Add support for x8 links.
Signed-off-by: NZhou Wang <wangzhou1@hisilicon.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NJingoo Han <jingoohan1@gmail.com>
Acked-by: NPratyush Anand <pratyush.anand@gmail.com>

Originally Xen PV drivers only use single-page ring to pass along
information. This might limit the throughput between frontend and
backend.

The patch extends Xenbus driver to support multi-page ring, which in
general should improve throughput if ring is the bottleneck. Changes to
various frontend / backend to adapt to the new interface are also
included.

Affected Xen drivers:
* blkfront/back
* netfront/back
* pcifront/back
* scsifront/back
* vtpmfront

The interface is documented, as before, in xenbus_client.c.
Signed-off-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NPaul Durrant <paul.durrant@citrix.com>
Signed-off-by: NBob Liu <bob.liu@oracle.com>
Cc: Konrad Wilk <konrad.wilk@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

Reading both the capability ID and "next" pointer at the same time lets us
parse the list with half the number of config reads.
Signed-off-by: NSean O. Stalley <sean.stalley@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

devm_ioremap_resource() validates the resource it receives, so if we check
for devm_ioremap_resource() failure, we need not check for failure of the
preceding platform_get_resource().
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Check for failure from platform_get_resource() (this check actually happens
inside devm_ioremap_resource()) before dereferencing the pointer returned
from platform_get_resource().
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Check for failure of devm_ioremap_resource().

devm_ioremap_resource() validates the resource it receives, so if we check
for devm_ioremap_resource() failure, we need not check for failure of the
preceding platform_get_resource().

[bhelgaas: changelog]
Signed-off-by: NJisheng Zhang <jszhang@marvell.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Communications with a hardware vendor confirm that the expected behaviour
on systems that set the FADT ASPM disable bit but which still grant full
PCIe control is for the OS to leave any BIOS configuration intact and
refuse to touch the ASPM bits.  This mimics the behaviour of Windows.
Signed-off-by: NMatthew Garrett <mjg59@coreos.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The PCI "ACPI additions for FW latency optimizations" ECN (link below)
defines two functions in the PCI _DSM:

  Function 8, "Reset Delay," applies to the entire hierarchy below a PCI
  host bridge.  If it returns one, the OS may assume that all devices in
  the hierarchy have already completed power-on reset delays.

  Function 9, "Device Readiness Durations," applies only to the object
  where it is located.  It returns delay durations required after various
  events if the device requires less time than the spec requires.  Delays
  from this function take precedence over the Reset Delay function.

Add support for Reset Delay and part of Device Readiness Durations.

[bhelgaas: changelog, comments]
Link: https://www.pcisig.com/specifications/conventional/pci_firmware/ECN_fw_latency_optimization_final.pdfSigned-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The find_pci_host_bridge() function can be useful to other PCI code so
export it.  Change its name to pci_find_host_bridge().
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The PCI Firmware Specification, r3.0, sec 4.6.4.1.3, defines a single UUID
for an ACPI _DSM method to provide device-specific control functions.  This
_DSM method support several functions, including PCI Express Slot
Information, PCI Express Slot Number, PCI Bus Capabilities, etc.

Move the UUID definition from pci/pci-label.c, where it could be used only
for one function, to pci/pci-acpi.c where it can be shared for all these
functions.

[bhelgaas: changelog]
Signed-off-by: NAaron Lu <aaron.lu@intel.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Fix a typo in one of the kernel messages.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use a semicolon, not a comma, to terminate a statement.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Add support for the Broadcom iProc PCIe controller.

pcie-iproc.c is the common core driver, and a front-end bus interface needs
to be added to support different bus interfaces.

pcie-iproc-platform.c contains the support for the platform bus interface.
Signed-off-by: NRay Jui <rjui@broadcom.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NScott Branden <sbranden@broadcom.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Export the following symbols so they can be referenced by a PCI host bridge
driver compiled as a kernel loadable module:

  pci_common_swizzle
  pci_create_root_bus
  pci_stop_root_bus
  pci_remove_root_bus
  pci_assign_unassigned_bus_resources
  pci_fixup_irqs
Signed-off-by: NRay Jui <rjui@broadcom.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>

Booting a v3.18 or newer Xen domU kernel with PCI devices passed through
results in an oops (this is a 32-bit 3.13.11 dom0 with a 64-bit 4.4.0
hypervisor and 32-bit domU):

  BUG: unable to handle kernel paging request at 0030303e
  IP: [<c06ed0e6>] acpi_ns_validate_handle+0x12/0x1a
  Call Trace:
   [<c06eda4d>] ? acpi_evaluate_object+0x31/0x1fc
   [<c06b78e1>] ? pci_get_hp_params+0x111/0x4e0
   [<c0407bc7>] ? xen_force_evtchn_callback+0x17/0x30
   [<c04085fb>] ? xen_restore_fl_direct_reloc+0x4/0x4
   [<c0699d34>] ? pci_device_add+0x24/0x450

Don't look for ACPI configuration information if ACPI has been disabled.

I don't think this is the best fix, because we can boot plain Linux (no
Xen) with "acpi=off", and we don't need this check in pci_get_hp_params().
There should be a better fix that would make Xen domU work the same way.
The domU kernel has ACPI support but it has no AML.  There should be a way
to initialize the ACPI data structures so things fail gracefully rather
than oopsing.  This is an interim fix to address the regression.

Fixes: 6cd33649 ("PCI: Add pci_configure_device() during enumeration")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=96301Reported-by: NMichael D Labriola <mlabriol@gdeb.com>
Tested-by: NMichael D Labriola <mlabriol@gdeb.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v3.18+

When sizing and assigning resources, we divide the resources into two
lists: the requested list and the additional list.  We don't consider the
alignment of additional VF(n) BAR space.

This is because the alignment required for the VF(n) BAR space is the size
of an individual VF BAR, not the size of the space for *all* VFs.  But we
want additional alignment to support partitioning on PowerNV.

Consider the additional IOV BAR alignment when sizing and assigning
resources.  When there is not enough system MMIO space to accomodate both
the requested list and the additional list, the PF's IOV BAR alignment will
not contribute to the bridge. When there is enough system MMIO space for
both lists, the additional alignment will contribute to the bridge.

The additional alignment is stored in the min_align of pci_dev_resource,
which is stored in the additional list by add_to_list() at the end of
pbus_size_mem(). The additional alignment is calculated in
pci_resource_alignment().  For an IOV BAR, we have arch dependent function
to get the alignment for different arch.

[bhelgaas: changelog, printk cast]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Per the SR-IOV spec r1.1, sec 3.3.14, the required alignment of a PF's IOV
BAR is the size of an individual VF BAR, and the size consumed is the
individual VF BAR size times NumVFs.

The PowerNV platform has additional alignment requirements to help support
its Partitionable Endpoint device isolation feature (see
Documentation/powerpc/pci_iov_resource_on_powernv.txt).

Add a pcibios_iov_resource_alignment() interface to allow platforms to
request additional alignment.

[bhelgaas: changelog, adapt to reworked pci_sriov_resource_alignment(),
drop "align" parameter]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

VFs are dynamically created when a driver enables them.  On some platforms,
like PowerNV, special resources are necessary to enable VFs.

Add platform hooks for enabling and disabling VFs.
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

On PowerNV, some resource reservation is needed for SR-IOV VFs that don't
exist at the bootup stage.  To do the match between resources and VFs, the
code need to get the VF's BDF in advance.

Rename virtfn_bus() and virtfn_devfn() to pci_iov_virtfn_bus() and
pci_iov_virtfn_devfn() and export them.

[bhelgaas: changelog, make "busnr" int]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

An SR-IOV device can change its First VF Offset and VF Stride based on the
values of ARI Capable Hierarchy and NumVFs.  The number of buses required
for all VFs is determined by NumVFs, First VF Offset, and VF Stride (see
SR-IOV spec r1.1, sec 2.1.2).

Previously pci_iov_bus_range() computed how many buses would be required by
TotalVFs, but this was based on a single NumVFs value and may not have been
the maximum for all NumVFs configurations.

Iterate over all valid NumVFs and calculate the maximum number of bus
numbers that could ever be required for VFs of this device.

[bhelgaas: changelog, compute busnr of NumVFs, not TotalVFs, remove
kerenl-doc comment marker]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

The First VF Offset and VF Stride fields depend on the NumVFs setting, so
refresh the cached fields in struct pci_sriov when updating NumVFs.  See
the SR-IOV spec r1.1, sec 3.3.9 and 3.3.10.

[bhelgaas: changelog, remove kernel-doc comment marker]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Most of PCI uses "res = &dev->resource[i]", not "res = dev->resource + i".
Use that style in iov.c also.

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Currently we don't store the individual VF BAR size.  We calculate it when
needed by dividing the PF's IOV resource size (which contains space for
*all* the VFs) by total_VFs or by reading the BAR in the SR-IOV capability
again.

Keep the individual VF BAR size in struct pci_sriov.barsz[], add
pci_iov_resource_size() to retrieve it, and use that instead of doing the
division or reading the SR-IOV capability BAR.

[bhelgaas: rename to "barsz[]", simplify barsz[] index computation, remove
SR-IOV capability BAR sizing]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

When we size VF BAR0, VF BAR1, etc., from the SR-IOV Capability of a PF, we
learn the alignment requirement and amount of space consumed by a single
VF.  But when VFs are enabled, *each* of the NumVFs consumes that amount of
space, so the total size of the PF resource is "VF BAR size * NumVFs".

Add a printk of the total space consumed by the VFs corresponding to what
we already do for normal non-IOV BARs.

No functional change; new message only.

[bhelgaas: split out into its own patch]
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

If we don't have space for all the bus numbers required to enable VFs,
print the largest bus number required and the range available.

No functional change; improved error message only.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Originally, EEH core probes on device_node or pci_dev to populate
EEH devices and PEs, which conflicts with the fact: SRIOV VFs are
usually enabled and created by PF's driver and they don't have the
corresponding device_nodes. Instead, SRIOV VFs have dynamically
created pci_dn, which can be used for EEH probe.

The patch reworks EEH probe for PowerNV and pSeries platforms to
do probing based on pci_dn, instead of pci_dev or device_node any
more.
Signed-off-by: NGavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

Intel has verified that there is no peer-to-peer between functions for the
below selection of 82580, 82576, 82575, I350, and 82571 multi-port devices.
This adds the necessary quirks to consider the functions isolated from each
other.  82571 quad-port devices are omitted due to likely lack of
ACS/isolation in the onboard switch, rendering quirks for the downstream
endpoints useless.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: John Ronciak <john.ronciak@intel.com>

Add suspend/resume support for the mvebu PCIe host driver.  Without this
commit, the system will panic at resume time when PCIe devices are
connected.

Note that we have to use the ->suspend_noirq() and ->resume_noirq() hooks,
because at resume time, the PCI fixups are done at ->resume_noirq() time,
so the PCIe controller has to be ready at this point.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NJason Cooper <jason@lakedaemon.net>

Previously, pci_scan_root_bus() created a root PCI bus, enumerated the
devices on it, and called pci_bus_add_devices(), which made the devices
available for drivers to claim them.

Most callers assigned resources to devices after pci_scan_root_bus()
returns, which may be after drivers have claimed the devices.  This is
incorrect; the PCI core should not change device resources while a driver
is managing the device.

Remove pci_bus_add_devices() from pci_scan_root_bus() and do it after any
resource assignment in the callers.

Note that ARM's pci_common_init_dev() already called pci_bus_add_devices()
after pci_scan_root_bus(), so we only need to remove the first call:

  pci_common_init_dev
    pcibios_init_hw
      pci_scan_root_bus
        pci_bus_add_devices        # first call
    pci_bus_assign_resources
    pci_bus_add_devices            # second call

[bhelgaas: changelog, drop "root_bus" var in alpha common_init_pci(),
return failure earlier in mn10300, add "return" in x86 pcibios_scan_root(),
return early if xtensa platform_pcibios_fixup() fails]
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: Richard Henderson <rth@twiddle.net>
CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
CC: Matt Turner <mattst88@gmail.com>
CC: David Howells <dhowells@redhat.com>
CC: Tony Luck <tony.luck@intel.com>
CC: Michal Simek <monstr@monstr.eu>
CC: Ralf Baechle <ralf@linux-mips.org>
CC: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
CC: Sebastian Ott <sebott@linux.vnet.ibm.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Chris Metcalf <cmetcalf@ezchip.com>
CC: Chris Zankel <chris@zankel.net>
CC: Max Filippov <jcmvbkbc@gmail.com>
CC: Thomas Gleixner <tglx@linutronix.de>

Make pci_ioremap_bar() fail if we're trying to map a BAR that hasn't been
assigned.

Normally pci_enable_device() will fail if a BAR hasn't been assigned, but a
driver can successfully call pci_enable_device_io() even if a memory BAR
hasn't been assigned.  That driver should not be able to use
pci_ioremap_bar() to map that unassigned memory BAR.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Use dev_warn() to complain about a pci_ioremap_bar() failure so we can
include the driver name, BAR number, and the resource itself.  We could use
dev_WARN() to also get the backtrace as we did previously, but I think
that's more information than we need.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

If a BAR is not inside any upstream bridge window, or if it conflicts with
another resource, mark it as IORESOURCE_UNSET so we don't try to use it.
We may be able to assign a different address for it.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Previously, pci_scan_bus() created a root PCI bus, enumerated the devices
on it, and called pci_bus_add_devices(), which made the devices available
for drivers to claim them.

Most callers assigned resources to devices after pci_scan_bus() returns,
which may be after drivers have claimed the devices.  This is incorrect;
the PCI core should not change device resources while a driver is managing
the device.

Remove pci_bus_add_devices() from pci_scan_bus() and do it after any
resource assignment in the callers.

[bhelgaas: changelog, check for failure in mcf_pci_init()]
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Geert Uytterhoeven <geert@linux-m68k.org>
CC: Guan Xuetao <gxt@mprc.pku.edu.cn>
CC: Richard Henderson <rth@twiddle.net>
CC: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
CC: Matt Turner <mattst88@gmail.com>

If there is a DT node available for the root bridge's parent device, use
the DMA configuration from that device node.  For example, Keystone PCI
devices would require dma_pfn_offset to be set correctly in the device
structure of the PCI device in order to have the correct DMA mask.  The DT
node will have dma-ranges defined for this.  Also support using the DT
property dma-coherent to allow coherent DMA operation by the PCI device.

Use the new helper function of_pci_dma_configure() to update the device DMA
configuration.  This fixes DMA on systems where DMA addresses are a
constant offset from CPU physical addresses.

Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> (AMD Seattle)
Signed-off-by: NMurali Karicheri <m-karicheri2@ti.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
CC: Joerg Roedel <joro@8bytes.org>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Russell King <linux@arm.linux.org.uk>
CC: Arnd Bergmann <arnd@arndb.de>

I don't have this hardware but it looks like we weren't adding bridge
devices as intended.  Maybe the bridge is always the last device?

Fixes: 05b12500 ("PCI: cpcihp: Iterate over all devices in slot, not functions 0-7")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NYijing Wang <wangyijing@huawei.com>
CC: stable@vger.kernel.org	# v3.9+

Commit fab4c256 ("PCI/AER: Add a TLP header print helper") introduced
the helper function __print_tlp_header(), but contrary to the intention,
the behaviour did change: Since we're taking the address of the parameter
t, the first 4 or 8 bytes printed will be the value of the pointer t
itself, and the remaining 12 or 8 bytes will be who-knows-what (something
from the stack).

We want to show the values of the four members of the struct
aer_header_log_regs; that can be done without ugly and error-prone casts.
On little-endian this should produce the same output as originally
intended, and since no-one has complained about getting garbage output so
far, I think big-endian should be ok too.

Fixes: fab4c256 ("PCI/AER: Add a TLP header print helper")
Signed-off-by: NRasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NBorislav Petkov <bp@suse.de>
CC: stable@vger.kernel.org	# v3.14+

Struct spear13xx_pcie_driver was in initdata, but we passed a pointer to it
to platform_driver_register(), which can use the pointer at arbitrary times
in the future, even after the initdata is freed.  That leads to crashes.

Move spear13xx_pcie_driver and things referenced by it
(spear13xx_pcie_probe() and dw_pcie_host_init()) out of initdata.

[bhelgaas: changelog]
Fixes: 6675ef21 ("PCI: spear: Fix Section mismatch compilation warning for probe()")
Signed-off-by: NMatwey V. Kornilov <matwey@sai.msu.ru>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
CC: stable@vger.kernel.org	# v3.17+

In xgene_pcie_map_bus(), we neglected to add in the register offset when
calculating the config space address.  This means all config accesses
operated on the first four bytes of config space.

Add the register offset to the config space base address.

Also correct the xgene_pcie_map_bus() prototype to fix a compiler warning.

[bhelgaas: changelog]
Fixes: 350f8be5 ("PCI: xgene: Convert to use generic config accessors")
Posting: http://lkml.kernel.org/r/1424214840-26498-1-git-send-email-fkan@apm.comSigned-off-by: NFeng Kan <fkan@apm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NTanmay Inamdar <tinamdar@apm.com>
Acked-by: NRob Herring <robh@kernel.org>

Add helper functions to get/put the root bus's host bridge device.

Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> (AMD Seattle)
Signed-off-by: NMurali Karicheri <m-karicheri2@ti.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NWill Deacon <will.deacon@arm.com>
CC: Joerg Roedel <joro@8bytes.org>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Russell King <linux@arm.linux.org.uk>
CC: Arnd Bergmann <arnd@arndb.de>

In Linux 4.0-rc1 ARM Versatile PCI build fails to build due to what
appears to be an API update.  This patch is a very simple correction,
merely posted as a heads-up to the maintainers.  Hopefully a better
fix can be forwarded to Linus.

[ arnd: the patch actually looks correct, so let's take this version ]
Signed-off-by: NJoachim Nilsson <troglobit@gmail.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>