ARM's lead licensee for the Cortex-A15 POP for TSMC 28nm HPM is progressing toward the tape out of its first chip in the coming months, ARM said.
My guess is that this would have to be Nvidia and the Tegra 4. Samsung and Apple both use Samsung fabs and Qualcomm doesn't use the A15 core. That really only leaves TI and Nvidia. There's no way ST is the lead licensee with their NovaThor chip and I think Nvidia has higher volume than TI at this point.