On Tue, 2012-11-20 at 19:38 +0530, Viresh Kumar wrote: > On 20 November 2012 19:08, Andy Shevchenko > <[email protected]> wrote: > > Currently the direction value is come from the generic slave configuration > > s/is come/comes > > > structure and explicitly as a preparation function parameter. The first one > > is > > kinda obsoleted. Thus, we have to store the value passed to the preparation > > function somewhere in our structures to be able to use it later. The best > > candidate to provide the storage is a custom channel structure. Until now we > > still keep and check the direction field of the slave config structure as > > well. > > > > Signed-off-by: Andy Shevchenko <[email protected]> > > --- > > drivers/dma/dw_dmac.c | 10 ++++++++-- > > drivers/dma/dw_dmac_regs.h | 2 ++ > > 2 files changed, 10 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c > > index 5e2c4dc..58c6d3c 100644 > > --- a/drivers/dma/dw_dmac.c > > +++ b/drivers/dma/dw_dmac.c > > @@ -178,9 +178,9 @@ static void dwc_initialize(struct dw_dma_chan *dwc) > > cfghi = dws->cfg_hi; > > cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK; > > } else { > > - if (dwc->dma_sconfig.direction == DMA_MEM_TO_DEV) > > + if (dwc->direction == DMA_MEM_TO_DEV) > > cfghi = DWC_CFGH_DST_PER(dwc->dma_sconfig.slave_id); > > - else if (dwc->dma_sconfig.direction == DMA_DEV_TO_MEM) > > + else if (dwc->direction == DMA_DEV_TO_MEM) > > cfghi = DWC_CFGH_SRC_PER(dwc->dma_sconfig.slave_id); > > } > > I have a doubt here. This routine is called both for memcpy and slave > transfers. > Earlier if (dws), code was used to check slave/non-slave transfer but with > your > earlier patch, for if (!dws) case too, there can be slave transfers > based on direction. > > Consider a situation. A channel is used for slave transfers and have > direction set > to DMA_DEV_TO_MEM. Now, channel is freed and used for memcpy. Now the > direction value is retained as we haven't updated it. So, is this a > potential bug?
Yeah, good point. I think we have to set direction in all possible entry points (prep functions only?). It means at least we need to update memcpy prep as well. I'll update patch tomorrow. -- Andy Shevchenko <[email protected]> Intel Finland Oy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
