Add pci_claim_bridge_resource() to claim a PCI-PCI bridge window.  This is
like regular pci_claim_resource(), except that if we fail to claim the
window, we check to see if we can reduce the size of the window and try
again.

This is for scenarios like this:

  pci_bus 0000:00: root bus resource [mem 0xc0000000-0xffffffff]
  pci 0000:00:01.0:   bridge window [mem 0xbdf00000-0xddefffff 64bit pref]
  pci 0000:01:00.0: reg 0x10: [mem 0xc0000000-0xcfffffff pref]

The 00:01.0 window is illegal: it starts before the host bridge window, so
we have to assume the [0xbdf00000-0xbfffffff] region is inaccessible.  We
can make it legal by clipping it to [mem 0xc0000000-0xddefffff 64bit pref].

Previously we discarded the 00:01.0 window and tried to reassign that part
of the hierarchy from scratch.  That is a problem because Linux doesn't
always assign things optimally.  For example, in this case, BIOS put the
01:00.0 device in a prefetchable window below 4GB, but after 5b285415,
Linux puts the prefetchable window above 4GB where the 32-bit 01:00.0
device can't use it.

Clipping the 00:01.0 window is less intrusive than completely reassigning
things and is sufficient to let us use most of the BIOS configuration.  Of
course, it's possible that devices below 00:01.0 will no longer fit.  If
that's the case, we'll have to reassign things.  But that's a separate
problem.

[bhelgaas: changelog, split into separate patch]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491Reported-by: NMarek Kordik <kordikmarek@gmail.com>
Fixes: 5b285415 ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v3.16+

pci_setup_bridge_io(), pci_setup_bridge_mmio(), and
pci_setup_bridge_mmio_pref() program the windows of PCI-PCI bridges.
Previously they accepted a pointer to the pci_bus of the secondary bus,
then looked up the bridge leading to that bus.  Pass the bridge directly,
which will make it more convenient for future callers.

No functional change.

[bhelgaas: changelog, split into separate patch]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=85491Reported-by: NMarek Kordik <kordikmarek@gmail.com>
Fixes: 5b285415 ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v3.16+

In 5b285415 ("PCI: Restrict 64-bit prefetchable bridge windows to
64-bit resources"), we added IORESOURCE_MEM_64 to the mask in
pci_assign_unassigned_root_bus_resources(), but not to the mask in
pci_assign_unassigned_bridge_resources().

Add IORESOURCE_MEM_64 to the pci_assign_unassigned_bridge_resources() type
mask.

Fixes: 5b285415 ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources")
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v3.16+

Increase the maximum BAR size from 8GB to 128GB.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Merge quoted strings that are broken across lines into a single entity.
The compiler merges them anyway, but checkpatch complains about it, and
merging them makes it easier to grep for strings.

No functional change.

[bhelgaas: changelog, do the same for everything under drivers/pci]
Signed-off-by: NRyan Desfosses <ryan@desfo.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Fix various whitespace errors.

No functional change.

[bhelgaas: fix other similar problems]
Signed-off-by: NRyan Desfosses <ryan@desfo.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use pci_is_bridge() to simplify code.  No functional change.

Requires: 326c1cda PCI: Rename pci_is_bridge() to pci_has_subordinate()
Requires: 1c86438c PCI: Add new pci_is_bridge() interface
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Add comments in the code to match the allocation strategy of 7c671426dfc3
("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources").

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

pbus_size_mem() previously returned 0 for failure and 1 for success.
Change it to return -ENOSPC for failure and 0 for success.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This patch changes the way we handle 64-bit prefetchable bridge windows to
make it more likely that we can assign space to all devices.

Previously we put all prefetchable resources in the prefetchable bridge
window.  If any of those resources was 32-bit only, we restricted the
window to be below 4GB.

After this patch, we only put 64-bit prefetchable resources in a 64-bit
prefetchable window.  We put all 32-bit prefetchable resources in the
non-prefetchable window, even if there are no 64-bit prefetchable
resources.

With the previous approach, if there was a 32-bit prefetchable resource
behind a bridge, we forced the bridge's prefetchable window below 4GB,
which meant that even if there was plenty of space above 4GB available, we
couldn't use it, and assignment of large 64-bit resources could fail, as
in the bugzilla below.

The new strategy is:

  1) If the prefetchable window is 64 bits wide, we put only 64-bit
     prefetchable resources in it.  Any 32-bit prefetchable resources go in
     the non-prefetchable window.

  2) If the prefetchable window is 32 bits wide, we put both 32- and 64-bit
     prefetchable resources in it.

  3) If there is no prefetchable window, all MMIO resources go in the
     non-prefetchable window.

This reduces performance for 32-bit prefetchable resources below a bridge
with a 64-bit prefetchable window.  We previously assigned prefetchable
space, but now we'll assign non-prefetchable space.  This is the case even
if there are no 64-bit prefetchable resources, or if they would all fit
below 4GB.  In those cases, the old strategy would work and would have
better performance.

[bhelgaas: write changelog, add bugzilla link, fold in mem64_mask removal]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=74151Tested-by: NGuo Chao <yan@linux.vnet.ibm.com>
Tested-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This is needed for some of the Xeon Phi type systems.

[bhelgaas: added Nikhil, use ARRAY_SIZE() to connect with decl, folded in
Kevin's "order < 0" fix to ARRAY_SIZE() usage]
Signed-off-by: NNikhil P Rao <nikhil.rao@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Some PCI functions used to be marked __devinit.  When CONFIG_HOTPLUG was
not set, these functions were discarded after boot.  A few callers of these
__devinit functions were marked __ref to indicate that they could safely
call the __devinit functions even though the callers were not __devinit.

But CONFIG_HOTPLUG and __devinit are now gone, and the need for the __ref
annotations is also gone, so remove them.  Relevant historical commits:

  54b956b9 Remove __dev* markings from init.h
  a8e4b9c1 PCI: add generic pci_hp_add_bridge()
  0ab2b57f PCI: fix section mismatch warning in pci_scan_child_bus
  451124a7 PCI: fix 4x section mismatch warnings
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

These interfaces:

  pcibios_resource_to_bus(struct pci_dev *dev, *bus_region, *resource)
  pcibios_bus_to_resource(struct pci_dev *dev, *resource, *bus_region)

took a pci_dev, but they really depend only on the pci_bus.  And we want to
use them in resource allocation paths where we have the bus but not a
device, so this patch converts them to take the pci_bus instead of the
pci_dev:

  pcibios_resource_to_bus(struct pci_bus *bus, *bus_region, *resource)
  pcibios_bus_to_resource(struct pci_bus *bus, *resource, *bus_region)

In fact, with standard PCI-PCI bridges, they only depend on the host
bridge, because that's the only place address translation occurs, but
we aren't going that far yet.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

pci_setup_bridge_io() accessed PCI_IO_BASE and PCI_IO_LIMIT using dword
(32-bit) reads and writes, which also access the Secondary Status register.
Since the Secondary Status register is in the upper 16 bits of the dword,
and we preserved those upper 16 bits, this had the effect of clearing any
of the write-1-to-clear bits that happened to be set in the Secondary
Status register.

That's not what we want, so use word (16-bit) accesses to update only
PCI_IO_BASE and PCI_IO_LIMIT.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

pci_bridge_check_ranges() determines whether the bridge supports an I/O
aperture and a prefetchable memory aperture.

Previously, if the I/O aperture was unsupported, disabled, or configured at
[io 0x0000-0x0fff], we wrote 0xf0 to PCI_IO_BASE and PCI_IO_LIMIT, which,
if the bridge supports it, enables the I/O aperture at [io 0xf000-0xffff].
The enabled aperture may conflict with other devices in the system.

Similarly, we wrote 0xfff0 to PCI_PREF_MEMORY_BASE and
PCI_PREF_MEMORY_LIMIT, which enables the prefetchable memory aperture at
[mem 0xfff00000-0xffffffff], and that may also conflict with other devices.

All we need to know is whether the base and limit registers are writable,
so we can use values that leave the apertures disabled, e.g., PCI_IO_BASE =
0xf0, PCI_IO_LIMIT = 0xe0, PCI_PREF_MEMORY_BASE = 0xfff0,
PCI_PREF_MEMORY_LIMIT = 0xffe0.

Writing non-zero values to both the base and limit registers means we
detect whether either or both are writable, as we did before.
Reported-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Based-on-patch-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Fix whitespace, capitalization, and spelling errors.  No functional change.
I know "busses" is not an error, but "buses" was more common, so I used it
consistently.

Signed-off-by: Marta Rybczynska <rybczynska@gmail.com> (pci_reset_bridge_secondary_bus())
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

When calculating window_alignment(), type information like IORESOURCE_MEM
and IORESOURCE_PREFETCH may not be enough.  For example, on powernv, we
need to know whether the window is 64-bit or not.

This patch passes the full resource type (res->flags) for window alignment.

[bhelgaas: changelog]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NGavin Shan <shangw@linux.vnet.ibm.com>

In __pci_bus_size_bridges() we check whether a bus is a root bus by testing
bus->self.  As indicated by commit 79af72d7 ("PCI: pci_is_root_bus
helper"), bus->self == NULL is not a proper way to check for a root bus.
One issue is that "virtual" buses added for SR-IOV (via virtfn_add_bus())
have bus->self == NULL but are not root buses.

This patch changes it to pci_is_root_bus() to check whether it is a root
bus.

[bhelgaas: changelog]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

An upstream bridge's I/O window must be at least as aligned as any
downstream device or bridge requires.  In particular, if the upstream
bridge supports 1K alignment but a downstream bridge requires 4K alignment,
the upstream window must also be 4K aligned.

Therefore, do not reduce the required alignment ("min_align") based on
the upstream bridge's capabilities.
Reported-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Suggested-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This patch changes the type of "size" to resource_size_t and makes the
corresponding dev_printk() change.

[bhelgaas: changelog]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

This patch fills in the missing description for two parameters of
pbus_size_mem().
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Normally, on one PCI bus there would be more devices than bridges.  When
calculating the depth of a PCI bus, it would be more time efficient to
enumerating through the child buses instead of the child devices.

Also by doing so, the code seems more self explaining.  Previously, it went
through the devices and checked whether a bridge introduced a child bus or
not, which needs more background knowledge to understand it.

This patch calculates the depth by enumerating the bus hierarchy.
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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 0c5be0cb ("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@pasglopReported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Tested-by: NGavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v3.10+

When hot-adding an ACPI host bridge, use
pci_assign_unassigned_root_bus_resources() instead of
pci_assign_unassigned_bus_resources().

The former is more aggressive and will release and reassign existing
resources if necessary.  This is safe at hot-add time because no drivers
are bound to devices below the new host bridge yet.

[bhelgaas: changelog, split __init changes out for reviewability]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Resource reallocation is currently done only at boot-time, but will
soon be done when host bridge is hot-added.  This patch removes the
__init annotations so the code will still be present after boot.

[bhelgaas: split __init changes out]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

We currently enable PCI bridges after scanning a bus and assigning
resources.  This is often done in arch code.

This patch changes this so we don't enable a bridge until necessary, i.e.,
until we enable a PCI device behind the bridge.  We do this in the generic
pci_enable_device() path, so this also removes the arch-specific code to
enable bridges.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Previously, we did resource assignment globally.  This patch splits up
pci_assign_unassigned_resources() so assignment is done for each root bus
in turn.  We check each root bus individually to see whether it needs any
reassignment, and if it does, we assign resources for just that bus.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

pci_realloc_detect() turns on automatic resource allocation when it finds
unassigned SR-IOV resources.  Previously it did this on a global basis, so
we enabled reallocation if any PCI device anywhere had an unassigned SR-IOV
resource.

This patch changes pci_realloc_detect() so it looks at a single bus, so we
can do this when a host bridge is hot-added.

[bhelgaas: changelog]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Previously we did not turn on automatic PCI resource reallocation for
unassigned IOV resources behind a host bridge with address offset.  This
patch fixes that bug.

The intent was that "!r->start" would check for a BAR containing zero.  But
that check is incorrect for host bridges that apply an offset, because in
that case the resource address is not the same as the bus address.

This patch fixes that by converting the resource address back to a bus
address before checking for zero.

[bhelgaas: changelog]
Suggested-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

When CONFIG_PCI_REALLOC_ENABLE_AUTO=y, pci_realloc_detect() looks at PCI
devices to see if any have SR-IOV resources that need to be assigned.  If
it finds any, it turns on automatic resource reallocation.

This patch changes pci_realloc_detect() so it uses pci_walk_bus() on
each root bus instead of using for_each_pci_dev().  This is a step
toward doing reallocation on a per-bus basis, so we can do it for
a hot-added host bridge.

[bhelgaas: changelog, rename callback to iov_resources_unassigned(), use
boolean for "unassigned"]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Drop the "bus" temporary variable.  No functional change, but simplifies
later patch slightly.

[bhelgaas: changelog, make same change in
pci_assign_unassigned_bridge_resources() to keep it parallel with
pci_assign_unassigned_resources()]
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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=56531Reported-and-tested-by: NAlexander E. Patrakov <patrakov@gmail.com>
Tested-by: NIllya Klymov <xanf@xanf.me>
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Cc: 3.9+ <stable@vger.kernel.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

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: NBjorn Helgaas <bhelgaas@google.com>

This fixes "no previous prototype" warnings found via "make W=1".
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

So could use assign_unassigned_bus_res pci root bus add
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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: NGavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

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: NGavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>