Messages in this thread | | | Date | Mon, 12 Aug 2013 12:45:23 +0530 | From | Sekhar Nori <> | Subject | Re: [PATCH v3 01/12] dma: edma: Setup parameters to DMA MAX_NR_SG at a time |
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On Monday 05 August 2013 09:44 PM, Joel Fernandes wrote: > Changes are made here for configuring existing parameters to support > DMA'ing them out in batches as needed. > > Also allocate as many as slots as needed by the SG list, but not more > than MAX_NR_SG. Then these slots will be reused accordingly. > For ex, if MAX_NR_SG=10, and number of SG entries is 40, still only > 10 slots will be allocated to DMA the entire SG list of size 40. > > Signed-off-by: Joel Fernandes <joelf@ti.com> > --- > drivers/dma/edma.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c > index 5f3e532..7b0853c 100644 > --- a/drivers/dma/edma.c > +++ b/drivers/dma/edma.c > @@ -222,9 +222,9 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg( > enum dma_slave_buswidth dev_width; > u32 burst; > struct scatterlist *sg; > - int i; > int acnt, bcnt, ccnt, src, dst, cidx; > int src_bidx, dst_bidx, src_cidx, dst_cidx; > + int i, num_slots_needed;
'nslots' is more to my liking. Better keep variable names short.
> > if (unlikely(!echan || !sgl || !sg_len)) > return NULL; > @@ -262,8 +262,11 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg( > > edesc->pset_nr = sg_len; > > - for_each_sg(sgl, sg, sg_len, i) { > - /* Allocate a PaRAM slot, if needed */ > + /* Allocate a PaRAM slot, if needed */ > + > + num_slots_needed = sg_len > MAX_NR_SG ? MAX_NR_SG : sg_len;
nslots = min(MAX_NR_SG, sg_len);
> + > + for (i = 0; i < num_slots_needed; i++) { > if (echan->slot[i] < 0) { > echan->slot[i] = > edma_alloc_slot(EDMA_CTLR(echan->ch_num), > @@ -273,6 +276,10 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg( > return NULL; > } > } > + } > + > + /* Configure PaRAM sets for each SG */ > + for_each_sg(sgl, sg, sg_len, i) { > > acnt = dev_width; > > @@ -330,6 +337,7 @@ static struct dma_async_tx_descriptor *edma_prep_slave_sg( > /* Configure A or AB synchronized transfers */ > if (edesc->absync) > edesc->pset[i].opt |= SYNCDIM; > +
Random extra newline.
The patch as such is fine, but I dont think it makes lot of sense standalone. This needs to be merged into the patch where you actually handle the entire SG list in batches.
Thanks, Sekhar
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