linux-kernel - [RFC PATCH 10/38] arm_mpam: resctrl: Add resctrl_arch_get

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Message-Id: <20251205215901.17772-11-james.morse@arm.com>
Date: Fri,  5 Dec 2025 21:58:33 +0000
From: James Morse <james.morse@....com>
To: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Cc: James Morse <james.morse@....com>,
	D Scott Phillips OS <scott@...amperecomputing.com>,
	carl@...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@...nel.org>,
	Dave Martin <dave.martin@....com>,
	Koba Ko <kobak@...dia.com>,
	Shanker Donthineni <sdonthineni@...dia.com>,
	fenghuay@...dia.com,
	baisheng.gao@...soc.com,
	Jonathan Cameron <jonathan.cameron@...wei.com>,
	Gavin Shan <gshan@...hat.com>,
	Ben Horgan <ben.horgan@....com>,
	rohit.mathew@....com,
	reinette.chatre@...el.com,
	Punit Agrawal <punit.agrawal@....qualcomm.com>
Subject: [RFC PATCH 10/38] arm_mpam: resctrl: Add resctrl_arch_get_config()

Implement resctrl_arch_get_config() by testing the live configuration for
a CPOR bitmap. For any other configuration type return the default.

Signed-off-by: James Morse <james.morse@....com>
---
 drivers/resctrl/mpam_resctrl.c | 43 ++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/resctrl/mpam_resctrl.c b/drivers/resctrl/mpam_resctrl.c
index a2deea1f4818..a26eb1f3efd0 100644
--- a/drivers/resctrl/mpam_resctrl.c
+++ b/drivers/resctrl/mpam_resctrl.c
@@ -168,6 +168,49 @@ static int mpam_resctrl_pick_domain_id(int cpu, struct mpam_component *comp)
 	return comp->comp_id;
 }
 
+u32 resctrl_arch_get_config(struct rdt_resource *r, struct rdt_ctrl_domain *d,
+			    u32 closid, enum resctrl_conf_type type)
+{
+	u32 partid;
+	struct mpam_config *cfg;
+	struct mpam_props *cprops;
+	struct mpam_resctrl_res *res;
+	struct mpam_resctrl_dom *dom;
+	enum mpam_device_features configured_by;
+
+	lockdep_assert_cpus_held();
+
+	if (!mpam_is_enabled())
+		return resctrl_get_default_ctrl(r);
+
+	res = container_of(r, struct mpam_resctrl_res, resctrl_res);
+	dom = container_of(d, struct mpam_resctrl_dom, resctrl_ctrl_dom);
+	cprops = &res->class->props;
+
+	partid = resctrl_get_config_index(closid, type);
+	cfg = &dom->ctrl_comp->cfg[partid];
+
+	switch (r->rid) {
+	case RDT_RESOURCE_L2:
+	case RDT_RESOURCE_L3:
+		configured_by = mpam_feat_cpor_part;
+		break;
+	default:
+		return resctrl_get_default_ctrl(r);
+	}
+
+	if (!r->alloc_capable || partid >= resctrl_arch_get_num_closid(r) ||
+	    !mpam_has_feature(configured_by, cfg))
+		return resctrl_get_default_ctrl(r);
+
+	switch (configured_by) {
+	case mpam_feat_cpor_part:
+		return cfg->cpbm;
+	default:
+		return resctrl_get_default_ctrl(r);
+	}
+}
+
 void resctrl_arch_reset_all_ctrls(struct rdt_resource *r)
 {
 	struct mpam_resctrl_res *res;
-- 
2.39.5