Request for I/O resources from device tree call 'pci_remap_iospace()' from 'devm_pci_remap_iospace()' which is also called from device tree function 'pci_parse_request_of_pci_ranges()'. If PCI_IOBASE is not defined and I/O resources are requested the following warning appears: WARNING: CPU: 2 PID: 1 at ../drivers/pci/pci.c:4066 pci_remap_iospace+0x3c/0x54 This architecture does not support memory mapped I/O Since there are architectures (like MIPS ralink) that can request I/O resources from device tree but don't have mappable I/O space and therefore don't define PCI_IOBASE avoid calling devm_pci_remap_iospace() in that case. Signed-off-by: Sergio Paracuellos <sergio.paracuellos@xxxxxxxxx> --- Hi all, This pach was part of a three patch series [0] and [1] but the other two patches have been already added through staging git tree. I would like also this patch going through the staging-tree to have all the three patches merged together in the same tree, but if it is not possible I can also live with that :). Changes in v3: - Went back to the same approach that was done in v1 of the series [0]. - Adjust commit message and description as I was suggested to do by Bjorn. v1 series: - [0]: https://lore.kernel.org/linux-pci/20210807072409.9018-2-sergio.paracuellos@xxxxxxxxx/T/#meb2e6c283f6d391407cb0c1158feea71de59b87d v2 series: - [1]: https://lore.kernel.org/all/20210822161005.22467-1-sergio.paracuellos@xxxxxxxxx/ Thanks in advance for your time. Best regards, Sergio Paracuellos drivers/pci/of.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/of.c b/drivers/pci/of.c index d84381ce82b5..7d7aab1d1d64 100644 --- a/drivers/pci/of.c +++ b/drivers/pci/of.c @@ -564,12 +564,14 @@ static int pci_parse_request_of_pci_ranges(struct device *dev, switch (resource_type(res)) { case IORESOURCE_IO: +#ifdef PCI_IOBASE err = devm_pci_remap_iospace(dev, res, iobase); if (err) { dev_warn(dev, "error %d: failed to map resource %pR\n", err, res); resource_list_destroy_entry(win); } +#endif break; case IORESOURCE_MEM: res_valid |= !(res->flags & IORESOURCE_PREFETCH); -- 2.25.1