Re: [PATCH v3 01/12] dma: edma: Setup parameters to DMA MAX_NR_SGat a time

From: Joel Fernandes
Date: Mon Aug 12 2013 - 19:56:36 EST


Dropped quite a few from the CC list...

On 08/12/2013 02:15 AM, Sekhar Nori wrote:
> 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@xxxxxx>
>> ---
>> 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);

I agree the original naming was quite long. I would rather using
something more descriptive though than nslots. How does slots_needed sound?

Thanks,

-Joel

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