linux.git/drivers/pci/setup-bus.c, branch v5.7.15

PCI: Add support for root bus sizing

2020-03-30T14:52:34+00:00

In certain cases we should be able to enumerate IO and MEM ranges of all
PCI devices installed in the system, and then set respective host bridge
apertures basing on calculated size and alignment.  Particularly when
firmware is broken and fails to assign bridge windows properly, like on
Alpha UP1500 platform.

Actually, almost everything is already in place, and required changes are
minimal:

- add "size_windows" flag to struct pci_host_bridge: when set, it
  instructs __pci_bus_size_bridges() to continue with the root bus;
- in the __pci_bus_size_bridges() path: add checks for bus->self,
  as it can legitimately be null for the root bus.

Link: https://lore.kernel.org/r/20200314194355.GA12510@mail.rc.ru
Tested-by: Matt Turner 
Signed-off-by: Ivan Kokshaysky 
Signed-off-by: Bjorn Helgaas

PCI: Allow adjust_bridge_window() to shrink resource if necessary

2020-01-29T22:57:28+00:00

Remove checks for resource size in adjust_bridge_window(). This is
necessary to allow pci_bus_distribute_available_resources() to function
when the kernel parameter "pci=hpmemsize=nn[KMG]" is used to allocate
resources. Because the kernel parameter sets the size of all hotplug
bridges to be the same, there are problems when nested hotplug bridges are
encountered. Fitting a downstream hotplug bridge with size X and normal
bridges with non-zero size Y into parent hotplug bridge with size X is
impossible, and hence the downstream hotplug bridge needs to shrink to fit
into its parent.

Add check for if bridge is extended or shrunken and reflect that in the
call to pci_dbg().

Reset the resource if its new size is zero (if we have run out of a bridge
window resource) to prevent the PCI resource assignment code from
attempting to assign a zero-sized resource.

Link: https://lore.kernel.org/r/PSXP216MB0438D3E2CFE64EBAA32AF691803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Set resource size directly in adjust_bridge_window()

2020-01-29T22:57:28+00:00

Change adjust_bridge_window() to set resource size directly instead of
using additional resource lists.

Because additional resource lists are optional resources, any algorithm
that requires guaranteed allocation that uses them cannot be guaranteed to
work.

Remove the resource from add_list, as a zero-sized additional resource is
redundant.

Update comment in pci_bus_distribute_available_resources() to reflect the
above changes.

Link: https://lore.kernel.org/r/PSXP216MB04386BA48874B56BC5CB0292803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Rename extend_bridge_window() to adjust_bridge_window()

2020-01-29T22:57:28+00:00

Rename extend_bridge_window() to adjust_bridge_window() to prepare for the
fact that the window will be able to shrink.  No functional change
intended.

Link: https://lore.kernel.org/r/PSXP216MB0438C47B3473D0C9DE531F18803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Rename extend_bridge_window() parameter

2020-01-29T22:57:28+00:00

In extend_bridge_window(), change "available" parameter name to "new_size".
This makes more sense as this parameter represents the new size for the
window.  No functional change intended.

Link: https://lore.kernel.org/r/PSXP216MB043853617ECA4118C472A417803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Consider alignment of hot-added bridges when assigning resources

2020-01-29T22:57:28+00:00

Change pci_bus_distribute_available_resources() to better handle bridges
with different resource alignment requirements.

The arguments io, mmio and mmio_pref represent the start and end
addresses of resource, into which we must fit the current bridge window.

The steps taken by pci_bus_distribute_available_resources():

- For io, mmio and mmio_pref, increase .start to align with the alignment
of the current bridge window (otherwise the current bridge window may
not fit within the available range).

- For io, mmio and mmio_pref, adjust the current bridge window to the
size after the above.

- Count the number of hotplug bridges and normal bridges on this bus.

- If the total number of bridges is one, give that bridge all of the
resources and return.

- If there are no hotplug bridges, return.

- For io, mmio and mmio_pref, increase .start by the amount required for
each bridge resource on the bus for non hotplug bridges, giving extra
room to make up for alignment of those resources.

- For io, mmio and mmio_pref, calculate the resource size per hotplug
bridge which is available after the previous steps.

- For io, mmio and mmio_pref, distribute the resources to each hotplug
bridge, with the sizes calculated above.

The motivation for fixing this is enabling devices that require greater
than 1MB alignment. This fixes the case where the user hot-adds devices
with BAR alignment >1MB and Linux fails to assign resources to it.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=199581
Link: https://lore.kernel.org/r/PSXP216MB0438C2BFD0FD3691ED9C83F4803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
Reported-by: Mika Westerberg
Signed-off-by: Nicholas Johnson
Signed-off-by: Bjorn Helgaas
Reviewed-by: Mika Westerberg

PCI: Remove local variable usage in pci_bus_distribute_available_resources()

2020-01-29T22:56:57+00:00

In pci_bus_distribute_available_resources(), use resource_size() rather
than the local available_io, etc.  No functional change intended; this just
makes the preceding patch smaller.

[bhelgaas: extracted from https://lore.kernel.org/r/PSXP216MB0438587C47CBEDF365B1EA27803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM]
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Pass size + alignment to pci_bus_distribute_available_resources()

2020-01-29T22:56:47+00:00

Change pci_bus_distribute_available_resources() arguments from
resource_size_t to struct resource to add more information required to get
the alignment correct for bridge windows with alignment >1M.

We require (size, alignment), instead of just (size) which is what is
currently available. The change from resource_size_t to struct resource
does just that.

Note that the struct resource arguments are passed by value and not by
reference. We do not want to pass by reference and change the resource size
of the parent bridge window. We only want the size information.

No functional change intended.

Link: https://lore.kernel.org/r/PSXP216MB0438587C47CBEDF365B1EA27803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
[bhelgaas: split parts to other patches to reduce the size of this one]
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Rename variables

2020-01-29T22:55:54+00:00

In pci_bus_distribute_available_resources(), rename:

  io         =>  io_per_hp
  mmio       =>  mmio_per_hp
  mmio_pref  =>  mmio_pref_per_hp

No functional change; this is just to make a subsequent patch smaller.

[bhelgaas: extracted from https://lore.kernel.org/r/PSXP216MB0438587C47CBEDF365B1EA27803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM]
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg

PCI: Remove unnecessary braces

2020-01-29T20:15:53+00:00

Remove unnecessary braces in pci_bus_distribute_available_resources().  No
functional changes.

Link: https://lore.kernel.org/r/PSXP216MB0438061CB4442460BB92A75F803C0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM
Signed-off-by: Nicholas Johnson 
Signed-off-by: Bjorn Helgaas 
Reviewed-by: Mika Westerberg