On Mon, Oct 01, 2018 at 02:49:34PM +0200, Thomas Petazzoni wrote:
> Commit ee1604381a371 ("PCI: mvebu: Only remap I/O space if
> configured") had the side effect that the PCI I/O mapping was created
> much earlier than before, at a point where the probe() of the driver
> could still fail. This is for example a problem if one gets an
> -EPROBE_DEFER at some point during probe(), after pci_ioremap_io() has
> been called.
>
> Indeed, there is currently no function to undo what pci_ioremap_io()
> did, and switching to pci_remap_iospace() is not an option in
> pci-mvebu due to the need for special memory attributes on Armada 38x.
>
> Reverting ee1604381a371 ("PCI: mvebu: Only remap I/O space if
> configured") would be a possibility, but it would require also
> reverting 42342073e38b5 ("PCI: mvebu: Convert to use pci_host_bridge
> directly"). So instead, we use an open-coded version of
> pci_host_probe() that creates the PCI I/O mapping at a point where we
> are guaranteed not to fail anymore.
>
> Reported-by: Jan Kundrát <jan.kundrat@xxxxxxxxx>
> Fixes: ee1604381a371 ("PCI: mvebu: Only remap I/O space if configured")
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxx>
Applied with Lorenzo's ack and Jan's tested-by to for-linux for v4.19,
thanks!
> ---
> drivers/pci/controller/pci-mvebu.c | 52 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 48 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
> index 50eb0729385b..a41d79b8d46a 100644
> --- a/drivers/pci/controller/pci-mvebu.c
> +++ b/drivers/pci/controller/pci-mvebu.c
> @@ -1145,7 +1145,6 @@ static int mvebu_pcie_parse_request_resources(struct mvebu_pcie *pcie)
> {
> struct device *dev = &pcie->pdev->dev;
> struct device_node *np = dev->of_node;
> - unsigned int i;
> int ret;
>
> INIT_LIST_HEAD(&pcie->resources);
> @@ -1179,13 +1178,58 @@ static int mvebu_pcie_parse_request_resources(struct mvebu_pcie *pcie)
> resource_size(&pcie->io) - 1);
> pcie->realio.name = "PCI I/O";
>
> + pci_add_resource(&pcie->resources, &pcie->realio);
> + }
> +
> + return devm_request_pci_bus_resources(dev, &pcie->resources);
> +}
> +
> +/*
> + * This is a copy of pci_host_probe(), except that it does the I/O
> + * remap as the last step, once we are sure we won't fail.
> + *
> + * It should be removed once the I/O remap error handling issue has
> + * been sorted out.
> + */
> +static int mvebu_pci_host_probe(struct pci_host_bridge *bridge)
> +{
> + struct mvebu_pcie *pcie;
> + struct pci_bus *bus, *child;
> + int ret;
> +
> + ret = pci_scan_root_bus_bridge(bridge);
> + if (ret < 0) {
> + dev_err(bridge->dev.parent, "Scanning root bridge failed");
> + return ret;
> + }
> +
> + pcie = pci_host_bridge_priv(bridge);
> + if (resource_size(&pcie->io) != 0) {
> + unsigned int i;
> +
> for (i = 0; i < resource_size(&pcie->realio); i += SZ_64K)
> pci_ioremap_io(i, pcie->io.start + i);
> + }
>
> - pci_add_resource(&pcie->resources, &pcie->realio);
> + bus = bridge->bus;
> +
> + /*
> + * We insert PCI resources into the iomem_resource and
> + * ioport_resource trees in either pci_bus_claim_resources()
> + * or pci_bus_assign_resources().
> + */
> + if (pci_has_flag(PCI_PROBE_ONLY)) {
> + pci_bus_claim_resources(bus);
> + } else {
> + pci_bus_size_bridges(bus);
> + pci_bus_assign_resources(bus);
> +
> + list_for_each_entry(child, &bus->children, node)
> + pcie_bus_configure_settings(child);
> }
>
> - return devm_request_pci_bus_resources(dev, &pcie->resources);
> + pci_bus_add_devices(bus);
> + return 0;
> }
>
> static int mvebu_pcie_probe(struct platform_device *pdev)
> @@ -1268,7 +1312,7 @@ static int mvebu_pcie_probe(struct platform_device *pdev)
> bridge->align_resource = mvebu_pcie_align_resource;
> bridge->msi = pcie->msi;
>
> - return pci_host_probe(bridge);
> + return mvebu_pci_host_probe(bridge);
> }
>
> static const struct of_device_id mvebu_pcie_of_match_table[] = {
> --
> 2.14.4
>
