linux-toradex.git/drivers/pci/setup-bus.c, branch v3.11

PCI: Retry allocation of only the resource type that failed

2013-07-26T13:32:20+00:00

Ben Herrenschmidt reported the following problem:

  - The bus has space for all desired MMIO resources, including optional
    space for SR-IOV devices
  - We attempt to allocate I/O port space, but it fails because the bus
    has no I/O space
  - Because of the I/O allocation failure, we retry MMIO allocation,
    requesting only the required space, without the optional SR-IOV space

This means we don't allocate the optional SR-IOV space, even though we
could.

This is related to 0c5be0cb0e ("PCI: Retry on IORESOURCE_IO type
allocations").

This patch changes how we handle allocation failures.  We will now retry
allocation of only the resource type that failed.  If MMIO allocation
fails, we'll retry only MMIO allocation.  If I/O port allocation fails,
we'll retry only I/O port allocation.

[bhelgaas: changelog]
Reference: https://lkml.kernel.org/r/1367712653.11982.19.camel@pasglop
Reported-by: Benjamin Herrenschmidt 
Tested-by: Gavin Shan 
Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas 
CC: stable@vger.kernel.org	# v3.10+

PCI / ACPI: Use boot-time resource allocation rules during hotplug

2013-06-22T23:01:35+00:00

On x86 platforms, the kernel respects PCI resource assignments from
the BIOS and only reassigns resources for unassigned BARs at boot
time.  However, with the ACPI-based hotplug (acpiphp), it ignores the
BIOS' PCI resource assignments completely and reassigns all resources
by itself.  This causes differences in PCI resource allocation
between boot time and runtime hotplug to occur, which is generally
undesirable and sometimes actively breaks things.

Namely, if there are enough resources, reassigning all PCI resources
during runtime hotplug should work, but it may fail if the resources
are constrained.  This may happen, for instance, when some PCI
devices with huge MMIO BARs are involved in the runtime hotplug
operations, because the current PCI MMIO alignment algorithm may
waste huge chunks of MMIO address space in those cases.

On the Alexander's Sony VAIO VPCZ23A4R the BIOS allocates limited
MMIO resources for the dock station which contains a device
(graphics adapter) with a 256MB MMIO BAR.  An attempt to reassign
that during runtime hotplug causes the dock station MMIO window to be
exhausted and acpiphp fails to allocate resources for the majority
of devices on the dock station as a result.

To prevent that from happening, modify acpiphp to follow the boot
time resources allocation behavior so that the BIOS' resource
assignments are respected during runtime hotplug too.

[rjw: Changelog]
References: https://bugzilla.kernel.org/show_bug.cgi?id=56531
Reported-and-tested-by: Alexander E. Patrakov 
Tested-by: Illya Klymov 
Signed-off-by: Jiang Liu 
Acked-by: Yinghai Lu 
Cc: 3.9+ 
Signed-off-by: Rafael J. Wysocki

PCI: Warn about failures instead of "must_check" functions

2013-04-17T16:21:12+00:00

These places capture return values to avoid "must_check" warnings,
but we didn't *do* anything with the return values, which causes
"set but not used" warnings.  We might as well do something instead
of just trying to evade the "must_check" warnings.

Signed-off-by: Bjorn Helgaas

PCI: Make local functions/structs static

2013-04-12T17:26:01+00:00

This fixes "no previous prototype" warnings found via "make W=1".

Signed-off-by: Bjorn Helgaas

PCI: Add root bus children dev's res to fail list

2013-01-25T20:45:00+00:00

We can stop trying according to try_number now and do not need to use
root_bus checking as stop sign.

In extreme case we could need to reallocate resource for device just
under root bus.  For PCI root bus hot-add, we need to retry to assign
resources to PCI devices just under pci root bus.

Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas 
Acked-by: Rafael J. Wysocki

PCI: Move out pci_enable_bridges out of assign_unsigned_bus_res

2012-11-03T22:20:30+00:00

So could use assign_unassigned_bus_res pci root bus add

Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas

PCI: Move pci_rescan_bus() back to probe.c

2012-11-03T22:20:07+00:00

We have pci_assign_unassigned_bus_resources() in as global function now.

Move pci_rescan_bus() back to probe.c where it should be.

Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas

PCI: Separate out pci_assign_unassigned_bus_resources()

2012-10-30T20:31:10+00:00

It is main portion of pci_rescan_bus().

Separate it out and prepare to use it for PCI root bus hot add later.

Signed-off-by: Yinghai Lu 
Signed-off-by: Bjorn Helgaas

PCI: Refactor pbus_size_mem()

2012-09-11T22:59:46+00:00

The original idea comes from Ram Pai.  This patch puts the chunk of
code for calculating the minimal alignment of memory window into a
separate inline function.

Signed-off-by: Gavin Shan 
Signed-off-by: Bjorn Helgaas

PCI: Align P2P windows using pcibios_window_alignment()

2012-09-11T22:59:46+00:00

This patch changes pbus_size_io() and pbus_size_mem() to do window (I/O,
memory and prefetchable memory) reassignment based on the minimal
alignments for the P2P bridge, which was retrieved by window_alignment().

[bhelgaas: changelog]
Signed-off-by: Gavin Shan 
Signed-off-by: Bjorn Helgaas