linux-kernel - [RFC 01/12] arm_mpam: Handle resource instances mapped to different controls

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Message-ID: <20230815152712.1760046-2-amitsinght@marvell.com>
Date:   Tue, 15 Aug 2023 20:57:01 +0530
From:   Amit Singh Tomar <amitsinght@...vell.com>
To:     <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <fenghua.yu@...el.com>, <reinette.chatre@...el.com>,
        <james.morse@....com>, <gcherian@...vell.com>, <robh@...nel.org>,
        <peternewman@...gle.com>, Amit Singh Tomar <amitsinght@...vell.com>
Subject: [RFC 01/12] arm_mpam: Handle resource instances mapped to different controls

At the moment, configuring multiple resource instances (mapped to same
control) under a resource class is not supported. For instance, on MARVELL
SoC MPAMF_IDR_NS[RIS_MAX] (under LLC MSC) is 0x2, and there are three
different resource at index 0,1,2. These are enumerated in
TAD_CMN_MPAM_RIS_E:

0: MSC
1: LTG
2: DTG

LLC MSC resource at index 1, and 2 have cache portion partitioning
feature, i.e., If MPAMCFG_PART_SEL_NS[RIS] is set to 1 (LTG) or to 2 (DTG),
then MPAMF_IDR_NS[HAS_CPOR_PART] is set to 1. LTG resource has 16
portion bitmap, and DTG has 18 portion bitmap (mapped to same
CPOR control), and only one can be configured.

LLC MSC resource at index 0 has the Priority partitioning features.
If MPAMCFG_PART_SEL_NS[RIS] is set to 0 (MSC), then MPAMF_IDR_NS[HAS_PRI_PART]
is set to 1, leaving HAS_CPOR_PART bit to 0. CPOR and PRI_PART are
mutually exclusive resources as far configuration is concerned.

With this change, multiple resource instances that maps to different
control, say LTG for CPOR, and MSC for PRI_PART is handled properly.

Signed-off-by: Amit Singh Tomar <amitsinght@...vell.com>
---
 drivers/platform/mpam/mpam_devices.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/mpam/mpam_devices.c b/drivers/platform/mpam/mpam_devices.c
index 589ff1ef2b6b..137cbff925ba 100644
--- a/drivers/platform/mpam/mpam_devices.c
+++ b/drivers/platform/mpam/mpam_devices.c
@@ -1829,6 +1829,19 @@ static void mpam_enable_init_class_features(struct mpam_class *class)
 	class->props = ris->props;
 }
 
+/* Club different resource properties under a class that resctrl uses,
+ * for instance, L3 cache that supports both CPOR, and DSPRI need to have
+ * knowledge of both cpbm_wd and dspri_wd.
+ */
+static void mpam_enable_club_class_features(struct mpam_class *class,
+					    struct mpam_msc_ris *ris)
+{
+	class->props.features |= ris->props.features;
+	class->props.cpbm_wd |= ris->props.cpbm_wd;
+	class->props.dspri_wd |= ris->props.dspri_wd;
+	class->props.num_csu_mon |= ris->props.num_csu_mon;
+}
+
 /* Merge all the common resource features into class. */
 static void mpam_enable_merge_features(void)
 {
@@ -1843,7 +1856,16 @@ static void mpam_enable_merge_features(void)
 
 		list_for_each_entry(comp, &class->components, class_list) {
 			list_for_each_entry(ris, &comp->ris, comp_list) {
-				__resource_props_mismatch(ris, class);
+				/* There can be multiple resources under a class which is
+				 * mapped to different controls, for instance L3 cache
+				 * can have both CPOR and DSPRI implemented, and following
+				 * would avoid property mismatch later on when different
+				 * resources are present.
+				 */
+				if (class->props.features != ris->props.features)
+					mpam_enable_club_class_features(class, ris);
+				else
+					__resource_props_mismatch(ris, class);
 
 				class->nrdy_usec = max(class->nrdy_usec,
 						     ris->msc->nrdy_usec);
-- 
2.25.1