linux-kernel - [RFC PATCH 14/36] arm_mpam: Add support for memory controller MSC on DT platforms

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Message-Id: <20250711183648.30766-15-james.morse@arm.com>
Date: Fri, 11 Jul 2025 18:36:26 +0000
From: James Morse <james.morse@....com>
To: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Cc: Rob Herring <robh@...nel.org>,
	Ben Horgan <ben.horgan@....com>,
	Rohit Mathew <rohit.mathew@....com>,
	Shanker Donthineni <sdonthineni@...dia.com>,
	Zeng Heng <zengheng4@...wei.com>,
	Lecopzer Chen <lecopzerc@...dia.com>,
	Carl Worth <carl@...amperecomputing.com>,
	shameerali.kolothum.thodi@...wei.com,
	D Scott Phillips OS <scott@...amperecomputing.com>,
	lcherian@...vell.com,
	bobo.shaobowang@...wei.com,
	tan.shaopeng@...itsu.com,
	baolin.wang@...ux.alibaba.com,
	Jamie Iles <quic_jiles@...cinc.com>,
	Xin Hao <xhao@...ux.alibaba.com>,
	peternewman@...gle.com,
	dfustini@...libre.com,
	amitsinght@...vell.com,
	David Hildenbrand <david@...hat.com>,
	Rex Nie <rex.nie@...uarmicro.com>,
	Dave Martin <dave.martin@....com>,
	Koba Ko <kobak@...dia.com>,
	James Morse <james.morse@....com>
Subject: [RFC PATCH 14/36] arm_mpam: Add support for memory controller MSC on DT platforms

From: Shanker Donthineni <sdonthineni@...dia.com>

The device-tree binding has two examples for MSC associated with
memory controllers. Add the support to discover the component_id
from the device-tree and create 'memory' RIS.

Signed-off-by: Shanker Donthineni <sdonthineni@...dia.com>
[ morse: split out of a bigger patch, added affinity piece ]
Signed-off-by: James Morse <james.morse@....com>
---
 drivers/platform/arm64/mpam/mpam_devices.c | 67 +++++++++++++++-------
 1 file changed, 47 insertions(+), 20 deletions(-)

diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index 5b886ba54ba8..f5abd5f0d41a 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -60,41 +60,63 @@ static int mpam_dt_parse_resource(struct mpam_msc *msc, struct device_node *np,
 				  u32 ris_idx)
 {
 	int err = 0;
-	u32 level = 0;
-	unsigned long cache_id;
-	struct device_node *cache;
+	u32 class_id = 0, component_id = 0;
+	struct device_node *cache = NULL, *memory = NULL;
+	enum mpam_class_types type = MPAM_CLASS_UNKNOWN;
 
 	do {
+		/* What kind of MSC is this? */
 		if (of_device_is_compatible(np, "arm,mpam-cache")) {
 			cache = of_parse_phandle(np, "arm,mpam-device", 0);
 			if (!cache) {
 				pr_err("Failed to read phandle\n");
 				break;
 			}
+			type = MPAM_CLASS_CACHE;
 		} else if (of_device_is_compatible(np->parent, "cache")) {
 			cache = of_node_get(np->parent);
+			type = MPAM_CLASS_CACHE;
+		} else if (of_device_is_compatible(np, "arm,mpam-memory")) {
+			memory = of_parse_phandle(np, "arm,mpam-device", 0);
+			if (!memory) {
+				pr_err("Failed to read phandle\n");
+				break;
+			}
+			type = MPAM_CLASS_MEMORY;
+		} else if (of_device_is_compatible(np, "arm,mpam-memory-controller-msc")) {
+			memory = of_node_get(np->parent);
+			type = MPAM_CLASS_MEMORY;
 		} else {
-			/* For now, only caches are supported */
-			cache = NULL;
+			/*
+			 * For now, only caches and memory controllers are
+			 * supported.
+			 */
 			break;
 		}
 
-		err = of_property_read_u32(cache, "cache-level", &level);
-		if (err) {
-			pr_err("Failed to read cache-level\n");
-			break;
-		}
-
-		cache_id = cache_of_calculate_id(cache);
-		if (cache_id == ~0UL) {
-			err = -ENOENT;
-			break;
+		/* Determine the class and component ids, based on type. */
+		if (type == MPAM_CLASS_CACHE) {
+			err = of_property_read_u32(cache, "cache-level", &class_id);
+			if (err) {
+				pr_err("Failed to read cache-level\n");
+				break;
+			}
+			component_id = cache_of_calculate_id(cache);
+			if (component_id == ~0UL) {
+				err = -ENOENT;
+				break;
+			}
+		} else if (type == MPAM_CLASS_MEMORY) {
+			err = of_node_to_nid(np);
+			component_id = (err == NUMA_NO_NODE) ? 0 : err;
+			class_id = 255;
 		}
 
-		err = mpam_ris_create(msc, ris_idx, MPAM_CLASS_CACHE, level,
-				      cache_id);
+		err = mpam_ris_create(msc, ris_idx, type, class_id,
+				      component_id);
 	} while (0);
 	of_node_put(cache);
+	of_node_put(memory);
 
 	return err;
 }
@@ -157,9 +179,14 @@ static int update_msc_accessibility(struct mpam_msc *msc)
 		cpumask_copy(&msc->accessibility, cpu_possible_mask);
 		err = 0;
 	} else {
-		err = -EINVAL;
-		pr_err("Cannot determine accessibility of MSC: %s\n",
-		       dev_name(&msc->pdev->dev));
+		if (of_device_is_compatible(parent, "memory")) {
+			cpumask_copy(&msc->accessibility, cpu_possible_mask);
+			err = 0;
+		} else {
+			err = -EINVAL;
+			pr_err("Cannot determine accessibility of MSC: %s\n",
+			       dev_name(&msc->pdev->dev));
+		}
 	}
 	of_node_put(parent);
 
-- 
2.39.5