[PATCH v4 5/6] fpga: dfl: support PF/VF starting with DFH

[Tianfei zhang <tianfei.zhang@xxxxxxxxx>]

From: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>

In OFS, it allows several PFs and VFs in static region or PR region.
Those PFs and VFs managed by DFL or a specific device, like virtio-net
device. Those PFs and VFs which managed by DFL can start with DFH, and
leverage VFIO to expose to an application or assign to a VM.

Signed-off-by: Matthew Gerlach <matthew.gerlach@xxxxxxxxxxxxxxx>
Signed-off-by: Tianfei Zhang <tianfei.zhang@xxxxxxxxx>
---
 drivers/fpga/dfl-pci.c |  2 ++
 drivers/fpga/dfl.c     | 22 +++++++++++++---------
 drivers/fpga/dfl.h     |  7 +++++++
 3 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
index 2e9abeca3625..7d8b53330152 100644
--- a/drivers/fpga/dfl-pci.c
+++ b/drivers/fpga/dfl-pci.c
@@ -275,6 +275,8 @@ static int find_dfls_by_default(struct pci_dev *pcidev,
 		len = pci_resource_len(pcidev, 0);
 
 		dfl_fpga_enum_info_add_dfl(info, start, len);
+	} else if (dfl_feature_is_afu(base)) {
+		dev_info(&pcidev->dev, "find AFU\n");
 	} else {
 		ret = -ENODEV;
 	}
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index 71e0725b6be0..db676f7482ec 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -900,9 +900,11 @@ static void build_info_free(struct build_feature_devs_info *binfo)
 		dfl_id_free(feature_dev_id_type(binfo->feature_dev),
 			    binfo->feature_dev->id);
 
-		list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
-			list_del(&finfo->node);
-			kfree(finfo);
+		if (!list_empty(&binfo->sub_features)) {
+			list_for_each_entry_safe(finfo, p, &binfo->sub_features, node) {
+				list_del(&finfo->node);
+				kfree(finfo);
+			}
 		}
 	}
 
@@ -1444,12 +1446,14 @@ dfl_fpga_feature_devs_enumerate(struct dfl_fpga_enum_info *info)
 	 * start enumeration for all feature devices based on Device Feature
 	 * Lists.
 	 */
-	list_for_each_entry(dfl, &info->dfls, node) {
-		ret = parse_feature_list(binfo, dfl->start, dfl->len);
-		if (ret) {
-			remove_feature_devs(cdev);
-			build_info_free(binfo);
-			goto unregister_region_exit;
+	if (!list_empty(&info->dfls)) {
+		list_for_each_entry(dfl, &info->dfls, node) {
+			ret = parse_feature_list(binfo, dfl->start, dfl->len);
+			if (ret) {
+				remove_feature_devs(cdev);
+				build_info_free(binfo);
+				goto unregister_region_exit;
+			}
 		}
 	}
 
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index 83c2c50975e5..08edaeeb7f80 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -421,6 +421,13 @@ static inline bool dfl_feature_is_port(void __iomem *base)
 		(FIELD_GET(DFH_ID, v) == DFH_ID_FIU_PORT);
 }
 
+static inline bool dfl_feature_is_afu(void __iomem *base)
+{
+	u64 v = readq(base + DFH);
+
+	return (FIELD_GET(DFH_TYPE, v) == DFH_TYPE_AFU);
+}
+
 static inline u8 dfl_feature_revision(void __iomem *base)
 {
 	return (u8)FIELD_GET(DFH_REVISION, readq(base + DFH));
-- 
2.26.2