ToastBucket
Very Active Member
Are the two M4 cores in the OMAP used for anything in the out-of-the-box Pyra OS? I am very interested in playing with these when I'm able to get a Pyra. I will likely be building my own barebones rootfs for experimentation with these but it would be interesting to start out using the preconfigured image, so I'd like to not clobber anything running down there.
UPDATE:
The M4 cores appear to interface with the A15's, I/O, and peripherals on the L3 cache. It also appears that communication between the A15's and the M4's can be done through a software communication layer called RPMsg. At this point we have nothing definitive, but have gathered resources for research which are posted below.
UPDATE:
The M4 cores appear to interface with the A15's, I/O, and peripherals on the L3 cache. It also appears that communication between the A15's and the M4's can be done through a software communication layer called RPMsg. At this point we have nothing definitive, but have gathered resources for research which are posted below.
- Video overview of remoteproc (34:07) and RPMsg (40:25) communication between the A8 core and PRU cores on an AM335x (at this point we can assume that this is similar on the OMAP5):
- Official kernel.org page for RPMsg: https://www.kernel.org/doc/Documentation/rpmsg.txt
- A TI forum post regarding setting up remoteproc and RPMsg on OMAP SoC's: https://e2e.ti.com/support/dsp/omap_applications_processors/f/42/t/315076
- Quick start guide for setting up RPMsg on AM335x, AM437x, AM572x, and K2G platforms: http://processors.wiki.ti.com/index.php/RPMsg_Quick_Start_Guide
- Orbstheorem's thread regarding the M4's: https://pyra-handheld.com/boards/threads/roadmap-using-the-cortex-m4-cpus.77494/
- fahrstuhl's thread regarding the M4's: https://pyra-handheld.com/boards/threads/uses-for-the-cortex-m4-cores-on-the-omap5.74515/
- A TI forum post regarding binary execution on the OMAP5 M4's: https://e2e.ti.com/support/omap/f/885/t/316051
- Most importantly the OMAP5342 TRM: (I'll let a mod add a link to this, not sure if I can for NDA reasons)
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