dev_dbg(&host->dev, "PCI bridge found\n"); > > + /* Must be a root bridge */ > + if (host->bus->parent) > + continue; > + > + dev_dbg(&host->dev, "PCI bridge is root bridge\n"); > + > + adev = ACPI_COMPANION(&host->dev); > + if (acpi_match_device_ids(adev, cxl_host_ids)) > + continue; > + > + dev_dbg(&host->dev, "PCI ACPI host found: %s\n", > + acpi_dev_name(adev)); > + > return host; > } >
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