fb_image.data format for cursors?

Is there any documentation for cursor support?  I'm trying to add cursor
support to my framebuffer driver, and I'm having a really hard time find a
description of anything.

In particular, what is the format of the image data in the fb_image.data
buffer?  For example, if fb_image.width = 12, and fb_image.height = 8,
how is the cursor data packed into the 'data' buffer?  That is, what is in
data[0], data[1], etc?

-- 
Timur Tabi
Linux kernel developer at Freescale