speed up ftdi by reorder to out-in42/942/3
authorPeter Henn <Peter.Henn@web.de>
Sun, 28 Oct 2012 21:08:37 +0000 (22:08 +0100)
committerAndreas Fritiofson <andreas.fritiofson@gmail.com>
Wed, 6 Mar 2013 19:03:37 +0000 (19:03 +0000)
commitef83a9ee9371f330075a5cb57b0dd515d75df8c2
tree07d55e242654447f20a6f4b94e6659e29706b931
parent0f1d00bda65975ede19fc20df3b490b08a7c1afd
speed up ftdi by reorder to out-in

When the ftdi driver calls finally the mpsse_flush function, it first
initiate the USB in and finally the corresponding USB out transaction.
Because data in is requested too early the USB device will always answer
the first USB in by a NAK. That can prevented by a simple reordering of
the out and then the in transfer and can improve the Jtag performance for
high JTAG clock rates.

Change-Id: I17abf1487c914c92e2e447ee6d30562ef629f327
Signed-off-by: Peter Henn <Peter.Henn@web.de>
Reviewed-on: http://openocd.zylin.com/942
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>
Reviewed-by: Xiaofan <xiaofanc@gmail.com>
src/jtag/drivers/mpsse.c