[PATCH V2 2/2] PCI: imx6: Add imx_pcie_perst_found() to inspect the parsed result

[Sherry Sun (OSS)]

From: Sherry Sun <sherry.sun at nxp.com>

Since pci_host_common_parse_port() doesn't return failure for "property
not found" (-ENODEV), the caller should inspect the parsed result and
decide whether to fall back to the legacy binding.
Add imx_pcie_perst_found() to inspect the parsed result.

Signed-off-by: Sherry Sun <sherry.sun at nxp.com>
Reviewed-by: Richard Zhu <hongxing.zhu at nxp.com>
---
 drivers/pci/controller/dwc/pci-imx6.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
index b137551871fc..34756f28fcc6 100644
--- a/drivers/pci/controller/dwc/pci-imx6.c
+++ b/drivers/pci/controller/dwc/pci-imx6.c
@@ -1287,6 +1287,18 @@ static void imx_pcie_assert_perst(struct imx_pcie *imx_pcie, bool assert)
 	}
 }
 
+static bool imx_pcie_perst_found(struct pci_host_bridge *bridge)
+{
+	struct pci_host_port *port;
+
+	list_for_each_entry(port, &bridge->ports, list) {
+		if (!list_empty(&port->perst))
+			return true;
+	}
+
+	return false;
+}
+
 static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -1299,15 +1311,12 @@ static int imx_pcie_host_init(struct dw_pcie_rp *pp)
 		/* Parse Root Port nodes if present */
 		ret = pci_host_common_parse_ports(dev, bridge);
 		if (ret) {
-			if (ret != -ENODEV) {
-				dev_err(dev, "Failed to parse Root Port nodes: %d\n", ret);
-				return ret;
-			}
+			dev_err(dev, "Failed to parse Root Port nodes: %d\n", ret);
+			return ret;
+		}
 
-			/*
-			 * Fall back to legacy binding for DT backwards
-			 * compatibility
-			 */
+		/* Fallback to legacy binding for DT backwards compatibility. */
+		if (!imx_pcie_perst_found(bridge)) {
 			ret = imx_pcie_parse_legacy_binding(imx_pcie);
 			if (ret)
 				return ret;
-- 
2.37.1