The list of interrupt events (INT_BUTTON_IGNORE, INT_PRESENCE_ON, etc.) was
copied from other hotplug drivers, but pciehp doesn't use them all.

Remove the interrupt events that aren't used by pciehp.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

It's platform-dependent, but an MMIO read to a non-existent PCI device
generally returns data with all bits set.  This happens when the host
bridge or Root Complex times out waiting for a response from the device and
fabricates return data to complete the CPU's read.

One example, reported in the bugzilla below, involved this hierarchy:

  pci 0000:00:1c.0: PCI bridge to [bus 02-3a] Root Port
  pci 0000:02:00.0: PCI bridge to [bus 03-0a] Upstream Port
  pci 0000:03:03.0: PCI bridge to [bus 05-07] Downstream Port
  pci 0000:05:00.0: PCI bridge to [bus 06-07] Thunderbolt Upstream Port
  pci 0000:06:00.0: PCI bridge to [bus 07]    Thunderbolt Downstream Port
  pci 0000:07:00.0: BCM57762 NIC

Unplugging the Thunderbolt switch and the NIC below it resulted in this:

  pciehp 0000:03:03.0: Surprise Removal
  tg3 0000:07:00.0: tg3_abort_hw timed out, TX_MODE_ENABLE will not clear MAC_TX_MODE=ffffffff
  pciehp 0000:06:00.0: unloading service driver pciehp
  pciehp 0000:06:00.0: pcie_isr: intr_loc 11f
  pciehp 0000:06:00.0: Switch interrupt received
  pciehp 0000:06:00.0: Latch open on Slot
  pciehp 0000:06:00.0: Attention button interrupt received
  pciehp 0000:06:00.0: Button pressed on Slot
  pciehp 0000:06:00.0: Presence/Notify input change
  pciehp 0000:06:00.0: Card present on Slot
  pciehp 0000:06:00.0: Power fault interrupt received
  pciehp 0000:06:00.0: Data Link Layer State change
  pciehp 0000:06:00.0: Link Up event

The pciehp driver correctly noticed that the Thunderbolt switch (05:00.0
and 06:00.0) and NIC (07:00.0) had been removed, and it called their driver
remove methods.

Since the NIC was already gone, tg3 received 0xffffffff when it tried to
read from the device.  The resulting timeout is a tg3 issue and not of
interest here.

Similarly, since the 06:00.0 Thunderbolt switch was already gone,
pcie_isr() received 0xffff when it tried to read PCI_EXP_SLTSTA, and pciehp
thought that was valid status showing that many events had happened: the
latch had been opened, the attention button had been pressed, a card was
now present, and the link was now up.  These are all wrong, of course, but
pciehp went on to try to power up and enumerate devices below the
non-existent bridge:

  pciehp 0000:06:00.0: PCI slot - powering on due to button press
  pciehp 0000:06:00.0: Surprise Insertion
  pci 0000:07:00.0 id reading try 50 times with interval 20 ms to get ffffffff

[bhelgaas: changelog, also check in pcie_poll_cmd() & pcie_do_write_cmd()]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=99841Suggested-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NJarod Wilson <jarod@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Previously, pci_setup_device() and similar functions searched the
pci_bus->slots list without any locking.  It was possible for another
thread to update the list while we searched it.

Add pci_dev_assign_slot() to search the list while holding pci_slot_mutex.

[bhelgaas: changelog, fold in CONFIG_SYSFS fix]
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Rajat Jain reported a deadlock when PCIe hot-add and AER recovery happen at
the same time:

thread 1:

  pciehp_enable_slot
    pciehp_configure_device
      pci_bus_add_devices
        pci_bus_add_device
          device_attach
            device_lock(dev)                       # acquire device lock
            ...
            pciehp_probe
              init_slot
                pci_hp_register
                  pci_create_slot
                    down_write(pci_bus_sem)        # deadlock here

thread 2:

  aer_isr_one_error
    aer_process_err_device
      do_recovery
        broadcast_error_message(..., report_error_detected)
          pci_walk_bus(..., cb=report_error_detected, ...)
            down_read(&pci_bus_sem)                # acquire pci_bus_sem
            report_error_detected(dev)             # cb()
              device_lock(dev)                     # deadlock here

Previously, the bus->devices and bus->slots list were protected by
pci_bus_sem.  In pci_create_slot(), we held it for writing so we could
add to the bus->slots list.

Add a new local pci_slot_mutex to protect bus->slots.  Hold pci_bus_sem for
reading while searching the bus->devices list.

[bhelgaas: changelog]
Link: http://lkml.kernel.org/r/CAA93t1qpPqbih+UB0McA_d_+2rVaNkXsinAUxYzK9+JXSS+L-g@mail.gmail.comReported-by: NRajat Jain <rajatja@google.com>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Move first slot status read into while to simplify code.
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Now in pci_hotplug_core.c, we randomly name a struct hotplug_slot and a
struct pci_slot.  It's easy to confuse them, so let us use "slot" for a
struct hotplug_slot and "pci_slot" for a struct pci_slot.

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

Mohit's email-id doesn't exist anymore as he has left the company.
Replace ST's id with mohit.kumar.dhaka@gmail.com.
Signed-off-by: NPratyush Anand <pratyush.anand@gmail.com>
Cc: Mohit Kumar <mohit.kumar.dhaka@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

pratyush.anand@st.com email-id doesn't exist anymore as I have left the
company.  Replace ST's id with pratyush.anand@gmail.com.
Signed-off-by: NPratyush Anand <pratyush.anand@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix a race where a pending interrupt could be received and the handler
called before the handler's data has been setup, by converting to
irq_set_chained_handler_and_data().

Search and conversion was done with coccinelle:

@@
expression E1, E2, E3;
@@
(
-if (irq_set_chained_handler(E1, E3) != 0)
-   BUG();
|
-irq_set_chained_handler(E1, E3);
)
-irq_set_handler_data(E1, E2);
+irq_set_chained_handler_and_data(E1, E3, E2);

@@
expression E1, E2, E3;
@@
(
-if (irq_set_chained_handler(E1, E3) != 0)
-   BUG();
...
|
-irq_set_chained_handler(E1, E3);
...
)
-irq_set_handler_data(E1, E2);
+irq_set_chained_handler_and_data(E1, E3, E2);
Reported-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Murali Karicheri <m-karicheri2@ti.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-pci@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org

The pciehp_handle_*() functions (pciehp_handle_attention_button(), etc.)
only contain a line or two of useful code, so it's clumsy to put
them in separate functions.  All they so is add an event to a work queue,
and it's clearer to see that directly in the ISR.

Inline them directly into pcie_isr().  No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRajat Jain <rajatja@google.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>

Rename queue_interrupt_event() to pciehp_queue_interrupt_event() so we can
make it extern and call it from pcie_isr().

No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRajat Jain <rajatja@google.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>

Nobody looks at the return value from queue_interrupt_event(), so errors
were silently ignored.  Convert it to a "void" function and note the error
in the dmesg log.

No functional change except the new message.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRajat Jain <rajatja@google.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>

Previously, when a Root Port's link was down, we didn't allow config access
to the Root Port, which meant that if the Root Port led to an empty slot,
"lspci" didn't even show the Root Port.

Allow config access to Root Port even when link is down.

[bhelgaas: changelog, fold in unused var fix]
Suggested-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NDuc Dang <dhdang@apm.com>
Signed-off-by: NTanmay Inamdar <tinamdar@apm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

When a CPU reads the Vendor and Device ID of a non-existent device, the
controller should fabricate return data of 0xFFFFFFFF.  Configuration
Request Retry Status (CRS) is not applicable in this case because the
device doesn't exist at all.

The X-Gene v1 PCIe controller has a bug in the CRS logic such that when CRS
is enabled, it fabricates return data of 0xFFFF0001 for this case, which
means "the device exists but is not ready."  That causes the PCI core to
retry the read until it times out after 60 seconds.

Disable CRS capability advertisement by clearing the CRS Software
Visibility bit in the Root Capabilities Register.

[bhelgaas: changelog and comment]
Tested-by: NIan Campbell <ian.campbell@citrix.com>
Tested-by: NMarcin Juszkiewicz <mjuszkiewicz@redhat.com>
Signed-off-by: NDuc Dang <dhdang@apm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NTanmay Inamdar <tinamdar@apm.com>

The pciehp debug logging is overly verbose and often redundant.  Almost all
of the information printed by dbg_ctrl() is also printed by the normal PCI
core enumeration code and by pcie_init().

Remove the redundant debug info.

When claiming a pciehp bridge, we print the slot characteristics, e.g.,

  Slot #6 AttnBtn- AttnInd- PwrInd- PwrCtrl- MRL- Interlock- NoCompl+ LLActRep+

Add the Hot-Plug Capable and Hot-Plug Surprise bits to this information,
and print it all in the same order as lspci does.

No functional change except the message text changes.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRajat Jain <rajatja@google.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>

Define PCIE_RC_LCSR and use it instead of the bare offset "0x80."
No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use "u32", not "uint32_t", for consistency.  Use "tmp", not "temp", for
consistency within the driver.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NRichard Zhu <Richard.Zhu@freescale.com>

No one uses pci_scan_bus_parented() any more, remove it.
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Use pci_scan_root_bus() instead of deprecated function
pci_scan_bus_parented().
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: xen-devel@lists.xenproject.org

Currently, the timeout is never detected as count has a value of -1 if a
timeout happens, but the code is checking for 0.  Also, this patch removes
the unneeded final wait if a timeout occurs.

[bhelgaas: reworked starting from http://lkml.kernel.org/r/1433543864-7252-1-git-send-email-troy.kisky@boundarydevices.com]
Signed-off-by: NTroy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

Update the Link Control Enable Clock Power Management bit the same
way we update the ASPM Control bits, with a single call of
pcie_capability_clear_and_set_word().

No functional change; this just makes both paths use the same style.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

All the DesignWare-based host drivers loop waiting for the link to come up,
but they do it several ways that are needlessly different.

Wait for the link to come up in a consistent style across all the
DesignWare drivers.  No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NPratyush Anand <pratyush.anand@gmail.com>

All other DesignWare-based drivers have a *_establish_link() function.

This functionality is trivial for Layerscape, but factor out a
ls_pcie_establish_link() for consistency with the other drivers.  No
functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NPratyush Anand <pratyush.anand@gmail.com>

All the other DesignWare-based drivers use dw_pcie_link_up(), so use it in
this driver, too, for consistency.  No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NPratyush Anand <pratyush.anand@gmail.com>

We already use dw_pcie_link_up() once in dra7xx_pcie_establish_link(), but
we duplicate its code later.  Use dw_pcie_link_up() for consistency.  No
functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-by: NPratyush Anand <pratyush.anand@gmail.com>

The commit referenced below deferred waiting for command completion until
the start of the next command, allowing hardware to do the latching
asynchronously.  Unfortunately, being ready to accept a new command is the
only indication we have that the previous command is completed.  In cases
where we need that state change to be enabled, we must still wait for
completion.  For instance, pciehp_reset_slot() attempts to disable anything
that might generate a surprise hotplug on slots that support presence
detection.  If we don't wait for those settings to latch before the
secondary bus reset, we negate any value in attempting to prevent the
spurious hotplug.

Create a base function with optional wait and helper functions so that
pcie_write_cmd() turns back into the "safe" interface which waits before
and after issuing a command and add pcie_write_cmd_nowait(), which
eliminates the trailing wait for asynchronous completion.  The following
functions are returned to their previous behavior:

  pciehp_power_on_slot
  pciehp_power_off_slot
  pcie_disable_notification
  pciehp_reset_slot

The rationale is that pciehp_power_on_slot() enables the link and therefore
relies on completion of power-on.  pciehp_power_off_slot() and
pcie_disable_notification() need a wait because data structures may be
freed after these calls and continued signaling from the device would be
unexpected.  And, of course, pciehp_reset_slot() needs to wait for the
scenario outlined above.

Fixes: 3461a068 ("PCI: pciehp: Wait for hotplug command completion lazily")
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org	# v3.17+

struct timeval uses a 32-bit field for representing seconds, which
will overflow in the year 2038 and beyond. Replace struct timeval with
64-bit ktime_t which is 2038 safe.  This is part of a larger effort to
remove instances of 32-bit timekeeping variables (timeval, time_t and
timespec) from the kernel.
Signed-off-by: NTina Ruchandani <ruchandani.tina@gmail.com>
Suggested-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NBoris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NDavid Vrabel <david.vrabel@citrix.com>

APM X-Gene v1 SoC supports its own implementation of MSI, which is not
compliant to GIC V2M specification for MSI Termination.

There is a single MSI block in X-Gene v1 SOC which serves all 5 PCIe ports.
This MSI block supports 2048 MSI termination ports coalesced into 16
physical HW IRQ lines and shared across all 5 PCIe ports.

As there are only 16 HW IRQs to serve 2048 MSI vectors, to support
set_affinity correctly for each MSI vectors, the 16 HW IRQs are statically
allocated to 8 X-Gene v1 cores (2 HW IRQs for each cores).  To steer MSI
interrupt to target CPU, MSI vector is moved around these HW IRQs lines.
With this approach, the total MSI vectors this driver supports is reduced
to 256.

[bhelgaas: squash doc, driver, maintainer update]
Signed-off-by: NDuc Dang <dhdang@apm.com>
Signed-off-by: NTanmay Inamdar <tinamdar@apm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>

Rename imx6_pcie_start_link() to imx6_pcie_establish_link() to follow the
convention of other DesignWare-based host drivers.  No functional change.
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NPratyush Anand <pratyush.anand@gmail.com>

In d74b9027 ("PCI: Consider additional PF's IOV BAR alignment in sizing
and assigning"), we store additional alignment in realloc_head and take
this into consideration for assignment.

In __assign_resources_sorted(), we changed dev_res->res->start, then used
resource_start() (which depends on res->start), so the recomputed res->end
was completely bogus.  Even if we'd had the correct size, the end would
have been off by one.

Preserve the resource size when we adjust its alignment.

[bhelgaas: changelog]
Fixes: d74b9027 ("PCI: Consider additional PF's IOV BAR alignment in sizing and assigning")
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NWei Yang <weiyang@linux.vnet.ibm.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>

David Ahern reported that d63e2e1f ("sparc/PCI: Clip bridge windows
to fit in upstream windows") fails to boot on sparc/T5-8:

  pci 0000:06:00.0: reg 0x184: can't handle BAR above 4GB (bus address 0x110204000)

The problem is that sparc64 assumed that dma_addr_t only needed to hold DMA
addresses, i.e., bus addresses returned via the DMA API (dma_map_single(),
etc.), while the PCI core assumed dma_addr_t could hold *any* bus address,
including raw BAR values.  On sparc64, all DMA addresses fit in 32 bits, so
dma_addr_t is a 32-bit type.  However, BAR values can be 64 bits wide, so
they don't fit in a dma_addr_t.  d63e2e1f added new checking that
tripped over this mismatch.

Add pci_bus_addr_t, which is wide enough to hold any PCI bus address,
including both raw BAR values and DMA addresses.  This will be 64 bits
on 64-bit platforms and on platforms with a 64-bit dma_addr_t.  Then
dma_addr_t only needs to be wide enough to hold addresses from the DMA API.

[bhelgaas: changelog, bugzilla, Kconfig to ensure pci_bus_addr_t is at
least as wide as dma_addr_t, documentation]
Fixes: d63e2e1f ("sparc/PCI: Clip bridge windows to fit in upstream windows")
Fixes: 23b13bc7 ("PCI: Fail safely if we can't handle BARs larger than 4GB")
Link: http://lkml.kernel.org/r/CAE9FiQU1gJY1LYrxs+ma5LCTEEe4xmtjRG0aXJ9K_Tsu+m9Wuw@mail.gmail.com
Link: http://lkml.kernel.org/r/1427857069-6789-1-git-send-email-yinghai@kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=96231Reported-by: NDavid Ahern <david.ahern@oracle.com>
Tested-by: NDavid Ahern <david.ahern@oracle.com>
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
CC: stable@vger.kernel.org	# v3.19+

pci_ari_enabled() is useful outside of drivers/pci, particularly for
deriving INTx routing via ACPI _PRT, so move it to the global header.
Also convert to bool return.
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NDon Dutile <ddutile@redhat.com>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

Previously we assumed that PCIe Root Ports and Downstream Ports had Links
on their secondary side.  That is true in most systems, but it is possible
to connect a switch with either an Upstream or a Downstream Port leading
downstream.

Instead of relying on the component type to identify devices that have
links leading downstream, use the "dev->has_secondary_link" field.

[bhelgaas: changelog]
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

The resource list is only used in the setup process and was never freed.
pci_add_resource() allocates a memory area to store the list item.

Fix the memory leak.
Tested-by: NRay Jui <rjui@broadcom.com>
Signed-off-by: NHauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRay Jui <rjui@broadcom.com>

The struct iproc_pcie.resources member was pointing to a stack variable and
is invalid after the registration function returned.

Remove this pointer and add a parameter to the function.
Tested-by: NRay Jui <rjui@broadcom.com>
Signed-off-by: NHauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NRay Jui <rjui@broadcom.com>

In d74b9027 ("PCI: Consider additional PF's IOV BAR alignment in sizing
and assigning"), it stores additional alignment in realloc_head and takes
this into consideration for assignment.

After getting the additional alignment, it reorders the head list so
resources with bigger alignment are ahead of resources with smaller
alignment.  It does this by iterating over the head list and inserting
ahead of any resource with smaller alignment.  This should be done for the
first occurrence, but the code currently iterates over the whole list.

Fix this by terminating the loop when we find the first smaller resource in
the head list.

[bhelgaas: changelog]
Fixes: d74b9027 ("PCI: Consider additional PF's IOV BAR alignment in sizing and assigning")
Signed-off-by: NWei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>

After b97ea289 ("PCI: Assign resources before drivers claim devices
(pci_scan_root_bus())"), pci_scan_root_bus() no longer adds the devices, so
it is equivalent to:

  pci_create_root_bus()
  pci_scan_child_bus()

Use pci_scan_root_bus() to simplify the code.

[bhelgaas: changelog]
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJingoo Han <jingoohan1@gmail.com>
CC: Mohit Kumar <mohit.kumar@st.com>

After b97ea289 ("PCI: Assign resources before drivers claim devices
(pci_scan_root_bus())"), pci_scan_root_bus() no longer adds the devices, so
it is equivalent to tegra_pcie_scan_bus().

Remove tegra_pcie_scan_bus() (the hw.scan method), so we use the generic
pci_scan_root_bus() path.

[bhelgaas: changelog]
Tested-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Acked-by: NThierry Reding <treding@nvidia.com>

After b97ea289 ("PCI: Assign resources before drivers claim devices
(pci_scan_root_bus())"), pci_scan_root_bus() no longer adds the devices, so
it is equivalent to mvebu_pcie_scan_bus().

Remove mvebu_pcie_scan_bus() (the hw.scan method), so we use the generic
pci_scan_root_bus() path.  We also need to use pci_common_init_dev()
instead of pci_common_init() so we can supply the host bridge device
pointer.

[bhelgaas: changelog]
Tested-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
CC: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
CC: Jason Cooper <jason@lakedaemon.net>

We allocate pcie_link_state for the component at the upstream end of a
Link.  Previously we did this by allocating pcie_link_state for Root Ports
and Downstream Ports.  This works fine for the typical topology:

  00:1c.0 Root Port       [bridge to bus 02]
  02:00.0 Upstream Port   [bridge to bus 03]
  03:00.0 Downstream Port [bridge to bus 04]
  04:00.0 Endpoint or Switch Port

However, it is possible to have a Root Port connected to a Downstream Port
instead of an Upstream Port, as in Robert White's ATCA system:

  00:1c.0 Root Port       [bridge to bus 02]
  02:00.0 Downstream Port [bridge to bus 03]
  03:01.0 Downstream Port [bridge to bus 04]
  04:00.0 Endpoint or Switch Port

In this topology, we wrongly allocated pcie_link_state for the 02:00.0
Downstream Port, which is actually the *downstream* end of a link.  This
led to the following NULL pointer dereference when we tried to connect this
link into the tree of links starting at the 00:1c.0 Root Port:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000088
  IP: [<ffffffff81550324>] pcie_aspm_init_link_state+0x744/0x850
  Hardware name: Kontron B3001/B3001, BIOS 4.6.3 08/07/2012
  Call Trace:
   [<ffffffff8153b865>] pci_scan_slot+0xd5/0x120
   [<ffffffff8153ca1d>] pci_scan_child_bus+0x2d/0xd0
   ...

Instead of relying on the component type to identify the upstream end of a
link, use the "dev->has_secondary_link" field.

This means it's now possible for an Upstream Port to have a link on its
secondary side, so alloc_pcie_link_state() needs to connect links
originating from both Upstream and Downstream Ports into the tree.

[bhelgaas: changelog, add comment]
Link: https://bugzilla.kernel.org/show_bug.cgi?id=94361
Link: http://lkml.kernel.org/r/54EB81B2.4050904@pobox.comReported-by: NRobert White <rwhite@pobox.com>
Signed-off-by: NYijing Wang <wangyijing@huawei.com>
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>