diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c index f2e5feba552678411145973529423509593dc37e..7fd64ac2cea11a052ef05cfbbe3b4efad9bfda1c 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -256,8 +256,28 @@ static int dw_pcie_ep_set_bar(struct pci_epc *epc, u8 func_no, u8 vfunc_no, if (ret) return ret; - if (ep->epf_bar[bar]) + /* + * Certain EPF drivers dynamically change the physical address of a BAR + * (i.e. they call set_bar() twice, without ever calling clear_bar(), as + * calling clear_bar() would clear the BAR's PCI address assigned by the + * host). + */ + if (ep->epf_bar[bar]) { + /* + * We can only dynamically change a BAR if the new BAR size and + * BAR flags do not differ from the existing configuration. + */ + if (ep->epf_bar[bar]->barno != bar || + ep->epf_bar[bar]->size != size || + ep->epf_bar[bar]->flags != flags) + return -EINVAL; + + /* + * When dynamically changing a BAR, skip writing the BAR reg, as + * that would clear the BAR's PCI address assigned by the host. + */ return 0; + } dw_pcie_dbi_ro_wr_en(pci);