arm_mpam: Add probe/remove for mpam msc driver and kbuild boiler plate

Probing MPAM is convoluted. MSCs that are integrated with a CPU may
only be accessible from those CPUs, and they may not be online.
Touching the hardware early is pointless as MPAM can't be used until
the system-wide common values for num_partid and num_pmg have been
discovered.

Start with driver probe/remove and mapping the MSC.

Cc: Carl Worth <carl@os.amperecomputing.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Fenghua Yu <fenghuay@nvidia.com>
Reviewed-by: Shaopeng Tan <tan.shaopeng@jp.fujitsu.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, 49 insertions, 0 deletions

diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
new file mode 100644
index 000000000000..540066903eca
--- /dev/null
+++ b/drivers/resctrl/mpam_internal.h
@@ -0,0 +1,49 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+// Copyright (C) 2025 Arm Ltd.
+
+#ifndef MPAM_INTERNAL_H
+#define MPAM_INTERNAL_H
+
+#include <linux/arm_mpam.h>
+#include <linux/cpumask.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+
+struct platform_device;
+
+struct mpam_msc {
+	/* member of mpam_all_msc */
+	struct list_head	all_msc_list;
+
+	int			id;
+	struct platform_device	*pdev;
+
+	/* Not modified after mpam_is_enabled() becomes true */
+	enum mpam_msc_iface	iface;
+	u32			nrdy_usec;
+	cpumask_t		accessibility;
+
+	/*
+	 * probe_lock is only taken during discovery. After discovery these
+	 * properties become read-only and the lists are protected by SRCU.
+	 */
+	struct mutex		probe_lock;
+	unsigned long		ris_idxs;
+	u32			ris_max;
+
+	/* mpam_msc_ris of this component */
+	struct list_head	ris;
+
+	/*
+	 * part_sel_lock protects access to the MSC hardware registers that are
+	 * affected by MPAMCFG_PART_SEL. (including the ID registers that vary
+	 * by RIS).
+	 * If needed, take msc->probe_lock first.
+	 */
+	struct mutex		part_sel_lock;
+
+	void __iomem		*mapped_hwpage;
+	size_t			mapped_hwpage_sz;
+};
+#endif /* MPAM_INTERNAL_H */