On 22 January 2026 15:29:02 CET, Koichiro Den <[email protected]> wrote: > >> To make sure that dw_pcie_ep_ib_atu_addr() cannot be called without already >> having a BAR configured, to we perhaps want something like: > >Thanks for the review. >Isn't the existing guard in dw_pcie_ep_ib_atu_addr sufficient? > > [...] > base = dw_pcie_ep_read_bar_assigned(ep, func_no, bar, epf_bar->flags); > if (!base) { > dev_err(dev, > "BAR%u not assigned, cannot set up sub-range > mappings\n", > bar); > return -EINVAL; > } >
Well, for a driver that does not call dw_pcie_ep_reset_bar() in their .init() to disable all BARs that are enabled in the controller by default, the host side will assign an PCI address even if no EPF has called set_bar() on that BAR. See e.g. https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/commit/drivers/pci/controller/dwc/pcie-tegra194.c?h=controller/dwc&id=42f9c66a6d0cc45758dab77233c5460e1cf003df There might be other EPC drivers that don't disable all BARs in their .init(), so I would say that simply checking if the BAR has an address is not sufficient to guarantee that an EPF driver has called set_bar(). I think the safest option is my second suggestion because then we know that we will only call dw_pcie_ep_ib_atu_addr() When: 1) If ep->epf_bar[bar] is set: https://github.com/torvalds/linux/blob/v6.19-rc6/drivers/pci/controller/dwc/pcie-designware-ep.c#L363 2) All the other requirements to dynamically update a BAR is also met: https://github.com/torvalds/linux/blob/v6.19-rc6/drivers/pci/controller/dwc/pcie-designware-ep.c#L368-L370 Kind regards, Niklas
