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: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Michael Reutman <mreutman@epiqsolutions.com>
Signed-off-by: Greg 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: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Signed-off-by: Nikhil Badola <nikhil.badola@freescale.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg 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: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Wu Liang feng <wulf@rock-chips.com>
Reviewed-by: Julius Werner <jwerner@google.com>
Reviewed-by: Doug Anderson <dianders@google.com>
Reviewed-by: Tomasz Figa <tfiga@google.com>
Reviewed-by: Pawel Osciak <posciak@google.com>
Reviewed-by: Sonny Rao <sonnyrao@google.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Doug Anderson <dianders@google.com>
Signed-off-by: Greg 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: Michael Grzeschik <m.grzeschik@pengutronix.de>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg 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: Peter Chen <peter.chen@freescale.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Tested-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg 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: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
CC: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Greg 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: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Xenia Ragiadakou <burzalodowa@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All patches here have been pending on linux-usb
and sitting in linux-next for a while now.
The biggest things in this tag are:
DWC3 learned proper usage of threaded IRQ
handlers and now we spend very little time
in hardirq context.
MUSB now has proper support for BeagleBone and
Beaglebone Black.
Tegra's USB support also got quite a bit of love
and is learning to use PHY layer and generic DT
attributes.
Other than that, the usual pack of cleanups and
non-critical fixes follow.
Signed-of-by: Felipe Balbi <balbi@ti.com>
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Merge tag 'usb-for-v3.12' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-next
Felipe writes:
usb: patches for v3.12 merge window
All patches here have been pending on linux-usb
and sitting in linux-next for a while now.
The biggest things in this tag are:
DWC3 learned proper usage of threaded IRQ
handlers and now we spend very little time
in hardirq context.
MUSB now has proper support for BeagleBone and
Beaglebone Black.
Tegra's USB support also got quite a bit of love
and is learning to use PHY layer and generic DT
attributes.
Other than that, the usual pack of cleanups and
non-critical fixes follow.
Signed-of-by: Felipe Balbi <balbi@ti.com>
Conflicts:
drivers/usb/gadget/udc-core.c
drivers/usb/host/ehci-tegra.c
drivers/usb/musb/omap2430.c
drivers/usb/musb/tusb6010.c
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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg 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: Matthieu CASTET <matthieu.castet@parrot.com>
Signed-off-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Felipe 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: Manjunath Goudar <manjunath.goudar@linaro.org>
[swarren, split Manjunath's patches more logically, limit this change
to export just handshake()]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 756aa6b3d5 (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 81463c1d70 (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: Christian Engelmayer <christian.engelmayer@frequentis.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Roger Quadros <rogerq@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
CC: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg 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
aa4d834298 (USB: EHCI: EHCI 1.1
addendum: preparation) and an almost full revert of commit
48f2497014 (USB: EHCI: EHCI 1.1
addendum: Basic LPM feature support) plus its follow-ons.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg 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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1583) changes ehci-hcd to use an hrtimer event for
unlinking empty (unused) async QHs instead of using a kernel timer.
The check for empty QHs is moved to a new routine, where it doesn't
require going through an entire scan of both the async and periodic
schedules. And it can unlink multiple QHs at once, unlike the current
code.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1582) changes ehci-hcd's strategy for unlinking async
QHs. Currently the driver never unlinks more than one QH at a time.
This can be inefficient and cause unnecessary delays, since a QH
cannot be reused while it is waiting to be unlinked.
The new strategy unlinks all the waiting QHs at once. In practice the
improvement won't be very big, because it's somewhat uncommon to have
two or more QHs waiting to be unlinked at any time. But it does
happen, and in any case, doing things this way makes more sense IMO.
The change requires the async unlinking code to be refactored
slightly. Now in addition to the routines for starting and ending an
unlink, there are new routines for unlinking a single QH and starting
an IAA cycle. This approach is needed because there are two separate
paths for unlinking async QHs:
When a transfer error occurs or an URB is cancelled, the QH
must be unlinked right away;
When a QH has been idle sufficiently long, it is unlinked
to avoid consuming DMA bandwidth uselessly.
In the first case we want the unlink to proceed as quickly as
possible, whereas in the second case we can afford to batch several
QHs together and unlink them all at once. Hence the division of
labor.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1581) replaces the iaa_watchdog kernel timer used by
ehci-hcd with an hrtimer event, in keeping with the general conversion
to high-res timers.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1580) makes ehci_iso_stream structures behave more like
QHs, in that they will remain allocated until their isochronous
endpoint is disabled. This will come in useful in the future, when
periodic bandwidth gets allocated as an altsetting is installed rather
than on-the-fly.
For now, the change to the ehci_iso_stream lifetimes means that each
structure is always deallocated at exactly one spot in
ehci_endpoint_disable() and never used again. As a result, it is no
longer necessary to use reference counting on these things, and the
patch removes it.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1579) adds an hrtimer event to handle deallocation of
iTDs and siTDs in ehci-hcd.
Because of the frame-oriented approach used by the EHCI periodic
schedule, the hardware can continue to access the Transfer Descriptor
for isochronous (or split-isochronous) transactions for up to a
millisecond after the transaction completes. The iTD (or siTD) must
not be reused before then.
The strategy currently used involves putting completed iTDs on a list
of cached entries and every so often returning them to the endpoint's
free list. The new strategy reduces overhead by putting completed
iTDs back on the free list immediately, although they are not reused
until it is safe to do so.
When the isochronous endpoint stops (its queue becomes empty), the
iTDs on its free list get moved to a global list, from which they will
be deallocated after a minimum of 2 ms. This delay is what the new
hrtimer event is for.
Overall this may not be a tremendous improvement over the current
code, but to me it seems a lot more clear and logical. In addition,
it removes the need for each iTD to keep a reference to the
ehci_iso_stream it belongs to, since the iTD never needs to be moved
back to the stream's free list from the global list.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1578) adds an hrtimer event to handle the death of an
EHCI controller. When a controller dies, it doesn't necessarily stop
running right away. The new event polls at 1-ms intervals to see when
all activity has safely stopped. This replaces a busy-wait polling
loop in the current code.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1577) adds hrtimer support for unlinking interrupt QHs
in ehci-hcd. The current code relies on a fixed delay of either 2 or
55 us, which is not always adequate and in any case is totally bogus.
Thanks to internal caching, the EHCI hardware may continue to access
an interrupt QH for more than a millisecond after it has been unlinked.
In fact, the EHCI spec doesn't say how long to wait before using an
unlinked interrupt QH. The patch sets the delay to 9 microframes
minimum, which ought to be adequate.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1576) adds hrtimer support for managing ehci-hcd's
async schedule. Just as with the earlier change to the periodic
schedule management, two new hrtimer events take care of everything.
One event polls at 1-ms intervals to see when the Asynchronous
Schedule Status (ASS) flag matches the Asynchronous Schedule Enable
(ASE) value; the schedule's state must not be changed until it does.
The other event delays for 15 ms after the async schedule becomes
empty before turning it off.
The new events replace a busy-wait poll and a kernel timer usage.
They also replace the rather illogical method currently used for
indicating the async schedule should be turned off: attempting to
unlink the dedicated QH at the head of the async list.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1573) adds hrtimer support for managing ehci-hcd's
periodic schedule. There are two issues to deal with.
First, the schedule's state (on or off) must not be changed until the
hardware status has caught up with the current command. This is
handled by an hrtimer event that polls at 1-ms intervals to see when
the Periodic Schedule Status (PSS) flag matches the Periodic Schedule
Enable (PSE) value.
Second, the schedule should not be turned off as soon as it becomes
empty. Turning the schedule on and off takes time, so we want to wait
until the schedule has been empty for a suitable period before turning
it off. This is handled by an hrtimer event that gets set to expire
10 ms after the periodic schedule becomes empty.
The existing code polls (for up to 1125 us and with interrupts
disabled!) to check the status, and doesn't implement a delay before
turning off the schedule. Furthermore, if the polling fails then the
driver decides that the controller has died. This has caused problems
for several people; some controllers can take 10 ms or more to turn
off their periodic schedules.
This patch fixes these issues. It also makes the "broken_periodic"
workaround unnecessary; there is no longer any danger of turning off
the periodic schedule after it has been on for less than 1 ms.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1572) begins the conversion of ehci-hcd over to using
high-resolution timers rather than old-fashioned low-resolution kernel
timers. This reduces overhead caused by timer roundoff on systems
where HZ is smaller than 1000. Also, the new timer framework
introduced here is much more logical and easily extended than the
ad-hoc approach ehci-hcd currently uses for timers.
An hrtimer structure is added to ehci_hcd, along with a bitflag array
and an array of ktime_t values, to keep track of which timing events
are pending and what their expiration times are.
Only the infrastructure for the timing operations is added in this
patch. Later patches will add routines for handling each of the
various timing events the driver needs. In some cases the new hrtimer
handlers will replace the existing handlers for ehci-hcd's kernel
timers; as this happens the old timers will be removed. In other
cases the new timing events will replace busy-wait loops.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1571) adds a new state for ehci-hcd's root hubs:
EHCI_RH_STOPPING. This value is used at times when the root hub is
being stopped and we don't know whether or not the hardware has
finished all its DMA yet.
Although the purpose may not be apparent, this distinction will come
in useful later on. Future patches will avoid actions that depend on
the root hub being operational (like turning on the async or periodic
schedules) when they see the state is EHCI_RH_STOPPING.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1570) adds a pointer for the end of ehci-hcd's
async-unlink list. The list (which is actually a queue) is singly
linked, so having a pointer to its end makes adding new entries easier
-- there's no longer any need to scan through the whole list.
In principle it could be changed to a standard doubly-linked list. It
turns out that doing so actually makes the code less clear, so I'm
leaving it as is.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1569) renames the ehci->reclaim list in ehci-hcd. The
word "reclaim" is used in the EHCI specification to mean something
quite different, and "unlink_next" is more descriptive of the list's
purpose anyway.
Similarly, the "reclaim" field in the ehci_stats structure is renamed
"iaa", which is more meaningful (to experts, anyway) and is a better
match for the "lost_iaa" field.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alan Stern