[PATCH v4 3/7] coresight: syscfg: Match feature capabilities separately from device class

[Amir Ayupov]

A feature loads on a device when the two share any match flag. That works
for device classes, where a feature wants any one of them, but not for
capabilities a device may or may not have: a feature that sets a class
and a capability would still load on a device of that class without the
capability.

Split the match flags into CS_CFG_MATCH_CLASS_MASK for device classes and
CS_CFG_MATCH_CAP_MASK for capabilities. A feature now loads on a device
that shares one of its classes and has all of its capabilities. Check
this once in cscfg_load_feat_csdev(), which both the feature and the
device registration paths call. No capability flags are defined yet, so
matching is unchanged.

Assisted-by: Devmate:Opus-5.5
Signed-off-by: Amir Ayupov <aaupov at fb.com>
---
 .../hwtracing/coresight/coresight-config.h    |  8 ++++
 .../hwtracing/coresight/coresight-syscfg.c    | 37 +++++++++++++------
 2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
index ae6295e308131..f04e73b91d9a6 100644
--- a/drivers/hwtracing/coresight/coresight-config.h
+++ b/drivers/hwtracing/coresight/coresight-config.h
@@ -7,6 +7,7 @@
 #ifndef _CORESIGHT_CORESIGHT_CONFIG_H
 #define _CORESIGHT_CORESIGHT_CONFIG_H
 
+#include <linux/bits.h>
 #include <linux/cleanup.h>
 #include <linux/coresight.h>
 #include <linux/types.h>
@@ -30,6 +31,13 @@
  */
 #define CS_CFG_MATCH_CLASS_SRC_ALL	0x0001	/* match any source */
 #define CS_CFG_MATCH_CLASS_SRC_ETM4	0x0002	/* match any ETMv4 device */
+#define CS_CFG_MATCH_CLASS_MASK		GENMASK_U32(7, 0)
+
+/*
+ * flags defining device capabilities a feature can require. A feature loads on
+ * a device that matches one of its classes and has all of its capabilities.
+ */
+#define CS_CFG_MATCH_CAP_MASK		GENMASK_U32(15, 8)
 
 /* flags defining device instance matching - used in config match desc data. */
 #define CS_CFG_MATCH_INST_ANY		0x80000000 /* any instance of a class */
diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
index a816c22c87bc8..3ee104e94a4cd 100644
--- a/drivers/hwtracing/coresight/coresight-syscfg.c
+++ b/drivers/hwtracing/coresight/coresight-syscfg.c
@@ -171,8 +171,22 @@ cscfg_alloc_csdev_feat(struct coresight_device *csdev, struct cscfg_feature_desc
 	return feat_csdev;
 }
 
-/* load one feature into one coresight device */
+static bool cscfg_match_feat_csdev(u32 feat_flags, u32 csdev_flags)
+{
+	/* The device must be in one of the feature's classes */
+	if (!(feat_flags & csdev_flags & CS_CFG_MATCH_CLASS_MASK))
+		return false;
+
+	/* The device must have every capability the feature requires */
+	if (feat_flags & ~csdev_flags & CS_CFG_MATCH_CAP_MASK)
+		return false;
+
+	return true;
+}
+
+/* Load the feature into the device if it matches, otherwise skip it. */
 static int cscfg_load_feat_csdev(struct coresight_device *csdev,
+				 u32 match_flags,
 				 struct cscfg_feature_desc *feat_desc,
 				 struct cscfg_csdev_feat_ops *ops)
 {
@@ -183,6 +197,9 @@ static int cscfg_load_feat_csdev(struct coresight_device *csdev,
 	if (!ops->load_feat)
 		return -EINVAL;
 
+	if (!cscfg_match_feat_csdev(feat_desc->match_flags, match_flags))
+		return 0;
+
 	feat_csdev = cscfg_alloc_csdev_feat(csdev, feat_desc);
 	if (!feat_csdev)
 		return -ENOMEM;
@@ -212,11 +229,11 @@ static int cscfg_add_feat_to_csdevs(struct cscfg_feature_desc *feat_desc)
 	int err;
 
 	list_for_each_entry(csdev_item, &cscfg_mgr->csdev_desc_list, item) {
-		if (csdev_item->match_flags & feat_desc->match_flags) {
-			err = cscfg_load_feat_csdev(csdev_item->csdev, feat_desc, &csdev_item->ops);
-			if (err)
-				return err;
-		}
+		err = cscfg_load_feat_csdev(csdev_item->csdev,
+					    csdev_item->match_flags, feat_desc,
+					    &csdev_item->ops);
+		if (err)
+			return err;
 	}
 	return 0;
 }
@@ -739,11 +756,9 @@ static int cscfg_add_feats_csdev(struct coresight_device *csdev,
 		return -EINVAL;
 
 	list_for_each_entry(feat_desc, &cscfg_mgr->feat_desc_list, item) {
-		if (feat_desc->match_flags & match_flags) {
-			err = cscfg_load_feat_csdev(csdev, feat_desc, ops);
-			if (err)
-				break;
-		}
+		err = cscfg_load_feat_csdev(csdev, match_flags, feat_desc, ops);
+		if (err)
+			break;
 	}
 	return err;
 }
-- 
2.52.0