Merge branch 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb

* 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (260 commits)
  usb: renesas_usbhs: fixup inconsistent return from usbhs_pkt_push()
  usb/isp1760: Allow to optionally trigger low-level chip reset via GPIOLIB.
  USB: gadget: midi: memory leak in f_midi_bind_config()
  USB: gadget: midi: fix range check in f_midi_out_open()
  QE/FHCI: fixed the CONTROL bug
  usb: renesas_usbhs: tidyup for smatch warnings
  USB: Fix USB Kconfig dependency problem on 85xx/QoirQ platforms
  EHCI: workaround for MosChip controller bug
  usb: gadget: file_storage: fix race on unloading
  USB: ftdi_sio.c: Use ftdi async_icount structure for TIOCMIWAIT, as in other drivers
  USB: ftdi_sio.c:Fill MSR fields of the ftdi async_icount structure
  USB: ftdi_sio.c: Fill LSR fields of the ftdi async_icount structure
  USB: ftdi_sio.c:Fill TX field of the ftdi async_icount structure
  USB: ftdi_sio.c: Fill the RX field of the ftdi async_icount structure
  USB: ftdi_sio.c: Basic icount infrastructure for ftdi_sio
  usb/isp1760: Let OF bindings depend on general CONFIG_OF instead of PPC_OF .
  USB: ftdi_sio: Support TI/Luminary Micro Stellaris BD-ICDI Board
  USB: Fix runtime wakeup on OHCI
  xHCI/USB: Make xHCI driver have a BOS descriptor.
  usb: gadget: add new usb gadget for ACM and mass storage
  ...

1 files changed, 45 insertions, 0 deletions

diff --git a/Documentation/usb/dwc3.txt b/Documentation/usb/dwc3.txt
new file mode 100644
index 0000000..7b590ed
--- /dev/null
+++ b/Documentation/usb/dwc3.txt
@@ -0,0 +1,45 @@
+
+ TODO
+~~~~~~
+Please pick something while reading :)
+
+- Convert interrupt handler to per-ep-thread-irq
+
+  As it turns out some DWC3-commands ~1ms to complete. Currently we spin
+  until the command completes which is bad.
+
+  Implementation idea:
+  - dwc core implements a demultiplexing irq chip for interrupts per
+    endpoint. The interrupt numbers are allocated during probe and belong
+    to the device. If MSI provides per-endpoint interrupt this dummy
+    interrupt chip can be replaced with "real" interrupts.
+  - interrupts are requested / allocated on usb_ep_enable() and removed on
+    usb_ep_disable(). Worst case are 32 interrupts, the lower limit is two
+    for ep0/1.
+  - dwc3_send_gadget_ep_cmd() will sleep in wait_for_completion_timeout()
+    until the command completes.
+  - the interrupt handler is split into the following pieces:
+    - primary handler of the device
+      goes through every event and calls generic_handle_irq() for event
+      it. On return from generic_handle_irq() in acknowledges the event
+      counter so interrupt goes away (eventually).
+
+    - threaded handler of the device
+      none
+
+    - primary handler of the EP-interrupt
+      reads the event and tries to process it. Everything that requries
+      sleeping is handed over to the Thread. The event is saved in an
+      per-endpoint data-structure.
+      We probably have to pay attention not to process events once we
+      handed something to thread so we don't process event X prio Y
+      where X > Y.
+
+    - threaded handler of the EP-interrupt
+      handles the remaining EP work which might sleep such as waiting
+      for command completion.
+
+  Latency:
+   There should be no increase in latency since the interrupt-thread has a
+   high priority and will be run before an average task in user land
+   (except the user changed priorities).