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From: Jonathan Cameron <Jonathan.Cameron@huawei.com>
To: Thomas Gleixner <tglx@linutronix.de>, Peter Zijlstra
	<peterz@infradead.org>, <linux-pm@vger.kernel.org>,
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	<x86@kernel.org>, Russell King <linux@armlinux.org.uk>, "Rafael J . Wysocki"
	<rafael@kernel.org>, Miguel Luis <miguel.luis@oracle.com>, James Morse
	<james.morse@arm.com>, Salil Mehta <salil.mehta@huawei.com>, Jean-Philippe
 Brucker <jean-philippe@linaro.org>, Catalin Marinas
	<catalin.marinas@arm.com>, Will Deacon <will@kernel.org>, Marc Zyngier
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CC: Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Dave
 Hansen <dave.hansen@linux.intel.com>, <linuxarm@huawei.com>,
	<justin.he@arm.com>, <jianyong.wu@arm.com>, Lorenzo Pieralisi
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Subject: [PATCH v8 05/16] ACPI: processor: Add acpi_get_processor_handle() helper
Date: Fri, 26 Apr 2024 14:51:15 +0100
Message-ID: <20240426135126.12802-6-Jonathan.Cameron@huawei.com>
In-Reply-To: <20240426135126.12802-1-Jonathan.Cameron@huawei.com>
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If CONFIG_ACPI_PROCESSOR provide a helper to retrieve the
acpi_handle for a given CPU allowing access to methods
in DSDT.

Tested-by: Miguel Luis <miguel.luis@oracle.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

---
v8: Code simplification suggested by Rafael.
    Fixup ;; spotted by Gavin
---
 drivers/acpi/acpi_processor.c | 11 +++++++++++
 include/linux/acpi.h          |  7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c
index 3b180e21f325..ecc2721fecae 100644
--- a/drivers/acpi/acpi_processor.c
+++ b/drivers/acpi/acpi_processor.c
@@ -35,6 +35,17 @@ EXPORT_PER_CPU_SYMBOL(processors);
 struct acpi_processor_errata errata __read_mostly;
 EXPORT_SYMBOL_GPL(errata);
 
+acpi_handle acpi_get_processor_handle(int cpu)
+{
+	struct acpi_processor *pr;
+
+	pr = per_cpu(processors, cpu);
+	if (pr)
+		return pr->handle;
+
+	return NULL;
+}
+
 static int acpi_processor_errata_piix4(struct pci_dev *dev)
 {
 	u8 value1 = 0;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 34829f2c517a..9844a3f9c4e5 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -309,6 +309,8 @@ int acpi_map_cpu(acpi_handle handle, phys_cpuid_t physid, u32 acpi_id,
 int acpi_unmap_cpu(int cpu);
 #endif /* CONFIG_ACPI_HOTPLUG_CPU */
 
+acpi_handle acpi_get_processor_handle(int cpu);
+
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
 int acpi_get_ioapic_id(acpi_handle handle, u32 gsi_base, u64 *phys_addr);
 #endif
@@ -1077,6 +1079,11 @@ static inline bool acpi_sleep_state_supported(u8 sleep_state)
 	return false;
 }
 
+static inline acpi_handle acpi_get_processor_handle(int cpu)
+{
+	return NULL;
+}
+
 #endif	/* !CONFIG_ACPI */
 
 extern void arch_post_acpi_subsys_init(void);
-- 
2.39.2