On Wed, Jan 29, 2020 at 06:29:20PM +0300, Sergei Miroshnichenko wrote:
> When movable BARs are enabled, and if a bridge contains a device with fixed
> (IORESOURCE_PCI_FIXED) or immovable BARs, the corresponding windows can't
What is the difference between fixed (IORESOURCE_PCI_FIXED) and
immovable BARs? I'm hesitant to add a new concept ("immovable") with
a different name but very similar meaning.
I understand that in the case of bridge windows, you may need to track
only part of the window, as opposed to a BAR where the entire BAR has
to be either fixed or movable, but I think adding a new term will be
confusing.
> be moved too far away from their original positions - they must still
> contain all the fixed/immovable BARs, like that:
>
> 1) Window position before a bus rescan:
>
> | <-- root bridge window --> |
> | |
> | | <-- bridge window --> | |
> | | movable BARs | **fixed BAR** | |
> ^^^^^^^^^^^^
>
> 2) Possible valid outcome after rescan and move:
>
> | <-- root bridge window --> |
> | |
> | | <-- bridge window --> | |
> | | **fixed BAR** | Movable BARs | |
> ^^^^^^^^^^^^
>
> An immovable area of a bridge window is a range that covers all the fixed
> and immovable BARs of direct children, and all the fixed area of children
> bridges:
>
> | <-- root bridge window --> |
> | |
> | | <-- bridge window level 1 --> | |
> | | ******************** immovable area ******************* | |
> | | | |
> | | **fixed BAR** | <-- bridge window level 2 --> | BARs | |
> | | | *********** immovable area *********** | | |
> | | | | | |
> | | | **fixed BAR** | BARs | **fixed BAR** | | |
> ^^^^
>
> To store these areas, the .immovable_range field has been added to struct
> pci_bus for every bridge window type: IO, MEM and PREFETCH. It is filled
> recursively from leaves to the root before a rescan.
>
> Signed-off-by: Sergei Miroshnichenko <s.miroshnichenko@xxxxxxxxx>
> ---
> drivers/pci/pci.h | 14 ++++++++
> drivers/pci/probe.c | 88 +++++++++++++++++++++++++++++++++++++++++++++
> include/linux/pci.h | 6 ++++
> 3 files changed, 108 insertions(+)
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index 3b4c982772d3..5f2051c8531c 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -404,6 +404,20 @@ static inline bool pci_dev_is_disconnected(const struct pci_dev *dev)
> return dev->error_state == pci_channel_io_perm_failure;
> }
>
> +static inline int pci_get_bridge_resource_idx(struct resource *r)
> +{
> + int idx = 1;
> +
> + if (r->flags & IORESOURCE_IO)
> + idx = 0;
> + else if (!(r->flags & IORESOURCE_PREFETCH))
> + idx = 1;
> + else if (r->flags & IORESOURCE_MEM_64)
> + idx = 2;
Random nit: No variables or elses required:
if (r->flags & IORESOURCE_IO)
return 0;
if (!(r->flags & IORESOURCE_PREFETCH))
return 1;
...
> + return idx;
> +}
