[PATCH v4 3/4] dma/ae4dma: add data path operations

[fengchengwen]

On 7/10/2026 3:22 PM, Raghavendra Ningoji wrote:
> On Mon, 7 Jul 2026 at 06:49, fengchengwen <fengchengwen at huawei.com> wrote:
>>
>>> +	if (last_idx != NULL)
>>> +		*last_idx = (uint16_t)(cmd_q->next_read - 1);
>>
>> 1\ the last_idx always non-NULL for driver, so no need for
>>    'if (last_idx != NULL)'
>> 2\ last_idx should be the last success completed index
> 
> Both fixed in v5. The NULL check is dropped, and last_idx now reports
> the ring_idx of the last *successfully* completed op.
> 
>> Consider four reqests, the hardware mark each request as following:
>>     req1   success
>>     req2   err
>>     req3   success
>>     req4   err
>> the cpl_count will be 4, and err_count will be 2
>> It will return 2 in current impl, and last_idx will be the req4's
>> But in this function, it should return 1, and last_idx should be req1's
> 
> Agreed - thanks for the clear example. rte_dma_completed() is reworked
> in v5 to stop at the first failed descriptor: it returns only the run of
> successful ops preceding the error (1 in your example), sets *has_error,
> and leaves the failed op in place with last_idx pointing at the last
> success (req1). The failed op and everything after it are then drained
> and reported by rte_dma_completed_status().
> 
> On a related note, while implementing the above I found the last_idx
> documentation for rte_dma_completed() and rte_dma_completed_status()
> to be identical:
> 
>     @param[out] last_idx
>       The last completed operation's ring_idx.
> 
> Since rte_dma_completed() only reports operations that completed
> *successfully* (it stops at the first error), its last_idx is really the
> last successfully completed operation's ring_idx, whereas for
> rte_dma_completed_status() it is the last completed operation regardless
> of status. Would a small doc clarification along these lines be welcome
> (as a separate patch)?

I think it is necessary to update.
Please also update rte_dma_completed_status, both in a separate patch

Thanks

> 
>     rte_dma_completed():
>     @param[out] last_idx
>       The last successfully completed operation's ring_idx.
> 
> I'm happy to send that as a separate dmadev doc patch if you agree.
> 
> Thanks,
> Raghavendra