ACPI / MPAM: Parse the MPAM table

Add code to parse the arm64 specific MPAM table, looking up the cache
level from the PPTT and feeding the end result into the MPAM driver.

This happens in two stages. Platform devices are created first for the
MSC devices. Once the driver probes it calls acpi_mpam_parse_resources()
to discover the RIS entries the MSC contains.

For now the MPAM hook mpam_ris_create() is stubbed out, but will update
the MPAM driver with optional discovered data about the RIS entries.

CC: Carl Worth <carl@os.amperecomputing.com>
Link: https://developer.arm.com/documentation/den0065/3-0bet/?lang=en
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Fenghua Yu <fenghuay@nvidia.com>
Tested-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>
Tested-by: Peter Newman <peternewman@google.com>
Tested-by: Carl Worth <carl@os.amperecomputing.com>
Tested-by: Gavin Shan <gshan@redhat.com>
Tested-by: Zeng Heng <zengheng4@huawei.com>
Tested-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Ben Horgan <ben.horgan@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/include/linux/arm_mpam.h b/include/linux/arm_mpam.h
new file mode 100644
index 000000000000..4b7f335181e0
--- /dev/null
+++ b/include/linux/arm_mpam.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2025 Arm Ltd. */
+
+#ifndef __LINUX_ARM_MPAM_H
+#define __LINUX_ARM_MPAM_H
+
+#include <linux/acpi.h>
+#include <linux/types.h>
+
+struct mpam_msc;
+
+enum mpam_msc_iface {
+	MPAM_IFACE_MMIO,	/* a real MPAM MSC */
+	MPAM_IFACE_PCC,		/* a fake MPAM MSC */
+};
+
+enum mpam_class_types {
+	MPAM_CLASS_CACHE,	/* Caches, e.g. L2, L3 */
+	MPAM_CLASS_MEMORY,	/* Main memory */
+	MPAM_CLASS_UNKNOWN,	/* Everything else, e.g. SMMU */
+};
+
+#define MPAM_CLASS_ID_DEFAULT	255
+
+#ifdef CONFIG_ACPI_MPAM
+int acpi_mpam_parse_resources(struct mpam_msc *msc,
+			      struct acpi_mpam_msc_node *tbl_msc);
+
+int acpi_mpam_count_msc(void);
+#else
+static inline int acpi_mpam_parse_resources(struct mpam_msc *msc,
+					    struct acpi_mpam_msc_node *tbl_msc)
+{
+	return -EINVAL;
+}
+
+static inline int acpi_mpam_count_msc(void) { return -EINVAL; }
+#endif
+
+static inline int mpam_ris_create(struct mpam_msc *msc, u8 ris_idx,
+				  enum mpam_class_types type, u8 class_id,
+				  int component_id)
+{
+	return -EINVAL;
+}
+
+#endif /* __LINUX_ARM_MPAM_H */