Hello.
Yauheni Kaliuta wrote:
> > From: Yauheni Kaliuta<yauheni.kaliuta@xxxxxxxxx>
> > The specification says about FLUSHFIFO, that it "May be set simultaneously
> > with TxPktRdy to abort the packet that is currently being loaded into the
> > FIFO". This is a situation, where TxPktRdy hasn't been set yet, but some
> > data already loaded into the fifo. It looks, that if TxPktRdy has been
> > set before and there is no loading in progress but we set FLUSHFIFO with
> > the TxPktRdy, controller tries to use the same logic to abort loading
> > and as the result just does nothing (because there is no loading in progress)
> > Signed-off-by: Yauheni Kaliuta<yauheni.kaliuta@xxxxxxxxx>
> > ---
> > drivers/usb/musb/musb_gadget.c | 2 ++
> > 1 files changed, 2 insertions(+), 0 deletions(-)
> > diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
> > index 0a50a35..830768f 100644
> > --- a/drivers/usb/musb/musb_gadget.c
> > +++ b/drivers/usb/musb/musb_gadget.c
> > @@ -1524,6 +1524,7 @@ static void musb_gadget_fifo_flush(struct usb_ep *ep)
> > csr = musb_readw(epio, MUSB_TXCSR);
> > if (csr& MUSB_TXCSR_FIFONOTEMPTY) {
> > csr |= MUSB_TXCSR_FLUSHFIFO | MUSB_TXCSR_P_WZC_BITS;
> > + csr &= ~MUSB_TXCSR_TXPKTRDY;
> A comment wouldn't hurt here either...
Is
/*
* Setting both TXPKTRDY and FLUSHFIFO makes controller to interrupt
"To" not needed.
* current FIFO loading, but not flushing the already loaded ones.
Only "flush".
*/
ok?
Yes, excluding the grammar. I see you have already posted the patch
though... too fast for me. :-)
> > musb_writew(epio, MUSB_TXCSR, csr);
> > /* REVISIT may be inappropriate w/o FIFONOTEMPTY ... */
> > musb_writew(epio, MUSB_TXCSR, csr);
> > @@ -1531,6 +1532,7 @@ static void musb_gadget_fifo_flush(struct usb_ep *ep)
> > } else {
> > csr = musb_readw(epio, MUSB_RXCSR);
> > csr |= MUSB_RXCSR_FLUSHFIFO | MUSB_RXCSR_P_WZC_BITS;
> > + csr &= ~MUSB_RXCSR_RXPKTRDY;
> This still contradicts the manual. Did you really see the issue here?
No issue (yet?). I wouldn't say it contradicts, FLUSHFIFO must reset it and
CPU can clear it when it unloaded (cleared) the fifo.
Reminding you again, read the description of the RXCSR.FlushFIFO bit:
"Note: FlushFIFO should only be used when RxPktRdy is set. At other times, it
may cause data to be corrupted."
But well, since I do not have an issue and I do not see a problem in the
documentation with it, agree, it's worth not to change, removing the chunk.
Thanks.
WBR, Sergei
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