Obviously, I would tend to agree with pgo - the OpenSDA from ARM is really a spec for the host software to talk to the SDA and the code you get from ARM will not be vendor specific.
ARM, for example, does not specify how the USB module should work for hardware.
ARM specs the NVIC, the SysTick, the IO set up registers (but NOT what the ALT functions would be) and some other generic hardware things, but the vendors add their own specific IO functions.
Most likely P&E will not release their code for the OpenSDA debugger debugging part - as Open really means the spec is open.
Update:
I downloaded CMSIS-DAP Beta 0.01 from the ARM web site, and there an Keil MDK project there to build what appears to be OpenSDA. (You can download and use MDK for upto 32K for free).
Give it a try, who knows?