1README for arch/mips/gt64120 directory and subdirectories
2
3Jun Sun, jsun@mvista.com or jsun@junsun.net
401/27, 2001
5
6MOTIVATION
7----------
8
9Many MIPS boards share the same system controller (or CPU companian chip),
10such as GT-64120.  It is highly desirable to let these boards share
11the same controller code instead of duplicating them.
12
13This directory is meant to hold all MIPS boards that use GT-64120 or GT-64120A.
14
15
16HOW TO ADD A BOARD
17------------------
18 
19. Create a subdirectory include/asm/gt64120/<board>.  
20
21. Create a file called gt64120_dep.h under that directory.
22
23. Modify include/asm/gt64120/gt64120.h file to include the new gt64120_dep.h
24  based on config options.  The board-dep section is at the end of 
25  include/asm/gt64120/gt64120.h file. There you can find all required
26  definitions include/asm/gt64120/<board>/gt64120_dep.h file must supply.
27
28. Create a subdirectory arch/mips/gt64120/<board> directory to hold
29  board specific routines.
30
31. The GT-64120 common code is supplied under arch/mips/gt64120/common directory.
32  It includes:
33	1) arch/mips/gt64120/pci.c -
34		common PCI routine, include the top-level pcibios_init()
35	2) arch/mips/gt64120/irq.c -
36		common IRQ routine, include the top-level do_IRQ() 
37	   [This part really belongs to arch/mips/kernel. jsun]
38 	3) arch/mips/gt64120/gt_irq.c -
39		common IRQ routines for GT-64120 chip.  Currently it only handles
40	 	the timer interrupt.
41
42. Board-specific routines are supplied under arch/mips/gt64120/<board> dir.
43	1) arch/mips/gt64120/<board>/pci.c - it provides bus fixup routine
44	2) arch/mips/gt64120/<board>/irq.c - it provides enable/disable irqs
45		and board irq setup routine (irq_setup)
46	3) arch/mips/gt64120/<board>/int-handler.S -
47		The first-level interrupt dispatching routine.
48	4) a bunch of other "normal" stuff (setup, prom, dbg_io, reset, etc)
49
50. Follow other "normal" procedure to modify configuration files, etc.
51
52
53TO-DO LIST
54----------
55
56. Expand arch/mips/gt64120/gt_irq.c to handle all GT-64120 interrupts.
57  We probably need to introduce GT_IRQ_BASE  in board-dep header file,
58  which is used the starting irq_nr for all GT irqs.
59
60  A function, gt64120_handle_irq(), will be added so that the first-level
61  irq dispatcher will call this function if it detects an interrupt
62  from GT-64120.
63
64. More support for GT-64120 PCI features (2nd PCI bus, perhaps)
65