⚠️ rework DMA and GPTMR

[stnolting]

• ⚠️ DMA: remove FIRQ-triggered auto-mode; re-arrange control register bist
• ⚠️ GPTMR: remove mode configuration bit; timer now always operate in "continuous" mode (interval timer)

[jpf91]

@stnolting Hmm any reason why the FIRQ trigger mode was removed? I was planning to use it :-)

[stnolting]

That was another completely over-engineered feature... 🙈

The DMA only has one channel, which also only has a single descriptor. Event-driven triggering therefore seems to make little sense.

In addition, it does not require much overhead to start the (pre-programmed) DMA from an interrupt-driven service routine.

I was planning to use it :-)

Can you give us a few details? Perhaps I was too hasty and there are actually real-word applications that would benefit greatly from this. 🤔