Previously the slot workqueue was used to handle events and enable or
disable the slot. That's no longer the case as those tasks are done
synchronously in the IRQ thread. The slot workqueue is thus merely used
to handle a button press after the 5 second delay and only one such work
item may be in flight at any given time. A separate workqueue isn't
necessary for this simple task, so use the system workqueue instead.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Up until now, pciehp's IRQ handler schedules a work item for each event,
which in turn schedules a work item to enable or disable the slot. This
double indirection was necessary because sleeping wasn't allowed in the
IRQ handler.
However it is now that pciehp has been converted to threaded IRQ handling
and polling, so handle events synchronously in pciehp_ist() and remove
the work item infrastructure (with the exception of work items to handle
a button press after the 5 second delay).
For link or presence change events, move the register read to determine
the current link or presence state behind acquisition of the slot lock
to prevent it from becoming stale while the lock is contended.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
We've just converted pciehp to threaded IRQ handling, but still cannot
sleep in pciehp_ist() because the function is also called in poll mode,
which runs in softirq context (from a timer).
Convert poll mode to a kthread so that pciehp_ist() always runs in task
context.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
pciehp's IRQ handler queues up a work item for each event signaled by
the hardware. A more modern alternative is to let a long running
kthread service the events. The IRQ handler's sole job is then to check
whether the IRQ originated from the device in question, acknowledge its
receipt to the hardware to quiesce the interrupt and wake up the kthread.
One benefit is reduced latency to handle the IRQ, which is a necessity
for realtime environments. Another benefit is that we can make pciehp
simpler and more robust by handling events synchronously in process
context, rather than asynchronously by queueing up work items. pciehp's
usage of work items is a historic artifact, it predates the introduction
of threaded IRQ handlers by two years. (The former was introduced in
2007 with commit 5d386e1ac4 ("pciehp: Event handling rework"), the
latter in 2009 with commit 3aa551c9b4 ("genirq: add threaded interrupt
handler support").)
Convert pciehp to threaded IRQ handling by retrieving the pending events
in pciehp_isr(), saving them for later consumption by the thread handler
pciehp_ist() and clearing them in the Slot Status register.
By clearing the Slot Status (and thereby acknowledging the events) in
pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which
would have the unpleasant side effect of starving devices sharing the
IRQ until pciehp_ist() has finished.
pciehp_isr() does not count how many times each event occurred, but
merely records the fact *that* an event occurred. If the same event
occurs a second time before pciehp_ist() is woken, that second event
will not be recorded separately, which is problematic according to
commit fad214b0aa ("PCI: pciehp: Process all hotplug events before
looking for new ones") because we may miss removal of a card in-between
two back-to-back insertions. We're about to make pciehp_ist() resilient
to missed events. The present commit regresses the driver's behavior
temporarily in order to separate the changes into reviewable chunks.
This doesn't affect regular slow-motion hotplug, only plug-unplug-plug
operations that happen in a timespan shorter than wakeup of the IRQ
thread.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Commit b440bde74f ("PCI: Add pci_ignore_hotplug() to ignore hotplug
events for a device") iterates over the devices on a hotplug port's
subordinate bus in pciehp's IRQ handler without acquiring pci_bus_sem.
It is thus possible for a user to cause a crash by concurrently
manipulating the device list, e.g. by disabling slot power via sysfs
on a different CPU or by initiating a remove/rescan via sysfs.
This can't be fixed by acquiring pci_bus_sem because it may sleep.
The simplest fix is to avoid the list iteration altogether and just
check the ignore_hotplug flag on the port itself. This works because
pci_ignore_hotplug() sets the flag both on the device as well as on its
parent bridge.
We do lose the ability to print the name of the device blocking hotplug
in the debug message, but that's probably bearable.
Fixes: b440bde74f ("PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org
When pciehp is unbound (e.g. on unplug of a Thunderbolt device), the
hotplug_slot struct is deregistered and thus freed before freeing the
IRQ. The IRQ handler and the work items it schedules print the slot
name referenced from the freed structure in various informational and
debug log messages, each time resulting in a quadruple dereference of
freed pointers (hotplug_slot -> pci_slot -> kobject -> name).
At best the slot name is logged as "(null)", at worst kernel memory is
exposed in logs or the driver crashes:
pciehp 0000:10:00.0:pcie204: Slot((null)): Card not present
An attacker may provoke the bug by unplugging multiple devices on a
Thunderbolt daisy chain at once. Unplugging can also be simulated by
powering down slots via sysfs. The bug is particularly easy to trigger
in poll mode.
It has been present since the driver's introduction in 2004:
https://git.kernel.org/tglx/history/c/c16b4b14d980
Fix by rearranging teardown such that the IRQ is freed first. Run the
work items queued by the IRQ handler to completion before freeing the
hotplug_slot struct by draining the work queue from the ->release_slot
callback which is invoked by pci_hp_deregister().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v2.6.4
- fix use-before-set error in ibmphp (Dan Carpenter)
- fix pciehp timeouts caused by Command Completed errata (Bjorn Helgaas)
- fix refcounting in pnv_php hotplug (Julia Lawall)
- clear pciehp Presence Detect and Data Link Layer Status Changed on
resume so we don't miss hotplug events (Mika Westerberg)
- only request pciehp control if we support it, so platform can use ACPI
hotplug otherwise (Mika Westerberg)
- convert SHPC to be builtin only (Mika Westerberg)
- request SHPC control via _OSC if we support it (Mika Westerberg)
- simplify SHPC handoff from firmware (Mika Westerberg)
* pci/hotplug:
PCI: Improve "partially hidden behind bridge" log message
PCI: Improve pci_scan_bridge() and pci_scan_bridge_extend() doc
PCI: Move resource distribution for single bridge outside loop
PCI: Account for all bridges on bus when distributing bus numbers
ACPI / hotplug / PCI: Drop unnecessary parentheses
ACPI / hotplug / PCI: Mark stale PCI devices disconnected
ACPI / hotplug / PCI: Don't scan bridges managed by native hotplug
PCI: hotplug: Add hotplug_is_native()
PCI: shpchp: Add shpchp_is_native()
PCI: shpchp: Fix AMD POGO identification
PCI: shpchp: Use dev_printk() for OSHP-related messages
PCI: shpchp: Remove get_hp_hw_control_from_firmware() wrapper
PCI: shpchp: Remove acpi_get_hp_hw_control_from_firmware() flags
PCI: shpchp: Rely on previous _OSC results
PCI: shpchp: Request SHPC control via _OSC when adding host bridge
PCI: shpchp: Convert SHPC to be builtin only
PCI: pciehp: Make pciehp_is_native() stricter
PCI: pciehp: Rename host->native_hotplug to host->native_pcie_hotplug
PCI: pciehp: Request control of native hotplug only if supported
PCI: pciehp: Clear Presence Detect and Data Link Layer Status Changed on resume
PCI: pnv_php: Add missing of_node_put()
PCI: pciehp: Add quirk for Command Completed errata
PCI: Add Qualcomm vendor ID
PCI: ibmphp: Fix use-before-set in get_max_bus_speed()
# Conflicts:
# drivers/acpi/pci_root.c
After a suspend/resume cycle the Presence Detect or Data Link Layer Status
Changed bits might be set. If we don't clear them those events will not
fire anymore and nothing happens for instance when a device is now
hot-unplugged.
Fix this by clearing those bits in a newly introduced function
pcie_reenable_notification(). This should be fine because immediately
after, we check if the adapter is still present by reading directly from
the status register.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable@vger.kernel.org
Clients such as hotplug and Downstream Port Containment (DPC) both need to
wait until a link becomes active or inactive.
Add a generic pcie_wait_link_active() interface and use it instead of
duplicating the code.
Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Several PCIe hotplug controllers have errata that mean they do not set the
Command Completed bit unless writes to the Slot Command register change
"Control" bits. Command Completed is never set for writes that only change
software notification "Enable" bits. This results in timeouts like this:
pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago)
When this erratum is present, avoid these timeouts by marking commands
"completed" immediately unless they change the "Control" bits.
Here's the text of the Intel erratum CF118. We assume this applies to all
Intel parts:
CF118 PCIe Slot Status Register Command Completed bit not always
updated on any configuration write to the Slot Control
Register
Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug,
the Slot Status Register (offset AAh) Command Completed
(bit[4]) status is updated under the following condition:
IOH will set Command Completed bit after delivering the new
commands written in the Slot Controller register (offset
A8h) to VPP. The IOH detects new commands written in Slot
Control register by checking the change of value for Power
Controller Control (bit[10]), Power Indicator Control
(bits[9:8]), Attention Indicator Control (bits[7:6]), or
Electromechanical Interlock Control (bit[11]) fields. Any
other configuration writes to the Slot Control register
without changing the values of these fields will not cause
Command Completed bit to be set.
The PCIe Base Specification Revision 2.0 or later describes
the “Slot Control Register” in section 7.8.10, as follows
(Reference section 7.8.10, Slot Control Register, Offset
18h). In hot-plug capable Downstream Ports, a write to the
Slot Control register must cause a hot-plug command to be
generated (see Section 6.7.3.2 for details on hot-plug
commands). A write to the Slot Control register in a
Downstream Port that is not hotplug capable must not cause a
hot-plug command to be executed.
The PCIe Spec intended that every write to the Slot Control
Register is a command and expected a command complete status
to abstract the VPP implementation specific nuances from the
OS software. IOH PCIe Slot Control Register implementation
is not fully conforming to the PCIe Specification in this
respect.
Implication: Software checking on the Command Completed status after
writing to the Slot Control register may time out.
Workaround: Software can read the Slot Control register and compare the
existing and new values to determine if it should check the
Command Completed status after writing to the Slot Control
register.
Per Sinan, the Qualcomm QDF2400 controller also does not set the Command
Completed bit unless writes to the Slot Command register change "Control"
bits.
Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html
Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de
Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60
Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60
Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
* pci/spdx:
PCI: Add SPDX GPL-2.0+ to replace implicit GPL v2 or later statement
PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate
PCI: Add SPDX GPL-2.0 to replace COPYING boilerplate
PCI: Add SPDX GPL-2.0 to replace GPL v2 boilerplate
PCI: Add SPDX GPL-2.0 when no license was specified
* pci/misc:
PCI: Add dummy pci_irqd_intx_xlate() for CONFIG_PCI=n build
PCI: Add wrappers for dev_printk()
PCI: Remove unnecessary messages for memory allocation failures
PCI: Add #defines for Completion Timeout Disable feature
hinic: Replace PCI pool old API
net: e100: Replace PCI pool old API
block: DAC960: Replace PCI pool old API
MAINTAINERS: Include more PCI files
PCI: Remove unneeded kallsyms include
powerpc/pci: Unroll two pass loop when scanning bridges
powerpc/pci: Use for_each_pci_bridge() helper
Add SPDX GPL-2.0+ to all PCI files that specified the GPL and allowed
either GPL version 2 or any later version.
Remove the boilerplate GPL version 2 or later language, relying on the
assertion in b24413180f ("License cleanup: add SPDX GPL-2.0 license
identifier to files with no license") that the SPDX identifier may be used
instead of the full boilerplate text.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Certain Thunderbolt 1 controllers claim to support Command Completed events
(value of 0b in the No Command Completed Support field of the Slot
Capabilities register) but in reality they neither set the Command
Completed bit in the Slot Status register nor signal a Command Completed
interrupt:
8086:1513 CV82524 [Light Ridge 4C 2010]
8086:151a DSL2310 [Eagle Ridge 2C 2011]
8086:151b CVL2510 [Light Peak 2C 2010]
8086:1547 DSL3510 [Cactus Ridge 4C 2012]
8086:1548 DSL3310 [Cactus Ridge 2C 2012]
8086:1549 DSL2210 [Port Ridge 1C 2011]
All known newer chips (Redwood Ridge and onwards) set No Command Completed
Support, indicating that they do not support Command Completed events.
The user-visible impact is that after unplugging such a device, 2 seconds
elapse until pciehp is unbound. That's because on ->remove,
pcie_write_cmd() is called via pcie_disable_notification() and every call
to pcie_write_cmd() takes 2 seconds (1 second for each invocation of
pcie_wait_cmd()):
[ 337.942727] pciehp 0000:0a:00.0:pcie204: Timeout on hotplug command 0x1038 (issued 21176 msec ago)
[ 340.014735] pciehp 0000:0a:00.0:pcie204: Timeout on hotplug command 0x0000 (issued 2072 msec ago)
That by itself has always been unpleasant, but the situation has become
worse with commit cc27b735ad ("PCI/portdrv: Turn off PCIe services during
shutdown"): Now pciehp is unbound on ->shutdown. Because Thunderbolt
controllers typically have 4 hotplug ports, every reboot and shutdown is
now delayed by 8 seconds, plus another 2 seconds for every attached
Thunderbolt 1 device.
Thunderbolt hotplug slots are not physical slots that one inserts cards
into, but rather logical hotplug slots implemented in silicon. Devices
appear beyond those logical slots once a PCI tunnel is established on top
of the Thunderbolt Converged I/O switch. One would expect commands written
to the Slot Control register to be executed immediately by the silicon, so
for simplicity we always assume NoCompl+ for Thunderbolt ports.
Fixes: cc27b735ad ("PCI/portdrv: Turn off PCIe services during shutdown")
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: stable@vger.kernel.org # v4.12+
Cc: Sinan Kaya <okaya@codeaurora.org>
Cc: Yehezkel Bernat <yehezkel.bernat@intel.com>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: Andreas Noever <andreas.noever@gmail.com>
Per ebfdc40969 ("checkpatch: attempt to find unnecessary 'out of memory'
messages"), when a memory allocation fails, the memory subsystem emits
generic "out of memory" messages (see slab_out_of_memory() for some of this
logging). Therefore, additional error messages in the caller don't add
much value.
Remove messages that merely report "out of memory".
This preserves some messages that report additional information, e.g.,
allocation failures that mean we drop hotplug events.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
[bhelgaas: changelog, squash patches, make similar changes to acpiphp,
cpqphp, ibmphp, keep warning when dropping hotplug event]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
It is possible that the hotplug event has already happened before the
driver is attached to a PCIe hotplug downstream port. If we just clear the
status we never get the hotplug interrupt and thus the event will be
missed.
To make sure that does not happen, we leave Presence Detect Changed bit
untouched during initialization. Then once the event is unmasked we get an
interrupt and handle the hotplug event properly.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
A surprise link down may retrain very quickly causing the same slot
generate a link up event before handling the link down event completes.
Since the link is active, the power off work queued from the first link
down will cause a second down event when power is disabled. However, the
link up event sets the slot state to POWERON_STATE before the event to
handle this is enqueued, making the second down event believe it needs to
do something.
This creates constant link up and down event cycle.
To prevent this it is better to handle each event at the time in order it
occurred, so change the driver to use ordered workqueue instead.
A normal device hotplug triggers two events (presense detect and link up)
that are already handled properly in the driver but we currently log an
error if we find an existing device in the slot. Since this is not an error
change the log level to be debug instead to avoid scaring users.
This is based on the original work by Ashok Raj.
Link: https://patchwork.kernel.org/patch/9469023
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly. This fixes what appears to be a bug
in passing the wrong pointer to the timer handler (address of ctrl pointer
instead of ctrl pointer).
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
When a power fault occurs, the power controller sets Power Fault Detected
in the Slot Status register, and pciehp_isr() queues an INT_POWER_FAULT
event to handle it.
It also clears Power Fault Detected, but since nothing has yet changed to
correct the power fault, the power controller will likely set it again
immediately, which may cause an infinite loop when pcie_isr() rechecks
Slot Status.
Fix that by masking off Power Fault Detected from new events if the driver
hasn't seen the power fault clear from the previous handling attempt.
Fixes: fad214b0aa ("PCI: pciehp: Process all hotplug events before looking for new ones")
Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: changelog, pull test out and add comment]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: stable@vger.kernel.org # 4.9+
If Slot Status indicates changes in both Data Link Layer Status and
Presence Detect, prioritize the Link status change.
When both events are observed, pciehp currently relies on the Slot Status
Presence Detect State (PDS) to agree with the Link Status Data Link Layer
Active status. The Presence Detect State, however, may be set to 1 through
out-of-band presence detect even if the link is down, which creates
conflicting events.
Since the Link Status accurately reflects the reachability of the
downstream bus, the Link Status event should take precedence over a
Presence Detect event. Skip checking the PDC status if we handled a link
event in the same handler.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
PCIe hotplug supports optional Attention and Power Indicators, which are
used internally by pciehp. Users can't control the Power Indicator, but
they can control the Attention Indicator by writing to a sysfs "attention"
file.
The Slot Control register has two bits for each indicator, and the PCIe
spec defines the encodings for each as (Reserved/On/Blinking/Off). For
sysfs "attention" writes, pciehp_set_attention_status() maps into these
encodings, so the only useful write values are 0 (Off), 1 (On), and 2
(Blinking).
However, some platforms use all four bits for platform-specific indicators,
and they need to allow direct user control of them while preventing pciehp
from using them at all.
Add a "hotplug_user_indicators" flag to the pci_dev structure. When set,
pciehp does not use either the Attention Indicator or the Power Indicator,
and the low four bits (values 0x0 - 0xf) of sysfs "attention" write values
are written directly to the Attention Indicator Control and Power Indicator
Control fields.
[bhelgaas: changelog, rename flag and accessors to s/attention/indicator/]
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Print slot name consistently as "Slot(%s)". I don't know whether that's
ideal, but we can at least do it the same way all the time. No functional
change intended.
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
In pcie_isr(), we return early if no status bits other than
PCI_EXP_SLTSTA_CC are set. This was introduced by dbd79aed1a ("pciehp:
fix NULL dereference in interrupt handler"), but it is no longer necessary
because all the subsequent pcie_isr() code is already predicated on a
status bit being set.
Remove the unnecessary test for ~PCI_EXP_SLTSTA_CC. No functional change
intended.
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Previously we read Slot Status to learn about hotplug events, then cleared
the events, then re-read Slot Status to find out what happened. But Slot
Status might have changed before the second read.
Capture the Slot Status once before clearing the events. Also capture the
Link Status if we had a link status change.
[bhelgaas: changelog, split to separate patch]
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mayurkumar Patel <mayurkumar.patel@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Previously we accumulated hotplug events, then processed them, essentially
like this:
events = 0
do {
status = read(Slot Status)
status &= EVENT_MASK # only look at events
events |= status # accumulate events
write(Slot Status, events) # clear events
} while (status)
process events
The problem is that as soon as we clear events in Slot Status, the hardware
may send notifications for new events, and we lose information about the
first events. For example, we might see two Presence Detect Changed
events, but lose the fact that the slot was temporarily empty:
read PCI_EXP_SLTSTA_PDC set, PCI_EXP_SLTSTA_PDS clear # slot empty
write PCI_EXP_SLTSTA_PDC # clear PDC event
read PCI_EXP_SLTSTA_PDC set, PCI_EXP_SLTSTA_PDS set # slot occupied
The current code does not process a removal; it only processes the
insertion, which fails because we didn't remove the original device.
To avoid this problem, read Slot Status once and process all the events
before reading it again, like this:
do {
read events
clear events
process events
} while (events)
[bhelgaas: changelog, add external loop around pciehp_isr()]
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mayurkumar Patel <mayurkumar.patel@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
After 1469d17dd3 ("PCI: pciehp: Handle invalid data when reading from
non-existent devices"), we returned IRQ_HANDLED when we failed to read
interrupt status from the bridge. I think it's better to return IRQ_NONE,
as we do in other cases where there's no interrupt pending. This will
facilitate refactoring the loop in pcie_isr(): we'll be able to call the
ISR in a loop as long as it returns IRQ_HANDLED.
Return IRQ_NONE if we couldn't read interrupt status.
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Rename "detected" and "intr_loc" to "status" and "events" for clarity.
"status" is the value we read from the Slot Status register; "events" is
the set of hot-plug events we need to process. No functional change
intended.
Tested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
If a hotplug port is suspended to D3cold, its slot status register cannot
be read. If that hotplug port happens to share its IRQ with other devices,
whenever an interrupt occurs for one of these devices, pciehp logs a
"no response from device" message and tries to read the PCI_EXP_SLTSTA
register, even though we know that will fail.
Ignore interrupts while we're in D3cold.
[bhelgaas: changelog]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
We queued interrupt events for the MRL being opened or closed, but the code
in interrupt_event_handler() that handles these events ignored them.
Stop enabling MRL interrupts and remove the ignored events.
Signed-off-by: Bjorn 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=99841
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Move first slot status read into while to simplify code.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rajat Jain <rajatja@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
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: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rajat Jain <rajatja@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
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: 3461a06866 ("PCI: pciehp: Wait for hotplug command completion lazily")
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v3.17+
During pciehp initialization, we previously wrote two hotplug commands:
pciehp_probe
pcie_init
pcie_disable_notification
pcie_write_cmd # command 1
pcie_init_notification
pcie_enable_notification
pcie_write_cmd # command 2
For controllers with errata like Intel CF118, we previously waited for a
timeout before issuing the second hotplug command because the first command
only updates interrupt enable bits and is not a "real" hotplug command, so
the controller doesn't report Command Completed for it.
But there's no need to disable notifications in the first place. If BIOS
left them enabled, we could easily take an interrupt before disabling them,
so there's no benefit in disabling them for the tiny window before we
enable them.
Drop the unnecessary pcie_disable_notification() call.
[bhelgaas: changelog]
Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Add more Slot Control debug output and move one print after
pcie_write_cmd() to be consistent with other debug output.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When we warned about a timeout on a hotplug command, we previously printed
the time between calls to pcie_write_cmd(), without accounting for any time
spent actually waiting. Consider this sequence:
pcie_write_cmd
write SLTCTL
cmd_started = jiffies # T1
pcie_write_cmd
pcie_wait_cmd
now = jiffies # T2
wait_event_timeout # we may wait here
if (timeout)
ctrl_info("Timeout on command issued %u msec ago",
jiffies_to_msecs(now - cmd_started))
We previously printed (T2 - T1), but that doesn't include the time spent in
wait_event_timeout().
Fix this by using the current jiffies value, not the one cached before
calling wait_event_timeout().
[bhelgaas: changelog, use current jiffies instead of adding timeout]
Fixes: 40b960831c ("PCI: pciehp: Compute timeout from hotplug command start time")
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
pcie_poll_cmd() take msecs instead of jiffies, so convert timeout to msecs.
Fixes: 40b960831c ("PCI: pciehp: Compute timeout from hotplug command start time")
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
4283c70e91 ("PCI: pciehp: Make pcie_wait_cmd() self-contained") added
a cache of the most recent command written to the Slot Control register.
This register is only 16 bits wide, but the cache ("slot_ctrl") is 32 bits.
Reduce slot_ctrl to a u16 so it matches the register size. No functional
change.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Powering off a hot-pluggable device, e.g., with pci_set_power_state(D3cold),
normally generates a hot-remove event that unbinds the driver.
Some drivers expect to remain bound to a device even while they power it
off and back on again. This can be dangerous, because if the device is
removed or replaced while it is powered off, the driver doesn't know that
anything changed. But some drivers accept that risk.
Add pci_ignore_hotplug() for use by drivers that know their device cannot
be removed. Using pci_ignore_hotplug() tells the PCI core that hot-plug
events for the device should be ignored.
The radeon and nouveau drivers use this to switch between a low-power,
integrated GPU and a higher-power, higher-performance discrete GPU. They
power off the unused GPU, but they want to remain bound to it.
This is a reimplementation of f244d8b623 ("ACPIPHP / radeon / nouveau:
Fix VGA switcheroo problem related to hotplug") but extends it to work with
both acpiphp and pciehp.
This fixes a problem where systems with dual GPUs using the radeon drivers
become unusable, freezing every few seconds (see bugzillas below). The
resume of the radeon device may also fail, e.g.,
This fixes problems on dual GPU systems where the radeon driver becomes
unusable because of problems while suspending the device, as in bug 79701:
[drm] radeon: finishing device.
radeon 0000:01:00.0: Userspace still has active objects !
radeon 0000:01:00.0: ffff8800cb4ec288 ffff8800cb4ec000 16384 4294967297 force free
...
WARNING: CPU: 0 PID: 67 at /home/apw/COD/linux/drivers/gpu/drm/radeon/radeon_gart.c:234 radeon_gart_unbind+0xd2/0xe0 [radeon]()
trying to unbind memory from uninitialized GART !
or while resuming it, as in bug 77261:
radeon 0000:01:00.0: ring 0 stalled for more than 10158msec
radeon 0000:01:00.0: GPU lockup ...
radeon 0000:01:00.0: GPU pci config reset
pciehp 0000:00:01.0:pcie04: Card not present on Slot(1-1)
radeon 0000:01:00.0: GPU reset succeeded, trying to resume
*ERROR* radeon: dpm resume failed
radeon 0000:01:00.0: Wait for MC idle timedout !
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77261
Link: https://bugzilla.kernel.org/show_bug.cgi?id=79701
Reported-by: Shawn Starr <shawn.starr@rogers.com>
Reported-by: Jose P. <lbdkmjdf@sharklasers.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Rajat Jain <rajatxjain@gmail.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Dave Airlie <airlied@redhat.com>
CC: stable@vger.kernel.org # v3.15+
During PCIe hot-plug initialization - pciehp_probe() - data structures
related to slot capabilities are set up. As part of this set up, ISRs are
put in place to handle slot events and all event bits are cleared out.
This patch adds the Data Link Layer State Changed (PCI_EXP_SLTSTA_DLLSC)
Slot Status bit to the event bits that are cleared out during
initialization.
If the BIOS doesn't clear DLLSC before handoff to the OS, pciehp notices
that it's set and interprets it as a new Link Up event, which results in
spurious messages:
pciehp 0000:82:04.0:pcie24: slot(4): Link Up event
pciehp 0000:82:04.0:pcie24: Device 0000:83:00.0 already exists at 0000:83:00, cannot hot-add
pciehp 0000:82:04.0:pcie24: Cannot add device at 0000:83:00
Prior to e48f1b67f6 ("PCI: pciehp: Use link change notifications for
hot-plug and removal"), pciehp ignored DLLSC.
Reference:
PCI-SIG. PCI Express Base Specification Revision 4.0 Version 0.3
(PCI-SIG, 2014): 7.8.11. Slot Status Register (Offset 1Ah).
[bhelgaas: add e48f1b67f6 ref and stable tag]
Fixes: e48f1b67f6 ("PCI: pciehp: Use link change notifications for hot-plug and removal")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=79611
Signed-off-by: Myron Stowe <myron.stowe@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org # v3.15+
"no_cmd_complete" is only used once, and it duplicates read-only
information we already have in the cached Slot Capabilities value.
Remove the field and use the existing macro NO_CMD_CMPL() instead.
[bhelgaas: changelog]
Signed-off-by: Rajat Jain <rajatxjain@gmail.com>
Signed-off-by: Rajat Jain <rajatjain@juniper.net>
Signed-off-by: Guenter Roeck <groeck@juniper.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
We use incorrect logic to decide whether a PCIe hotplug controller
generates command completion events.
5808639bfa ("pciehp: fix slow probing") assumed that the Slot Status
"Command Completed" bit was set only for commands affecting slot power,
indicators, or electromechanical interlock. That assumption is false: per
sec. 6.7.3.2 of PCIe spec r3.0, a write targeting any portion of the Slot
Control register is a command, and (if command completed events are
supported) software must wait for a command to complete before issuing the
next command.
5808639bfa was to fix boot-time timeouts (see bugzilla below) on a Lenovo
Thinkpad R61 with an Intel hotplug controller. The controller probably has
the Intel CF118 erratum, which means it doesn't report Command Completed
unless the Slot Control power, indicator, or interlock bits are changed.
This causes a timeout because pciehp always waits for Command Complete (if
supported), regardless of which bits are changed.
Remove the incorrect logic because the timeouts have been addressed
differently by these changes:
PCI: pciehp: Wait for hotplug command completion lazily
PCI: pciehp: Compute timeout from hotplug command start time
Link: https://bugzilla.kernel.org/show_bug.cgi?id=10751
Tested-by: Rajat Jain <rajatxjain@gmail.com> (IDT 807a controller)
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
If we issue a hotplug command, go do something else, then come back and
wait for the command to complete, we don't have to wait the whole timeout
period, because some of it elapsed while we were doing something else.
Keep track of the time we issued the command, and wait only until the
timeout period from that point has elapsed.
For controllers with errata like Intel CF118, we previously timed out
before issuing the second hotplug command:
At time T1 (during boot):
- Write DLLSCE, ABPE, PDCE, etc. to Slot Control
At time T2 (hotplug event):
- Wait for command completion (CC) in Slot Status
- Timeout at T2 + 1 second because CC is never set in Slot Status
- Write PCC, PIC, etc. to Slot Control
With this change, we wait until T1 + 1 second instead of T2 + 1 second.
If the hotplug event is more than 1 second after the boot-time
initialization, we won't wait for the timeout at all.
We still emit a "Timeout on hotplug command" message if it timed out; we
should see this on the first hotplug event on every controller with this
erratum, as well as on real errors on controllers without the erratum.
Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html
Tested-by: Rajat Jain <rajatxjain@gmail.com> (IDT 807a controller)
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Previously we issued a hotplug command and waited for it to complete. But
there's no need to wait until we're ready to issue the *next* command. The
next command will probably be much later, so the first one may have already
completed and we may not have to actually wait at all.
Because of hardware errata, some controllers generate command completion
events for some commands but not others. In the case of Intel CF118 (see
spec update reference), the controller indicates command completion only
for Slot Control writes that change the value of the following bits:
Power Controller Control
Power Indicator Control
Attention Indicator Control
Electromechanical Interlock Control
Changes to other bits, e.g., the interrupt enable bits, do not cause the
Command Completed bit to be set. Controllers from AMD and Nvidia are
reported to have similar errata.
These errata cause timeouts when pcie_enable_notification() enables
interrupts. Previously that timeout occurred at boot-time. With this
change, the timeout occurs later, when we change the state of the slot
power, indicators, or interlock. This speeds up boot but causes a timeout
at the first hotplug event on the slot. Subsequent events don't timeout
because only the first (boot-time) hotplug command updates Slot Control
without touching the power/indicator/interlock controls.
Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html
Tested-by: Rajat Jain <rajatxjain@gmail.com> (IDT 807a controller)
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
pcie_wait_cmd() waits for the controller to finish a hotplug command. Move
the associated logic (to determine whether waiting is required and whether
we're using interrupts or polling) from pcie_write_cmd() to
pcie_wait_cmd().
No functional change.
Tested-by: Rajat Jain <rajatxjain@gmail.com> (IDT 807a controller)
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
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: Ryan Desfosses <ryan@desfo.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Fix various whitespace errors.
No functional change.
[bhelgaas: fix other similar problems]
Signed-off-by: Ryan Desfosses <ryan@desfo.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
In case of a spurious "cmd completed", pcie_write_cmd() does not clear it,
but yet expects more "cmd completed" events to be generated. This does not
happen because the previous (spurious) event has not been acknowledged.
Fix that.
Signed-off-by: Rajat Jain <rajatxjain@gmail.com>
Signed-off-by: Rajat Jain <rajatjain@juniper.net>
Signed-off-by: Guenter Roeck <groeck@juniper.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
