On Tue, Jul 19, 2011 at 10:34 PM, Jassi Brar <jassisinghbrar@xxxxxxxxx> wrote:
>
> On Wed, Jul 20, 2011 at 10:41 AM, Vikram Pandita <vikram.pandita@xxxxxx> wrote:
> > From: Anand Gadiyar <gadiyar@xxxxxx>
> >
> > This patch enables the DMA mode1 RX support.
> > This feature is enabled based on the short_not_ok flag passed from
> > gadget drivers.
> >
> > This will result in a thruput performance gain of around
> > 40% for USB mass-storage/mtp use cases.
> >
> > Signed-off-by: Anand Gadiyar <gadiyar@xxxxxx>
> > Signed-off-by: Moiz Sonasath <m-sonasath@xxxxxx>
> > Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
> > Tested-by: Vikram Pandita <vikram.pandita@xxxxxx>
> > ---
> > v1 - initial push
> > v2 - fixed whitespace issues as per Sergei Shtylyov<sshtylyov@xxxxxxxxxx> comments
> > v3 - restor authorship to Anand Gadiyar <gadiyar@xxxxxx>
> > v4 - adding my signed-off as per Kevin Hilman <khilman@xxxxxx>
> >
> > drivers/usb/musb/musb_gadget.c | 68 ++++++++++++++++++++++++---------------
> > 1 files changed, 42 insertions(+), 26 deletions(-)
>
> > @@ -683,6 +684,18 @@ static void rxstate(struct musb *musb, struct musb_request *req)
> >
> > if (csr & MUSB_RXCSR_RXPKTRDY) {
> > len = musb_readw(epio, MUSB_RXCOUNT);
> > +
> > + /*
> > + * Enable Mode 1 for RX transfers only for mass-storage
> > + * use-case, based on short_not_ok flag which is set only
> > + * from file_storage and f_mass_storage drivers
> > + */
> > +
> > + if (request->short_not_ok && len == musb_ep->packet_sz)
> > + use_mode_1 = 1;
> > + else
> > + use_mode_1 = 0;
> > +
> There is nothing UMS class specific in this patch...
> (request->short_not_ok && len == musb_ep->packet_sz) may not be the
> signature of, and only of, Mass Storage Functions. So maybe removing
> the UMS mention from
> comment and change-log is a good idea.
Have you grepped the code in drivers/usb/gadget/*.*
only UMS sets this flag today and hence the use of this flag.
As i understand, on UMS, CSW/data/CBW - the data part size is a known
size and to be safe that mode=1 dma is not stuck up,
the mode is enabled only for the gadget driver that sets short_not_ok
flag - and that today happens to be only UMS.
> You might want to add is-ep-type-bulk-out check to the condition
> though, so that it doesn't affect
> cases that you didn't verify.
TX path (IN host), already uses the mode=1 DMA and hence the comment
is not valid.
This patch just also enables mode=1 on RX path.
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