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From: Sunil V L <sunilvl@ventanamicro.com>
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	=?UTF-8?q?Bj=C3=B6rn=20T=C3=B6pel?= <bjorn@kernel.org>,
	Sunil V L <sunilvl@ventanamicro.com>
Subject: [RFC PATCH v4 11/20] ACPI: scan.c: Define weak function to populate dependencies
Date: Mon, 15 Apr 2024 22:31:04 +0530
Message-Id: <20240415170113.662318-12-sunilvl@ventanamicro.com>
In-Reply-To: <20240415170113.662318-1-sunilvl@ventanamicro.com>
References: <20240415170113.662318-1-sunilvl@ventanamicro.com>
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Some architectures like RISC-V need to add dependencies without explicit
_DEP. Define a weak function which can be implemented by the architecture.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 drivers/acpi/scan.c     | 11 +++++++++++
 include/acpi/acpi_bus.h |  1 +
 2 files changed, 12 insertions(+)

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 07e91616b7d4..8e23b9508716 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2073,11 +2073,22 @@ int acpi_scan_add_dep(acpi_handle handle, struct acpi_handle_list *dep_devices)
 	return count;
 }
 
+u32 __weak arch_acpi_add_auto_dep(acpi_handle handle) { return 0; }
+
 static u32 acpi_scan_check_dep(acpi_handle handle)
 {
 	struct acpi_handle_list dep_devices;
 	u32 count = 0;
 
+	/*
+	 * Some architectures like RISC-V need to add dependencies for
+	 * all devices which use GSI to the interrupt controller so that
+	 * interrupt controller is probed before any of those devices.
+	 * Instead of mandating _DEP on all the devices, detect the
+	 * dependency and add automatically.
+	 */
+	count += arch_acpi_add_auto_dep(handle);
+
 	/*
 	 * Check for _HID here to avoid deferring the enumeration of:
 	 * 1. PCI devices.
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 28a9b87c23fa..5fba4075d764 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -994,6 +994,7 @@ static inline void acpi_put_acpi_dev(struct acpi_device *adev)
 int acpi_wait_for_acpi_ipmi(void);
 
 int acpi_scan_add_dep(acpi_handle handle, struct acpi_handle_list *dep_devices);
+u32 arch_acpi_add_auto_dep(acpi_handle handle);
 #else	/* CONFIG_ACPI */
 
 static inline int register_acpi_bus_type(void *bus) { return 0; }
-- 
2.40.1