Did Buddha commit psychogenic death at Cāpāla Shrine?

According to SN 51.10 : > So at the Cāpāla Tree-shrine the Buddha, mindful and aware, > surrendered the life force. When he did so there was a great > earthquake, awe-inspiring and hair-raising, and thunder cracked the > sky. Then, understanding this matter, on that occasion the Buddha > expressed this heartfelt sentiment: > > “Comparing the incomparable with the creation of prolonged life, the > sage surrendered the life force. Happy inside, serene, he shattered > self-creation like a suit of armor.” Why did Buddha surrender his life three months in advance, or was it a foregone conclusion? Is perfection of concentration, the four bases of psychic power , mandatory to surrender it? What is required?