When a USB device is reset, the xHCI hardware must know, in order to match
the device state and disable all endpoints except control endpoint 0.
Issue a Reset Device command after a USB device is successfully reset.
Wait on the command to finish, and then cache or free the disabled
endpoint rings.

There are four different USB device states that the xHCI hardware tracks:
 - disabled/enabled - device connection has just been detected,
 - default - the device has been reset and has an address of 0,
 - addressed - the device has a non-zero address but no configuration has
   been set,
 - configured - a set configuration succeeded.

The USB core may issue a port reset when a device is in any state, but the
Reset Device command will fail for a 0.96 xHC if the device is not in the
addressed or configured state.  Don't consider this failure as an error,
but don't free any endpoint rings if this command fails.

A storage driver may request that the USB device be reset during error
handling, so use GPF_NOIO instead of GPF_KERNEL while allocating memory
for the Reset Device command.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

All commands that can be issued to the xHCI hardware can come back with
vendor-specific "informational" completion codes.  These are to be treated
like a successful completion code.  Refactor out the code to test for the
range of these codes and print debugging messages.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The xHCI driver issues a Configure Endpoint command for two reasons:
 - a new configuration or alternate interface setting is selected
 - a quirky Fresco Logic prototype requires the command after a Reset
   Endpoint command.
The xHCI driver only waits on the command in the first case.

When a configure endpoint command completes, the driver needs to know why
the command was generated.  When the driver only supported selecting an
initial configuration, the check was simple.  Unfortunately that check
doesn't work now that the driver supports alternate interfaces.  If an
endpoint must be dropped (because it's not in the new alternate setting)
and no new endpoints are added, the math involving
xhci_last_valid_endpoint() will assign -1 to an unsigned integer and cause
an out-of-bounds array access.

Move the check for the quirky hardware sooner and avoid the bad array
access.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The xHCI 0.95 and 0.96 specification defines several transfer buffer
request completion codes that indicate a USB transaction error occurred.
When a stall, babble, transaction, or split transaction error completion code
is set, the xHCI has halted that endpoint ring.  Software must issue a
Reset Endpoint command and a Set Transfer Ring Dequeue Pointer command
to clean up the halted ring.

The USB device driver is supposed to call into usb_reset_endpoint() when
an endpoint stalls.  That calls into the xHCI driver to issue the proper
commands.  However, drivers don't call that function for the other
errors that cause the xHC to halt the endpoint ring.  If a babble,
transaction, or split transaction error occurs, check if the endpoint
context reports a halted condition, and clean up the endpoint ring if it
does.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

An xHCI host controller manufacturer can choose to implement several
vendor-specific informational completion codes.  These are all to be
treated like a successful transfer completion.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When the xHCI hardware says a transfer completed with a split
transaction error, set the URB status to -EPROTO.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The transfer descriptor (TD) is a series of transfer request buffers
(TRBs) that describe the buffer pointer, length, and other
characteristics.  The xHCI controllers want to know an estimate of how
long the TD is, for caching reasons.  In each TRB, there is a "TD size"
field that provides a rough estimate of the remaining buffers to be
transmitted, including the buffer pointed to by that TRB.

The TD size is 5 bits long, and contains the remaining size in bytes,
right shifted by 10 bits.  So a remaining TD size less than 1024 would get
a zero in the TD size field, and a remaining size greater than 32767 would
get 31 in the field.

This patches fixes a bug in the TD_REMAINDER macro that is triggered when
the URB has a scatter gather list with a size bigger than 32767 bytes.
Not all host controllers pay attention to the TD size field, so the bug
will not appear on all USB 3.0 hosts.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

It's not surprising that the transfer request buffer (TRB) physical to
virtual address translation function has bugs in it, since I wrote most of
it at 4am last October.  Add a test suite to check the TRB math.  This
runs at memory initialization time, and causes the driver to fail to load
if the TRB math fails.

Please excuse the excessively long lines in the test vectors; they can't
really be made shorter and still be readable.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

CONFIG_USB_HCD_STAT was used in an abandoned patch to track host
controller throughput statistics.  Since CONFIG_USB_HCD_STAT will never be
defined, remove code that can never run.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In order to giveback a canceled URB, we must ensure that the xHCI
hardware will not access the buffer in an URB.  We can't modify the
buffer pointers on endpoint rings without issuing and waiting for a stop
endpoint command.  Since URBs can be canceled in interrupt context, we
can't wait on that command.  The old code trusted that the host
controller would respond to the command, and would giveback the URBs in
the event handler.  If the hardware never responds to the stop endpoint
command, the URBs will never be completed, and we might hang the USB
subsystem.

Implement a watchdog timer that is spawned whenever a stop endpoint
command is queued.  If a stop endpoint command event is found on the
event ring during an interrupt, we need to stop the watchdog timer with
del_timer().  Since del_timer() can fail if the timer is running and
waiting on the xHCI lock, we need a way to signal to the timer that
everything is fine and it should exit.  If we simply clear
EP_HALT_PENDING, a new stop endpoint command could sneak in and set it
before the watchdog timer can grab the lock.

Instead we use a combination of the EP_HALT_PENDING flag and a counter
for the number of pending stop endpoint commands
(xhci_virt_ep->stop_cmds_pending).  If we need to cancel the watchdog
timer and del_timer() succeeds, we decrement the number of pending stop
endpoint commands.  If del_timer() fails, we leave the number of pending
stop endpoint commands alone.  In either case, we clear the
EP_HALT_PENDING flag.

The timer will decrement the number of pending stop endpoint commands
once it obtains the lock.  If the timer is the tail end of the last stop
endpoint command (xhci_virt_ep->stop_cmds_pending == 0), and the
endpoint's command is still pending (EP_HALT_PENDING is set), we assume
the host is dying.  The watchdog timer will set XHCI_STATE_DYING, try to
halt the xHCI host, and give back all pending URBs.

Various other places in the driver need to check whether the xHCI host
is dying.  If the interrupt handler ever notices, it should immediately
stop processing events.  The URB enqueue function should also return
-ESHUTDOWN.  The URB dequeue function should simply return the value
of usb_hcd_check_unlink_urb() and the watchdog timer will take care of
giving the URB back.  When a device is disconnected, the xHCI hardware
structures should be freed without issuing a disable slot command (since
the hardware probably won't respond to it anyway).  The debugging
polling loop should stop polling if the host is dying.

When a device is disconnected, any pending watchdog timers are killed
with del_timer_sync().  It must be synchronous so that the watchdog
timer doesn't attempt to access the freed endpoint structures.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In the old code, there was a race condition between the stop endpoint
command and the URB submission process.  When the stop endpoint command is
handled by the event handler, the endpoint ring is assumed to be stopped.
When a stop endpoint command is queued, URB submissions are to not ring
the doorbell.  The old code would check the number of pending URBs to be
canceled, and would not ring the doorbell if it was non-zero.

However, the following race condition could occur with the old code:

1. Cancel an URB, add it to the list of URBs to be canceled, queue the stop
   endpoint command, and increment ep->cancels_pending to 1.
2. The URB finishes on the HW, and an event is enqueued to the event ring
   (at the same time as 1).
3. The stop endpoint command finishes, and the endpoint is halted.  An
   event is queued to the event ring.
4. The event handler sees the finished URB, notices it was to be
   canceled, decrements ep->cancels_pending to 0, and removes it from the to
   be canceled list.
5. The event handler drops the lock and gives back the URB.  The
   completion handler requeues the URB (or a different driver enqueues a new
   URB).  This causes the endpoint's doorbell to be rung, since
   ep->cancels_pending == 0.  The endpoint is now running.
6. A second URB is canceled, and it's added to the canceled list.
   Since ep->cancels_pending == 0, a new stop endpoint command is queued, and
   ep->cancels_pending is incremented to 1.
7. The event handler then sees the completed stop endpoint command.  The
   handler assumes the endpoint is stopped, but it isn't.  It attempts to
   move the dequeue pointer or change TDs to cancel the second URB, while the
   hardware is actively accessing the endpoint ring.

To eliminate this race condition, a new endpoint state bit is introduced,
EP_HALT_PENDING.  When this bit is set, a stop endpoint command has been
queued, and the command handler has not begun to process the URB
cancellation list yet.  The endpoint doorbell should not be rung when this
is set.  Set this when a stop endpoint command is queued, clear it when
the handler for that command runs, and check if it's set before ringing a
doorbell.  ep->cancels_pending is eliminated, because it is no longer
used.

Make sure to ring the doorbell for an endpoint when the stop endpoint
command handler runs, even if the canceled URB list is empty.  All
canceled URBs could have completed and new URBs could have been enqueued
without the doorbell being rung before the command was handled.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The trb_in_td() function in the xHCI driver is supposed to translate a
physical transfer buffer request (TRB) into a virtual pointer to the ring
segment that TRB is in.

Unfortunately, a mistake in this function may cause endless loops as the
driver searches through the linked list of ring segments over and over
again.  Fix a couple bugs that may lead to loops or bad output:

1. Bail out if we get a NULL pointer when translating the segment's
private structure and the starting DMA address of the segment chunk.  If
this happens, we've been handed a starting TRB pointer from a different
ring.

2. Make sure the function works when there's multiple segments in the
ring.  In the while loop to search through the ring segments, use the
current segment variable (cur_seg), rather than the starting segment
variable (start_seg) that is passed in.

3. Stop searching the ring if we've run through all the segments in the
ring.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

For a USB hub to work under an xHCI host controller, the xHC's internal
scheduler must be made aware of the hub's characteristics.  Add an xHCI
hook that the USB core will call after it fetches the hub descriptor.
This hook will add hub information to the slot context for that device,
including whether it has multiple TTs or a single TT, the number of ports
on the hub, and TT think time.

Setting up the slot context for the device is different for 0.95 and 0.96
xHCI host controllers.

Some of the slot context reserved fields in the 0.95 specification were
changed into hub fields in the 0.96 specification.  Don't set the TT think
time or number of ports for a hub if we're dealing with a 0.95-compliant
xHCI host controller.

The 0.95 xHCI specification says that to modify the hub flag, we need to
issue an evaluate context command.  The 0.96 specification says that flag
can be set with a configure endpoint command.  Issue the correct command
based on the version reported by the hardware.

This patch does not add support for multi-TT hubs.  Multi-TT hubs expose
a single TT on alt setting 0, and multi-TT on alt setting 1.  The xHCI
driver can't handle setting alternate interfaces yet.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In the xHCI driver, configure endpoint commands that are submitted to the
hardware may involve one of two data structures.  If the configure
endpoint command is setting up a new configuration or modifying max packet
sizes, the data structures and completions are statically allocated in the
xhci_virt_device structure.  If the command is being used to set up
streams or add hub information, then the data structures are dynamically
allocated, and placed on a device command waiting list.

Break out the code to check whether a completed command is in the device
command waiting list.  Fix a subtle bug in the old code: continue
processing the command if the command isn't in the wait list.  In the old
code, if there was a command in the wait list, but it didn't match the
completed command, the completed command event would be dropped.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Some commands to the xHCI hardware cannot be allowed to fail due to out of
memory issues or the command ring being full.

Add a way to reserve a TRB on the command ring, and make all command
queueing functions indicate whether they are using a reserved TRB.

Add a way to pre-allocate all the memory a command might need.  A command
needs an input context, a variable to store the status, and (optionally) a
completion for the caller to wait on.  Change all code that assumes the
input device context, status, and completion for a command is stored in
the xhci virtual USB device structure (xhci_virt_device).

Store pending completions in a FIFO in xhci_virt_device.  Make the event
handler for a configure endpoint command check to see whether a pending
command in the list has completed.  We need to use separate input device
contexts for some configure endpoint commands, since multiple drivers can
submit requests at the same time that require a configure endpoint
command.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The xhci_ring structure contained information that is really related to an
endpoint, not a ring.  This will cause problems later when endpoint
streams are supported and there are multiple rings per endpoint.

Move the endpoint state and cancellation information into a new virtual
endpoint structure, xhci_virt_ep.  The list of TRBs to be cancelled should
be per endpoint, not per ring, for easy access.  There can be only one TRB
that the endpoint stopped on after a stop endpoint command (even with
streams enabled); move the stopped TRB information into the new virtual
endpoint structure.  Also move the 31 endpoint rings and temporary ring
storage from the virtual device structure (xhci_virt_device) into the
virtual endpoint structure (xhci_virt_ep).
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Interrupt transfers are submitted to the xHCI hardware using the same TRB
type as bulk transfers.  Re-use the bulk transfer enqueueing code to
enqueue interrupt transfers.

Interrupt transfers are a bit different than bulk transfers.  When the
interrupt endpoint is to be serviced, the xHC will consume (at most) one
TD.  A TD (comprised of sg list entries) can take several service
intervals to transmit.  The important thing for device drivers to note is
that if they use the scatter gather interface to submit interrupt
requests, they will not get data sent from two different scatter gather
lists in the same service interval.

For now, the xHCI driver will use the service interval from the endpoint's
descriptor (bInterval).  Drivers will need a hook to poll at a more
frequent interval.  Set urb->interval to the interval that the xHCI
hardware will use.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The xHCI hardware reports the number of bytes untransferred for a given
transfer buffer.  If the hardware reports a bytes untransferred value
greater than the submitted buffer size, we want to play it safe and say no
data was transferred.  If the driver considers a short packet to be an
error, remember to set -EREMOTEIO.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make sure that the driver that submitted the URB considers a short packet
an error before setting -EREMOTEIO during a short control transfer.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make sure that the amount of data the xHC says was transmitted is less
than or equal to the size of the requested transfer buffer.  Before, if
the host controller erroneously reported that the number of bytes
untransferred was bigger than the buffer in the URB, urb->actual_length
could be set to a very large size.

Make sure urb->actual_length <= urb->transfer_buffer_length.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

On a successful transfer, urb->td is freed before the URB is ready to be
given back to the driver.  Don't touch urb->td after it's freed.  This bug
would have only shown up when xHCI debugging was turned on, and the freed
memory was quickly reused for something else.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The 0.95 xHCI spec says that non-control endpoints will be halted if a
babble is detected on a transfer.  The 0.96 xHCI spec says all types of
endpoints will be halted when a babble is detected.  Some hardware that
claims to be 0.95 compliant halts the control endpoint anyway.

When a babble is detected on a control endpoint, check the hardware's
output endpoint context to see if the endpoint is marked as halted.  If
the control endpoint is halted, a reset endpoint command must be issued
and the transfer ring dequeue pointer needs to be moved past the stopped
transfer.  Basically, we treat it as if the control endpoint had stalled.

Handle bulk babbling endpoints as if we got a completion event with a
stall completion code.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Use trb_comp_code instead of getting the completion code from the transfer
event every time.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This Fresco Logic xHCI host controller chip revision puts bad data into
the output endpoint context after a Reset Endpoint command.  It needs a
Configure Endpoint command (instead of a Set TR Dequeue Pointer command)
after the reset endpoint command.

Set up the input context before issuing the Reset Endpoint command so we
don't copy bad data from the output endpoint context.  The HW also can't
handle two commands queued at once, so submit the TRB for the Configure
Endpoint command in the event handler for the Reset Endpoint command.

Devices that stall on control endpoints before a configuration is selected
will not work under this Fresco Logic xHCI host controller revision.

This patch is for prototype hardware that will be given to other companies
for evaluation purposes only, and should not reach consumer hands.  Fresco
Logic's next chip rev should have this bug fixed.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When a control endpoint stalls, the next control transfer will clear the
stall.  The USB core doesn't call down to the host controller driver's
endpoint_reset() method when control endpoints stall, so the xHCI driver
has to do all its stall handling for internal state in its interrupt handler.

When the host stalls on a control endpoint, it may stop on the data phase
or status phase of the control transfer.  Like other stalled endpoints,
the xHCI driver needs to queue a Reset Endpoint command and move the
hardware's control endpoint ring dequeue pointer past the failed control
transfer (with a Set TR Dequeue Pointer or a Configure Endpoint command).

Since the USB core doesn't call usb_hcd_reset_endpoint() for control
endpoints, we need to do this in interrupt context when we get notified of
the stalled transfer.  URBs may be queued to the hardware before these two
commands complete.  The endpoint queue will be restarted once both
commands complete.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Full speed devices have varying max packet sizes (8, 16, 32, or 64) for
endpoint 0.  The xHCI hardware needs to know the real max packet size
that the USB core discovers after it fetches the first 8 bytes of the
device descriptor.

In order to fix this without adding a new hook to host controller drivers,
the xHCI driver looks for an updated max packet size for control
endpoints.  If it finds an updated size, it issues an evaluate context
command and waits for that command to finish.  This should only happen in
the initialization and device descriptor fetching steps in the khubd
thread, so blocking should be fine.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Refactor out the code issue, wait for, and parse the event completion code
for a configure endpoint command.  Modify it to support the evaluate
context command, which has a very similar submission process.  Add
functions to copy parts of the output context into the input context
(which will be used in the evaluate context command).
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Different sections of the xHCI 0.95 specification had opposing
requirements for the chain bit in a link transaction request buffer (TRB).
The chain bit is used to designate that adjacent TRBs are all part of the
same scatter gather list that should be sent to the device.  Link TRBs can
be in the middle, or at the beginning or end of these chained TRBs.

Sections 4.11.5.1 and 6.4.4.1 both stated the link TRB "shall have the
chain bit set to 1", meaning it is always chained to the next TRB.
However, section 4.6.9 on the stop endpoint command has specific cases for
what the hardware must do for a link TRB with the chain bit set to 0.  The
0.96 specification errata later cleared up this issue by fixing the
4.11.5.1 and 6.4.4.1 sections to state that a link TRB can have the chain
bit set to 1 or 0.

The problem is that the xHCI cancellation code depends on the chain bit of
the link TRB being cleared when it's at the end of a TD, and some 0.95
xHCI hardware simply stops processing the ring when it encounters a link
TRB with the chain bit cleared.

Allow users who are testing 0.95 xHCI prototypes to set a module parameter
(link_quirk) to turn on this link TRB work around.  Cancellation may not
work if the ring is stopped exactly on a link TRB with chain bit set, but
cancellation should be a relatively uncommon case.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Correct the xHCI code to handle stalls on USB endpoints.  We need to move
the endpoint ring's dequeue pointer past the stalled transfer, or the HW
will try to restart the transfer the next time the doorbell is rung.

Don't attempt to clear a halt on an endpoint if we haven't seen a stalled
transfer for it.  The USB core will attempt to clear a halt on all
endpoints when it selects a new configuration.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Adds support for controllers that use 64-byte contexts.  The following context
data structures are affected by this: Device, Input, Input Control, Endpoint,
and Slot.  To accommodate the use of either 32 or 64-byte contexts, a Device or
Input context can only be accessed through functions which look-up and return
pointers to their contained contexts.
Signed-off-by: NJohn Youn <johnyoun@synopsys.com>
Acked-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Pass back a babble error when this error code is seen in the transfer event TRB.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add more debugging to the irq handler, slot context initialization, ring
operations, URB cancellation, and MMIO writes.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The Event Handler Busy bit in the event ring dequeue pointer is write 1 to
clear.  Fix the interrupt service routine to clear that bit after the
event handler has run.

xhci_set_hc_event_deq() is designed to update the event ring dequeue pointer
without changing any of the four reserved bits in the lower nibble.  The event
handler busy (EHB) bit is write one to clear, so the new value must always
contain a zero in that bit in order to preserve the EHB value.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When there is a short packet on a control transfer, the xHCI host controller
hardware will generate two events.  The first event will be for the data stage
TD with a completion code for a short packet.  The second event will be for the
status stage with a successful completion code.  Before this patch, the xHCI
driver would giveback the short control URB when it received the event for the
data stage TD.  Then it would become confused when it saw a status stage event
for the endpoint for an URB it had already finished processing.

Change the xHCI host controller driver to wait for the status stage event when
it receives a short transfer completion code for a data stage TD.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

There are several xHCI data structures that use two 32-bit fields to
represent a 64-bit address.  Since some architectures don't support 64-bit
PCI writes, the fields need to be written in two 32-bit writes.  The xHCI
specification says that if a platform is incapable of generating 64-bit
writes, software must write the low 32-bits first, then the high 32-bits.
Hardware that supports 64-bit addressing will wait for the high 32-bit
write before reading the revised value, and hardware that only supports
32-bit writes will ignore the high 32-bit write.

Previous xHCI code represented 64-bit addresses with two u32 values.  This
lead to buggy code that would write the 32-bits in the wrong order, or
forget to write the upper 32-bits.  Change the two u32s to one u64 and
create a function call to write all 64-bit addresses in the proper order.
This new function could be modified in the future if all platforms support
64-bit writes.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When an endpoint on a device under an xHCI host controller stalls, the
host controller driver must let the hardware know that the USB core has
successfully cleared the halt condition.  The HCD submits a Reset Endpoint
Command, which will clear the toggle bit for USB 2.0 devices, and set the
sequence number to zero for USB 3.0 devices.

The xHCI urb_enqueue will accept new URBs while the endpoint is halted,
and will queue them to the hardware rings.  However, the endpoint doorbell
will not be rung until the Reset Endpoint Command completes.

Don't queue a reset endpoint command for root hubs.  khubd clears halt
conditions on the roothub during the initialization process, but the roothub
isn't a real device, so the xHCI host controller doesn't need to know about the
cleared halt.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The 0.95 xHCI specification requires software to set the "TD size" field
in each transaction request block (TRB).  This field gives the host
controller an indication of how much data is remaining in the TD
(including the buffer in the current TRB).  Set this field in bulk TRBs
and data stage TRBs for control transfers.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Greg KH introduced a bug into xhci_trb_virt_to_dma() when he changed the
type of offset to dma_addr_t from unsigned int and dropped the casts to
unsigned int around the virtual address pointer subtraction.

trb and seg->trbs are both valid pointers to virtual addresses, so the
compiler will mod the subtraction by the size of union trb (16 bytes).
segment_offset is an unsigned long, which is guaranteed to be at least as
big as a void *.

Drop the void * casts in the first if statement because trb and seg->trbs
are both pointers of the same type (pointers to union trb).
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Force the compiler to write the cycle bit of the Link TRB last.  This
ensures that the hardware doesn't think it owns the Link TRB before we set
the chain bit.  Reported by Oliver in this thread:
	http://marc.info/?l=linux-usb&m=124091532410219&w=2Reported-by: NOliver Neukum <oliver@neukum.org>
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Make all globally visible functions start with xhci_ and mark functions as
static if they're only called within the same C file.  Fix some long lines
while we're at it.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>