What does "is up top" mean?

Context:
My name is Stephen King. I'm writing the first draft of this part at my desk (the one under the eave) on a snowy morning in December of 1997. There are things on my mind. Some are worries (bad eyes, Christmas shopping not even started, wife under the weather with a virus), some are good things (our younger son made a surprise visit home from college, I got to play Vince Taylor's "Brand New Cadillac" with The Wallflowers at a concert), but right now all that stuff is up top. I'm in another place, a basement place where there are lots of bright lights and clear images. This is a place I've built for myself over the years. It's a far-seeing place. I know it's a little strange, a little bit of a contradiction, that a far-seeing place / should also be a basement place, but that's how it is with me. If you construct your own far-seeing place, you might put it in a treetop or on the roof of the World Trade Center or on the edge of the Grand Canyon. That's your little red wagon, as Robert McCammon says in one of his novels. This book is scheduled to be published in the
More:
http://www.amphi.com/media/1307040/what%20writing%20is.pdf