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>

This patch implements a weak function to return the default I/O or memory
window alignment for a P2P bridge.  By default, I/O windows are aligned to
4KiB or 1KiB and memory windows are aligned to 4MiB.  Some platforms, e.g.,
powernv, have special alignment requirements and can override
pcibios_window_alignment().

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

Correct spelling typo in drivers/pci/hotplug.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Some bridges support I/O windows with 1K alignment, not just the 4K
alignment defined by the PCI spec.  For example, see the IOBL_ADR register
and the EN1K bit in the CNF register in the Intel 82870P2 (P64H2).

This patch adds support for sizing the window in 1K increments based
on the requirements of downstream devices.

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

9d265124 and 15a260d5 added quirks for P2P bridges that support
I/O windows that start/end at 1K boundaries, not just the 4K boundaries
defined by the PCI spec.  For details, see the IOBL_ADR register and the
EN1K bit in the CNF register in the Intel 82870P2 (P64H2).

These quirks complicate the code that reads P2P bridge windows
(pci_read_bridge_io() and pci_cfg_fake_ranges()) because the bridge
I/O resource is updated in the HEADER quirk, in pci_read_bridge_io(),
in pci_setup_bridge(), and again in the FINAL quirk.  This is confusing
and makes it impossible to reassign the bridge windows after FINAL
quirks are run.

This patch adds support for 1K windows in the generic paths, so the
HEADER quirk only has to enable this support.  The FINAL quirk, which
used to undo damage done by pci_setup_bridge(), is no longer needed.

This removes "if (!res->start) res->start = ..." from pci_read_bridge_io();
that was part of 9d265124 to avoid overwriting the resource filled in
by the quirk.  Since pci_read_bridge_io() itself now knows about
granularity, the quirk no longer updates the resource and this test is no
longer needed.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Warning(drivers/pci/setup-bus.c:277): No description found for parameter 'fail_head'
Warning(drivers/pci/setup-bus.c:277): Excess function parameter 'failed_list' description in 'assign_requested_resources_sorted'
Signed-off-by: NWanpeng Li <liwp.linux@gmail.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Replace the struct pci_bus secondary/subordinate members with the
struct resource busn_res.  Later we'll build a resource tree of these
bus numbers.

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

Add a new config option, PCI_REALLOC_ENABLE_AUTO, which will
automatically try to re-allocate PCI resources if PCI_IOV support is
enabled and the SR-IOV resources are unassigned.  Behavior can still be
controlled using the pci=realloc= parameter.

-v2: According to Jesse, adding one CONFIG option for distribution to
     disable it or enable it.
-v3: update Kconfig text (jbarnes)
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

let user know they could try if pci=realloc could help.

-v2: update suggestion text.
Suggested-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Let the user could enable and disable with pci=realloc=on or pci=realloc=off

Also
1. move variable and functions near the place they are used.
2. change macro to function
3. change related functions and variable to static and _init
4. update parameter description accordingly.

This will let us add a config option to control default behavior, and
still allow the user to turn off automatic reallocation if it fails on
their platform until a permanent solution is found.

-v2: still honor pci=realloc, and treat it as pci=realloc=on
     also use enum instead of ...
-v3: update kernel-paramenters.txt according to Jesse.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

When enabling pci reallocation for a pci bridge, we clear the small size
in in bridge and re-assign with requested + optional size for first
several tries, but Ram mention could have problem with one case:
	https://bugzilla.kernel.org/show_bug.cgi?id=15960

After checking the booting log in
	https://lkml.org/lkml/2010/4/19/44
	[regression, bisected] Xonar DX invalid PCI I/O range since 977d17bb

We should not stop too early for io ports.
	Apr 19 10:19:38 [kernel] pci 0000:04:00.0: BAR 7: can't assign io (size 0x4000)
	Apr 19 10:19:38 [kernel] pci 0000:05:01.0: BAR 8: assigned [mem 0x80400000-0x805fffff]
	Apr 19 10:19:38 [kernel] pci 0000:05:01.0: BAR 7: can't assign io (size 0x2000)
	Apr 19 10:19:38 [kernel] pci 0000:05:02.0: BAR 7: can't assign io (size 0x1000)
	Apr 19 10:19:38 [kernel] pci 0000:05:03.0: BAR 7: can't assign io (size 0x1000)
	Apr 19 10:19:38 [kernel] pci 0000:08:00.0: BAR 7: can't assign io (size 0x1000)
	Apr 19 10:19:38 [kernel] pci 0000:09:04.0: BAR 0: can't assign io (size 0x100)
and clear 00:1c.0 to retry again.

This patch removes IORESOUCE_IO checking, and tries one more time.  It
gives us a chance to get an allocation for the 00:1c.0 io port range
because the range from 0x4000 to 0x8000 will be freed and we can use it.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

No architecture defines its own pci_flags, so the core symbol does not
need to be weak.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

If we move resource assignment functions into the core, we'll still
need a way for architectures to prevent reassignment, e.g., the
"pci_probe_only" functionality, and we'll need a generic, always
available way the core can test for that.  The "pci_flags"
arrangement used by several architectures seems like a convenient
way to do this.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Otherwise when rescan is used for cardbus, assigned resources will get
cleared.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Tested-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

We should not set the requested size to -2; that will confuse the
resource list sorting with align when SIZEALIGN is used.

Change to STARTALIGN and pass align from start;  we are safe to do that
just as we do that regular pci bridge.  In the long run, we should just
treat cardbus like a regular pci bridge.

Also fix the case when realloc_head is not passed: we should keep the
requested size.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Tested-by: NDominik Brodowski <linux@dominikbrodowski.net>
Acked-by: NRam Pai <linuxram@us.ibm.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Some BIOSes enable prefetch on both MEM0 and MEM1.  But the cardbus code
assumes MEM1 is non-pref...

Discussion could be found at:
	https://lkml.org/lkml/2012/1/12/1
	https://bugzilla.kernel.org/show_bug.cgi?id=41622#c23Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Tested-by: NDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

Only one user; just use add_to_list instead.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

For use in debugging resource reallocation.
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>