[0/3] usb: dwc3: gadget: Reduce register read/write operations

Message

Thinh Nguyen Nov. 30, 2021, 2:53 a.m. UTC

Depends on the device platform, a register read/write may take a few
microseconds to complete. A register read on a HAPS platform takes ~2us where
as register write takes less than 1us. These delays impact performance of small
transfers or interface(s) with many endpoints such as UASP interface. For large
transfer size and low rate of events generated, this series does not make much
of a difference.

This series avoids register read/write operations where they are not needed.
On the HAPS platform with UASP in SSP Gen 2x2 speed, we observed almost double
in performance speed when testing 4KB transfers reading and writing.


Thinh Nguyen (3):
  usb: dwc3: gadget: Skip checking Update Transfer status
  usb: dwc3: gadget: Ignore Update Transfer cmd params
  usb: dwc3: gadget: Skip reading GEVNTSIZn

 drivers/usb/dwc3/gadget.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)


base-commit: 4d012040161cba054208555300d9fdf2b8925c34