On Mon, Mar 11, 2019 at 04:31:12PM +0300, Sergey Miroshnichenko wrote:
> When the movable BARs feature is enabled, don't rely on the memory gaps
> reserved by the BIOS/bootloader/firmware, but instead rearrange the BARs
> and bridge windows starting from the root.
>
> Endpoint device's BARs, after being released, are resorted and written
> back by the pci_assign_unassigned_root_bus_resources().
>
> The last step of writing the recalculated windows to the bridges is done
> by the new pci_setup_bridges() function.
>
> Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
> ---
> drivers/pci/pci.h | 1 +
> drivers/pci/probe.c | 22 ++++++++++++++++++++++
> drivers/pci/setup-bus.c | 11 ++++++++++-
> 3 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 224d88634115..e06e8692a7b1 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -248,6 +248,7 @@ void __pci_bus_assign_resources(const struct pci_bus *bus,
> struct list_head *realloc_head,
> struct list_head *fail_head);
> bool pci_bus_clip_resource(struct pci_dev *dev, int idx);
> +void pci_bus_release_root_bridge_resources(struct pci_bus *bus);
>
> void pci_reassigndev_resource_alignment(struct pci_dev *dev);
> void pci_disable_bridge_window(struct pci_dev *dev);
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 1cf6ec960236..692752c71f71 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -3299,6 +3299,25 @@ static void pci_bus_rescan_done(struct pci_bus *bus)
> pm_runtime_put(&bus->dev);
> }
>
> +static void pci_setup_bridges(struct pci_bus *bus)
> +{
> + struct pci_dev *dev;
> +
> + list_for_each_entry(dev, &bus->devices, bus_list) {
> + struct pci_bus *child;
> +
> + if (!pci_dev_is_added(dev) || pci_dev_is_ignored(dev))
> + continue;
> +
> + child = dev->subordinate;
> + if (child)
> + pci_setup_bridges(child);
> + }
> +
> + if (bus->self)
> + pci_setup_bridge(bus);
> +}
> +
> /**
> * pci_rescan_bus - Scan a PCI bus for devices
> * @bus: PCI bus to scan
> @@ -3321,8 +3340,11 @@ unsigned int pci_rescan_bus(struct pci_bus *bus)
> pci_bus_rescan_prepare(root);
>
> max = pci_scan_child_bus(root);
> +
> + pci_bus_release_root_bridge_resources(root);
> pci_assign_unassigned_root_bus_resources(root);
>
> + pci_setup_bridges(root);
> pci_bus_rescan_done(root);
> } else {
> max = pci_scan_child_bus(bus);
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index be7d4e6d7b65..36a1907d9509 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -1584,7 +1584,7 @@ static void pci_bridge_release_resources(struct pci_bus *bus,
> pci_printk(KERN_DEBUG, dev, "resource %d %pR released\n",
> PCI_BRIDGE_RESOURCES + idx, r);
> /* keep the old size */
> - r->end = resource_size(r) - 1;
> + r->end = pci_movable_bars_enabled() ? 0 : (resource_size(r) - 1);
Doesn't this mean we're throwing away the information about the BAR
size, and we'll have to size the BAR again somewhere? I would like to
avoid that. But I don't know yet where you rely on this, so maybe
it's not possible to avoid it.
> r->start = 0;
> r->flags = 0;
>
> @@ -1637,6 +1637,15 @@ static void pci_bus_release_bridge_resources(struct pci_bus *bus,
> pci_bridge_release_resources(bus, type);
> }
>
> +void pci_bus_release_root_bridge_resources(struct pci_bus *root_bus)
> +{
> + pci_bus_release_bridge_resources(root_bus, IORESOURCE_IO, whole_subtree);
> + pci_bus_release_bridge_resources(root_bus, IORESOURCE_MEM, whole_subtree);
> + pci_bus_release_bridge_resources(root_bus,
> + IORESOURCE_MEM_64 | IORESOURCE_PREFETCH,
> + whole_subtree);
> +}
> +
> static void pci_bus_dump_res(struct pci_bus *bus)
> {
> struct resource *res;
> --
> 2.20.1
>
