ACPI: ARM Performance Monitoring Unit Table (APMT) initial support

ARM Performance Monitoring Unit Table describes the properties of PMU
support in ARM-based system. The APMT table contains a list of nodes,
each represents a PMU in the system that conforms to ARM CoreSight PMU
architecture. The properties of each node include information required
to access the PMU (e.g. MMIO base address, interrupt number) and also
identification. For more detailed information, please refer to the
specification below:
 * APMT: https://developer.arm.com/documentation/den0117/latest
 * ARM Coresight PMU:
        https://developer.arm.com/documentation/ihi0091/latest

The initial support adds the detection of APMT table and generic
infrastructure to create platform devices for ARM CoreSight PMUs.
Similar to IORT the root pointer of APMT is preserved during runtime
and each PMU platform device is given a pointer to the corresponding
APMT node.

Signed-off-by: Besar Wicaksono <bwicaksono@nvidia.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20220929002834.32664-1-bwicaksono@nvidia.com
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/acpi_apmt.h b/include/linux/acpi_apmt.h
new file mode 100644
index 000000000000..40bd634d082f
--- /dev/null
+++ b/include/linux/acpi_apmt.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * ARM CoreSight PMU driver.
+ * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES.
+ *
+ */
+
+#ifndef __ACPI_APMT_H__
+#define __ACPI_APMT_H__
+
+#include <linux/acpi.h>
+
+#ifdef CONFIG_ACPI_APMT
+void acpi_apmt_init(void);
+#else
+static inline void acpi_apmt_init(void) { }
+#endif /* CONFIG_ACPI_APMT */
+
+#endif /* __ACPI_APMT_H__ */