Anurag Kumar Vulisha
d59f6a6e35
commit 5ee858975b upstream.
The current code in dwc3_gadget_ep_reclaim_completed_trb() will
check for IOC/LST bit in the event->status and returns if
IOC/LST bit is set. This logic doesn't work if multiple TRBs
are queued per request and the IOC/LST bit is set on the last
TRB of that request.
Consider an example where a queued request has multiple queued
TRBs and IOC/LST bit is set only for the last TRB. In this case,
the core generates XferComplete/XferInProgress events only for
the last TRB (since IOC/LST are set only for the last TRB). As
per the logic in dwc3_gadget_ep_reclaim_completed_trb()
event->status is checked for IOC/LST bit and returns on the
first TRB. This leaves the remaining TRBs left unhandled.
Similarly, if the gadget function enqueues an unaligned request
with sglist already in it, it should fail the same way, since we
will append another TRB to something that already uses more than
one TRB.
To aviod this, this patch changes the code to check for IOC/LST
bits in TRB->ctrl instead.
At a practical level, this patch resolves USB transfer stalls seen
with adb on dwc3 based HiKey960 after functionfs gadget added
scatter-gather support around v4.20.
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Yang Fei <fei.yang@intel.com>
Cc: Thinh Nguyen <thinhn@synopsys.com>
Cc: Tejas Joglekar <tejas.joglekar@synopsys.com>
Cc: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Cc: Jack Pham <jackp@codeaurora.org>
Cc: Todd Kjos <tkjos@google.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linux USB List <linux-usb@vger.kernel.org>
Cc: stable <stable@vger.kernel.org>
Tested-by: Tejas Joglekar <tejas.joglekar@synopsys.com>
Reviewed-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
[jstultz: forward ported to mainline, reworded commit log, reworked
to only check trb->ctrl as suggested by Felipe]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("hub_wq").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.