[PATCH v2 1/8] cxl: Add helper function to retrieve a feature entry

[<shiju.jose@huawei.com>]

From: Shiju Jose <shiju.jose@huawei.com>

Add helper function to retrieve a feature entry from the supported
features list, if supported.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 drivers/cxl/core/core.h     |  2 ++
 drivers/cxl/core/features.c | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 1803aedb25ca..16bc717376fc 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -123,6 +123,8 @@ int cxl_ras_init(void);
 void cxl_ras_exit(void);
 
 #ifdef CONFIG_CXL_FEATURES
+struct cxl_feat_entry *cxl_get_feature_entry(struct cxl_dev_state *cxlds,
+					     const uuid_t *feat_uuid);
 size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
 		       enum cxl_get_feat_selection selection,
 		       void *feat_out, size_t feat_out_size, u16 offset,
diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 048ba4fc3538..202c8c21930c 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -203,6 +203,29 @@ int devm_cxl_setup_features(struct cxl_dev_state *cxlds)
 }
 EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_features, "CXL");
 
+struct cxl_feat_entry *cxl_get_feature_entry(struct cxl_dev_state *cxlds,
+					     const uuid_t *feat_uuid)
+{
+	struct cxl_features_state *cxlfs = to_cxlfs(cxlds);
+	struct cxl_feat_entry *feat_entry;
+	int count;
+
+	if (!cxlfs || !cxlfs->entries || !cxlfs->entries->num_features)
+		return NULL;
+
+	/*
+	 * Retrieve the feature entry from the supported features list,
+	 * if the feature is supported.
+	 */
+	feat_entry = cxlfs->entries->ent;
+	for (count = 0; count < cxlfs->entries->num_features; count++, feat_entry++) {
+		if (uuid_equal(&feat_entry->uuid, feat_uuid))
+			return feat_entry;
+	}
+
+	return NULL;
+}
+
 size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
 		       enum cxl_get_feat_selection selection,
 		       void *feat_out, size_t feat_out_size, u16 offset,
-- 
2.43.0