When PCIe hotplug port is transitioned into D3hot, the link to the
downstream component will go down. If hotplug interrupt generation is
enabled when that happens, it will trigger immediately, waking up the
system and bringing the link back up.
To prevent this, disable hotplug interrupt generation when system suspend
is entered. This does not prevent wakeup from low power states according
to PCIe 4.0 spec section 6.7.3.4:
Software enables a hot-plug event to generate a wakeup event by
enabling software notification of the event as described in Section
6.7.3.1. Note that in order for software to disable interrupt generation
while keeping wakeup generation enabled, the Hot-Plug Interrupt Enable
bit must be cleared.
So as long as we have set the slot event mask accordingly, wakeup should
work even if slot interrupt is disabled. The port should trigger wake and
then send PME to the root port when the PCIe hierarchy is brought back up.
Limit this to systems using native PME mechanism to make sure older Apple
systems depending on commit e3354628c376 ("PCI: pciehp: Support interrupts
sent from D3hot") still continue working.
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>
The spec has timing requirements when waiting for a link to become active
after a conventional reset. Implement those hard delays when waiting for
an active link so pciehp and dpc drivers don't need to duplicate this.
For devices that don't support data link layer active reporting, wait the
fixed time recommended by the PCIe spec.
Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
When the PCI hotplug core and its first user, cpqphp, were introduced in
February 2002 with historic commit a8a2069f432c, cpqphp allocated a slot
struct for its internal use plus a hotplug_slot struct to be registered
with the hotplug core and linked the two with pointers:
https://git.kernel.org/tglx/history/c/a8a2069f432c
Nowadays, the predominant pattern in the tree is to embed ("subclass")
such structures in one another and cast to the containing struct with
container_of(). But it wasn't until July 2002 that container_of() was
introduced with historic commit ec4f214232cf:
https://git.kernel.org/tglx/history/c/ec4f214232cf
pnv_php, introduced in 2016, did the right thing and embedded struct
hotplug_slot in its internal struct pnv_php_slot, but all other drivers
cargo-culted cpqphp's design and linked separate structs with pointers.
Embedding structs is preferrable to linking them with pointers because
it requires fewer allocations, thereby reducing overhead and simplifying
error paths. Casting an embedded struct to the containing struct
becomes a cheap subtraction rather than a dereference. And having fewer
pointers reduces the risk of them pointing nowhere either accidentally
or due to an attack.
Convert all drivers to embed struct hotplug_slot in their internal slot
struct. The "private" pointer in struct hotplug_slot thereby becomes
unused, so drop it.
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>
Acked-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com> # drivers/pci/hotplug/rpa*
Acked-by: Sebastian Ott <sebott@linux.ibm.com> # drivers/pci/hotplug/s390*
Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> # drivers/platform/x86
Cc: Len Brown <lenb@kernel.org>
Cc: Scott Murray <scott@spiteful.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Oliver OHalloran <oliveroh@au1.ibm.com>
Cc: Gavin Shan <gwshan@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Corentin Chary <corentin.chary@gmail.com>
Cc: Darren Hart <dvhart@infradead.org>
Of the members which were just moved from pciehp's slot struct to the
controller struct, rename "lock" to "state_lock" and rename "work" to
"button_work" for clarity. Perform the rename separately to the
unification of the two structs per Sinan's request.
No functional change intended.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sinan Kaya <okaya@kernel.org>
pciehp was originally introduced together with shpchp in a single
commit, c16b4b14d980 ("PCI Hotplug: Add SHPC and PCI Express hot-plug
drivers"):
https://git.kernel.org/tglx/history/c/c16b4b14d980
shpchp supports up to 31 slots per controller, hence uses separate slot
and controller structs. pciehp has a 1:1 relationship between slot and
controller and therefore never required this separation. Nevertheless,
because much of the code had been copy-pasted between the two drivers,
pciehp likewise uses separate structs to this very day.
The artificial separation of data structures adds unnecessary complexity
and bloat to pciehp and requires constantly chasing pointers at runtime.
Simplify the driver by merging struct slot into struct controller.
Merge the slot constructor pcie_init_slot() and the destructor
pcie_cleanup_slot() into the controller counterparts.
No functional change intended.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
The WiGig Bus Extension (WBE) specification allows tunneling PCIe over
IEEE 802.11. A product implementing this spec is the wil6210 from
Wilocity (now part of Qualcomm Atheros). It integrates a PCIe switch
with a wireless network adapter:
00.0-+ [1ae9:0101] Upstream Port
+-00.0-+ [1ae9:0200] Downstream Port
| +-00.0 [168c:0034] Atheros AR9462 Wireless Network Adapter
+-02.0 [1ae9:0201] Downstream Port
+-03.0 [1ae9:0201] Downstream Port
Wirelessly attached devices presumably appear below the hotplug ports
with device ID [1ae9:0201]. Oddly, the Downstream Port [1ae9:0200]
leading to the wireless network adapter is likewise Hotplug Capable,
but has its Presence Detect State bit hardwired to zero. Even if the
Link Active bit is set, Presence Detect is zero, so this cannot be
caused by in-band presence detection but only by broken hardware.
pciehp assumes an empty slot if Presence Detect State is zero,
regardless of Link Active being one. Consequently, up until v4.18 it
removes the wireless network adapter in pciehp_resume(). From v4.19 it
already does so in pciehp_probe().
Be lenient towards broken hardware and assume the slot is occupied if
Link Active is set: Introduce pciehp_card_present_or_link_active()
and use it in lieu of pciehp_get_adapter_status() everywhere, except
in pciehp_handle_presence_or_link_change() whose log messages depend
on which of Presence Detect State or Link Active is set.
Remove the Presence Detect State check from __pciehp_enable_slot()
because it is only called if either of Presence Detect State or Link
Active is set.
Caution: There is a possibility that broken hardware exists which has
working Presence Detect but hardwires Link Active to one. On such
hardware the slot will now incorrectly be considered always occupied.
If such hardware is discovered, this commit can be rolled back and a
quirk can be added which sets is_hotplug_bridge = 0 for [1ae9:0200].
Link: https://bugzilla.kernel.org/show_bug.cgi?id=200839
Reported-and-tested-by: David Yang <mmyangfl@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rajat Jain <rajatja@google.com>
Cc: Ashok Raj <ashok.raj@intel.com>
pciehp's ->enable_slot, ->disable_slot, ->get_attention_status and
->reset_slot callbacks are currently implemented by wrapper functions
that do nothing else but call down to a backend function. The backends
are not called from anywhere else, so drop the wrappers and use the
backends directly as callbacks, thereby shaving off a few lines of
unnecessary code.
No functional change intended.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Drop the following includes from pciehp source files which no longer use
any of the included symbols:
* <linux/sched/signal.h> in pciehp.h
<linux/signal.h> in pciehp_hpc.c
Added by commit de25968cc8 ("fix more missing includes") to
accommodate for a call to signal_pending().
The call was removed by commit 262303fe32 ("pciehp: fix wait command
completion").
* <linux/interrupt.h> in pciehp_core.c
Added by historic commit f308a2dfbe63 ("PCI: add PCI Express Port Bus
Driver subsystem") to accommodate for a call to free_irq():
https://git.kernel.org/tglx/history/c/f308a2dfbe63
The call was removed by commit 407f452b05 ("pciehp: remove
unnecessary free_irq").
* <linux/time.h> in pciehp_core.c and pciehp_hpc.c
Added by commit 34d03419f0 ("PCIEHP: Add Electro Mechanical
Interlock (EMI) support to the PCIE hotplug driver."),
which was reverted by commit bd3d99c170 ("PCI: Remove untested
Electromechanical Interlock (EMI) support in pciehp.").
* <linux/module.h> in pciehp_ctrl.c, pciehp_hpc.c and pciehp_pci.c
Added by historic commit c16b4b14d980 ("PCI Hotplug: Add SHPC and PCI
Express hot-plug drivers"):
https://git.kernel.org/tglx/history/c/c16b4b14d980
Module-related symbols were neither used back then in those files,
nor are they used today.
* <linux/slab.h> in pciehp_ctrl.c
Added by commit 5a0e3ad6af ("include cleanup: Update gfp.h and
slab.h includes to prepare for breaking implicit slab.h inclusion from
percpu.h") to accommodate for calls to kmalloc().
The calls were removed by commit 0e94916e60 ("PCI: pciehp: Handle
events synchronously").
* "../pci.h" in pciehp_ctrl.c
Added by historic commit 67f4660b72f2 ("PCI: ASPM patch for") to
accommodate for usage of the global variable pcie_mch_quirk:
https://git.kernel.org/tglx/history/c/67f4660b72f2
The global variable was removed by commit 0ba379ec0f ("PCI: Simplify
hotplug mch quirk").
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
If both hot-add and power fault were observed in a single interrupt, we
handled the hot-add first, then the power fault, in this path:
pciehp_ist
if (events & (PDC | DLLSC))
pciehp_handle_presence_or_link_change
case OFF_STATE:
pciehp_enable_slot
__pciehp_enable_slot
board_added
pciehp_power_on_slot
ctrl->power_fault_detected = 0
pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_PWR_ON, PCI_EXP_SLTCTL_PCC)
pciehp_green_led_on(p_slot) # power LED on
pciehp_set_attention_status(p_slot, 0) # attention LED off
if ((events & PFD) && !ctrl->power_fault_detected)
ctrl->power_fault_detected = 1
pciehp_set_attention_status(1) # attention LED on
pciehp_green_led_off(slot) # power LED off
This left the attention indicator on (even though the hot-add succeeded)
and the power indicator off (even though the slot power was on).
Fix this by checking for power faults before checking for new devices.
Prior to 0e94916e60, this was successful because everything was chained
through work queues and the order was:
INT_PRESENCE_ON -> INT_POWER_FAULT -> ENABLE_REQ
The ENABLE_REQ cleared the power fault at the end, but now everything is
handled inline with the interrupt thread, such that the work ENABLE_REQ was
doing happens before power fault handling now.
Fixes: 0e94916e60 ("PCI: pciehp: Handle events synchronously")
Signed-off-by: Keith Busch <keith.busch@intel.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
- To avoid bus errors, enable PASID only if entire path supports End-End
TLP prefixes (Sinan Kaya)
- Unify slot and bus reset functions and remove hotplug knowledge from
callers (Sinan Kaya)
- Add Function-Level Reset quirks for Intel and Samsung NVMe devices to
fix guest reboot issues (Alex Williamson)
- Add function 1 DMA alias quirk for Marvell 88SS9183 PCIe SSD Controller
(Bjorn Helgaas)
* pci/virtualization:
PCI: Add function 1 DMA alias quirk for Marvell 88SS9183
PCI: Delay after FLR of Intel DC P3700 NVMe
PCI: Disable Samsung SM961/PM961 NVMe before FLR
PCI: Export pcie_has_flr()
PCI: Rename pci_try_reset_bus() to pci_reset_bus()
PCI: Deprecate pci_reset_bus() and pci_reset_slot() functions
PCI: Unify try slot and bus reset API
PCI: Hide pci_reset_bridge_secondary_bus() from drivers
IB/hfi1: Use pci_try_reset_bus() for initiating PCI Secondary Bus Reset
PCI: Handle error return from pci_reset_bridge_secondary_bus()
PCI/IOV: Tidy pci_sriov_set_totalvfs()
PCI: Enable PASID only if entire path supports End-End TLP prefixes
# Conflicts:
# drivers/pci/hotplug/pciehp_hpc.c
On driver probe and on resume from system sleep, pciehp checks the
Presence Detect State bit in the Slot Status register to bring up an
occupied slot or bring down an unoccupied slot. Both code paths are
identical, so deduplicate them per Mika's request.
On probe, an additional check is performed to disable power of an
unoccupied slot. This can e.g. happen if power was enabled by BIOS.
It cannot happen once pciehp has taken control, hence is not necessary
on resume: The Slot Control register is set to the same value that it
had on suspend by pci_restore_state(), so if the slot was occupied,
power is enabled and if it wasn't, power is disabled. Should occupancy
have changed during the system sleep transition, power is adjusted by
bringing up or down the slot per the paragraph above.
To allow for deduplication of the presence check, move the power check
to pcie_init(). This seems safer anyway, because right now it is
performed while interrupts are already enabled, and although I can't
think of a scenario where pciehp_power_off_slot() and the IRQ thread
collide, it does feel brittle.
However this means that pcie_init() may now write to the Slot Control
register before the IRQ is requested. If both the CCIE and HPIE bits
happen to be set, pcie_wait_cmd() will wait for an interrupt (instead
of polling the Command Completed bit) and eventually emit a timeout
message. Additionally, if a level-triggered INTx interrupt is used,
the user may see a spurious interrupt splat. Avoid by disabling
interrupts before disabling power. (Normally the HPIE and CCIE bits
should be clear on probe, but conceivably they may already have been
set e.g. by BIOS.)
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>
Ensure accessibility of a hotplug port's config space when accessed via
sysfs by resuming its parent to D0.
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>
If a hotplug port is able to send an interrupt, one would naively assume
that it is accessible at that moment. After all, if it wouldn't be
accessible, i.e. if its parent is in D3hot and the link to the hotplug
port is thus down, how should an interrupt come through?
It turns out that assumption is wrong at least for Thunderbolt: Even
though its parents are in D3hot, a Thunderbolt hotplug port is able to
signal interrupts. Because the port's config space is inaccessible and
resuming the parents may sleep, the hard IRQ handler has to defer
runtime resuming the parents and reading the Slot Status register to the
IRQ thread.
If the hotplug port uses a level-triggered INTx interrupt, it needs to
be masked until the IRQ thread has cleared the signaled events. For
simplicity, this commit also masks edge-triggered MSI/MSI-X interrupts.
Note that if the interrupt is shared (which can only happen for INTx),
other devices are starved from receiving interrupts until the IRQ thread
is scheduled, has runtime resumed the hotplug port's parents and has
read and cleared the Slot Status register.
That delay is dominated by the 10 ms D3hot->D0 transition time of each
parent port. The worst case is a Thunderbolt downstream port at the
end of a daisy chain: There may be up to six Thunderbolt controllers
in-between it and the root port, each comprising an upstream and
downstream port, plus its own upstream port. That's 13 x 10 = 130 ms.
Possible mitigations are polling the interrupt while it's disabled or
reducing the d3_delay of Thunderbolt ports if possible.
Open code masking of the interrupt instead of requesting it with the
IRQF_ONESHOT flag to minimize the period during which it is masked.
(IRQF_ONESHOT unmasks the IRQ only after the IRQ thread has finished.)
PCIe r4.0 sec 6.7.3.4 states that "If wake generation is required by the
associated form factor specification, a hotplug capable Downstream Port
must support generation of a wakeup event (using the PME mechanism) on
hotplug events that occur when the system is in a sleep state or the
Port is in device state D1, D2, or D3Hot."
This would seem to imply that PME needs to be enabled on the hotplug
port when it is runtime suspended. pci_enable_wake() currently doesn't
enable PME on bridges, it may be necessary to add an exemption for
hotplug bridges there. On "Light Ridge" Thunderbolt controllers, the
PME_Status bit is not set when an interrupt occurs while the hotplug
port is in D3hot, even if PME is enabled. (I've tested this on a Mac
and we hardcode the OSC_PCI_EXPRESS_PME_CONTROL bit to 0 on Macs in
negotiate_os_control(), modifying it to 1 didn't change the behavior.)
(Side note: Section 6.7.3.4 also states that "PME and Hot-Plug Event
interrupts (when both are implemented) always share the same MSI or
MSI-X vector". That would only seem to apply to Root Ports, however
the section never mentions Root Ports, only Downstream Ports. This is
explained in the definition of "Downstream Port" in the "Terms and
Acronyms" section of the PCIe Base Spec: "The Ports on a Switch that
are not the Upstream Port are Downstream Ports. All Ports on a Root
Complex are Downstream Ports.")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
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>
Thunderbolt hotplug ports that were occupied before system sleep resume
with their downstream link in "off" state. Only after the Thunderbolt
controller has reestablished the PCIe tunnels does the link go up.
As a result, a spurious Presence Detect Changed and/or Data Link Layer
State Changed event occurs.
The events are not immediately acted upon because tunnel reestablishment
happens in the ->resume_noirq phase, when interrupts are still disabled.
Also, notification of events may initially be disabled in the Slot
Control register when coming out of system sleep and is reenabled in the
->resume_noirq phase through:
pci_pm_resume_noirq()
pci_pm_default_resume_early()
pci_restore_state()
pci_restore_pcie_state()
It is not guaranteed that the events are acted upon at all: PCIe r4.0,
sec 6.7.3.4 says that "a port may optionally send an MSI when there are
hot-plug events that occur while interrupt generation is disabled, and
interrupt generation is subsequently enabled." Note the "optionally".
If an MSI is sent, pciehp will gratuitously turn the slot off and back
on once the ->resume_early phase has commenced.
If an MSI is not sent, the extant, unacknowledged events in the Slot
Status register will prevent future notification of presence or link
changes.
Commit 13c65840fe ("PCI: pciehp: Clear Presence Detect and Data Link
Layer Status Changed on resume") fixed the latter by clearing the events
in the ->resume phase. Move this to the ->resume_noirq phase to also
fix the gratuitous disable/enablement of the slot.
The commit further restored the Slot Control register in the ->resume
phase, but that's dispensable because as shown above it's already been
done in the ->resume_noirq phase.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
The ->reset_slot callback introduced by commits:
2e35afaefe ("PCI: pciehp: Add reset_slot() method") and
06a8d89af5 ("PCI: pciehp: Disable link notification across slot reset")
disables notification of Presence Detect Changed and Data Link Layer
State Changed events for the duration of a secondary bus reset.
However a bus reset not only triggers these events, but may also clear
the Presence Detect State bit in the Slot Status register and the Data
Link Layer Link Active bit in the Link Status register momentarily.
According to Sinan Kaya:
"I know for a fact that bus reset clears the Data Link Layer Active bit
as soon as link goes down. It gets set again following link up.
Presence detect depends on the HW implementation. QDT root ports
don't change presence detect for instance since nobody actually
removed the card. If an implementation supports in-band presence
detect, the answer is yes. As soon as the link goes down, presence
detect bit will get cleared until recovery."
https://lkml.kernel.org/r/42e72f83-3b24-f7ef-e5bc-290fae99259a@codeaurora.org
In-band presence detect is also covered in Table 4-15 in PCIe r4.0,
sec 4.2.6.
pciehp should therefore ensure that any parts of the driver that access
those bits do not run concurrently to a bus reset. The only precaution
the commits took to that effect was to halt interrupt polling. They
made no effort to drain the slot workqueue, cancel an outstanding
Attention Button work, or block slot enable/disable requests via sysfs
and in the ->probe hook.
Now that pciehp is converted to enable/disable the slot exclusively from
the IRQ thread, the only places accessing the two above-mentioned bits
are the IRQ thread and the ->probe hook. Add locking to serialize them
with a bus reset. This obviates the need to halt interrupt polling.
Do not add locking to the ->get_adapter_status sysfs callback to afford
users unfettered access to that bit. Use an rw_semaphore in lieu of a
regular mutex to allow parallel execution of the non-reset code paths
accessing the critical bits, i.e. the IRQ thread and the ->probe hook.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Rajat Jain <rajatja@google.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Sinan Kaya <okaya@kernel.org>
Per PCIe r4.0, sec 6.7.3.4, a "port may optionally send an MSI when
there are hot-plug events that occur while interrupt generation is
disabled, and interrupt generation is subsequently enabled."
On probe, we currently clear all event bits in the Slot Status register
with the notable exception of the Presence Detect Changed bit. Thereby
we seek to receive an interrupt for an already occupied slot once event
notification is enabled.
But because the interrupt is optional, users may have to specify the
pciehp_force parameter on the command line, which is inconvenient.
Moreover, now that pciehp's event handling has become resilient to
missed events, a Presence Detect Changed interrupt for a slot which is
powered on is interpreted as removal of the card. If the slot has
already been brought up by the BIOS, receiving such an interrupt on
probe causes the slot to be powered off and immediately back on, which
is likewise undesirable.
Avoid both issues by making the behavior of pciehp_force the default and
clearing the Presence Detect Changed bit on probe.
Note that the stated purpose of pciehp_force per the MODULE_PARM_DESC
("Force pciehp, even if OSHP is missing") seems nonsensical because the
OSHP control method is only relevant for SHCP slots according to the
PCI Firmware specification r3.0, sec 4.8.
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>
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>
When a device is hotplugged, Presence Detect and Link Up events often do
not occur simultaneously, but with a lag of a few milliseconds. Only
the first event received is relevant, the other one can be disregarded.
Moreover, Stefan Roese reports that on certain platforms, Link State and
Presence Detect may flap for up to 100 ms before stabilizing, suggesting
that such events should be disregarded for at least this long:
https://lkml.kernel.org/r/20180130084121.18653-1-sr@denx.de
On slot enablement, pciehp_check_link_status() waits for 100 ms per
PCIe r4.0, sec 6.7.3.3, then probes the hotplugged device's vendor
register for up to 1 second.
If this succeeds, the link is definitely up, so ignore any Presence
Detect or Link State events that occurred up to this point.
pciehp_check_link_status() then checks the Link Training bit in the
Link Status register. This is the final opportunity to detect
inaccessibility of the device and abort slot enablement. Any link
or presence change that occurs afterwards will cause the slot to be
disabled again immediately after attempting to enable it.
The astute reviewer may appreciate that achieving this behavior would be
more complicated had pciehp not just been converted to enable/disable
the slot exclusively from the IRQ thread: When the slot is enabled via
sysfs, each link or presence flap would otherwise cause the IRQ thread
to run and it would have to sense that those events are belonging to a
concurrent slot enablement operation and disregard them. It would be
much more difficult than this mere 3 line change.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Stefan Roese <sr@denx.de>
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>
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
Rename pci_reset_bridge_secondary_bus() to pci_bridge_secondary_bus_reset()
and move the declaration from linux/pci.h to drivers/pci.h to be used
internally in PCI directory only.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Commit 01fd61c0b9 ("PCI: Add a return type for
pci_reset_bridge_secondary_bus()") added a return value to the function to
return if a device is accessible following a reset. Callers are not
checking the value.
Pass error code up high in the stack if device is not accessible.
Fixes: 01fd61c0b9 ("PCI: Add a return type for pci_reset_bridge_secondary_bus()")
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
- 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>
