On 27.04.2016 04:26, Bjorn Helgaas wrote:
On Fri, Apr 15, 2016 at 07:06:37PM +0200, Tomasz Nowicki wrote:
As we now have valid PCI host bridge device reference we can
introduce code that is going to find its bus domain number using
ACPI _SEG method.
Note that _SEG method is optional, therefore _SEG absence means
that all PCI buses belong to domain 0.
While at it, for the sake of code clarity we put ACPI and DT domain
assign methods into the corresponding helpers.
Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
Reviewed-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
Tested-by: Jeremy Linton <jeremy.linton@xxxxxxx>
Tested-by: Duc Dang <dhdang@xxxxxxx>
Tested-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
Tested-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
Tested-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
---
drivers/acpi/pci_root.c | 18 ++++++++++++++++++
drivers/pci/pci.c | 11 +++++++++--
include/linux/pci-acpi.h | 2 ++
3 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 4581e0e..d9a70c4 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -419,6 +419,24 @@ out:
}
EXPORT_SYMBOL(acpi_pci_osc_control_set);
+int acpi_pci_bus_domain_nr(struct device *parent)
+{
+ struct acpi_device *acpi_dev = to_acpi_device(parent);
+ unsigned long long segment = 0;
+ acpi_status status;
+
+ /*
+ * If _SEG method does not exist, following ACPI spec (6.5.6)
+ * all PCI buses belong to domain 0.
+ */
+ status = acpi_evaluate_integer(acpi_dev->handle, METHOD_NAME__SEG, NULL,
+ &segment);
We already have code in acpi_pci_root_add() to evaluate _SEG. We
don't want to evaluate it *twice*, do we?
Ideally we do not want.
The main intention here was to avoid using "void *sysdata" to retrieve
domain number. sysdata means something different for each architectures.
This would be common way for all arch using PCI_DOMAINS_GENERIC option
such as ARM64.
I was sort of expecting that if you added it here, we'd remove the
existing call, but it looks like you're keeping both?
I leave _SEG evaluation in acpi_pci_root_add to keep support for IA64
and x86 which are still using arch-specific sysdata (struct
pci_sysdata->domain for x86 and struct pci_controller->segment for IA64)
to retrieve domain number.
ARM64 uses PCI_DOMAINS_GENERIC for DT boot method, it would be
consistent to keep it for ACPI too.
I am open to suggestions, do you think we should use sysdata for ARM64?
Thanks,
Tomasz
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