[PATCH v6 1/5] PCI: dwc: Allow adjusting the number of ob/ib windows in glue driver
From: Randolph Lin <randolph@andestech.com>
Date: 2025-10-03 02:35:55
Also in:
linux-pci, linux-riscv, lkml
Subsystem:
pci driver for synopsys designware, pci native host bridge and endpoint drivers, pci subsystem, the rest · Maintainers:
Jingoo Han, Manivannan Sadhasivam, Lorenzo Pieralisi, Krzysztof Wilczyński, Bjorn Helgaas, Linus Torvalds
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@andestech.com> --- 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..56c1e45adc06 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_ib_windows > ib) + 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