linux-kernel - [PATCH v3 25/29] arm_mpam: Probe for long/lwd mbwu counters

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Message-Id: <20251017185645.26604-26-james.morse@arm.com>
Date: Fri, 17 Oct 2025 18:56:41 +0000
From: James Morse <james.morse@....com>
To: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-acpi@...r.kernel.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@...hat.com>,
	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>,
	Rob Herring <robh@...nel.org>,
	Rohit Mathew <rohit.mathew@....com>,
	Rafael Wysocki <rafael@...nel.org>,
	Len Brown <lenb@...nel.org>,
	Lorenzo Pieralisi <lpieralisi@...nel.org>,
	Hanjun Guo <guohanjun@...wei.com>,
	Sudeep Holla <sudeep.holla@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Danilo Krummrich <dakr@...nel.org>,
	Jeremy Linton <jeremy.linton@....com>,
	Gavin Shan <gshan@...hat.com>,
	Ben Horgan <ben.horgan@....com>
Subject: [PATCH v3 25/29] arm_mpam: Probe for long/lwd mbwu counters

From: Rohit Mathew <rohit.mathew@....com>

mpam v0.1 and versions above v1.0 support optional long counter for
memory bandwidth monitoring. The MPAMF_MBWUMON_IDR register has fields
indicating support for long counters.

Probe these feature bits.

The mpam_feat_msmon_mbwu feature is used to indicate that bandwidth
monitors are supported, instead of muddling this with which size of
bandwidth monitors, add an explicit 31 bit counter feature.

Signed-off-by: Rohit Mathew <rohit.mathew@....com>
[ morse: Added 31bit counter feature to simplify later logic ]
Signed-off-by: James Morse <james.morse@....com>
Reviewed-by: Ben Horgan <ben.horgan@....com>
Tested-by: Fenghua Yu <fenghuay@...dia.com>
---
Changes since v2:
 * Added 31 bit counter type feature.
 * Altered commit message.
---
 drivers/resctrl/mpam_devices.c  | 13 +++++++++++--
 drivers/resctrl/mpam_internal.h |  3 +++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index deb1dcc6f6b1..f4d07234ce10 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -777,16 +777,25 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
 				dev_err_once(dev, "Counters are not usable because not-ready timeout was not provided by firmware.");
 		}
 		if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_MBWU, msmon_features)) {
-			bool hw_managed;
+			bool has_long, hw_managed;
 			u32 mbwumon_idr = mpam_read_partsel_reg(msc, MBWUMON_IDR);
 
 			props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumon_idr);
-			if (props->num_mbwu_mon)
+			if (props->num_mbwu_mon) {
 				mpam_set_feature(mpam_feat_msmon_mbwu, props);
+				mpam_set_feature(mpam_feat_msmon_mbwu_31counter, props);
+			}
 
 			if (FIELD_GET(MPAMF_MBWUMON_IDR_HAS_RWBW, mbwumon_idr))
 				mpam_set_feature(mpam_feat_msmon_mbwu_rwbw, props);
 
+			has_long = FIELD_GET(MPAMF_MBWUMON_IDR_HAS_LONG, mbwumon_idr);
+			if (props->num_mbwu_mon && has_long) {
+				mpam_set_feature(mpam_feat_msmon_mbwu_44counter, props);
+				if (FIELD_GET(MPAMF_MBWUMON_IDR_LWD, mbwumon_idr))
+					mpam_set_feature(mpam_feat_msmon_mbwu_63counter, props);
+			}
+
 			/* Is NRDY hardware managed? */
 			hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, MBWU);
 			if (hw_managed)
diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 28c475d18d86..ff38b4bbfc2b 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -158,6 +158,9 @@ enum mpam_device_features {
 	mpam_feat_msmon_csu_xcl,
 	mpam_feat_msmon_csu_hw_nrdy,
 	mpam_feat_msmon_mbwu,
+	mpam_feat_msmon_mbwu_31counter,
+	mpam_feat_msmon_mbwu_44counter,
+	mpam_feat_msmon_mbwu_63counter,
 	mpam_feat_msmon_mbwu_capture,
 	mpam_feat_msmon_mbwu_rwbw,
 	mpam_feat_msmon_mbwu_hw_nrdy,
-- 
2.39.5