linux-toradex.git/drivers/usb/host/xhci.h, branch v3.17

xhci: Blacklist using streams on the Etron EJ168 controller

2014-08-01T22:49:34+00:00

Streams on the EJ168 do not work as they should. I've spend 2 days trying
to get them to work, but without success.

The first problem is that when ever you ring the stream-ring doorbell, the
controller starts executing trbs at the beginning of the first ring segment,
event if it ended somewhere else previously. This can be worked around by
allowing enqueing only one td (not a problem with how streams are typically
used) and then resetting our copies of the enqueueing en dequeueing pointers
on a td completion to match what the controller seems to be doing.

This way things seem to start working with uas and instead of being able
to complete only the very first scsi command, the scsi core can probe the disk.

But then things break later on when td-s get enqueued with more then one
trb. The controller does seem to increase its dequeue pointer while executing
a stream-ring (data transfer events I inserted for debugging do trigger).
However execution seems to stop at the final normal trb of a multi trb td,
even if there is a data transfer event inserted after the final trb.

The first problem alone is a serious deviation from the spec, and esp.
dealing with cancellation would have been very tricky if not outright
impossible, but the second problem simply is a deal breaker altogether,
so this patch simply disables streams.

Note this will cause the usb-storage + uas driver pair to automatically switch
to using usb-storage instead of uas on these devices, essentially reverting
to the 3.14 and earlier behavior when uas was marked CONFIG_BROKEN.

https://bugzilla.redhat.com/show_bug.cgi?id=1121288
https://bugzilla.kernel.org/show_bug.cgi?id=80101

Cc: stable@vger.kernel.org # 3.15
Signed-off-by: Hans de Goede 
Signed-off-by: Greg Kroah-Hartman

usb: host: xhci-plat: add clock support

2014-05-27T22:33:13+00:00

Some platforms (such as the Armada 38x ones) can gate the clock of
their USB controller. This patch adds the support for one clock in
xhci-plat, by enabling it during probe and disabling it on remove.

To achieve this, it adds a 'struct clk *' member in xhci_hcd. While
only used for now in xhci-plat, it might be used by other drivers in
the future. Moreover, the xhci_hcd structure already holds other
members such as msix_count and msix_entries, which are MSI-X specific,
and therefore only used by xhci-pci.

Signed-off-by: Gregory CLEMENT 
Signed-off-by: Thomas Petazzoni 
Acked-by: Felipe Balbi 
Acked-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

xhci: rework command timeout and cancellation,

2014-05-20T01:03:25+00:00

Use one timer to control command timeout.

start/kick the timer every time a command is completed and a
new command is waiting, or a new command is added to a empty list.

If the timer runs out, then tag the current command as "aborted", and
start the xhci command abortion process.

Previously each function that submitted a command had its own timer.
If that command timed out, a new command structure for the
command was created and it was put on a cancel_cmd_list list,
then a pci write to abort the command ring was issued.

when the ring was aborted, it checked if the current command
was the one to be canceled, later when the ring was stopped the
driver got ownership of the TRBs in the command ring,
compared then to the TRBs in the cancel_cmd_list,
and turned them into No-ops.

Now, instead, at timeout we tag the status of the command in the
command queue to be aborted, and start the ring abortion.
Ring abortion stops the command ring and gives control of the
commands to us.
All the aborted commands are now turned into No-ops.

If the ring is already stopped when the command times outs its not possible
to start the ring abortion, in this case the command is turnd to No-op
right away.

All these changes allows us to remove the entire cancel_cmd_list code.

The functions waiting for a command to finish no longer have their own timeouts.
They will wait either until the command completes normally,
or until the whole command abortion is done.

Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

xhci: Use completion and status in global command queue

2014-05-20T01:03:25+00:00

Remove the per-device command list and handle_cmd_in_cmd_wait_list()
and use the completion and status variables found in the
command structure in the global command list.

Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

xhci: Add a global command queue

2014-05-20T01:03:25+00:00

Create a list to store command structures, add a structure to it every time
a command is submitted, and remove it from the list once we get a
command completion event matching the command.

Callers that wait for completion will free their command structures themselves.
The other command structures are freed in the command completion event handler.

Also add a check that prevents queuing commands if host is dying

Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

xhci: Use command structures when queuing commands on the command ring

2014-05-20T01:03:25+00:00

To create a global command queue we require that each command put on the
command ring is submitted with a command structure.

Functions that queue commands and wait for completion need to allocate a command
before submitting it, and free it once completed. The following command queuing
functions need to be modified.

xhci_configure_endpoint()
xhci_address_device()
xhci_queue_slot_control()
xhci_queue_stop_endpoint()
xhci_queue_new_dequeue_state()
xhci_queue_reset_ep()
xhci_configure_endpoint()

xhci_configure_endpoint() could already be called with a command structure,
and only xhci_check_maxpacket and xhci_check_bandwidth did not do so. These
are changed and a command structure is now required. This change also simplifies
the configure endpoint command completion handling and the "goto bandwidth_change"
handling code can be removed.

In some cases the command queuing function is called in interrupt context.
These commands needs to be allocated atomically, and they can't wait for
completion. These commands will in this patch be freed directly after queuing,
but freeing will be moved to the command completion event handler in a later
patch once we get the global command queue up.(Just so that we won't leak
memory in the middle of the patch set)

Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

usb: xhci: Use IS_ENABLED() macro

2014-05-20T01:03:24+00:00

Using the IS_ENABLED() macro can make the code shorter and easier to read.

Signed-off-by: Fabio Estevam 
Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

usb: xhci: Prefer endpoint context dequeue pointer over stopped_trb

2014-04-25T16:34:10+00:00

We have observed a rare cycle state desync bug after Set TR Dequeue
Pointer commands on Intel LynxPoint xHCs (resulting in an endpoint that
doesn't fetch new TRBs and thus an unresponsive USB device). It always
triggers when a previous Set TR Dequeue Pointer command has set the
pointer to the final Link TRB of a segment, and then another URB gets
enqueued and cancelled again before it can be completed. Further
investigation showed that the xHC had returned the Link TRB in the TRB
Pointer field of the Transfer Event (CC == Stopped -- Length Invalid),
but when xhci_find_new_dequeue_state() later accesses the Endpoint
Context's TR Dequeue Pointer field it is set to the first TRB of the
next segment.

The driver expects those two values to be the same in this situation,
and uses the cycle state of the latter together with the address of the
former. This should be fine according to the XHCI specification, since
the endpoint ring should be stopped when returning the Transfer Event
and thus should not advance over the Link TRB before it gets restarted.
However, real-world XHCI implementations apparently don't really care
that much about these details, so the driver should follow a more
defensive approach to try to work around HC spec violations.

This patch removes the stopped_trb variable that had been used to store
the TRB Pointer from the last Transfer Event of a stopped TRB. Instead,
xhci_find_new_dequeue_state() now relies only on the Endpoint Context,
requiring a small amount of additional processing to find the virtual
address corresponding to the TR Dequeue Pointer. Some other parts of the
function were slightly rearranged to better fit into this model.

This patch should be backported to kernels as old as 2.6.31 that contain
the commit ae636747146ea97efa18e04576acd3416e2514f5 "USB: xhci: URB
cancellation support."

Signed-off-by: Julius Werner 
Cc: stable@vger.kernel.org
Signed-off-by: Mathias Nyman 
Signed-off-by: Greg Kroah-Hartman

xhci: For streams the dequeue ptr must be read from the stream ctx

2014-03-04T23:38:02+00:00

This fixes TR dequeue validation failing on Intel XHCI controllers with the
following warning:

Mismatch between completed Set TR Deq Ptr command & xHCI internal state.

Interestingly enough reading the deq ptr from the ep ctx after a
TR Deq Ptr command does work on a Nec XHCI controller, it seems the Nec
writes the ptr to both the ep and stream contexts when streams are used.

Signed-off-by: Hans de Goede 
Signed-off-by: Sarah Sharp

xhci: Set SCT field for Set TR dequeue on streams

2014-03-04T23:38:01+00:00

Nec XHCI controllers don't seem to care, but without this Intel XHCI
controllers reject Set TR dequeue commands with a COMP_TRB_ERR, leading
to the following warning:

WARN Set TR Deq Ptr cmd invalid because of stream ID configuration

And very shortly after this the system completely freezes.

Signed-off-by: Hans de Goede 
Signed-off-by: Sarah Sharp