F7 optimizations

[DzikuVx]

Things that @DieHertz did in betaflight/betaflight#5674 or at least some of them.

So far, after enabling caches, prefetch and ART, load at 8kHz went from 1200% to 900%. Let's say it's a porgress.

As a goal I would like to see 8kHz mode on F7 working.

I'm also considering decoupling some tasks from main loop again but this time without really giving users much options about them

[DieHertz]

Main gains came from ensuring critical functions go into fast instruction RAM

[DzikuVx]

@DieHertz yes, this is what I'm expecting. Small steps tho

[digitalentity]

Apart from required verification that D-Cache doesn't break DMA - LGTM

[DieHertz]

I recommend placing dma buffers into dTCM ram on F7 to avoid having to think about it

[DieHertz]

This is not necessary, I thought I have removed it to not introduce any changes into lib folder

[teckel12]

👍

[DzikuVx]

It still has some space left for speedup, but should be flyable with 8kHz

Todo: RX task, Baro task and maybe OSD

[DzikuVx]

[DzikuVx]

Tested LED and DSHOT, both are still working so looks like there is no DMA problems

[digitalentity]

Cool!

[teckel12]

@DzikuVx What's up with your taskbar on the left? Are you some kind of MONSTER? 😉

[DzikuVx]

@teckel12 this is the best place for taskbar on widescreen. It just takes less space than on the bottom

[DzikuVx]

F745 tested on OmnibusF7. Todo:

• setup all F7 to use ITCM_RAM
• test F4 and F3 if they are working without any problem
• flight test with DSHOT

[DzikuVx]

By pure coincidence tested on F722-STD with DSHOT600 and 4kHz mode (GPS and mag). All fine

[teckel12]

@DzikuVx Nice work!