[Letux-kernel] 1.5GHz problems

[Matthijs van Duin]

On 2 August 2016 at 11:55, H. Nikolaus Schaller <hns at goldelico.com> wrote:
> well, we need to find someone to try this in parallel to me.
> Or postpone until other (simpler) means to identify the issue show no success.

Well I wasn't planning on attempting to solder anything onto my uEVM
even if I had the time, but I found a moment to at least make a simple
setup for CCS debugserver that only attaches to DAP and makes no
attempt to touch the Cortex-A15 subsystem (which might be deadlocked).

https://github.com/mvduin/omap5-dap

If your setup matched mine you should be able to start the ./dss
commandline, wait a bit, then press enter to connect to the target.
You may however need to tweak paths hardcoded in the dss script and/or
adjust the target configuration for a different JTAG adapter.

It includes utility code for I2C and an untested example for dumping
pmic registers. The i2c code was working on am335x so it should work
on omap5 too. I just commented out the clock calculation stuff since
it would need to be revised and linux will have initialized those
registers anyway. The problem is that the code only works with irqs
enabled because this causes the peripheral to change behaviour (I
don't immediately recall the details), but obviously doing this makes
it impossible to sneak behind linux' back.

If linux has crashed sufficiently well however then you *should* be
able to call i2c0_init() and then e.g. pmic_read(0x100,7) would read
the pmic's RTC registers.

It's all a bit unpolished, but maybe it is of use

Matthijs