Connecting to JTAG with OpenOCD needs a few changes in the cortex_a.c source to enable support for Cortex-A15. If you actually make those changes and play with debug registers, you will discover that DBGEN and SPIDEN signals/fuses are disabled, so debug mode is not accessible.
I have not yet tried flashing.
that's not true, i currently play with openocd, flyswatter2 and ifc6410 (another apq8064 box) and i discovered, that problem is how openocd handles writing to crtlstat register. seems openocd implements dap ver. 0 way, but not dap ver. 1 and dap ver. 2 ways. i'm currently diving to arm coresight documentation and openocd code.