[PATCH v8 08/17] ACPI: pci_link: Clear the dependencies after probe

Sunil V L
2024-08-12T01:00:32Z

RISC-V platforms need to use dependencies between PCI host bridge, Link
devices and the interrupt controllers to ensure probe order. The
dependency is like below.

Interrupt controller <-- Link Device <-- PCI Host bridge.

If there is no dependency between Link device and PCI Host Bridge,
then PCI devices may be probed prior to Link devices. If a PCI
device is probed before its Link device, we won't be able to find
its INTx mapping.

So, add the link device's HID to dependency honor list and clear the
dependency after probe is done so that the dependent devices are
unblocked to probe.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Tested-by: BjÃ¶rn TÃ¶pel <bjorn@rivosinc.com>
---
drivers/acpi/pci_link.c | 2 ++
drivers/acpi/scan.c | 1 +
2 files changed, 3 insertions(+)

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index aa1038b8aec4..b727db968f33 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -748,6 +748,8 @@ static int acpi_pci_link_add(struct acpi_device *device,
if (result)
kfree(link);

+ acpi_dev_clear_dependencies(device);
+
return result < 0 ? result : 1;
}

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 28a221f956d7..753539a1f26b 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -863,6 +863,7 @@ static const char * const acpi_honor_dep_ids[] = {
"INTC10CF", /* IVSC (MTL) driver must be loaded to allow i2c access to camera sensors */
"RSCV0001", /* RISC-V PLIC */
"RSCV0002", /* RISC-V APLIC */
+ "PNP0C0F", /* PCI Link Device */
NULL
};

--
2.43.0