Separate the Orion host controller driver from ehci-hcd host
code into its own driver module because of following reason.

With the multiplatform changes in arm-soc tree, it becomes
possible to enable the mvebu platform (which uses
ehci-orion) at the same time as other platforms that require
a conflicting EHCI bus glue. At the moment, this results
in a warning like

drivers/usb/host/ehci-hcd.c:1297:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1277:0: note: this is the location of the previous definition
drivers/usb/host/ehci-orion.c:334:31: warning: 'ehci_orion_driver' defined but not used [-Wunused-variable]

and an ehci driver that only works on one of them.

With the infrastructure added by Alan Stern in patch 3e023203
"USB: EHCI: prepare to make ehci-hcd a library module", we can
avoid this problem by turning a bus glue into a separate
module, as we do here for the orion bus glue.

An earlier version of this patch was included in 3.9 but caused
a regression there, which has subsequently been fixed.

While we are here, use the opportunity to disabiguate the two
Marvell EHCI controller implementations in Kconfig.

In V4 (arnd):
- Improve Kconfig text

In V3:
- More detail provided in commit message regarding this patch.
- Replaced hcd_name string "ehci-orion" into "orion-ehci".
- MODULE_LICENSE is GPL v2.
- In ehci_init_driver calling second argument passed  as NULL instead of
  ehci_orion_overrides because ehci_orion_overrides is removed.

In V2:
- Tegra patch related changes removed from this patch.
Signed-off-by: NManjunath Goudar <manjunath.goudar@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NJason Cooper <jason@lakedaemon.net>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This lets us use the ehci-platform driver on platforms without special
requirements for their ehci controllers. In particular, this is true
for the vt8500/wm8x50 platforms, which currently have a separate
driver that causes problems with multiplatform configurations.
Tested-by: NTony Prisk <linux@prisktech.co.nz>
Tested-by: NPeter Vasil <petervasil@gmail.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
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 (as1668) consolidates two nearly identical code paths in
ehci_urb_dequeue().  The test for !qh can be removed because it will
never succeed; the fact that usb_hcd_check_unlink_urb() returned 0
means that urb must be queued and therefore urb->hcpriv must point to
a QH.
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 (as1634) simplifies some of the code associated with the
per-port change bits added in EHCI-1.1, and in particular it fixes a
bug in the logic of ehci_hub_status_data().  Even if the change bit
doesn't indicate anything happened on a particular port, we still have
to notify the core about changes to the suspend or reset status.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1663) fixes a regression caused by commit
6e0c3339 (USB: EHCI: unlink one async
QH at a time).  In order to avoid keeping multiple QHs in an unusable
intermediate state, that commit changed unlink_empty_async() so that
it unlinks only one empty QH at a time.

However, when the EHCI root hub is suspended, _all_ async QHs need to
be unlinked.  ehci_bus_suspend() used to do this by calling
unlink_empty_async(), but now this only unlinks one of the QHs, not
all of them.

The symptom is that when the root hub is resumed, USB communications
don't work for some period of time.  This is because ehci-hcd doesn't
realize it needs to restart the async schedule; it assumes that
because some QHs are already on the schedule, the schedule must be
running.

The easiest way to fix the problem is add a new function that unlinks
all the async QHs when the root hub is suspended.

This patch should be applied to all kernels that have the 6e0c3339
commit.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-and-tested-by: NAdrian Bassett <adrian.bassett@hotmail.co.uk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1645) converts ehci-omap over to the new "ehci-hcd is a
library" approach, so that it can coexist peacefully with other EHCI
platform drivers and can make use of the private area allocated at
the end of struct ehci_hcd.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1660) works around a hardware problem present in some
(if not all) Intel EHCI controllers.  After a QH has been unlinked
from the async schedule and the corresponding IAA interrupt has
occurred, the controller is not supposed access the QH and its qTDs.
There certainly shouldn't be any more DMA writes to those structures.
Nevertheless, Intel's controllers have been observed to perform a
final writeback to the QH's overlay region and to the most recent qTD.
For more information and a test program to determine whether this
problem is present in a particular controller, see

	http://marc.info/?l=linux-usb&m=135492071812265&w=2
	http://marc.info/?l=linux-usb&m=136182570800963&w=2

This patch works around the problem by always waiting for two IAA
cycles when unlinking an async QH.  The extra IAA delay gives the
controller time to perform its final writeback.

Surprisingly enough, the effects of this silicon bug have gone
undetected until quite recently.  More through luck than anything
else, it hasn't caused any apparent problems.  However, it does
interact badly with the path that follows this one, so it needs to be
addressed.

This is the first part of a fix for the regression reported at:

	https://bugs.launchpad.net/bugs/1088733Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NStephen Thirlwall <sdt@dr.com>
CC: <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit d57ada0c.

All of these are wrong and need to be reverted for now.

Cc: Manjunath Goudar <manjunath.goudar@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 6ed3c43d.

All of these are wrong, and need to be reverted for now.

Cc: Manjunath Goudar <manjunath.goudar@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the multiplatform changes in arm-soc tree, it becomes
possible to enable the mvebu platform (which uses
ehci-orion) at the same time as other platforms that require
a conflicting EHCI bus glue. At the moment, this results
in a warning like

drivers/usb/host/ehci-hcd.c:1297:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1277:0: note: this is the location of the previous definition
drivers/usb/host/ehci-orion.c:334:31: warning: 'ehci_orion_driver' defined but not used [-Wunused-variable]

and an ehci driver that only works on one of them.

With the infrastructure added by Alan Stern in patch 3e023203
"USB: EHCI: prepare to make ehci-hcd a library module", we can
avoid this problem by turning a bus glue into a separate
module, as we do here for the orion bus glue.
Signed-off-by: NManjunath Goudar <manjunath.goudar@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the multiplatform changes in arm-soc tree, it becomes
possible to enable the vt8500 platform at the same time
as other platforms that require a conflicting EHCI bus
glue. At the moment, this results in a warning like

drivers/usb/host/ehci-hcd.c:1277:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1257:0: note: this is the location of the previous definition
drivers/usb/host/ehci-omap.c:319:31: warning: 'ehci_hcd_omap_driver' defined but not used [-Wunused-variable]

and an ehci driver that only works on one of them.

With the infrastructure added by Alan Stern in patch 3e023203
"USB: EHCI: prepare to make ehci-hcd a library module", we can
avoid this problem by turning a bus glue into a separate
module, as we do here for the vt8500 bus glue.
Signed-off-by: NManjunath Goudar <manjunath.goudar@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NTony Prisk <linux@prisktech.co.nz>
Cc: Alexey Charkov <alchark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1650) adds calls to the new
usb_hcd_{start,end}_port_resume() functions to ehci-hcd.  Now EHCI
root hubs won't be runtime suspended while they are sending a resume
signal to one of their ports.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NMing Lei <ming.lei@canonical.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1643b) fixes a build error in ehci-hcd when compiling for
ARM with allmodconfig:

drivers/usb/host/ehci-hcd.c:1285:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1255:0: note: this is the location of the previous definition
drivers/usb/host/ehci-mxc.c:280:31: warning: 'ehci_mxc_driver' defined but not used [-Wunused-variable]
drivers/usb/host/ehci-hcd.c:1285:0: warning: "PLATFORM_DRIVER" redefined [enabled by default]
drivers/usb/host/ehci-hcd.c:1255:0: note: this is the location of the previous definition

The fix is to convert ehci-mxc over to the new "ehci-hcd is a library"
scheme so that it can coexist peacefully with the ehci-platform
driver.  As part of the conversion the ehci_mxc_priv data structure,
which was allocated dynamically, is now placed where it belongs: in
the private area at the end of struct ehci_hcd.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1641) fixes a minor bug in ehci-hcd left over from when
the Chipidea driver was converted to the "ehci-hcd is a library"
scheme.  The test for whether the Chipidea platform driver is active
should be IS_ENABLED(), not defined().
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 (as1627) splits the ehci-hcd core code, which has become a
separate library module, out from the ChipIdea host driver.  Instead
of #include-ing ehci-hcd.c directly, the ChipIdea module will now use
the ehci-hcd library in a normal fashion.

This fixes a build error caused by commit
3e023203 (USB: EHCI: prepare to make
ehci-hcd a library module); I had forgotten about the unorthodox way
the ChipIdea driver uses the ehci-hcd code.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NAlexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1626) splits the ehci-platform code from ehci-hcd out
into its own separate driver module.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch (as1625) splits the PCI portion of ehci-hcd out into its
own separate driver module, called ehci-pci.  Consistently with the
current practice, the decision whether to build this module is not
user-configurable.  If EHCI and PCI are enabled then the module will
be built, always.
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 (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 (as1623) removes the ehci_port_power() routine and all the
places that call it.  There's no reason for ehci-hcd to change the
port power settings; the hub driver takes care of all that stuff.

There is one exception: When the controller is resumed from
hibernation or following a loss of power, the ports that are supposed
to be handed over to a companion controller must be powered on first.
Otherwise the handover won't work.  This process is not visible to the
hub driver, so it has to be handled in ehci-hcd.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
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>

The users have been converted to use the ehci platform driver instead, thus
making the ehci-cns3xxx driver obsolete, so remove it.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The platform code has been converted to use the ehci-platform driver instead
thus obsoleting the ehci-au1xxx driver, which can be removed.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The platform code has been migrated to register the ehci-platform driver, thus
obsoleting the ehci-xls driver, which can be removed.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The platform code registering the Loongson 1B EHCI driver has now been
converted to register the ehci-platform driver instead, thus obsoleting the
ehci-ls1x driver, which can be removed.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This driver is not registered by any in-tree user. If needed it the EHCI
driver can be reinstatied using the ehci-platform driver with caps_offset to
0x100.
Signed-off-by: NFlorian Fainelli <florian@openwrt.org>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
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>

Just like for the in-tree early console debug port driver, the
hypervisor - when using a debug port based console - also needs to be
told about controller resets, so it can suppress using and then
re-initialize the debug port accordingly.

Other than the in-tree driver, the hypervisor driver actually cares
about doing this only for the device where the debug is port actually
in use, i.e. it needs to be told the coordinates of the device being
reset (quite obviously, leveraging the addition done for that would
likely benefit the in-tree driver too).
Signed-off-by: NJan Beulich <jbeulich@suse.com>
Acked-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This change adds OHCI and EHCI support for the tilegx's on-chip
USB hardware.
Signed-off-by: NChris Metcalf <cmetcalf@tilera.com>

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 (as1588) adjusts the locking in ehci-hcd's various halt,
shutdown, and suspend/resume pathways.  We want to hold the spinlock
while writing device registers and accessing shared variables, but not
while polling in a loop.

In addition, there's no need to call ehci_work() at times when no URBs
can be active, i.e., in ehci_stop() and ehci_bus_suspend().

Finally, ehci_adjust_port_wakeup_flags() is called only in situations
where interrupts are enabled; therefore it can use spin_lock_irq
rather than spin_lock_irqsave.
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>

This patch (as1584) fixes a minor bug that has been present in
ehci-hcd since the beginning.

Scanning the schedules for URB completions is single-threaded.  If a
completion interrupt occurs while an URB is being given back, the
interrupt handler realizes that a scan is in progress on another CPU
and avoids starting a new one.

This means that completion events can be lost.  If an URB completes
after it has been scanned but while a scan is still in progress, the
driver won't notice and won't rescan the completed URB.

The patch fixes the problem by adding a new flag to indicate that
another scan is needed after the current scan is done.  The flag gets
set whenever a completion interrupt occurs while a scan is in
progress.  The rescan will see the completion, thus preventing it from
getting lost.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>