linux-kernel - [PATCH v1 13/14] arm_mpam: Handle resource instances mapped to different controls

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Message-ID: <20240117141405.3063506-14-amitsinght@marvell.com>
Date: Wed, 17 Jan 2024 19:44:04 +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>,
        <dfustini@...libre.com>, <jonathan.cameron@...wei.com>,
        Amit Singh Tomar <amitsinght@...vell.com>
Subject: [PATCH v1 13/14] 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 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>
---
Changes since RFC:
	* Trimmed down the commit message.
	* Tried to handle the corner case as suggested by Jonathan
	  by calling the __resource_props_mismatch even when different
	  controls are enumerated at different RIS index.
---
 drivers/platform/mpam/mpam_devices.c | 36 ++++++++++++++++++++++++----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/platform/mpam/mpam_devices.c b/drivers/platform/mpam/mpam_devices.c
index 388d57281fd8..df7ac2c8bcb3 100644
--- a/drivers/platform/mpam/mpam_devices.c
+++ b/drivers/platform/mpam/mpam_devices.c
@@ -1788,11 +1788,15 @@ __resource_props_mismatch(struct mpam_msc_ris *ris, struct mpam_class *class)
 
 	lockdep_assert_held(&mpam_list_lock); /* we modify class */
 
-	/* Clear missing features */
-	cprops->features &= rprops->features;
+	/* Clear missing features, we don't want to clear features,
+	 * when different controls are implemented at different RIS
+	 * index.
+	 */
+	if (class->props.features == ris->props.features)
+		cprops->features &= rprops->features;
 
 	/* Clear incompatible features */
-	if (cprops->cpbm_wd != rprops->cpbm_wd)
+	if (cprops->cpbm_wd != rprops->cpbm_wd && rprops->cpbm_wd)
 		mpam_clear_feature(mpam_feat_cpor_part, &cprops->features);
 	if (cprops->mbw_pbm_bits != rprops->mbw_pbm_bits)
 		mpam_clear_feature(mpam_feat_mbw_part, &cprops->features);
@@ -1802,14 +1806,14 @@ __resource_props_mismatch(struct mpam_msc_ris *ris, struct mpam_class *class)
 		cprops->bwa_wd = min(cprops->bwa_wd, rprops->bwa_wd);
 
 	/* For num properties, take the minimum */
-	if (cprops->num_csu_mon != rprops->num_csu_mon)
+	if (cprops->num_csu_mon != rprops->num_csu_mon && rprops->num_csu_mon)
 		cprops->num_csu_mon = min(cprops->num_csu_mon, rprops->num_csu_mon);
 	if (cprops->num_mbwu_mon != rprops->num_mbwu_mon)
 		cprops->num_mbwu_mon = min(cprops->num_mbwu_mon, rprops->num_mbwu_mon);
 
 	if (cprops->intpri_wd != rprops->intpri_wd)
 		cprops->intpri_wd = min(cprops->intpri_wd, rprops->intpri_wd);
-	if (cprops->dspri_wd != rprops->dspri_wd)
+	if (cprops->dspri_wd != rprops->dspri_wd && rprops->dspri_wd)
 		cprops->dspri_wd = min(cprops->dspri_wd, rprops->dspri_wd);
 
 	/* {int,ds}pri may not have differing 0-low behaviour */
@@ -1845,6 +1849,20 @@ 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. This is needed when two controls
+ * are enumerated under differnt RIS Index.
+ */
+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)
 {
@@ -1860,6 +1878,14 @@ 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 with different
+				 * RIS.
+				 */
+				if (class->props.features != ris->props.features)
+					mpam_enable_club_class_features(class, ris);
 
 				class->nrdy_usec = max(class->nrdy_usec,
 						     ris->msc->nrdy_usec);
-- 
2.25.1