Get rid of space before open square bracket.

Caught by checkpatch: "ERROR: space prohibited before open square
bracket '['"
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Get rid of space between function name and open parenthesis.

Caught by checkpatch: "WARNING: space prohibited between function name
and open parenthesis '('"
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Get rid of spaces before comma.

Caught by checkpatch: "ERROR: space prohibited before that ','"
Signed-off-by: NGeyslan G. Bem <geyslan@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Michael Reutman reports that an AMD/ATI EHCI host controller on one of
his computers does not stop transferring data when an active bulk QH
is unlinked from the async schedule.  Apparently that host controller
fails to implement the IAA mechanism correctly when an active QH is
unlinked.  This leads to data corruption, because the controller
continues to update the QH in memory when the driver doesn't expect
it.  As a result, the next URB submitted for that QH can hang, because
the link pointers for the TD queue have been messed up.  This
misbehavior is observed quite regularly.

To be fair, the EHCI spec (section 4.8.2) says that active QHs should
not be unlinked.  It goes on to recommend a procedure that involves
waiting for the QH to go inactive before unlinking it.  In the real
world this is impractical, not least because the QH may _never_ go
inactive.  (What were they thinking?)  Sometimes we have no choice but
to unlink an active QH.

In an attempt to avoid the problems that can ensue, this patch changes
how the driver decides when the unlink is complete.  In addition to
waiting through two IAA cycles, in cases where the QH was not known to
be inactive beforehand we now wait until a 2-ms period has elapsed
with the host controller making no change to the QH data structure
(the hw_current and hw_token fields in particular).  The intuition
here is that after such a long period, the endpoint must be NAKing and
hopefully the QH has been dropped from the host controller's internal
cache.  There's no way to know if this reasoning is really valid --
the spec is no help in this regard -- but at least this approach fixes
Michael's problem.

The test for whether the QH is already known to be inactive involves
the reason for unlinking the QH originally.  If it was unlinked
because it had halted, or it stopped in response to a short read, or
it overlaid a dummy TD (a silicon bug), then it certainly is inactive.
If it was unlinked because the TD queue was empty and no TDs have been
added to the queue in the meantime, then it must be inactive.  Or if
the hardware status indicates that the QH is currently halted (even if
that wasn't the reason for unlinking it), then it is inactive.
Otherwise, if none of those checks apply, we go through the 2-ms
delay.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-by: NMichael Reutman <mreutman@epiqsolutions.com>
Tested-by: NMichael Reutman <mreutman@epiqsolutions.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch replaces the "exception" bitflag in the ehci_qh structure
with a more explicit "unlink_reason" bitmask.  This is for use in the
following patch, where we will need to have a good idea of the
reason for unlinking a QH, not just "something exceptional happened".
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NMichael Reutman <mreutman@epiqsolutions.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds a new warning message to ehci-hcd.  The warning is
triggered whenever the driver finds that the hardware has set the
Active bit in a QH at a time when the driver expects the QH to be
completely idle.  Such bugs have been observed by users in the past,
and since they can lead to serious problems (such as inability to
unlink an URB that never completes), it would be good to know about
them when they occur.

This won't fix these bugs; that's a bigger job for a later patch.  But
success isn't guaranteed, since this depends on aspects of the
hardware which are not documented in the EHCI spec or for which the
spec's recommendations are clearly unworkable.  It therefore seems
worthwhile to check for these bugs proactively.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-by: NMichael Reutman <mreutman@epiqsolutions.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Incoming packets in high speed are randomly corrupted by h/w
resulting in multiple errors. This workaround makes FS as
default mode in all affected socs by disabling HS chirp
signalling.This errata does not affect FS and LS mode.

Forces all HS devices to connect in FS mode for all socs
affected by this erratum:
P3041 and P2041 rev 1.0 and 1.1
P5020 and P5010 rev 1.0 and 2.0
P5040, P1010 and T4240 rev 1.0
Signed-off-by: NRamneek Mehresh <ramneek.mehresh@freescale.com>
Signed-off-by: NNikhil Badola <nikhil.badola@freescale.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix compilation error in fsl ehci drv because ehci_reset()
and ehci_adjust_port_wakeup_flags() were not exported, and
are used when PM is enabled
Signed-off-by: NRamneek Mehresh <ramneek.mehresh@freescale.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Rockchip rk3288 EHCI controller doesn't properly detect
the case when a device is removed during suspend. Specifically,
when usb resume from suspend, the EHCI controller maintaining
the USB state (FLAG_CF is 1, Current Connect Status is 1),
but a USB device (like a USB camera on rk3288) may have been
disconnected actually.

Let's add a quirk to force ehci to go into the
usb_root_hub_lost_power() path and reset after resume.
This should generally reset the whole controller and all
ports and initialize everything cleanly again, and bring
the devices back up.

As part of this, rename the "hibernation" paramter of
ehci_resume() to force_reset since hibernation is simply
another case where we can't trust the autodetected status
and need to force a reset of devices.
Signed-off-by: NWu Liang feng <wulf@rock-chips.com>
Reviewed-by: NJulius Werner <jwerner@google.com>
Reviewed-by: NDoug Anderson <dianders@google.com>
Reviewed-by: NTomasz Figa <tfiga@google.com>
Reviewed-by: NPawel Osciak <posciak@google.com>
Reviewed-by: NSonny Rao <sonnyrao@google.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NDoug Anderson <dianders@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current EHCI implementation is prepared to toggle the
PORT_POWER bit to enable or disable a USB-Port. In some
cases this port power can not be just toggled by the PORT_POWER
bit, and the gpio-regulator is needed to be toggled too.

This patch defines a port power control interface ehci_port_power for
ehci core use, it toggles PORT_POWER bit as well as calls platform
defined .port_power if it is defined.
Signed-off-by: NMichael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Acked-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Platform drivers sometimes need to perform specific handling of hub
control requests. Make this possible by exporting the ehci_hub_control()
function which can then be called from a custom hub control handler in
the default case.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

According to Freescale imx28 Errata, "ENGR119653 USB: ARM to USB
register error issue", All USB register write operations must
use the ARM SWP instruction. So, we implement a special ehci_write
for imx28.

Discussion for it at below:
http://marc.info/?l=linux-usb&m=137996395529294&w=2

Without this patcheset, imx28 works unstable at high AHB bus loading.
If the bus loading is not high, the imx28 usb can work well at the most
of time. There is a IC errata for this problem, usually, we consider
IC errata is a problem not a new feature, and this workaround is needed
for that, so we need to add them to stable tree 3.11+.

Cc: stable@vger.kernel.org
Cc: robert.hodaszi@digi.com
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Tested-by: NMarc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In the drivers that no longer need it, it is removed.
It is removed from the Makefile. Drivers not fully converted
to dynamic debug have it shifted down into the individual
drivers.
Signed-off-by: NOliver Neukum <oneukum@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch continues the scheduling changes in ehci-hcd by adding a
table to store the bandwidth allocation below each TT.  This will
speed up the scheduling code, as it will no longer need to read
through the entire schedule to compute the bandwidth currently in use.

Properly speaking, the FS/LS budget calculations should be done in
terms of full-speed bytes per microframe, as described in the USB-2
spec.  However the driver currently uses microseconds per microframe,
and the scheduling code isn't robust enough at this point to change
over.  For the time being, we leave the calculations as they are.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch significantly changes the scheduling code in ehci-hcd.
Instead of calculating the current bandwidth utilization by trudging
through the schedule and adding up the times used by the existing
transfers, we will now maintain a table holding the time used for each
of 64 microframes.  This will drastically speed up the bandwidth
computations.

In addition, it eliminates a theoretical bug.  An isochronous endpoint
may have bandwidth reserved even at times when it has no transfers
listed in the schedule.  The table will keep track of the reserved
bandwidth, whereas adding up entries in the schedule would miss it.

As a corollary, we can keep bandwidth reserved for endpoints even
when they aren't in active use.  Eventually the bandwidth will be
reserved when a new alternate setting is installed; for now the
endpoint's reservation takes place when its first URB is submitted.

A drawback of this approach is that transfers with an interval larger
than 64 microframes will have to be charged for bandwidth as though
the interval was 64.  In practice this shouldn't matter much;
transfers with longer intervals tend to be rather short anyway (things
like hubs or HID devices).

Another minor drawback is that we will keep track of two different
period and phase values: the actual ones and the ones used for
bandwidth allocation (which are limited to 64).  This adds only a
small amount of overhead: 3 bytes for each endpoint.

The patch also adds a new debugfs file named "bandwidth" to display
the information stored in the new table.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch begins the process of unifying the scheduling parameters
that ehci-hcd uses for interrupt and isochronous transfers.  It
creates an ehci_per_sched structure, which will be stored in both
ehci_qh and ehci_iso_stream structures, and will contain the common
scheduling information needed for both.

Initially we merely create the new structure and move some existing
fields into it.  Later patches will add more fields and utilize these
structures in improved scheduling algorithms.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ehci-hcd is inconsistent in the sentinel values it uses to indicate
that no frame number has been assigned for a periodic transfer.  Some
places it uses NO_FRAME (defined as 65535), other places it uses -1,
and elsewhere it uses 9999.

This patch defines a value for NO_FRAME which can fit in a 16-bit
signed integer, and changes the code to use it everywhere.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch updates the iso_stream_schedule() routine in ehci-sched.c
to handle cases where an underrun causes an isochronous endpoint's
queue to empty out, but the client driver wants to maintain
synchronization with the device (i.e., the URB_ISO_ASAP flag is not
set).  This could not happen until recently, when ehci-hcd switched
over to completing URBs in a tasklet.

(This may seem like an unlikely case to worry about, but underruns are
all too common with the snd-usb-audio driver, which doesn't use
URB_ISO_ASAP.)

As part of the fix, some URBs may need to be given back when they are
submitted.  This is necessary when the URB's scheduled slots all fall
before the current value of ehci->last_iso_frame, and as an
optimization we do it also when the slots all fall before the current
frame number.

As a second part of the fix, we may need to skip some but not all of
an URB's packets.  This is necessary when some of the URB's scheduled
slots fall before the current value of ehci->last_iso_frame and some
of them fall after the current frame number.  A new field
(first_packet) is added to struct ehci_iso_sched, to indicate how many
packets should be skipped.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
CC: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The debugging code for ehci is enabled to run if the DEBUG flag is defined.
This patch enables the debugging code also when the kernel is configured
with dynamic debugging on.
Signed-off-by: NXenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch removes ehci_vdbg debugging statements from EHCI host controller
driver because they produce too much information, lowering the signal to noise
ratio when debugging, and because they are not used anymore.
Signed-off-by: NXenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ehci-hcd currently unlinks an interrupt QH when it becomes empty, that
is, after its last URB completes.  This works well because in almost
all cases, the completion handler for an interrupt URB resubmits the
URB; therefore the QH doesn't become empty and doesn't get unlinked.

When we start using tasklets for URB completion, this scheme won't work
as well.  The resubmission won't occur until the tasklet runs, which
will be some time after the completion is queued with the tasklet.
During that delay, the QH will be empty and so will be unlinked
unnecessarily.

To prevent this problem, this patch adds a 5-ms time delay before empty
interrupt QHs are unlinked.  Most often, during that time the interrupt
URB will be resubmitted and thus we can avoid unlinking the QH.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The has_hostpc capability bit indicates that the host controller has the
HOSTPC register extensions, but at the same time enables clock disabling
power saving features with the PHY Low Power Clock Disable (PHCD) bit.

However, some host controllers have the HOSTPC extensions but don't
support the low-power feature, so the PHCD bit must not be set on those
controllers. Add a separate capability bit for the low-power feature
instead, and change all existing users of has_hostpc to use this new
capability bit.

The idea for this commit is taken from an old 2012 commit that never got
merged ("disociate chipidea PHY low power suspend control from hostpc")
Inspired-by: NMatthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: NTuomas Tynkkynen <ttynkkynen@nvidia.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NStephen Warren <swarren@nvidia.com>
Reviewed-by: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NFelipe Balbi <balbi@ti.com>

In order to split ehci-hcd.c into separate modules, handshake() must be
exported. Rename the symbol to add an ehci_ prefix, to avoid any naming
clashes.
Signed-off-by: NManjunath Goudar <manjunath.goudar@linaro.org>
[swarren, split Manjunath's patches more logically, limit this change
to export just handshake()]
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Tested-by: NThierry Reding <thierry.reding@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 756aa6b3 (ehci-hub: improved
over-current recovery) added port power cycling on overcurrent indications as
needed by the MPC8349 USB controller after resolving of the overcurrent
situation in order to have the host state machine assert the correct port
status again.

Commit 81463c1d (EHCI: only power off port if
over-current is active) solved a thus resulting issue of endless overcurrent
changes in combination with the MAX4967 USB power supply chip that signals
overcurrent when power is not enabled by only powering off a port if the
overcurrent is currently active.

Added quirks flag need_oc_pp_cycle in order to specify the needed behaviour as
there is no common behaviour that can comply with both requirements.
Activated the quirks handling for Freescale 83xx based boards.
Signed-off-by: NChristian Engelmayer <christian.engelmayer@frequentis.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1665) changes the way ehci-hcd's end_unlink_async()
routine works in order to avoid recursive execution and to be more
efficient:

	Now when an IAA cycle ends, a new one gets started up right
	away (if it is needed) instead of waiting until the
	just-unlinked QH has been processed.

	The async_iaa list is renamed to async_idle, which better
	expresses its new purpose: It is now the list of QHs which are
	now completely idle and are waiting to be processed by
	end_unlink_async().

	A new flag is added to track whether an IAA cycle is in
	progress, because the list formerly known as async_iaa no
	longer stores the QHs waiting for the IAA to finish.

	The decision about how many QHs to process when an IAA cycle
	ends is now made at the end of the cycle, when we know the
	current state of the hardware, rather than at the beginning.
	This means a bunch of logic got moved from start_iaa_cycle()
	to end_unlink_async().
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1664) converts ehci-hcd's async_unlink, async_iaa, and
intr_unlink from singly-linked lists to standard doubly-linked
list_heads.  Originally it didn't seem necessary to use list_heads,
because items are always added to and removed from these lists in FIFO
order.  But now with more list processing going on, it's easier to use
the standard routines than continue with a roll-your-own approach.

I don't know if the code ends up being notably shorter, but the
patterns will be more familiar to any kernel hacker.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1662) does some more QH-related cleanup in ehci-hcd.
The qh->needs_rescan flag is currently used for two different
purposes; the patch replaces it with two separate flags for greater
clarity: qh->dequeue_during_giveback indicates that a completion
handler dequeued an URB (implying that a rescan is needed), and
qh->exception indicates that the QH is in an exceptional state
requiring an unlink (either it encountered an I/O error or an unlink
was requested).

The new flags get set where the dequeue, exception, or unlink request
occurred, rather than where the unlink is started.  This is so that in
the future, if we need to, we will be able to tell apart unlinks that
truly were required from those that were carried out merely because
the QH wasn't being used.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1642) adds an ehci->priv field for private use by EHCI
platform drivers.  The space was provided some time ago, but it didn't
have a name.

Until now none of the platform drivers has used this private space,
but that's about to change in the next patch of this series.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Without this, platform drivers e.g. ehci-omap.c will see a
different version of struct ehci_hcd than ehci-hcd.c and
break reference to 'debug_dir' and 'priv' members when
CONFIG_USB_DEBUG is enabled.
Signed-off-by: NRoger Quadros <rogerq@ti.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1630) cleans up a few minor items resulting from the
split-up of the ehci-hcd driver:

	Remove the product_desc string from the ehci_driver_overrides
	structure.  All drivers will use the generic "EHCI Host
	Controller" string.  (This was requested by Felipe Balbi.)

	Allow drivers to pass a NULL pointer to ehci_init_driver()
	if they don't have to override any settings.

	Remove a #define symbol that is no longer used from the
	ChipIdea host driver.

	Rename overrides to pci_overrides in ehci-pci.c, for
	consistency with ehci-platform.c.

	Mark the *_overrides structures as __initdata.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reviewed-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1624) prepares ehci-hcd for being split up into a core
library and separate platform driver modules.  A generic
ehci_hc_driver structure is created, containing all the "standard"
values, and a new mechanism is added whereby a driver module can
specify a set of overrides to those values.  In addition the
ehci_setup(), ehci_suspend(), and ehci_resume() routines need to be
EXPORTed for use by the drivers.

As a side effect of this change, a few routines no longer need to be
marked __maybe_unused.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
CC: Felipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1622) removes the USB-2.1 Link Power Management code
from the ehci-hcd driver.  This code was never integrated with
usbcore, it is full of bugs, and it was not getting used by anybody.

However, the debugging code for dumping the LPM-related fields in the
EHCI registers is left in place.  In theory it might be useful to see
these values, even though we don't use them.

This essentially amounts to a partial revert of commit
aa4d8342 (USB: EHCI: EHCI 1.1
addendum: preparation) and an almost full revert of commit
48f24970 (USB: EHCI: EHCI 1.1
addendum: Basic LPM feature support) plus its follow-ons.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation for splitting the ehci-hcd driver into a core library
and separate platform-specific driver modules, this patch (as1617)
changes the way ehci_read_frame_index() is handled.

Since the same core library will have to work with both PCI and
non-PCI platforms, the quirk handler routine will be compiled
unconditionally.  The decision about whether to call it or simply to
read the frame index register is made at run time, based on whether
the frame_index_bug quirk flag is set.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation for splitting the ehci-hcd driver into a core library
and separate platform-specific driver modules, this patch (as1616)
moves the console logging macros from ehci-dbg.c to ehci.h, where they
will be available to the platform drivers.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NFelipe Balbi <balbi@ti.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1609) changes the way ehci-hcd uses the "Isochronous
Scheduling Threshold" in its calculations.  Until now the code has
ignored the threshold except for certain Intel PCI-based controllers.
This violates the EHCI spec.

The new code takes the threshold into account always, removing the
need for the fs_i_thresh quirk flag.  In addition it implements the
"full frame cache" setting more efficiently, moving forward only as
far as the next frame boundary instead of always moving forward 8
microframes.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1608) reworks the logic used by ehci-hcd for scheduling
isochronous transfers.  Now the modular calculations are all based on
a window that starts at the last frame scanned for isochronous
completions.  No transfer descriptors for any earlier frames can
possibly remain on the schedule, so there can be no confusion from
schedule wrap-around.  This removes the need for a "slop" region of
arbitrary size.

There's no need to check for URBs that are longer than the schedule
length.  With the old code they could throw things off by wrapping
around and appearing to end in the near future rather than the distant
future.  Now such confusion isn't possible, and the existing test for
submissions that extend too far into the future will also catch those
that exceed the schedule length.  (But there still has to be an
initial test to handle the case where the schedule already extends as
far into the future as possible.)

Delays caused by IRQ latency won't confuse the algorithm unless they
are ridiculously long (over 250 ms); they will merely reduce how far
into the future new transfers can be scheduled.  A few people have
reported problems caused by delays of 50 ms or so.  Now instead of
failing completely, isochronous transfers will experience a brief
glitch and then continue normally.

(Whether this is truly a good thing is debatable.  A latency as large
as 50 ms generally indicates a bug is present, and complete failure of
audio or video transfers draws people's attention pretty vividly.
Making the transfers more robust also makes it easier for such bugs to
remain undetected.)

Finally, ehci->next_frame is renamed to ehci->last_iso_frame, because
that better describes what it is: the last frame to have been scanned
for isochronous completions.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1589) resolves some unlikely races involving system
shutdown or controller death in ehci-hcd:

	Shutdown races with both root-hub resume and controller
	resume.

	Controller death races with root-hub suspend.

A new bitflag is added to indicate that the controller has been shut
down (whether for system shutdown or because it died).  Tests are
added in the suspend and resume pathways to avoid reactivating the
controller after any sort of shutdown.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1587) simplifies ehci-hcd's scan_isoc() routine by
eliminating some local variables, declaring boolean-valued values as
bool rather than unsigned, changing variable names to make more sense,
and so on.

The logic at the end of the routine is cut down significantly.  The
scanning doesn't have to catch up all the way to where the hardware
is; it merely has to catch up to where the hardware was when the last
interrupt occurred.  If the hardware has made more progress since then
and issued another interrupt, a rescan will catch up to it.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1586) replaces the kernel timer used by ehci-hcd as an
I/O watchdog with an hrtimer event.

Unlike in the current code, the watchdog event is now always enabled
whenever any isochronous URBs are active.  This will prevent bugs
caused by the periodic schedule wrapping around with no completion
interrupts; the watchdog handler is guaranteed to scan the isochronous
transfers at least once during each iteration of the schedule.  The
extra overhead will be negligible: one timer interrupt every 100 ms.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1585) fixes a bug in ehci-hcd's scheme for scanning
interrupt QHs.

Currently a single routine takes care of scanning everything on the
periodic schedule.  Whenever an interrupt occurs, it scans all
isochronous and interrupt URBs scheduled for frames that have elapsed
since the last scan.

This has two disadvantages.  The first is relatively minor: An
interrupt QH is likely to end up getting scanned multiple times,
particularly if the last scan was not fairly recent.  (The current
code avoids this by maintaining a periodic_stamp in each interrupt
QH.)

The second is more serious.  The periodic schedule wraps around.  If
the last scan occurred during frame N, and the next scan occurs when
the schedule has gone through an entire cycle and is back at frame N,
the scanning code won't look at any frames other than N.  Consequently
it won't see any QHs that completed during frame N-1 or earlier.

The patch replaces the entire frame-based approach for scanning
interrupt QHs with a new routine using a list-based approach, the same
as for async QHs.  This has a slight disadvantage, because it means
that all interrupt QHs have to be scanned every time.  But it is more
robust than the current approach.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>