On Mon, Jan 21, 2013 at 11:00:44AM +0200, Andy Shevchenko wrote: > Currently the driver returns full length of the active descriptor which is > wrong. We have to go throught the active descriptor and sum up the length of > unsent children in the chain along with the actual data in the DMA channel why do you mean by children here? > registers. > > The cyclic case is not handled by this patch due to len field in the > descriptor > structure is left untouched by the original code. > > Signed-off-by: Andy Shevchenko <[email protected]> > --- > drivers/dma/dw_dmac.c | 93 > ++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 92 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c > index d1b9ba2..4325c68 100644 > --- a/drivers/dma/dw_dmac.c > +++ b/drivers/dma/dw_dmac.c > @@ -941,6 +941,97 @@ err_desc_get: > return NULL; > } > > +/* --------------------- Calculate residue ---------------------------- */ > + > +static inline size_t dwc_get_rest(struct dw_dma_chan *dwc, struct dw_desc > *desc) > +{ > + enum dma_transfer_direction direction = dwc->direction; > + > + if (direction == DMA_MEM_TO_DEV || direction == DMA_MEM_TO_MEM) > + return desc->len - (channel_readl(dwc, SAR) - desc->lli.sar); > + else if (direction == DMA_DEV_TO_MEM) > + return desc->len - (channel_readl(dwc, DAR) - desc->lli.dar); > + > + return 0; hmmm, why not use BLOCK_TS value. That way you dont need to look at direction and along with burst can easily calculate residue...
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