Hi, I messed up the register names in the commit log. Will fix in v2.
On 05/22/2014 05:30 PM, Daniel Mack wrote: > When a 0-length packet is received on the bus, desc->pd6 contains 1, and ... 'desc->pd0' ... > the current residue calculation reports back that 1 byte has been > transferred. This is not according to what the datasheet says, but it's > been the case on an AM335x board, very reproducible. > > Fix this by looking at bit 19 in PD2 of the completed packet. This bit > will tell us if a zero-length packet was received on a queue. If it's > set, ignore pd2 and report a total length of 0. ... 'ignore pd0' ... > > Signed-off-by: Daniel Mack <[email protected]> > --- > drivers/dma/cppi41.c | 13 ++++++++++--- > 1 file changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c > index d028f36..8f8b0b6 100644 > --- a/drivers/dma/cppi41.c > +++ b/drivers/dma/cppi41.c > @@ -86,6 +86,9 @@ > > #define USBSS_IRQ_PD_COMP (1 << 2) > > +/* Packet Descriptor */ > +#define PD2_ZERO_LENGTH (1 << 19) > + > struct cppi41_channel { > struct dma_chan chan; > struct dma_async_tx_descriptor txd; > @@ -307,7 +310,7 @@ static irqreturn_t cppi41_irq(int irq, void *data) > __iormb(); > > while (val) { > - u32 desc; > + u32 desc, len; > > q_num = __fls(val); > val &= ~(1 << q_num); > @@ -319,9 +322,13 @@ static irqreturn_t cppi41_irq(int irq, void *data) > q_num, desc); > continue; > } > - c->residue = pd_trans_len(c->desc->pd6) - > - pd_trans_len(c->desc->pd0); > > + if (c->desc->pd2 & PD2_ZERO_LENGTH) > + len = 0; > + else > + len = pd_trans_len(c->desc->pd0); > + > + c->residue = pd_trans_len(c->desc->pd6) - len; > dma_cookie_complete(&c->txd); > c->txd.callback(c->txd.callback_param); > } > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
