[FEATURE][IMPROVMENT] Add a new scheduling type for topology #3817

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1. iuliana-prodan

   added

   enhancementNew feature or requestNew feature or request

   on Feb 4, 2021
2. iuliana-prodan

   assigned

   iuliana-prodan

   ,

   dbaluta

   and

   lgirdwood

   on Feb 4, 2021
3. iuliana-prodan commented on Feb 4, 2021

   

   iuliana-prodan

   on Feb 4, 2021

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   @lgirdwood If we choose the alternative solution 1 (add a new scheduling type for topology) I see:

   • some redundant code - when creating a pipeline we use the pipeline_is_timer_driven() and based on this we choose SCHEDULE_LL_TIMER or SCHEDULE_LL_DMA. So, we should remove this, actually both LL_TIMER and LL_DMA are timer driven;
   • some duplicate code - dma_multi_chan_domain should remain the same for non-timer DMA_DOMAIN, just is dma_multi_chan_domain_is_pending we should not use the task->start for scheduling;
   • we'll need to add a new SOF_DOMAIN_DMA in sof_ipc_pipe_sched_time_domain (topology.h) and a new type of scheduler (scheduler.h). In both cases this will be a just a subtype of SOF_TIMER_DOMAIN_DMA, respectively of SOF_SCHEDULE_LL_DMA.

   So, my proposal is to change synchronous mode from DMA_MULTI_CHAN_DOMAIN to no timer depended.
   My only concern is the Intel platforms: how they use the synchronous mode for this and if they really use the task->start. I'll need to look closer on that.

   👍React with 👍2Reacted by Paul Olaru and Liam Girdwood
4. iuliana-prodan

   assigned

   paulstelian97

   on Feb 4, 2021
5. lgirdwood commented on Feb 5, 2021

   

   lgirdwood

   on Feb 5, 2021

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   @iuliana-prodan it may be clearer for everyone if you were to describe the rules for the current 2 types today and then the rules for the 3rd type. i.e for LL_TIMER (from the top of my head, so I may be missing important details).

   1. LL_TIMER task are ordered and scheduled to run in same sequence on synchronous timer tick. timer is rearmed at end of work so that work is run every 1ms. Timer needs to be on same clock domain as audio interfaces. If the total length of work >1ms then it fails and recovers at next earliest tick.