What is the difference between DMA-Engine and DMA-Controller?

Question

1. As mentioned above, what is the difference between a dma engine and a dma-controller (on focus on linux)?

2. When does the linux dma engine come into

Answer 1

According to this document, http://www.asprom.com/application/intel_3.pdf:

The 82C37 DMA controllers should not be confused with the DMA engines found in some earlier MCH (Memory Controller Hub) components. These DMA controllers are tied to the ISA/LPC bus and used mostly for transfers to/from slow devices such as floppy disk controllers.

So it seems it is a device found on previous platfroms that used MCHs devices.