Per Mika's request, add an explicit break to the last case of switch
statements everywhere in pciehp to be more defensive towards future
amendments.
Per Gustavo's request, mark all non-empty implicit fallthroughs with a
comment to silence warnings triggered by -Wimplicit-fallthrough=2.
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>
Acked-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
pciehp's IRQ thread ensures accessibility of the port by runtime resuming
its parent to D0. However when the slot is enabled/disabled, the port
itself needs to be in D0 because its secondary bus is accessed in:
pciehp_check_link_status(),
pciehp_configure_device() (both called from board_added())
and
pciehp_unconfigure_device() (called from remove_board()).
Thus, acquire a runtime PM ref on enable/disablement of the slot.
Yinghai Lu additionally discovered that some SkyLake servers feature a
Power Controller for their PCIe hotplug ports (PCIe r3.1, sec 6.7.1.8)
which requires the port to be in D0 when invoking
pciehp_power_on_slot() (likewise called from board_added()).
If slot power is turned on while in D3hot, link training later fails:
https://lkml.kernel.org/r/20170205073454.GA253@wunner.de
The spec is silent about such a requirement, but it seems prudent to
assume that any hotplug port with a Power Controller may need this.
The present commit holds a runtime PM ref whenever slot power is turned
on and off, but it doesn't keep the port in D0 as long as slot power is
on. If vendors determine that's necessary, they need to amend pciehp to
acquire a runtime PM ref in pciehp_power_on_slot() and release one in
pciehp_power_off_slot().
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
A hotplug port's Slot Status register does not count how often each type
of event occurred, it only records the fact *that* an event has occurred.
Previously pciehp queued a work item for each event. But if it missed
an event, e.g. removal of a card in-between two back-to-back insertions,
it queued up the wrong work item or no work item at all. Commit
fad214b0aa ("PCI: pciehp: Process all hotplug events before looking
for new ones") sought to improve the situation by shrinking the window
during which events may be missed.
But Stefan Roese reports unbalanced Card present and Link Up events,
suggesting that we're still missing events if they occur very rapidly.
Bjorn Helgaas responds that he considers pciehp's event handling
"baroque" and calls for its simplification and rationalization:
https://lkml.kernel.org/r/20180202192045.GA53759@bhelgaas-glaptop.roam.corp.google.com
It gets worse once a hotplug port is runtime suspended: The port can
signal an interrupt while it and its parents are in D3hot, i.e. while
it is inaccessible. By the time we've runtime resumed all parents to D0
and read the port's Slot Status register, we may have missed an arbitrary
number of events. Event handling therefore needs to be reworked to
become resilient to missed events.
Assume that a Presence Detect Changed event has occurred.
Consider the following truth table:
- Slot is in OFF_STATE and is currently empty. => Do nothing.
(The event is trailing a Link Down or we've
missed an insertion and subsequent removal.)
- Slot is in OFF_STATE and is currently occupied. => Turn the slot on.
- Slot is in ON_STATE and is currently empty. => Turn the slot off.
- Slot is in ON_STATE and is currently occupied. => Turn the slot off,
(Be cautious and assume the card in then back on.
the slot isn't the same as before.)
This leads to the following simple algorithm:
1 If the slot is in ON_STATE, turn it off unconditionally.
2 If the slot is currently occupied, turn it on.
Because those actions are now carried out synchronously, rather than by
scheduled work items, pciehp reacts to the *current* situation and
missed events no longer matter.
Data Link Layer State Changed events can be handled identically to
Presence Detect Changed events. Note that in the above truth table,
a Link Up trailing a Card present event didn't have to be accounted for:
It is filtered out by pciehp_check_link_status().
As for Attention Button Pressed events, PCIe r4.0, sec 6.7.1.5 says:
"Once the Power Indicator begins blinking, a 5-second abort interval
exists during which a second depression of the Attention Button cancels
the operation." In other words, the user can only expect the system to
react to a button press after it starts blinking. Missed button presses
that occur in-between are irrelevant.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stefan Roese <sr@denx.de>
Cc: Mayurkumar Patel <mayurkumar.patel@intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
No callers of pciehp_enable/disable_slot() outside of pciehp_ctrl.c
remain, so declare the functions static. For now this requires forward
declarations. Those can be eliminated by reshuffling functions once the
ongoing effort to refactor the driver has settled.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Previously slot enablement and disablement could happen concurrently.
But now it's under the exclusive control of the IRQ thread, rendering
the locking obsolete. Drop it.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Besides the IRQ thread, there are several other places in the driver
which enable or disable the slot:
- pciehp_probe() enables the slot if it's occupied and the pciehp_force
module parameter is used.
- pciehp_resume() enables or disables the slot after system sleep.
- pciehp_queue_pushbutton_work() enables or disables the slot after the
5 second delay following an Attention Button press.
- pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or
disable the slot on sysfs write.
This requires locking and complicates pciehp's state machine.
A simplification can be achieved by enabling and disabling the slot
exclusively from the IRQ thread.
Amend the functions listed above to request slot enable/disablement from
the IRQ thread by either synthesizing a Presence Detect Changed event or,
in the case of a disable user request (via sysfs or an Attention Button
press), submitting a newly introduced force disable request. The latter
is needed because the slot shall be forced off despite being occupied.
For this force disable request, avoid colliding with Slot Status register
bits by using a bit number greater than 16.
For synchronous execution of requests (on sysfs write), wait for the
request to finish and retrieve the result. There can only ever be one
sysfs write in flight due to the locking in kernfs_fop_write(), hence
there is no risk of returning the result of a different sysfs request to
user space.
The POWERON_STATE and POWEROFF_STATE is now no longer entered by the
above-listed functions, but solely by the IRQ thread when it begins a
power transition. Afterwards, it moves to STATIC_STATE. The same
applies to canceling the Attention Button work, it likewise becomes an
IRQ thread only operation.
An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is
never observed by the IRQ thread itself, only by functions called in a
different context, such as pciehp_sysfs_enable_slot(). So remove
handling of these states from pciehp_handle_button_press() and
pciehp_handle_link_change() which are exclusively called from the IRQ
thread.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
handle_button_press_event() currently determines whether the slot has
been turned on or off by looking at the Power Controller Control bit in
the Slot Control register. This assumes that an attention button
implies presence of a power controller even though that's not mandated
by the spec. Moreover the Power Controller Control bit is unreliable
when a power fault occurs (PCIe r4.0, sec 6.7.1.8). This issue has
existed since the driver was introduced in 2004.
Fix by replacing STATIC_STATE with ON_STATE and OFF_STATE and tracking
whether the slot has been turned on or off. This is also a required
ingredient to make pciehp resilient to missed events, which is the
object of an upcoming commit.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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>
If the attention button is pressed to power on the slot AND the user
powers on the slot via sysfs before 5 seconds have elapsed AND powering
on the slot fails because either the slot is unoccupied OR the latch is
open, we neglect turning off the green LED so it keeps on blinking.
That's because the error path of pciehp_sysfs_enable_slot() doesn't call
pciehp_green_led_off(), unlike pciehp_power_thread() which does.
The bug has been present since 2004 when the driver was introduced.
Fix by deduplicating common code in pciehp_sysfs_enable_slot() and
pciehp_power_thread() into a wrapper function pciehp_enable_slot() and
renaming the existing function to __pciehp_enable_slot(). Same for
pciehp_disable_slot(). This will also simplify the upcoming rework of
pciehp's event handling.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Since commit 0f4bd8014d ("PCI: hotplug: Drop checking of PCI_BRIDGE_
CONTROL in *_unconfigure_device()"), pciehp_unconfigure_device() can no
longer fail, so declare it and its sole caller remove_board() void, in
keeping with the usual kernel pattern that enablement can fail, but
disablement cannot. No functional change intended.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
pciehp_disable_slot() checks if the ctrl attribute of the slot is NULL
and bails out if so. However the function is not called prior to the
attribute being set in pcie_init_slot(), and pcie_init_slot() is not
called if ctrl is NULL. So the check is unnecessary. Drop it.
It has been present ever since the driver was introduced in 2004, but it
was already unnecessary back then:
https://git.kernel.org/tglx/history/c/c16b4b14d980
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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>
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>
* pci/pm:
x86/platform/intel-mid: Constify mid_pci_platform_pm
PCI: pciehp: Add runtime PM support for PCIe hotplug ports
ACPI / hotplug / PCI: Make device_is_managed_by_native_pciehp() public
ACPI / hotplug / PCI: Use cached copy of PCI_EXP_SLTCAP_HPC bit
PCI: Unfold conditions to block runtime PM on PCIe ports
PCI: Consolidate conditions to allow runtime PM on PCIe ports
PCI: Activate runtime PM on a PCIe port only if it can suspend
PCI: Speed up algorithm in pci_bridge_d3_update()
PCI: Autosense device removal in pci_bridge_d3_update()
PCI: Don't acquire ref on parent in pci_bridge_d3_update()
USB: UHCI: report non-PME wakeup signalling for Intel hardware
PCI: Check for PME in targeted sleep state
If an error occurs when enabling a slot, pciehp_power_thread() turns off
the power indicator. But if the only error is that the slot was already
enabled, we should leave the power indicator on.
Return success if called to enable an already-enabled slot.
This is in the same spirit of the special handling for EEXISTS when
pciehp_configure_device() determines the slot devices already exist.
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>
Linux 4.8 added support for runtime suspending PCIe ports to D3hot with
commit 006d44e49a ("PCI: Add runtime PM support for PCIe ports"), but
excluded hotplug ports. Those are now afforded runtime PM by the present
commit.
Hotplug ports require a few extra considerations:
- The configuration space of the port remains accessible in D3hot, so all
the functions to read or modify the Slot Status and Slot Control
registers need not be modified. Even turning on slot power doesn't seem
to require the port to be in D0, at least the PCIe spec doesn't say so
and I confirmed that by testing with a Thunderbolt controller.
- However D0 is required to access devices on the secondary bus. This
happens in pciehp_check_link_status() and pciehp_configure_device() (both
called from board_added()) and in pciehp_unconfigure_device() (called
from remove_board()), so acquire a runtime PM ref for their invocation.
- The hotplug port stays active as long as it has active children. If all
hotplugged devices below the port runtime suspend, the port is allowed to
runtime suspend as well. Plug and unplug detection continues to work in
D3hot.
- Hotplug interrupts are delivered in-band, so while the hotplug port
itself is allowed to go to D3hot, its parent ports must stay in D0 for
interrupts to come through. Add a corresponding restriction to
pci_dev_check_d3cold().
- Runtime PM may only be allowed if the hotplug port is handled natively by
the OS. On ACPI systems, the port may alternatively be handled by the
firmware and things break if the OS puts the port into D3 behind the
firmware's back: E.g. Thunderbolt hotplug ports on non-Macs are handled
by Intel's firmware in System Management Mode and the firmware is known
to access devices on the port's secondary bus without checking first if
the port is in D0: https://bugzilla.kernel.org/show_bug.cgi?id=53811
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: Mika Westerberg <mika.westerberg@linux.intel.com>
Long ago, we updated a "switch_save" field based on the latch status. But
switch_save was unused, and ed6cbcf2ac ("[PATCH] pciehp: miscellaneous
cleanups") removed it.
We no longer use the latch status, so remove calls to
pciehp_get_latch_status(). 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>
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>
Previously we read Slot Status when handling a surprise event. But Slot
Status might have changed since we identified the event, and the event_type
already tells us whether to enable or disable the slot, so there's no need
to read it again.
Remove handle_surprise_event() and queue the power work directly.
[bhelgaas: changelog]
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>
Acked-by: Rajat Jain <rajatxjain@gmail.com>
Clear the LED attention status after a successful device add. It is
possible the attention LED was on from a previous power fault or link
failure, and a subsequent successful device insert insertion should clear
it.
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When called from pciehp_sysfs_disable_slot(), the call to
pciehp_disable_slot() was not protected by the hotplug mutex.
Hold slot->hotplug_lock while calling pciehp_disable_slot().
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rajat Jain <rajatxjain@gmail.com>
Up to now, work items to be queued to be handled by pciehp_power_thread()
are allocated using kmalloc() in three different locations. If not needed,
kfree() is called to free the allocated data.
Introduce a separate function to allocate the work item and queue it, and
call it only if needed. This reduces code duplication and avoids having to
free memory if the work item does not need to get executed.
[bhelgaas: tweak "no memory" message, make pciehp_queue_power_work() static]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
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>
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: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rajat Jain <rajatja@google.com>
Acked-by: Yinghai 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: 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 PCIe spec (r3.0, sec 7.8.9) says Hot-Plug Surprise indicates support
for surprise *removal*, but pciehp checked this to determine if it should
handle presence detect interrupts for device *addition*.
Allow surprise device addition even if the slot doesn't advertise support
for surprise removal.
Keith has a platform with slots for front-loading SFF devices. The slots
do not have attention buttons and do not support surprise removal, but they
do have presence detect. In that case, we still want to use presence
detect for device addition.
Keith's original patch handled surprise insertions only if Hot-Plug Capable
is set. I think that test is superfluous because pciehp only claims slots
that advertise Hot-Plug Capable (see get_port_device_capability()).
Link: http://lkml.kernel.org/r/1419275223-14602-1-git-send-email-keith.busch@intel.com
Based-on-patch-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rajat Jain <rajatxjain@gmail.com>
Merge quoted strings that are broken across lines into a single entity.
The compiler merges them anyway, but checkpatch complains about it, and
merging them makes it easier to grep for strings.
No functional change.
[bhelgaas: changelog, do the same for everything under drivers/pci]
Signed-off-by: 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 a card is physically yanked out, it should immediately be removed,
regardless of the "surprise" capability bit. Thus:
- Always handle the physical removal - regardless of the "surprise" bit.
- Don't use "surprise" capability when making decisions about enabling
presence detect notifications.
- Reword the comments to indicate the intent.
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>
If we found device already exists during hot add device, we should leave
it, not turn the slot off.
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Today it is there is no protection around pciehp_enable_slot() and
pciehp_disable_slot() to ensure that they complete before another
hot-plug operation can be done on that particular slot.
This patch introduces the slot->hotplug_lock to ensure that any hotplug
operations (add / remove) complete before another hotplug event can begin
processing on that particular slot.
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>
Today, this is how all the hotplug and unplug events work:
Hotplug / Removal needs to be done
=> Set slot->state (protected by slot->lock) to either
POWERON_STATE (for enabling) or POWEROFF_STATE (for disabling).
=> Submit the work item for pciehp_power_thread() to slot->wq.
Problem:
There is a problem if the hotplug events can happen fast enough that
they do not give SW enough time to add or remove the new devices.
=> Assume: Event for unplug comes (e.g. surprise removal). But
before the pciehp_power_thread() work item was executed, the
card was replaced by another card, causing surprise hotplug event.
=> What goes wrong:
=> The hot-removal event sets slot->state to POWEROFF_STATE, and
schedules the pciehp_power_thread().
=> The hot-add event sets slot->state to POWERON_STATE, and
schedules the pciehp_power_thread().
=> Now the pciehp_power_thread() is scheduled twice, and on both
occasions it will find POWERON_STATE and will try to add the
devices on the slot, and will fail complaining that the devices
already exist.
=> Why this is a problem: If the device was replaced between the hot
removal and hot-add, then we should unload the old driver and
reload the new one. This does not happen today. The kernel or the
driver is not even aware that the device was replaced.
The problem is that the pciehp_power_thread() only looks at the
slot->state which would only contain the *latest* state - not
the actual event (add / remove) that was the intent of the IRQ
handler who submitted the work.
What this patch does:
=> Hotplug events pass on an actual request (for addition or removal)
to pciehp_power_thread() which is local to that work item
submission.
=> pciehp_power_thread() does not need to look at slote->state and
hence no locks needed in that.
=> Essentially this results in all the hotplug and unplug events
"replayed" by pciehp_power_thread().
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>
It does not make much sense to refuse to disable a slot if an adapter is
not present or the latch is open. If an adapter is not present, it provides
an even better reason to disable the device slot.
This is specially a problem for link state hot-plug, because some ports use
in band mechanism for presence detection. Thus when link goes down,
presence detect also goes down. We _want_ that the removal should take
place in such case.
Thus remove the checks for adapter and latch in pciehp_disable_slot()
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>
A lot of systems do not have the fancy buttons and LEDs, and instead
want to rely only on the Link state change events to drive the hotplug
and removal state machinery.
(http://www.spinics.net/lists/hotplug/msg05802.html)
This patch adds support for that functionality. Here are the details
about the patch itself:
* Define and use interrupt events for linkup / linkdown.
* Make the pcie_isr() also look at link events, and direct control to
corresponding (new) link state change handler function.
* Introduce the functions to handle link-up and link-down events and
queue the add / removal work in the slot->wq to be processed by
pciehp_power_thread()
As a side note, this patch also fixes the bug
https://bugzilla.kernel.org/show_bug.cgi?id=65521 "pciehp ignores Data Link
Layer State Changed bit."
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>
Previously, the caller checked ATTN_LED() or PWR_LED() to see whether the
slot has indicators before setting the indicator state. That clutters the
caller unnecessarily, so this moves the test inside the callees. The test
may not even be necessary; per spec it should be harmless to try to turn on
a non-existent LED. But checking first does avoid unnecessary hotplug
commands.
No functional change.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
These functions:
pcie_enable_notification()
pciehp_power_off_slot()
pciehp_get_power_status()
pciehp_get_attention_status()
pciehp_set_attention_status()
pciehp_get_latch_status()
pciehp_get_adapter_status()
pcie_write_cmd()
now always return success, so this patch makes them void and drops the
error-checking code in their callers.
No functional change.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
When we have a hotplug-capable PCIe port with a second hotplug-capable
PCIe port below it, removing the device below the upstream port causes
a deadlock.
The deadlock happens because we use the pciehp_wq workqueue to run
pciehp_power_thread(), which uses pciehp_disable_slot() to remove devices
below the upstream port. When we remove the downstream PCIe port, we call
pciehp_remove(), the pciehp driver's .remove() method. That calls
flush_workqueue(pciehp_wq), which deadlocks because the
pciehp_power_thread() work item is still running.
This patch avoids the deadlock by creating a workqueue for every PCIe port
and removing the single shared workqueue.
Here's the call path that leads to the deadlock:
pciehp_queue_pushbutton_work
queue_work(pciehp_wq) # queue pciehp_power_thread
...
pciehp_power_thread
pciehp_disable_slot
remove_board
pciehp_unconfigure_device
pci_stop_and_remove_bus_device
...
pciehp_remove # pciehp driver .remove method
pciehp_release_ctrl
pcie_cleanup_slot
flush_workqueue(pciehp_wq)
This is fairly urgent because it can be caused by simply unplugging a
Thunderbolt adapter, as reported by Daniel below.
[bhelgaas: changelog]
Reference: http://lkml.kernel.org/r/CAMVG2ssiRgcTD1bej2tkUUfsWmpL5eNtPcNif9va2-Gzb2u8nQ@mail.gmail.com
Reported-and-tested-by: Daniel J Blueman <daniel@quora.org>
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org
Use non-ordered workqueue for attention button events.
Attention button events on each slot can be handled asynchronously. So
we should use non-ordered workqueue. This patch also removes ordered
workqueue in pciehp as a result.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
We need to wait for 1000 ms after Data Link Layer Link Active (DLLLA)
bit reads 1b before sending configuration request. Currently pciehp
does this wait after checking Link Training (LT) bit. But we need it
before checking LT bit because LT is still set even after DLLLA bit is
set on some platforms.
Acked-by: Yinghai Lu <yinghai@kernel.org>
Tested-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Naoki Yanagimoto reported that configuration read on some hot-added
PCIe device returns invalid value. This patch fixes this problem.
According to the PCIe spec, software must wait for at least 1 second
to judge if the hot-added device is broken after Data Link Layer State
Changed Event. This patch changes pciehp driver to wait for 1 second
after the Data Link Layer State Changed Event is detected before
initiating a configuration access instead of 100 ms.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Naoki Yanagimoto <yanagimoto@np.css.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
* Rename pciehp_wq to pciehp_ordered_wq and add non-ordered pciehp_wq
which is used instead of the system workqueue. This is to remove
the use of flush_scheduled_work() which is deprecated and scheduled
for removal.
* With cmwq in place, there's no point in creating workqueues lazily.
Create both pciehp_wq and pciehp_ordered_wq upfront.
* Include workqueue.h from pciehp.h.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Stanse found a cut&pasted memory leak in pciehp_queue_pushbutton_work
and shpchp_queue_pushbutton_work. info is not freed/assigned on all
paths. Fix that.
Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Enabling power fault detected event notification in current pciehp
might cause power fault interrupt storm on some machines. On those
machines. On those machines, power fault detected bit in the slot
status register was set again immediately when it is cleared in the
interrupt service routine, and next power fault detected interrupt was
notified again. Therefore, disable power fault detected event
notification for now.
This patch also removes unnecessary handling for power fault cleared
event because this event is not supported by PCIe spec.
Tested-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Current pciehp returns successfully on read/write failure with dummy
state values. It should return error instead.
With this patch, pciehp no longer uses hotplug_slot_info data
structure. So this also removes hotplug_slot_info related code. But
note that it still allocates hotplug_slot_info because it is required
by pci hotplug core.
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
