linux-kernel - [PATCH 1/3] perf/arm-cmn: Fix DTC domain detection

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Message-Id: <3076ee83d0554f6939fbb6ee49ab2bdb28d8c7ee.1697824215.git.robin.murphy@arm.com>
Date:   Fri, 20 Oct 2023 18:51:25 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     will@...nel.org
Cc:     mark.rutland@....com, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, jeremy.linton@....com,
        ilkka@...amperecomputing.com, renyu.zj@...ux.alibaba.com
Subject: [PATCH 1/3] perf/arm-cmn: Fix DTC domain detection

It transpires that dtm_unit_info is another register which got shuffled
in CMN-700 without me noticing. Fix that in a way which also proactively
fixes the fragile laziness of its consumer, just in case any further
fields ever get added alongside dtc_domain.

Fixes: 23760a014417 ("perf/arm-cmn: Add CMN-700 support")
Signed-off-by: Robin Murphy <robin.murphy@....com>
---
 drivers/perf/arm-cmn.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
index 913dc04b3a40..f1ac8d0cdb3b 100644
--- a/drivers/perf/arm-cmn.c
+++ b/drivers/perf/arm-cmn.c
@@ -112,7 +112,9 @@
 
 #define CMN_DTM_PMEVCNTSR		0x240
 
-#define CMN_DTM_UNIT_INFO		0x0910
+#define CMN650_DTM_UNIT_INFO		0x0910
+#define CMN_DTM_UNIT_INFO		0x0960
+#define CMN_DTM_UNIT_INFO_DTC_DOMAIN	GENMASK_ULL(1, 0)
 
 #define CMN_DTM_NUM_COUNTERS		4
 /* Want more local counters? Why not replicate the whole DTM! Ugh... */
@@ -2117,6 +2119,16 @@ static int arm_cmn_init_dtcs(struct arm_cmn *cmn)
 	return 0;
 }
 
+static unsigned int arm_cmn_dtc_domain(struct arm_cmn *cmn, void __iomem *xp_region)
+{
+	int offset = CMN_DTM_UNIT_INFO;
+
+	if (cmn->part == PART_CMN650 || cmn->part == PART_CI700)
+		offset = CMN650_DTM_UNIT_INFO;
+
+	return FIELD_GET(CMN_DTM_UNIT_INFO_DTC_DOMAIN, readl_relaxed(xp_region + offset));
+}
+
 static void arm_cmn_init_node_info(struct arm_cmn *cmn, u32 offset, struct arm_cmn_node *node)
 {
 	int level;
@@ -2248,7 +2260,7 @@ static int arm_cmn_discover(struct arm_cmn *cmn, unsigned int rgn_offset)
 		if (cmn->part == PART_CMN600)
 			xp->dtc = 0xf;
 		else
-			xp->dtc = 1 << readl_relaxed(xp_region + CMN_DTM_UNIT_INFO);
+			xp->dtc = 1 << arm_cmn_dtc_domain(cmn, xp_region);
 
 		xp->dtm = dtm - cmn->dtms;
 		arm_cmn_init_dtm(dtm++, xp, 0);
-- 
2.39.2.101.g768bb238c484.dirty