PCI: pciehp: Cancel bringup sequence if card is not present

If a PCIe hotplug slot has an Attention Button, the normal hot-add flow is:

- Slot is empty and slot power is off
- User inserts card in slot and presses Attention Button
- OS blinks Power Indicator for 5 seconds
- After 5 seconds, OS turns on Power Indicator, turns on slot power, and
enumerates the device

Previously, if a user pressed the Attention Button on an *empty* slot,
pciehp logged the following messages and blinked the Power Indicator
until a second button press:

[0.000] pciehp: Button press: will power on in 5 sec
[0.001] # Power Indicator starts blinking
[5.001] # 5 second timeout; slot is empty, so we should cancel the
request to power on and turn off Power Indicator

[7.000] # Power Indicator still blinking
[8.000] # possible card insertion
[9.000] pciehp: Button press: canceling request to power on

The first button press incorrectly left the slot in BLINKINGON_STATE, so
the second was interpreted as a "cancel power on" event regardless of
whether a card was present.

If the slot is empty, turn off the Power Indicator and return from
BLINKINGON_STATE to OFF_STATE after 5 seconds, effectively canceling the
request to power on. Putting the slot in OFF_STATE also means the second
button press will correctly request a slot power on if the slot is
occupied.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/20230512021518.336460-1-clementwei90@163.com
Fixes: d331710ea78f ("PCI: pciehp: Become resilient to missed events")
Suggested-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Rongguang Wei <weirongguang@kylinos.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>

PCI: pciehp: Simplify Attention Button logging

Previously, pressing the Attention Button always logged two lines, the
first from pciehp_ist() and the second from pciehp_handle_button_press():

Attention button pressed
Powering on due to button press

Since pciehp_handle_button_press() always logs the more detailed message,
remove the generic "Attention button pressed" message. Reword the
pciehp_handle_button_press() to be of the form:

Button press: will power on in 5 sec
Button press: will power off in 5 sec
Button press: canceling request to power on
Button press: canceling request to power off
Button press: ignoring invalid state %#x

Link: https://lore.kernel.org/r/20230522214051.619337-1-helgaas@kernel.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>

PCI: pciehp: Reduce noisiness on hot removal

When a PCIe card is hot-removed, the Presence Detect State and Data Link
Layer Link Active bits often do not clear simultaneously. I've seen delays
of up to 244 msec between the two events with Thunderbolt.

After pciehp has brought down the slot in response to the first event, the
other bit may still be set. It's not discernible whether it's set because
a new card is already in the slot or if it will soon clear. So pciehp
tries to bring up the slot and in the latter case fails with a bunch of
messages, some of them at KERN_ERR severity. If the slot is no longer
occupied, the messages are false positives and annoy users.

Stuart Hayes reports the following splat on hot removal:

KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Link Up
KERN_INFO pcieport 0000:3c:06.0: pciehp: Timeout waiting for Presence Detect
KERN_ERR pcieport 0000:3c:06.0: pciehp: link training error: status 0x0001
KERN_ERR pcieport 0000:3c:06.0: pciehp: Failed to check link status

Dongdong Liu complains about a similar splat:

KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Link Down
KERN_INFO iommu: Removing device 0000:87:00.0 from group 12
KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Card present
KERN_INFO pcieport 0000:80:10.0: Data Link Layer Link Active not set in 1000 msec
KERN_ERR pciehp 0000:80:10.0:pcie004: Failed to check link status

Users are particularly irritated to see a bringup attempt even though the
slot was explicitly brought down via sysfs. In a perfect world, we could
avoid this by setting Link Disable on slot bringdown and re-enabling it
upon a Presence Detect State change. In reality however, there are broken
hotplug ports which hardwire Presence Detect to zero, see 80696f991424
("PCI: pciehp: Tolerate Presence Detect hardwired to zero"). Conversely,
PCIe r1.0 hotplug ports hardwire Link Active to zero because Link Active
Reporting wasn't specified before PCIe r1.1. On unplug, some ports first
clear Presence then Link (see Stuart Hayes' splat) whereas others use the
inverse order (see Dongdong Liu's splat). To top it off, there are hotplug
ports which flap the Presence and Link bits on slot bringup, see
6c35a1ac3da6 ("PCI: pciehp: Tolerate initially unstable link").

pciehp is designed to work with all of these variants. Surplus attempts at
slot bringup are a lesser evil than not being able to bring up slots at
all. Although we could try to perfect the behavior for specific hotplug
controllers, we'd risk breaking others or increasing code complexity.

But we can certainly minimize annoyance by emitting only a single message
with KERN_INFO severity if bringup is unsuccessful:

* Drop the "Timeout waiting for Presence Detect" message in
pcie_wait_for_presence(). The sole caller of that function,
pciehp_check_link_status(), ignores the timeout and carries on. It emits
error messages of its own and I don't think this particular message adds
much value.

* There's a single error condition in pciehp_check_link_status() which
does not emit a message. Adding one allows dropping the "Failed to check
link status" message emitted by board_added() if
pciehp_check_link_status() returns a non-zero integer.

* Tone down all messages in pciehp_check_link_status() to KERN_INFO
severity and rephrase them to look as innocuous as possible. To this
end, move the message emitted by pcie_wait_for_link_delay() to its
callers.

As a result, Stuart Hayes' splat becomes:

KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Link Up
KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Cannot train link: status 0x0001

Dongdong Liu's splat becomes:

KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Card present
KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): No link

The messages now merely serve as information that presence or link bits
were set a little longer than expected. Bringup failures which are not
false positives are still reported, albeit no longer at KERN_ERR severity.

Link: https://lore.kernel.org/linux-pci/20200310182100.102987-1-stuart.w.hayes@gmail.com/
Link: https://lore.kernel.org/linux-pci/1547649064-19019-1-git-send-email-liudongdong3@huawei.com/
Link: https://lore.kernel.org/r/b45e46fd8a6aa6930aaac9d7718c2e4b787a4e5e.1595935071.git.lukas@wunner.de
Reported-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Reported-by: Dongdong Liu <liudongdong3@huawei.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>

treewide: Use fallthrough pseudo-keyword

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

PCI: pciehp: Prevent deadlock on disconnect

This addresses deadlocks in these common cases in hierarchies containing
two switches:

- All involved ports are runtime suspended and they are unplugged. This
can happen easily if the drivers involved automatically enable runtime
PM (xHCI for example does that).

- System is suspended (e.g., closing the lid on a laptop) with a dock +
something else connected, and the dock is unplugged while suspended.

These cases lead to the following deadlock:

INFO: task irq/126-pciehp:198 blocked for more than 120 seconds.
irq/126-pciehp D 0 198 2 0x80000000
Call Trace:
schedule+0x2c/0x80
schedule_timeout+0x246/0x350
wait_for_completion+0xb7/0x140
kthread_stop+0x49/0x110
free_irq+0x32/0x70
pcie_shutdown_notification+0x2f/0x50
pciehp_remove+0x27/0x50
pcie_port_remove_service+0x36/0x50
device_release_driver+0x12/0x20
bus_remove_device+0xec/0x160
device_del+0x13b/0x350
device_unregister+0x1a/0x60
remove_iter+0x1e/0x30
device_for_each_child+0x56/0x90
pcie_port_device_remove+0x22/0x40
pcie_portdrv_remove+0x20/0x60
pci_device_remove+0x3e/0xc0
device_release_driver_internal+0x18c/0x250
device_release_driver+0x12/0x20
pci_stop_bus_device+0x6f/0x90
pci_stop_bus_device+0x31/0x90
pci_stop_and_remove_bus_device+0x12/0x20
pciehp_unconfigure_device+0x88/0x140
pciehp_disable_slot+0x6a/0x110
pciehp_handle_presence_or_link_change+0x263/0x400
pciehp_ist+0x1c9/0x1d0
irq_thread_fn+0x24/0x60
irq_thread+0xeb/0x190
kthread+0x120/0x140

INFO: task irq/190-pciehp:2288 blocked for more than 120 seconds.
irq/190-pciehp D 0 2288 2 0x80000000
Call Trace:
__schedule+0x2a2/0x880
schedule+0x2c/0x80
schedule_preempt_disabled+0xe/0x10
mutex_lock+0x2c/0x30
pci_lock_rescan_remove+0x15/0x20
pciehp_unconfigure_device+0x4d/0x140
pciehp_disable_slot+0x6a/0x110
pciehp_handle_presence_or_link_change+0x263/0x400
pciehp_ist+0x1c9/0x1d0
irq_thread_fn+0x24/0x60
irq_thread+0xeb/0x190
kthread+0x120/0x140

What happens here is that the whole hierarchy is runtime resumed and the
parent PCIe downstream port, which got the hot-remove event, starts
removing devices below it, taking pci_lock_rescan_remove() lock. When the
child PCIe port is runtime resumed it calls pciehp_check_presence() which
ends up calling pciehp_card_present() and pciehp_check_link_active(). Both
of these use pcie_capability_read_word(), which notices that the underlying
device is already gone and returns PCIBIOS_DEVICE_NOT_FOUND with the
capability value set to 0. When pciehp gets this value it thinks that its
child device is also hot-removed and schedules its IRQ thread to handle the
event.

The deadlock happens when the child's IRQ thread runs and tries to acquire
pci_lock_rescan_remove() which is already taken by the parent and the
parent waits for the child's IRQ thread to finish.

Prevent this from happening by checking the return value of
pcie_capability_read_word() and if it is PCIBIOS_DEVICE_NOT_FOUND stop
performing any hot-removal activities.

[bhelgaas: add common scenarios to commit log]
Link: https://lore.kernel.org/r/20191029170022.57528-2-mika.westerberg@linux.intel.com
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: pciehp: Avoid returning prematurely from sysfs requests

A sysfs request to enable or disable a PCIe hotplug slot should not
return before it has been carried out. That is sought to be achieved by
waiting until the controller's "pending_events" have been cleared.

However the IRQ thread pciehp_ist() clears the "pending_events" before
it acts on them. If pciehp_sysfs_enable_slot() / _disable_slot() happen
to check the "pending_events" after they have been cleared but while
pciehp_ist() is still running, the functions may return prematurely
with an incorrect return value.

Fix by introducing an "ist_running" flag which must be false before a sysfs
request is allowed to return.

Fixes: 32a8cef274fe ("PCI: pciehp: Enable/disable exclusively from IRQ thread")
Link: https://lore.kernel.org/linux-pci/1562226638-54134-1-git-send-email-wangxiongfeng2@huawei.com
Link: https://lore.kernel.org/r/4174210466e27eb7e2243dd1d801d5f75baaffd8.1565345211.git.lukas@wunner.de
Reported-and-tested-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v4.19+

PCI: pciehp: Refer to "Indicators" instead of "LEDs" in comments

The PCIe spec doesn't mention "green LEDs" or "amber LEDs". Replace those
terms with "Power Indicator" and "Attention Indicator" so the comments
match the spec language. Comment changes only.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: pciehp: Remove pciehp_green_led_{on,off,blink}()

Remove pciehp_green_led_{on,off,blink}() and use pciehp_set_indicators()
instead, since the code is mostly the same.

[bhelgaas: drop set_power_indicator() wrapper to reduce the number of
interfaces]
Link: https://lore.kernel.org/r/20190903111021.1559-5-efremov@linux.com
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

PCI: pciehp: Combine adjacent indicator updates

Combine adjacent updates of power and attention indicators into a single
pciehp_set_indicators() call. This sends one command to the hotplug
controller instead of two.

Link: https://lore.kernel.org/r/20190903111021.1559-3-efremov@linux.com
Signed-off-by: Denis Efremov <efremov@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>

PCI: pciehp: Log messages with pci_dev, not pcie_device

Log messages with pci_dev, not pcie_device. Factor out common message
prefixes with dev_fmt().

Example output change:

- pciehp 0000:00:06.0:pcie004: Slot(0) Powering on due to button press
+ pcieport 0000:00:06.0: pciehp: Slot(0) Powering on due to button press

Link: https://lore.kernel.org/lkml/20190509141456.223614-8-helgaas@kernel.org
Signed-off-by: Frederick Lawler <fred@fredlawl.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

PCI: pciehp: Ignore Link State Changes after powering off a slot

During a safe hot remove, the OS powers off the slot, which may cause a
Data Link Layer State Changed event. The slot has already been set to
OFF_STATE, so that event results in re-enabling the device, making it
impossible to safely remove it.

Clear out the Presence Detect Changed and Data Link Layer State Changed
events when the disabled slot has settled down.

It is still possible to re-enable the device if it remains in the slot
after pressing the Attention Button by pressing it again.

Fixes the problem that Micah reported below: an NVMe drive power button may
not actually turn off the drive.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=203237
Reported-by: Micah Parrish <micah.parrish@hpe.com>
Tested-by: Micah Parrish <micah.parrish@hpe.com>
Signed-off-by: Sergey Miroshnichenko <s.miroshnichenko@yadro.com>
[bhelgaas: changelog, add bugzilla URL]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.19+

PCI: hotplug: Embed hotplug_slot

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>

PCI: pciehp: Rename controller struct members for clarity

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>

PCI: pciehp: Unify controller and slot structs

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>

PCI: pciehp: Tolerate Presence Detect hardwired to zero

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>

PCI: pciehp: Drop hotplug_slot_ops wrappers

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>

PCI: pciehp: Drop unnecessary includes

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 de25968cc87c ("fix more missing includes") to
accommodate for a call to signal_pending().
The call was removed by commit 262303fe329a ("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 407f452b05f9 ("pciehp: remove
unnecessary free_irq").

* <linux/time.h> in pciehp_core.c and pciehp_hpc.c
Added by commit 34d03419f03b ("PCIEHP: Add Electro Mechanical
Interlock (EMI) support to the PCIE hotplug driver."),
which was reverted by commit bd3d99c17039 ("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 5a0e3ad6af86 ("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 0e94916e6091 ("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 0ba379ec0fb1 ("PCI: Simplify
hotplug mch quirk").

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: pciehp: Differentiate between surprise and safe removal

When removing PCI devices below a hotplug bridge, pciehp marks them as
disconnected if the card is no longer present in the slot or it quiesces
them if the card is still present (by disabling INTx interrupts, bus
mastering and SERR# reporting).

To detect whether the card is still present, pciehp checks the Presence
Detect State bit in the Slot Status register. The problem with this
approach is that even if the card is present, the link to it may be
down, and it that case it would be better to mark the devices as
disconnected instead of trying to quiesce them. Moreover, if the card
in the slot was quickly replaced by another one, the Presence Detect
State bit would be set, yet trying to quiesce the new card's devices
would be wrong and the correct thing to do is to mark the previous
card's devices as disconnected.

Instead of looking at the Presence Detect State bit, it is better to
differentiate whether the card was surprise removed versus safely
removed (via sysfs or an Attention Button press). On surprise removal,
the devices should be marked as disconnected, whereas on safe removal it
is correct to quiesce the devices.

The knowledge whether a surprise removal or a safe removal is at hand
does exist further up in the call stack: A surprise removal is
initiated by pciehp_handle_presence_or_link_change(), a safe removal by
pciehp_handle_disable_request().

Pass that information down to pciehp_unconfigure_device() and use it in
lieu of the Presence Detect State bit. While there, add kernel-doc to
pciehp_unconfigure_device() and pciehp_configure_device().

Tested-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Keith Busch <keith.busch@intel.com>

PCI: pciehp: Avoid implicit fallthroughs in switch statements

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>

PCI: pciehp: Resume to D0 on enable/disable

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>

PCI: pciehp: Become resilient to missed events

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
fad214b0aa72 ("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>

PCI: pciehp: Declare pciehp_enable/disable_slot() static

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>

PCI: pciehp: Drop enable/disable lock

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>

PCI: pciehp: Enable/disable exclusively from IRQ thread

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>

PCI: pciehp: Track enable/disable status

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>

PCI: pciehp: Drop slot workqueue

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>

PCI: pciehp: Handle events synchronously

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>

PCI: pciehp: Stop blinking on slot enable failure

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>

PCI: pciehp: Declare pciehp_unconfigure_device() void

Since commit 0f4bd8014db5 ("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>

PCI: pciehp: Drop unnecessary NULL pointer check

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>

PCI: Mark fall-through switch cases before enabling -Wimplicit-fallthrough

In preparation to enabling -Wimplicit-fallthrough, mark switch cases where
we are expecting to fall through.

Warning level 2 was used: -Wimplicit-fallthrough=2

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: Add SPDX GPL-2.0+ to replace GPL v2 or later boilerplate

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 b24413180f56 ("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>

PCI: pciehp: Fix race condition handling surprise link down

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>

Revert "PCI: pciehp: Add runtime PM support for PCIe hotplug ports"

This reverts commit 68db9bc814362e7f24371c27d12a4f34477d9356.

Yinghai reported that the following manual hotplug sequence:

# echo 0 > /sys/bus/pci/slots/8/power
# echo 1 > /sys/bus/pci/slots/8/power

worked in v4.9, but fails in v4.10-rc1, and that reverting 68db9bc81436
("PCI: pciehp: Add runtime PM support for PCIe hotplug ports") makes it
work again.

Fixes: 68db9bc81436 ("PCI: pciehp: Add runtime PM support for PCIe hotplug ports")
Link: https://lkml.kernel.org/r/CAE9FiQVCMCa7iVyuwp9z6VrY0cE7V_xghuXip28Ft52=8QmTWw@mail.gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=193951
Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: pciehp: Leave power indicator on when enabling already-enabled slot

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>

PCI: pciehp: Add runtime PM support for PCIe hotplug ports

Linux 4.8 added support for runtime suspending PCIe ports to D3hot with
commit 006d44e49a25 ("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>

PCI: pciehp: Remove useless pciehp_get_latch_status() calls

Long ago, we updated a "switch_save" field based on the latch status. But
switch_save was unused, and ed6cbcf2ac70 ("[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>

PCI: pciehp: Clean up dmesg "Slot(%s)" messages

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>

PCI: pciehp: Don't re-read Slot Status when handling surprise event

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>

PCI: pciehp: Clear attention LED on device add

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>

PCI: pciehp: Always protect pciehp_disable_slot() with hotplug mutex

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>

PCI: pciehp: Queue power work requests in dedicated function

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>

PCI: pciehp: Inline the "handle event" functions into the ISR

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>

PCI: pciehp: Rename queue_interrupt_event() to pciehp_queue_interrupt_event()

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>

PCI: pciehp: Make queue_interrupt_event() void

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>

PCI: pciehp: Clean up debug logging

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>

PCI: pciehp: Handle surprise add even if surprise removal isn't supported

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>

PCI: Merge multi-line quoted strings

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>

PCI: Whitespace cleanup

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>

PCI: pciehp: Cleanup whitespace

Minor whitespace cleanup; no functional change.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

PCI: pciehp: Remove a non-existent card, regardless of "surprise" capability

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>

PCI: pciehp: Don't turn slot off when hot-added device already exists

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>

PCI: pciehp: Add hotplug_lock to serialize hotplug events

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>

PCI: pciehp: Ensure very fast hotplug events are also processed

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>

PCI: pciehp: Don't check adapter or latch status while disabling

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>

PCI: pciehp: Use link change notifications for hot-plug and removal

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>

PCI: pciehp: Move Attention & Power Indicator support tests to accessors

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>

PCI: pciehp: Make various functions void since they can't fail

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>

PCI: pciehp: Use per-slot workqueues to avoid deadlock

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

PCI: pciehp: Handle push button event asynchronously

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>

PCI: pciehp: Handle push button event asynchronously

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>

PCI: pciehp: wait 1000 ms before Link Training check

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>

PCI: pciehp: change wait time for valid configuration access

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>

pciehp: update workqueue usage

* 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>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

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>

PCI hotplug: fix memory leaks

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>

PCI pciehp: fix power fault interrupt storm problem

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>

PCI: pciehp: return error on read/write failure

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>

PCI: pciehp: remove error message definitions

Remove (almost) unused error message definitions.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove hpc_ops

The struct hpc_ops seems a set of hooks to controller specific
routines. But, it is meaningless because no hotplug controller driver
follows this framework.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove pci_dev field

Since we have a pointer to pcie_device in struct controller, we don't
need a pointer to pci_dev.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove crit_sect mutex

The crit_sect mutex defined in struct controller is to serialize
hot-plug operations against multiple slots under the same bus. But,
since PCIe doesnstream port has only one slot at most, it is
meaningless and we don't need it.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove slot_device_offset field

Since the device number of the hot-slot under the PCIe downstream port
is always 0, the slot_device_offset field in the slot is meaningless
and we don't need it.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove hp_slot field

The hp_slot field is to identify the slot under the same
controller. But, since PCIe downstream port has only one slot at most,
it is meaningless and we don't need it.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove device field

The device field in the struct slot is not necessary because it is
always 0 in pciehp driver.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove bus field

The bus field in struct slot is not necessary.

Acked-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: Simplify hotplug mch quirk.

There is a very old quirk for the intel E7502 E7320 and E7525 memory
controller hubs that disables usage of msi interrupts on pcie hotplug
bridges of those devices, and disables changing the affinity of irqs.

Today all we have to do to disable msi on a specific device is to set
dev->no_msi, which is much more straightforward than the previous
logic.

The re-running of this fixup after pci hotplug happens below these
devices is totally bogus. All of the state we change is pure software
state and we don't change the hardware at all. Which means hotplug on
the lower devices doesn't have a chance to change this state. So we
can safely remove the special case from the pciehp driver and the pcie
portdriver.

I suspect the special case was someone's expermental debug code that
slipped in. Certainly it isn't mentioned in commit
6fb8880a61510295aece04a542767161f624dffe aka BKrev:
41966101LJ_ogfOU0m2aE6teZfQnuQ where the code first appears.

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

headers: smp_lock.h redux

* Remove smp_lock.h from files which don't need it (including some headers!)
* Add smp_lock.h to files which do need it
* Make smp_lock.h include conditional in hardirq.h
It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT

This will make hardirq.h inclusion cheaper for every PREEMPT=n config
(which includes allmodconfig/allyesconfig, BTW)

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

PCI hotplug: pciehp: remove unnecessary wait after turning power off

The pciehp driver waits for 1000 msec after turning power off to make
sure the power has been completely removed. But this 1000 msec wait is
not needed if a slot doesn't implement power control because software
cannot control the power. Power will be automatically removed at adapter
removal time on such a slot

Tested-by: "Phil Endecott" <phil_pibbu_endecott@chezphil.org>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI hotplug: pciehp: message refinement

This patch refines messages in pciehp module. The main changes are as
follows:

- remove the trailing "."
- remove __func__ as much as possible
- capitalize the first letter of messages
- show PCI device address including its domain

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI hotplug: pciehp: poll data link layer link active

This patch adds polling mechanism for Data Link Layer Link Active bit
after turning power on, instead of waiting for 1000 msec. This reduces
reduce the unnecessary long wait.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: remove 'name' parameter

We do not need to manage our own name parameter, especially since
the PCI core can change it on our behalf, in the case of duplicate
slot names.

Remove 'name' from pciehp's version of struct slot, and remove
unused 'task_list' as well.

Cc: kristen.c.accardi@intel.com
Acked-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: pciehp: replace printk with dev_printk

This patch replaces printks within pciehp module with dev_printks.

Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

pciehp: move msleep after power off

According to the PCI Express specification, we must wait for at least
1 second after turning power off before taking any action that relies
on power having been removed from the slot/adapter. For this, current
pciehp wait for 1 second after issuing the power off command in
hpc_power_off_slot() function. But waiting for 1 second in
hpc_power_off_slot() can make pciehp probing slow-down because pciehp
probe code calls hpc_power_off_slot() if the slot is not occupied just
in case. We don't need to wait for 1 second at the pciehp probe time
because there is no action on that empty slot. So move 1 second wait
from hpc_power_off_slot() to the caller of hpc_power_off_slot().

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

pciehp: fix NULL dereference in interrupt handler

Fix the following NULL dereference problem reported from Pierre Ossman
and Ingo Molnar.

pciehp: HPC vendor_id 8086 device_id 27d0 ss_vid 0 ss_did 0
pciehp: pciehp_find_slot: slot (device=0x0) not found
BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
IP: [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113
PGD 0
Oops: 0000 [1]
CPU 0
Modules linked in:
Pid: 1, comm: swapper Tainted: G W 2.6.26-rc3-sched-devel.git-00001-g2b99b26-dirty #170
RIP: 0010:[<ffffffff80494a8b>] [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113
RSP: 0000:ffff81003f83fbb0 EFLAGS: 00010046
RAX: 0000000000000039 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000046
RBP: ffff81003f83fbd0 R08: 0000000000000001 R09: ffffffff80245103
R10: 0000000000000020 R11: 0000000000000000 R12: ffff81003ea53a30
R13: 0000000000000000 R14: 0000000000000011 R15: ffffffff80495926
FS: 0000000000000000(0000) GS:ffffffff80be7400(0000) knlGS:0000000000000000
CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000070 CR3: 0000000000201000 CR4: 00000000000006a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 1, threadinfo ffff81003f83e000, task ffff81003f840000)
Stack: 0000000000000008 ffff81003f83fbf6 ffff81003ea53a30 0000000000000008
ffff81003f83fc10 ffffffff80495ab4 0000000000000011 0000000000000002
0000000000000202 0000000000000202 00000000fffffff4 ffff81003ea53a30
Call Trace:
[<ffffffff80495ab4>] pcie_isr+0x18e/0x1bc
[<ffffffff80260831>] request_irq+0x106/0x12f
[<ffffffff80495fb6>] pcie_init+0x15e/0x6cc
[<ffffffff804933a3>] pciehp_probe+0x64/0x541
[<ffffffff8048f4e7>] pcie_port_probe_service+0x4c/0x76
[<ffffffff8054af70>] driver_probe_device+0xd4/0x1f0
[<ffffffff8054b108>] __driver_attach+0x7c/0x7e
[<ffffffff8054b08c>] ? __driver_attach+0x0/0x7e
[<ffffffff8054a4b6>] bus_for_each_dev+0x53/0x7d
[<ffffffff8054ad3c>] driver_attach+0x1c/0x1e
[<ffffffff8054a9c2>] bus_add_driver+0xdd/0x25b
[<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b
[<ffffffff8054b288>] driver_register+0x5f/0x13e
[<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b
[<ffffffff8048f441>] pcie_port_service_register+0x47/0x49
[<ffffffff80c09d52>] pcied_init+0x15/0x8b
[<ffffffff80bf3938>] kernel_init+0x75/0x243
[<ffffffff808639d2>] ? _spin_unlock_irq+0x2b/0x3a
[<ffffffff80228d1f>] ? finish_task_switch+0x57/0x9a
[<ffffffff8020c258>] child_rip+0xa/0x12
[<ffffffff8020bcec>] ? restore_args+0x0/0x30
[<ffffffff80bf38c3>] ? kernel_init+0x0/0x243
[<ffffffff8020c24e>] ? child_rip+0x0/0x12

Code: 83 80 00 00 00 48 39 f0 75 e1 0f b6 c9 48 c7 c2 00 0e 8d 80 48 c7 c6 8a 60 a6 80 48 c7 c7 10 db a8 80 31 c0 e8 3f 8d d9 ff 31 db <48> 8b 43 70 48 8d 75 ef 48 89 df ff 50 30 80 7d ef 00 74 37 48
RIP [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113
RSP <ffff81003f83fbb0>
CR2: 0000000000000070
Kernel panic - not syncing: Fatal exception

The situation under which it occurs is hw and timing related: it appears
to happen on a system that has PCI hotplug hardware but with no active
hotplug cards, and another interrupt in the same (shared) IRQ line
arrives too early, before the hotplug-slot entry has been set up - as
triggered by CONFIG_DEBUG_SHIRQ=y:

This patch contains the following two fixes.

(1) Clear all events bits in Slot Status register to prevent the pciehp
driver from detecting the spurious events that would have been occur
before pciehp loading.

(2) Add check whether slot initialization had been already done.

This is short term fix. We need more structural fixes to install
interrupt handler after slot initialization is done.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

pciehp: Fix wrong slot capability check

Current pciehp saves only 8bits of Slot Capability registers in
ctrl->ctrlcap. But it refers more than 8bit for checking EMI capability.
It is clearly a bug and EMI would never work. To fix this problem,
this patch saves full Slot Capability contens in ctrl->slot_cap. It also
reduce the redundant reads of Slot Capability register. And this pach
also cleans up the macros to check the slot capabilitys (e.g. MRL_SENS(),
and so on).

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

PCI: replace remaining __FUNCTION__ occurrences

__FUNCTION__ is gcc-specific, use __func__

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: wait for 1000ms before LED operation after power off

After turning power off, we must wait for at least 1 second *before*
LED operation.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PCI Hotplug: pciehp: remove needless hp_slot calculation

Remove needless hp_slot calculation. This has no functional changes.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PCIE: Make use of the previously split out pcie_init_enable_events() function

Make use of the previously split out pcie_init_enable_events() function
to reinitialize the hotplug hardware on resume from suspend, but only
when pciehp_force==1. Otherwise behaviour is unmodified.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PCIE: fix PCIe Hotplug so that it works with ExpressCard slots on Dell notebooks (and others?) in conjunction with modparam of pciehp_force=1.

Fix pciehp_probe() to deal with ExpressCard cards
that were inserted prior to the driver being loaded.

Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pci hotplug: kernel-doc fixes

acpiphp.h: not using kernel-doc, so change /** to /*
acpiphp_core.c: lots of kernel-doc cleanups
acpiphp_glue.c: lots of kernel-doc cleanups
acpiphp_ibm.c: lots of kernel-doc cleanups
cpqphp_core.c: lots of kernel-doc cleanups
cpqphp_ctrl.c: lots of kernel-doc cleanups
fakephp.c: correct kernel-doc notation
pciehp_ctrl.c: correct kernel-doc notation
rpadlpar_core.c: correct function names & kernel-doc notation
rpaphp_core.c: correct kernel-doc notation
shpchp_ctrl.c: correct kernel-doc notation

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Kristen Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: remove trailing whitespace from pciehp_ctrl.c

Remove trailing whitespaces from pciehp_ctrl.c.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PCI: hotplug: pciehp: wait for 1 second after power off slot

According to the specification, we must wait for at least 1 second
after turning power off before taking any action that relies on power
having been removed from the slot/adapter.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

PCI: fix multiple definition of `queue_pushbutton_work'

Fix duplicate names in shpchp and pciehp.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: Event handling rework

The event handler of PCIEHP driver is unnecessarily very complex. In
addition, current event handler can only a fixed number of events at
the same time, and some of events would be lost if several number of
events happened at the same time.

This patch simplify the event handler using 'work queue', and it also
fix the above-mentioned issue.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: cleanup wait command completion

This patch cleans up the code to wait for command completion.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: cleanup pciehp.h

This patch cleans up pciehp.h. This has no functional change.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: remove unnecessary php_ctlr

The struct php_ctlr seems to be only for complicating codes. This
patch removes struct php_ctlr and related codes.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: Remove unnecessary check in pciehp_ctrl.c

this was spotted by coverity (cid #819). We dereference p_slot
earlier in the function, and i found no way it could become NULL
anywhere.

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp - add missing locking

This patch fixes the problem that system will panic if multiple power
on/off operations are issued to the same slot in parallel. This
problem can be easily reproduced by commands below.

# while true; do echo 1 > power; echo 0 > power; done &
# while true; do echo 1 > power; echo 0 > power; done &

The cause is lack of locking for enable/disable operations. This patch
fixes this problem.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp: fix improper info messages

The slot number displayed in info messages would cause a confusion
because those are displayed in several ways (decimal and hex).
Furthermore, those slot number is not same as slot name (directory
name). This patch fixes those improper info messages.

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

pciehp - fix wrong return value

This patch fixes the problem that trying to enable already enabled
slot disables the slot by returning the proper value from
pciehp_enable_slot()/pciehp_disable_slot().

Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] PCI hotplug: convert semaphores to mutex

semaphore to mutex conversion.

the conversion was generated via scripts, and the result was validated
automatically via a script as well.

build tested with allyesconfig.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] PCI Express Hotplug: clear sticky power-fault bit

Per the PCI Express spec, the power-fault-detected bit in the
slot status register can be set anytime hardware detects a power
fault, regardless of whether the slot has a device populated in
it or not. This bit is sticky and must be explicitly cleared.
This patch is needed to allow hot-add after such a power fault
has been detected.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] pciehp: reduce debug message verbosity

Reduce the number of debug messages generated if pciehp debug is
enabled. I tried to restrict this to removing debug messages that
are either early-driver-debug type messages, or print information
that can be inferred through other debug prints.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] pciehp: miscellaneous cleanups

Remove un-necessary header includes, remove dead code, remove
some hardcoded constants...

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] pciehp: remove redundant data structures

State information is currently stored in per-slot as well as
per-pci-function data structures in pciehp. There's a lot of
overlap in the information kept, and some of it is never used.
This patch consolidates the state information to per-slot and
eliminates unused data structures. The biggest change is to
eliminate the pci_func structure and the code around managing
its lists.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] pciehp: reduce dependence on ACPI

Reduce the PCI Express hotplug driver's dependence on ACPI.
We don't walk the acpi namespace anymore to build a list of
bridges and devices. We go to ACPI only to run the _OSC or
_OSHP methods to transition control of hotplug hardware from
system BIOS to the hotplug driver, and to run the _HPP
method to get hotplug device parameters like cache line size,
latency timer and SERR/PERR enable from BIOS.

Note that one of the side effects of this patch is that pciehp
does not automatically enable the hot-added device or its DMA
bus mastering capability now. It expects the device driver to
do that. This may break some drivers and we will have to fix
them as they are reported.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] patch 1/8] pciehp: use the PCI core for hotplug resource management

This patch converts the pci express hotplug controller driver
to use the PCI core for resource management. This eliminates a
lot of duplicated code and integrates pciehp with the system's
normal PCI handling code.

Signed-off-by: Rajesh Shah <rajesh.shah@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

[PATCH] pciehp: Use dword accessors for PCI_ROM_ADDRESS

PCI_ROM_ADDRESS is a 32 bit register and as such should be accessed
using pci_bus_{read,write}_config_dword(). A recent audit of drivers/
turned up several cases of byte- and word-sized accesses. The harmful
ones were fixed by Linus directly. This patches up one of the remaining
harmless-but-still-wrong cases caught in the dragnet.

Signed-off-by: Adam Kropelin <akropel1@rochester.rr.com>
Cc: <kristen.c.accardi@intel.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

[PATCH] PCI Hotplug: new contact info

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!