The usb topology after this change will have symlinks between usb3 ports
and their usb2 peers, for example:

usb2/2-1/2-1:1.0/2-1-port1/peer => ../../../../usb3/3-1/3-1:1.0/3-1-port1
usb2/2-1/2-1:1.0/2-1-port2/peer => ../../../../usb3/3-1/3-1:1.0/3-1-port2
usb2/2-1/2-1:1.0/2-1-port3/peer => ../../../../usb3/3-1/3-1:1.0/3-1-port3
usb2/2-1/2-1:1.0/2-1-port4/peer => ../../../../usb3/3-1/3-1:1.0/3-1-port4
usb2/2-0:1.0/usb2-port1/peer    => ../../../usb3/3-0:1.0/usb3-port1
usb2/2-0:1.0/usb2-port2/peer    => ../../../usb3/3-0:1.0/usb3-port2
usb2/2-0:1.0/usb2-port3/peer    => ../../../usb3/3-0:1.0/usb3-port3
usb2/2-0:1.0/usb2-port4/peer    => ../../../usb3/3-0:1.0/usb3-port4

usb3/3-1/3-1:1.0/usb3-1-port1/peer => ../../../../usb2/2-1/2-1:1.0/2-1-port1
usb3/3-1/3-1:1.0/usb3-1-port2/peer => ../../../../usb2/2-1/2-1:1.0/2-1-port2
usb3/3-1/3-1:1.0/usb3-1-port3/peer => ../../../../usb2/2-1/2-1:1.0/2-1-port3
usb3/3-1/3-1:1.0/usb3-1-port4/peer => ../../../../usb2/2-1/2-1:1.0/2-1-port4
usb3/3-0:1.0/usb3-port1/peer       => ../../../usb2/2-0:1.0/usb2-port1
usb3/3-0:1.0/usb3-port2/peer       => ../../../usb2/2-0:1.0/usb2-port2
usb3/3-0:1.0/usb3-port3/peer       => ../../../usb2/2-0:1.0/usb2-port3
usb3/3-0:1.0/usb3-port4/peer       => ../../../usb2/2-0:1.0/usb2-port4

Introduce link_peers_report() to notify on all link_peers() failure
cases.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI identifies peer ports by setting their 'group_token' and
'group_position' _PLD data to the same value.  If a platform has tier
mismatch [1] , ACPI can override the default (USB3 defined) peer port
association for internal hubs.  External hubs follow the default peer
association scheme.

Location data is cached as an opaque cookie in usb_port_location data.

Note that we only consider the group_token and group_position attributes
from the _PLD data as ACPI specifies that group_token is a unique
identifier.

When we find port location data for a port then we assume that the
firmware will also describe its peer port.  This allows the
implementation to only ever set the peer once.  This leads to a question
about what happens when a pm runtime event occurs while the peer
associations are still resolving.  Since we only ever set the peer
information once, a USB3 port needs to be prevented from suspending
while its ->peer pointer is NULL (implemented in a subsequent patch).

There is always the possibility that firmware mis-identifies the ports,
but there is not much the kernel can do in that case.

[1]: xhci 1.1 appendix D figure 131
[2]: acpi 5 section 6.1.8

[alan]: don't do default peering when acpi data present
Suggested-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Given that root hub port peers are already established, external hub peer
ports can be determined by traversing the device topology:

1/ ascend to the parent hub and find the upstream port_dev

2/ walk ->peer to find the peer port

3/ descend to the peer hub via ->child

4/ find the port with the matching port id

Note that this assumes the port labeling scheme required by the
specification [1].

[1]: usb3 3.1 section 10.3.3
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Assume that the peer of a superspeed port is the port with the same id
on the shared_hcd root hub.  This identification scheme is required of
external hubs by the USB3 spec [1].  However, for root hubs, tier mismatch
may be in effect [2].  Tier mismatch can only be enumerated via platform
firmware.  For now, simply perform the nominal association.

A new lock 'usb_port_peer_mutex' is introduced to synchronize port
device add/remove with peer lookups.  It protects peering against
changes to hcd->shared_hcd, hcd->self.root_hub, hdev->maxchild, and
port_dev->child pointers.

[1]: usb 3.1 section 10.3.3
[2]: xhci 1.1 appendix D

Cc: Alan Stern <stern@rowland.harvard.edu>
[alan: usb_port_peer_mutex locking scheme]
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current port name "portX" is ambiguous.  Before adding more port
messages rename ports to "<hub-device-name>-portX"

This is an ABI change, but the suspicion is that it will go unnoticed as
the port power control implementation has been broken since its
introduction.  If however, someone was relying on the old name we can
add sysfs links from the old name to the new name.

Additionally, it unifies/simplifies port dev_printk messages and modifies
instances of:
	dev_XXX(hub->intfdev, ..."port %d"...
	dev_XXX(&hdev->dev, ..."port%d"...
into:
	dev_XXX(&port_dev->dev, ...

Now that the names are unique usb_port devices it would be nice if they
could be included in /sys/bus/usb.  However, it turns out that this
breaks 'lsusb -t'.  For now, create a dummy port driver so that print
messages are prefixed "usb 1-1-port3" rather than the
subsystem-ambiguous " 1-1-port3".

Finally, it corrects an odd usage of sscanf("port%d") in usb-acpi.c.
Suggested-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A hub indicates whether it supports per-port power control via the
wHubCharacteristics field in its descriptor.  If it is not supported
a hub will still emulate ClearPortPower(PORT_POWER) requests by
stopping the link state machine.  However, since this does not save
power do not bother suspending.

This also consolidates support checks into a
hub_is_port_power_switchable() helper.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The USB core doesn't properly handle mutual exclusion between
resetting a hub and changing the power states of the hub's ports.  We
need to avoid sending port-power requests to the hub while it is being
reset, because such requests cannot succeed.

This patch fixes the problem by keeping track of when a reset is in
progress.  At such times, attempts to suspend (power-off) a port will
fail immediately with -EBUSY, and calls to usb_port_runtime_resume()
will update the power_is_on flag and return immediately.  When the
reset is complete, hub_activate() will automatically restore each port
to the proper power state.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of having to audit all sysfs attributes, to ensure we get them
right, use the default macros the driver core provides us (read-only,
read-write) to make the code simpler, and to prevent any mistakes from
ever happening.
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Userspace can tell the kernel to power off any USB port, including ones
that are visible and connectible to users.  When an attached USB device
goes into suspend, the port will be powered off if the
pm_qos_no_port_poweroff file for its port is set to 0, the device does
not have remote wakeup enabled, and the device is marked as persistent.

If the user disconnects the USB device while the port is powered off,
the current code does not handle that properly.  If you disconnect a
device, and then run `lsusb -v -s` for the device, the device disconnect
does not get handled by the USB core.  The runtime resume of the port
fails, because hub_port_debounce_be_connected() returns -ETIMEDOUT.

This means the port resume fails and khubd doesn't handle the USB device
disconnect.  This leaves the device listed in lsusb, and the port's
runtime_status will be permanently marked as "error".

Fix this by ignoring the return value of hub_port_debounce_be_connected.
Users can disconnect USB devices while the ports are powered off, and we
must be able to handle that.

This patch should be backported to kernels as old as 3.9, that
contain the commit ad493e5e "usb: add
usb port auto power off mechanism"
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Lan Tianyu <tianyu.lan@intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>

usb_hub_to_struct_hub() can return NULL in some unlikely cases.
Add checks where appropriate, or pass the hub pointer as an additional
argument if it's known to be valid.

The places it makes sense to check usb_hub_to_struct_hub()
are picked based on feedback from Alan Stern.
Signed-off-by: NMathias Nyman <mathias.nyman@linux.intel.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The "runtime idle" helper routine, rpm_idle(), currently ignores
return values from .runtime_idle() callbacks executed by it.
However, it turns out that many subsystems use
pm_generic_runtime_idle() which checks the return value of the
driver's callback and executes pm_runtime_suspend() for the device
unless that value is not 0.  If that logic is moved to rpm_idle()
instead, pm_generic_runtime_idle() can be dropped and its users
will not need any .runtime_idle() callbacks any more.

Moreover, the PCI, SCSI, and SATA subsystems' .runtime_idle()
routines, pci_pm_runtime_idle(), scsi_runtime_idle(), and
ata_port_runtime_idle(), respectively, as well as a few drivers'
ones may be simplified if rpm_idle() calls rpm_suspend() after 0 has
been returned by the .runtime_idle() callback executed by it.

To reduce overall code bloat, make the changes described above.
Tested-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NKevin Hilman <khilman@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>

Remove the call to dev_pm_qos_hide_flags(), added by commit 6e30d7cb
"usb: Add driver/usb/core/(port.c,hub.h) files", from
usb_port_device_release(), because (1) it is completely unnecessary
(the flags have been removed already by the PM core during the
unregistration of the device object) and (2) it triggers a NULL
pointer dereference in sysfs_find_dirent() (dev->kobj.sd is NULL at
this point).
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1675) removes the CONFIG_USB_SUSPEND option, essentially
replacing it everywhere with CONFIG_PM_RUNTIME (except for one place
in hub.c, where it is replaced with CONFIG_PM because the code needs
to be used in both runtime and system PM).  The net result is code
shrinkage and simplification.

There's very little point in keeping CONFIG_USB_SUSPEND because almost
everybody enables it.  The few that don't will find that the usbcore
module has gotten somewhat bigger and they will have to take active
measures if they want to prevent hubs from being runtime suspended.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
CC: Peter Chen <peter.chen@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 88bb965e.

The linux-next branch of linux-pm tree has replaced
acpi_power_resource_(un)register_device() with new routines.
Commit 88bb965e will cause conflict in the linux-next tree.
So revert it and this will not affect other functions. Will
send a new patch with new routines after 3.9 merge window.
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to set power.async_suspend for usb port in order
to allow it to be suspended and resumed asynchronously during
system sleep transitions.

The power.async_suspend flag is also set for devices that don't have
suspend or resume callbacks, because otherwise they would make the
main suspend/resume thread wait for their "asynchronous" children
(during suspend) or parents (during resume), effectively negating the
possible gains from executing these devices' suspend and resume
callbacks asynchronously.
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to expose usb port's pm qos flags(pm_qos_no_power_off,
pm_qos_remote_wakeup) to user space. User can set pm_qos_no_power_off
flag to prohibit the port from being powered off.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to add usb port auto power off mechanism.
When usb device is suspending, usb core will suspend usb port and
usb port runtime pm callback will clear PORT_POWER feature to
power off port if all conditions were met. These conditions are
remote wakeup disable, pm qos NO_POWER_OFF flag clear and persist
enable. When it resumes, power on port again.

Add did_runtime_put in the struct usb_port to ensure
pm_runtime_get/put(portdev) to be called pairedly.  Set did_runtime_put
to true when call pm_runtime_put(portdev) during suspending. The
pm_runtime_get(portdev) only will be called when did_runtime_put
is set to true during resuming. Set did_runtime_put to false after
calling pm_runtime_get(portdev).

Make clear_port_feature() and hdev_to_hub() as global symbol.
Rename clear_port_feature() to usb_clear_port_feature() and
hdev_to_hub() to usb_hub_to_struct_hub().

Extend hub_port_debounce() with the fuction of debouncing to
be connected. Add two wraps: hub_port_debounce_be_connected()
and hub_port_debouce_be_stable().

Increase HUB_DEBOUNCE_TIMEOUT to 2000 because some usb ssds
needs around 1.5 or more to make the hub port status to be
connected steadily after being powered off and powered on.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to add runtime pm callback for usb port device.
Set/clear PORT_POWER feature in the resume/suspend callback.
Add portnum for struct usb_port to record port number. Do
pm_rumtime_get_sync/put(portdev) when a device is plugged/unplugged
to prevent it from being powered off when it is active.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to register usb port's acpi power resources. Create
link between usb port device and its acpi power resource.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Some platforms provide usb port connect types through ACPI. This
patch is to add this new attribute to expose these information
to user space.
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to fix compilation error and warning on the arm and blackfin.
Add linux/slab.h head file to driver/usb/core/port.c. These are reported
from 0-DAY kernel build testing backend.

head:   6e30d7cb
commit: 6e30d7cb [26/26] usb: Add driver/usb/core/(port.c,hub.h) files
config: make ARCH=arm at91_dt_defconfig

All error/warnings:

   drivers/usb/core/port.c: In function 'usb_port_device_release':
>> drivers/usb/core/port.c:25:2: error: implicit declaration of function 'kfree' [-Werror=implicit-function-declaration]
   drivers/usb/core/port.c: In function 'usb_hub_create_port_device':
>> drivers/usb/core/port.c:38:2: error: implicit declaration of function 'kzalloc' [-Werror=implicit-function-declaration]
>> drivers/usb/core/port.c:38:40: error: 'GFP_KERNEL' undeclared (first use in this function)
   drivers/usb/core/port.c:38:40: note: each undeclared identifier is reported only once for each function it appears in
   cc1: some warnings being treated as errors

head:   6e30d7cb
commit: 6e30d7cb [26/26] usb: Add driver/usb/core/(port.c,hub.h) files
config: make ARCH=blackfin BF526-EZBRD_defconfig

All warnings:

   drivers/usb/core/port.c: In function 'usb_port_device_release':
   drivers/usb/core/port.c:25:2: error: implicit declaration of function 'kfree' [-Werror=implicit-function-declaration]
   drivers/usb/core/port.c: In function 'usb_hub_create_port_device':
   drivers/usb/core/port.c:38:2: error: implicit declaration of function 'kzalloc' [-Werror=implicit-function-declaration]
>> drivers/usb/core/port.c:38:11: warning: assignment makes pointer from integer without a cast [enabled by default]
   cc1: some warnings being treated as errors
Reported-by: NFengguang Wu <wfg@linux.intel.com>
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch is to create driver/usb/core/(port.c,hub.h) files and move usb
port related code into port.c.
Signed-off-by: NLan Tianyu <tianyu.lan@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>