[RFC 02/12] arm_mpam: resctrl: Detect priority partitioning capability

[Amit Singh Tomar]

ARM MPAM supports different control that can be applied to different
resources in the system, for instance priority partitioning control
where priority value is generated from one MSC, propagates over
interconnect to other MSC (known as downstream priority), or can be
applied within an MSC for internal operations.

This change lets the resctrl know the about MSC's priority partitioning
capability.

Signed-off-by: Amit Singh Tomar <amitsinght@xxxxxxxxxxx>
---
 drivers/platform/mpam/mpam_resctrl.c | 14 ++++++++++++++
 include/linux/resctrl.h              |  4 ++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/platform/mpam/mpam_resctrl.c b/drivers/platform/mpam/mpam_resctrl.c
index 1dbfb6f6dd34..09618d9ceb1d 100644
--- a/drivers/platform/mpam/mpam_resctrl.c
+++ b/drivers/platform/mpam/mpam_resctrl.c
@@ -435,6 +435,16 @@ static bool cache_has_usable_cpor(struct mpam_class *class)
 	return (class->props.cpbm_wd <= RESCTRL_MAX_CBM);
 }
 
+static bool cache_has_usable_priority_part(struct mpam_class *class)
+{
+	struct mpam_props *cprops = &class->props;
+
+	if (!mpam_has_feature(mpam_feat_dspri_part, cprops))
+		return false;
+
+	return (class->props.dspri_wd <= RESCTRL_MAX_DSPRI);
+}
+
 static bool cache_has_usable_csu(struct mpam_class *class)
 {
 	struct mpam_props *cprops;
@@ -691,6 +701,7 @@ static int mpam_resctrl_resource_init(struct mpam_resctrl_res *res)
 	    res->resctrl_res.rid == RDT_RESOURCE_L3) {
 		bool has_csu = cache_has_usable_csu(class);
 		bool has_mbwu = class_has_usable_mbwu(class);
+		bool has_ppart = cache_has_usable_priority_part(class);
 
 		/* TODO: Scaling is not yet supported */
 		r->cache.cbm_len = class->props.cpbm_wd;
@@ -718,6 +729,9 @@ static int mpam_resctrl_resource_init(struct mpam_resctrl_res *res)
 			exposed_alloc_capable = true;
 		}
 
+		if (has_ppart)
+			r->priority_cap = true;
+
 		/*
 		 * MBWU counters may be 'local' or 'total' depending on where
 		 * they are in the topology. If The counter is on the L3, its
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 3ad308e9e226..a98ba5828211 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -38,6 +38,8 @@ int proc_resctrl_show(struct seq_file *m,
  */
 #define RESCTRL_MAX_CBM			32
 
+#define RESCTRL_MAX_DSPRI               63
+
 /* The format for packing fields into the u64 'id' exposed to user-space */
 #define RESCTRL_ID_CLOSID	GENMASK_ULL(31, 0)
 #define RESCTRL_ID_RMID		GENMASK_ULL(63, 32)
@@ -195,6 +197,7 @@ struct resctrl_membw {
  * @rid:		The index of the resource
  * @alloc_capable:	Is allocation available on this machine
  * @mon_capable:	Is monitor feature available on this machine
+ * @priority_capable:   Is priority partitioning feature available on this machine
  * @num_rmid:		Number of RMIDs available
  * @cache_level:	Which cache level defines scope of this resource
  * @cache:		Cache allocation related data
@@ -212,6 +215,7 @@ struct rdt_resource {
 	int			rid;
 	bool			alloc_capable;
 	bool			mon_capable;
+	bool                    priority_cap;
 	int			num_rmid;
 	int			cache_level;
 	struct resctrl_cache	cache;
-- 
2.25.1