[PATCH v5 1/5] PCI: dwc: Allow adjusting the number of ob/ib windows in glue driver

[Randolph Lin]

The number of ob/ib windows is determined through write-read loops
on registers in the core driver. Some glue drivers need to adjust
the number of ob/ib windows to meet specific requirements,such as
hardware limitations. This change allows the glue driver to adjust
the number of ob/ib windows to satisfy platform-specific constraints.
The glue driver may adjust the number of ob/ib windows, but the values
must stay within hardware limits.

Signed-off-by: Randolph Lin <randolph@xxxxxxxxxxxxx>
---
 drivers/pci/controller/dwc/pcie-designware.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 89aad5a08928..8ca7777a73e0 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -907,8 +907,16 @@ void dw_pcie_iatu_detect(struct dw_pcie *pci)
 		max = 0;
 	}
 
-	pci->num_ob_windows = ob;
-	pci->num_ib_windows = ib;
+	if (!pci->num_ob_windows)
+		pci->num_ob_windows = ob;
+	else if (pci->num_ob_windows > ob)
+		dev_err(pci->dev, "Adjusted ob windows exceed the limit\n");
+
+	if (!pci->num_ib_windows)
+		pci->num_ib_windows = ib;
+	else if (pci->num_ob_windows > ob)
+		dev_err(pci->dev, "Adjusted ib windows exceed the limit\n");
+
 	pci->region_align = 1 << fls(min);
 	pci->region_limit = (max << 32) | (SZ_4G - 1);
 
-- 
2.34.1