Fix for scheduler bugs

[xiulipan]

Now both ipc process task and pipeline copy task are using scheduler. Need to care about the run order of the task. Fix some bugs in scheduler that will cause the wrong order of task.

1. use different IRQ to let Ppl copy run in higher IRQ level.
2. clear scheduler IRQ earlier to let DAI IRQ schedule can run in time.
3. clear arch task IRQ earlier to make sure all task IRQ goes on time.

[lgirdwood]

Can you check master for a similar patch by @tlauda and backport.

[xiulipan]

I did not see any similar patch.
@tlauda
Do you make some change like this in master?

[lgirdwood]

Can you change the commit message, the real fix here is to move irq_clear before edf_get_next as there is a race when adding a new task.

[xiulipan]

@lgirdwood
Ping.
Checked PRs and found no similar patches.

[xiulipan]

@lgirdwood
Fix one more potential risk in arch task.

task: clear interrupt earlier

list_item_for_safe is safe for item deletion, but when a new item is
appended to the list. It seems the item could not be go through.
To fix this limitation, move interrupt clear to make sure every IRQ is
handled.
Do not try to handle two task with one IRQ handler.

Signed-off-by: Pan Xiuli <[email protected]>

[lgirdwood]

Can you change the commit message, the real fix here is to move irq_clear before edf_get_next as there is a race when adding a new task.

[xiulipan]

@lgirdwood
I have test with this patches with tracev enable.
There will still be a race that new task added in
tracev_pipe("edf");

I am now try to refine the schedule_edf function to let it can handle multiple task that have be added.
Or just close the IRQ when we have some task to run.

[xiulipan]

@lgirdwood
PR updated.
Test with
aplay -D hw:0,0 -f dat /dev/zero & arecord -D hw:0,0 -f dat /dev/null -vv -i and pressing space
No firmware xrun now.