Messages in this thread | | | Subject | Re: [PATCH 2/3] dmaeninge: xilinx_dma: Fix bug in multiple frame stores scenario in vdma | From | Jose Abreu <> | Date | Thu, 15 Dec 2016 16:10:20 +0000 |
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Hi Kedar,
On 15-12-2016 15:11, Kedareswara rao Appana wrote: > When VDMA is configured for more than one frame in the h/w > for example h/w is configured for n number of frames and user > Submits n number of frames and triggered the DMA using issue_pending API. > In the current driver flow we are submitting one frame at a time > but we should submit all the n number of frames at one time as the h/w > Is configured for n number of frames. > > This patch fixes this issue. > > Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com> > --- > drivers/dma/xilinx/xilinx_dma.c | 43 +++++++++++++++++++++++++---------------- > 1 file changed, 26 insertions(+), 17 deletions(-) > > diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c > index 736c2a3..4f3fa94 100644 > --- a/drivers/dma/xilinx/xilinx_dma.c > +++ b/drivers/dma/xilinx/xilinx_dma.c > @@ -1087,23 +1087,33 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan) > tail_segment->phys); > } else { > struct xilinx_vdma_tx_segment *segment, *last = NULL; > - int i = 0; > + int i = 0, j = 0; > > if (chan->desc_submitcount < chan->num_frms) > i = chan->desc_submitcount; > > - list_for_each_entry(segment, &desc->segments, node) { > - if (chan->ext_addr) > - vdma_desc_write_64(chan, > - XILINX_VDMA_REG_START_ADDRESS_64(i++), > - segment->hw.buf_addr, > - segment->hw.buf_addr_msb); > - else > - vdma_desc_write(chan, > - XILINX_VDMA_REG_START_ADDRESS(i++), > - segment->hw.buf_addr); > - > - last = segment; > + for (j = 0; j < chan->num_frms; ) { > + list_for_each_entry(segment, &desc->segments, node) { > + if (chan->ext_addr) > + vdma_desc_write_64(chan, > + XILINX_VDMA_REG_START_ADDRESS_64(i++), > + segment->hw.buf_addr, > + segment->hw.buf_addr_msb); > + else > + vdma_desc_write(chan, > + XILINX_VDMA_REG_START_ADDRESS(i++), > + segment->hw.buf_addr); > + > + last = segment;
Hmm, is it possible to submit more than one segment? If so, then i and j will get out of sync.
> + } > + list_del(&desc->node); > + list_add_tail(&desc->node, &chan->active_list); > + j++;
But if i is non zero and pending_list has more than num_frms then i will not wrap-around as it should and will write to invalid framebuffer location, right?
> + if (list_empty(&chan->pending_list)) > + break; > + desc = list_first_entry(&chan->pending_list, > + struct xilinx_dma_tx_descriptor, > + node); > } > > if (!last) > @@ -1114,14 +1124,13 @@ static void xilinx_vdma_start_transfer(struct xilinx_dma_chan *chan) > vdma_desc_write(chan, XILINX_DMA_REG_FRMDLY_STRIDE, > last->hw.stride); > vdma_desc_write(chan, XILINX_DMA_REG_VSIZE, last->hw.vsize);
Maybe a check that all framebuffers contain valid addresses should be done before programming vsize so that VDMA does not try to write to invalid addresses.
> + > + chan->desc_submitcount += j; > + chan->desc_pendingcount -= j; > } > > chan->idle = false; > if (!chan->has_sg) { > - list_del(&desc->node); > - list_add_tail(&desc->node, &chan->active_list); > - chan->desc_submitcount++; > - chan->desc_pendingcount--; > if (chan->desc_submitcount == chan->num_frms) > chan->desc_submitcount = 0;
"desc_submitcount >= chan->num_frms would be safer here.
> } else {
Best regards, Jose Miguel Abreu
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