This patch (as1300) adds native scatter-gather support to ehci-hcd.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch deals with reducing the memory footprint for sierra driver.
This optimization is aimed for embedded software customers.

Some sierra modems can expose upwards of 7 USB interfaces, each possibly
offering different services. In general, interfaces used for the
exchange of wireless data require much higher throughput, hence require
more memory (i.e. more URBs) than lower performance interfaces. URBs
used for the IN direction are pre-allocated by the driver and this patch
introduces a way to configure the number of IN URBs allocated on a
per-interface basis. Interfaces with lower throughput requirements
receive fewer URBs, thereby reducing the RAM memory consumed by the
driver.

NOTE1: This driver has always pre-allocated URBs for the IN direction.

NOTE2: The number of URBs pre-allocated for the low-performance
interfaces has already been extensively tested in previous versions of
this driver.

We also added the capability to log function calls by adding DEBUG flag.
Please note that  this flag is commented out because this is the default
state
for it.
Signed-off-by: NElina Pasheva <epasheva@sierrawireless.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Without Interface Association Descriptor, the CDC serial and
RNDIS functions did not work correctly when added to a
composite gadget with other functions.  This is because, it
defined two interfaces and some hosts tried to treat each
interface separatelly.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Moved code initialising fsg_common structure to fsg_common_init()
function which is called from fsg_bind().  Moreover, changed
reference counting mechanism: fsg_common has a reference counter
which counts how many fsg_dev structures uses it.  When this
reaches zero fsg_common_release() is run which unregisters
LUN devices and frees memory.

fsg_common_init() takes pointer to fsg_common structure as an
argument.  If it is NULL function allocates storage otherwise
uses pointed to memory (handy if fsg_common is a field of another
structure or a static variable).

fsg_common_release() will free storage only if
free_storage_on_release is set -- it is initialised by
fsg_common_init(): set if allocation was done, unset
otherwise (one may overwrite it of course).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Using version of fsg_buffhd structure with buf field being an
array of characters with predefined size.  Since mass storage
function does not define changing buffer size on run-time it is
not required for the field to be a pointer to void and allocating
space dynamically.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In the final version, many fsg_dev structures will (be able to)
refer to a single fsg_common structure and so it is required
to move common data to another object which can be shared.

Situation where many fsg_dev structures refer single fsg_common
structure is when a single instance of MSF is used in several
USB configurations.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Removed code that was included when CONFIG_USB_FILE_STORAGE_TEST
was defined.  If this functionality is required one may still use
the original File-backed Storage Gadget.  It has been agreed that
testing functionality is not required in the composite function.

Also removed fsg_suspend() and fsg_resume() which were no
operations.

Moreover, storage_common.c has been modified in such a way that
defining certain macros skips parts of the file.  Those macros
are:
* FSG_NO_INTR_EP -- skips interrupt endpoint descriptors
* FSG_NO_DEVICE_STRINGS -- skips certain strings
* FSG_NO_OTG -- skips OTG descriptor
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Copied file_storage.c to f_mass_storage.c which will be used as
template for the Mass Storage composite Function.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Since storage_common.c no longer references mod_data object
it is now possible to include it before mod_data object is
defined.  This makes it possible to move some defines that
are used as default values of mod_data fields to be defined
in storage_common.c file (where they should be set from
the beginning).

Also, show_ro(), show_file(), store_ro() and store_file()
have been moved to storage_common.c with LUN's device's
drvdata changed from pointing to fsg_dev to pointing to
rw_semaphore (&fsg->filesem).
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

removable and cdrom flag has been added to the fsg_lun structure
removing any references to mod_data object from storage_common.c.

As of read-only flag, previously it was set if a read-only
backing file was specified (which is good) and remained set
even after the file has been closed (which may be considered an
issue).  Currently, the initial read-only flag is preserved so
if it was unset each time file is opened code will try to open
it read-write even if previous file was opened read-only.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Prefixed some identifiers that were defined in storage_common.c file
with "fsg_".  Not all identifiers were prefixed but the ones that are
most likely to produce conflicts when used with other USB functions.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Moved parts of the file_storage.c file which do not reference fsg_dev
structure to newly created storage_common.c file. dump_msg() and
dump_cdb() have been changed to macros to remove fsg_dev reference.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The Freescale MX27 and MX31 SoCs have a EHCI controller onboard.
The controller is capable of USB on the go. This patch adds
a driver to support all three of them.

Users have to pass details about serial interface configuration in the
platform data.

The USB OTG core used here is the ARC core, so the driver should
be renamed and probably be merged with ehci-fsl.c eventually.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1298) fixes a bug in the new scatter-gather URB
facility.  If an URB uses a scatterlist then it should not have the
URB_NO_INTERRUPT flag set; otherwise the system won't be notified when
the transfer completes.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Acked-by: NDavid Vrabel <david.vrabel@csr.com>
CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1297) adds a "remove" attribute to each USB device's
directory in sysfs.  Writing to this attribute causes the device to be
deconfigured (the same as writing 0 to the "bConfigurationValue"
attribute) and then tells the hub driver to disable the device's
upstream port.  The device remains locked during these activities so
there is no possibility of it getting reconfigured in between.  The
port will remain disabled until after the device is unplugged.

The purpose of this is to provide a means for user programs to imitate
the "Safely remove hardware" applet in Windows.  Some devices do
expect their ports to be disabled before they are unplugged, and they
provide visual feedback to users indicating when they can safely be
unplugged.

The security implications are minimal.  Writing to the "remove"
attribute is no more dangerous than writing to the
"bConfigurationValue" attribute.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Cc: David Zeuthen <davidz@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1296) gets rid of the fixed DMA-buffer mapping used by
the hub driver for its status URB.  This URB doesn't get used much --
mainly when a device is plugged in or unplugged -- so the dynamic
mapping overhead is minimal.  And most systems have many fewer
external hubs than root hubs, which don't need a mapped buffer anyway.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The EHCI specification says that an EHCI host controller may cache part of
the isochronous schedule.  The EHCI controller must advertise how much it
caches in the schedule through the HCCPARAMS register isochronous
scheduling threshold (IST) bits.

In theory, adding new iTDs within the IST should be harmless.  The HW will
follow the old cached linked list and miss the new iTD.  SW will notice HW
missed the iTD and return 0 for the transfer length.

However, Intel ICH9 chipsets (and some later chipsets) have issues when SW
attempts to schedule a split transaction within the IST.  All transfers
will cease being sent out that port, and the drivers will see isochronous
packets complete with a length of zero.  Start of frames may or may not
also disappear, causing the device to go into auto-suspend.  This "bus
stall" will continue until a control or bulk transfer is queued to a
device under that roothub.

Most drivers will never cause this behavior, because they use multiple
URBs with multiple packets to keep the bus busy.  If you limit the number
of URBs to one, you may be able to hit this bug.

Make sure the EHCI driver does not schedule full-speed transfers within
the IST under an Intel chipset.  Make sure that when we fall behind the
current microframe plus IST, we schedule the new transfer at the next
periodic interval after the IST.

Don't change the scheduling for new transfers, since the schedule slop will
always be greater than the IST.  Allow high speed isochronous transfers to
be scheduled within the IST, since this doesn't trigger the Intel chipset
bug.

Make sure that if the host caches the full frame, the EHCI driver's
internal isochronous threshold (ehci->i_thresh) is set to
8 microframes + 2 microframes wiggle room.  This is similar to what is done in
the case where the host caches less than the full frame.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Change the constant SCHEDULE_SLOP to be 80 microframes, instead of 10
frames.  It was always multiplied by 8 to convert frames to microframes.
SCHEDULE_SLOP is only used in ehci-sched.c.
Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
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>

xhci_quiesce() is basically a no-op right now.  It's only called if
HC_IS_RUNNING() is true, and the body of the function consists of a
BUG_ON if HC_IS_RUNNING() is false.  For the new xHCI watchdog timer, we
need a new function that clears the xHCI running bit in the command
register, but doesn't wait for the halt status to show up in the status
register.  Re-purpose xhci_quiesce() to do that.
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>

usb: better error handling in usb_port_suspend

- disable remote wakeup only if it was enabled
- refuse to autosuspend if remote wakeup fails to be enabled
Signed-off-by: NOliver Neukum <oliver@neukum.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

this driver has been sitting in linux-omap tree for quite
some time. It adds support for omap's ehci controller.
Signed-off-by: NFelipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: NVikram Pandita <vikram.pandita@ti.com>
Signed-off-by: NAjay Kumar Gupta <ajay.gupta@ti.com>
Signed-off-by: NAnand Gadiyar <gadiyar@ti.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This adds a minimal generic driver for ULPI connected transceivers,
using the OTG framework functions recently introduced.

The driver got a table to match the ULPI chips, which currently only has
one entry for NXP's ISP 1504 transceiver.
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: Heikki Krogerus <ext-heikki.krogerus@nokia.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This adds support for OTG transceivers directly connected to the ULPI
interface. In particular, the following details are added

- a struct for low level io functions (read/write)
- a priv field to be used as 'viewport' by low level access functions
- an (*init) and (*shutdown) callbacks, along with static inline helpers
- a (*set_vbus) callback to switch the port power on and off
- a flags field for per-transceiver settings
- some defines for the flags bitmask to configure platform specific
  details
Signed-off-by: NDaniel Mack <daniel@caiaq.de>
Cc: Heikki Krogerus <ext-heikki.krogerus@nokia.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add the wusb_phy_rate sysfs file to Wireless USB host controllers.  This
sets the maximum PHY rate that will be used for all connected devices.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Print ep number, direction and type; and current window in asl and pzl
debugfs files.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Modify both host and gadget USB drivers for at91sam9g10.
This add a clock management equivalent to at91sam9261 on usb drivers.
It also add the way of handling gadget pull-ups (like the at91sam9261).
Signed-off-by: NHong Xu <hong.xu@atmel.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>

Now that control requests targeted at an endpoint can be handled at the
function level, move the UAC-specific control request handling code from
the audio gadget driver to the audio function driver.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Control requests targeted at an endpoint (that is sent to EP0 but
specifying the target endpoint address in wIndex) are dispatched to the
current configuration's setup callback, requiring all gadget drivers to
dispatch the requests to the correct function driver.

To avoid this, record which endpoints are used by each function in the
composite driver SET CONFIGURATION handler and dispatch requests
targeted at endpoints to the correct function.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Correct priority problem in the use of ! and &.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression E; constant C; @@
- !E & C
+ !(E & C)
// </smpl>
Signed-off-by: NJulia Lawall <julia@diku.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fix type and format warning in the new sg code.  Remove the very chatty
debug messages that were left in by mistake and use min_t() as required
(no one seems to agree on a type for buffer sizes).
Reported-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Check urb->interval on interrupt transfers and allow those with valid
values (6 <= interval <= 16).
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Support urbs with scatter-gather lists by trying to fit sg list elements
into page lists in one or more qTDs.  qTDs must end on a wMaxPacketSize
boundary so if this isn't possible the urb's sg list must be copied into
bounce buffers.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The WHCI HCD will also support urbs with scatter-gather lists.  Add a
usb_bus field to indicated how many sg list elements are supported by
the HCD.  Use this to decide whether to pass the scatter-list to the HCD
or not.

Make the usb-storage driver use this new field.
Signed-off-by: NDavid Vrabel <david.vrabel@csr.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

I can't see any reason why these would not be static.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add bus glue driver for Xilinx USB host controller. The controller can be
configured as HS only or HS/FS hybrid. The driver uses the device tree file
to configure the driver according to the setting in the hardware system.

This driver has been tested with usbtest using the NET2280 PCI card.
Signed-off-by: NJulie Zhu <julie.zhu@xilinx.com>
Signed-off-by: NJohn Linn <john.linn@xilinx.com>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Use dev_dbg() instead of an unconditional printk(KERN_DEBUG).  This has
two benefits; one is that it identifies the USB device which the messages
related to, and the other is that the messages won't be produced unless
debug is turned on.

Enable the debug messages when CONFIG_USB_STORAGE_DEBUG is set.
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>