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From: Sunil V L <sunilvl@ventanamicro.com>
To: linux-arm-kernel@lists.infradead.org,
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	Atish Kumar Patra <atishp@rivosinc.com>,
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	Marc Zyngier <maz@kernel.org>,
	=?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn@kernel.org>,
	Sunil V L <sunilvl@ventanamicro.com>
Subject: [RFC PATCH v4 20/20] ACPI: pci_link: Clear the dependencies after probe
Date: Mon, 15 Apr 2024 22:31:13 +0530
Message-Id: <20240415170113.662318-21-sunilvl@ventanamicro.com>
In-Reply-To: <20240415170113.662318-1-sunilvl@ventanamicro.com>
References: <20240415170113.662318-1-sunilvl@ventanamicro.com>
Precedence: bulk
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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 added between Link device and PCI Host Bridge,
then the PCI end points can get probed prior to link device unable to
get mapping for INTx.

So, add the link device's HID to dependency honor list and also clear it
after its probe.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 drivers/acpi/pci_link.c | 3 +++
 drivers/acpi/scan.c     | 1 +
 2 files changed, 4 insertions(+)

diff --git a/drivers/acpi/pci_link.c b/drivers/acpi/pci_link.c
index aa1038b8aec4..48cdcedafad6 100644
--- a/drivers/acpi/pci_link.c
+++ b/drivers/acpi/pci_link.c
@@ -748,6 +748,9 @@ static int acpi_pci_link_add(struct acpi_device *device,
 	if (result)
 		kfree(link);
 
+	if (IS_ENABLED(CONFIG_ARCH_ACPI_DEFERRED_GSI))
+		acpi_dev_clear_dependencies(device);
+
 	return result < 0 ? result : 1;
 }
 
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 086ae040a5ad..32865af071ce 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -835,6 +835,7 @@ 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
 };
 
-- 
2.40.1