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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:03 EST.

1	
2	The Amiga Buddha and Catweasel IDE Driver (part of ide.c) was written by
3	Geert Uytterhoeven based on the following specifications:
4	
5	------------------------------------------------------------------------
6	
7	Register map of the Buddha IDE controller and the
8	Buddha-part of the Catweasel Zorro-II version
9	
10	The Autoconfiguration has been implemented just as Commodore
11	described  in  their  manuals, no tricks have been used (for
12	example leaving some address lines out of the equations...).
13	If you want to configure the board yourself (for example let
14	a  Linux  kernel  configure the card), look at the Commodore
15	Docs.  Reading the nibbles should give this information:
16	
17	Vendor number: 4626 ($1212)
18	product number: 0 (42 for Catweasel Z-II)
19	Serial number: 0
20	Rom-vector: $1000
21	
22	The  card  should be a Z-II board, size 64K, not for freemem
23	list, Rom-Vektor is valid, no second Autoconfig-board on the
24	same card, no space preference, supports "Shutup_forever".
25	
26	Setting  the  base address should be done in two steps, just
27	as  the Amiga Kickstart does:  The lower nibble of the 8-Bit
28	address is written to $4a, then the whole Byte is written to
29	$48, while it doesn't matter how often you're writing to $4a
30	as  long as $48 is not touched.  After $48 has been written,
31	the  whole card disappears from $e8 and is mapped to the new
32	address just written.  Make sure $4a is written before $48,
33	otherwise your chance is only 1:16 to find the board :-).
34	
35	The local memory-map is even active when mapped to $e8:
36	
37	$0-$7e		Autokonfig-space, see Z-II docs.
38	
39	$80-$7fd	reserved
40	
41	$7fe		Speed-select Register: Read & Write
42			(description see further down)
43	
44	$800-$8ff	IDE-Select 0 (Port 0, Register set 0)
45	
46	$900-$9ff	IDE-Select 1 (Port 0, Register set 1)
47	
48	$a00-$aff	IDE-Select 2 (Port 1, Register set 0)
49	
50	$b00-$bff	IDE-Select 3 (Port 1, Register set 1)
51	
52	$c00-$cff	IDE-Select 4 (Port 2, Register set 0,
53	                          Catweasel only!)
54	
55	$d00-$dff	IDE-Select 5 (Port 3, Register set 1,
56				      Catweasel only!)
57	
58	$e00-$eff	local expansion port, on Catweasel Z-II the 
59			Catweasel registers are also mapped here.
60			Never touch, use multidisk.device!
61			
62	$f00		read only, Byte-access: Bit 7 shows the 
63			level of the IRQ-line of IDE port 0. 
64	
65	$f01-$f3f	mirror of $f00
66	
67	$f40		read only, Byte-access: Bit 7 shows the 
68			level of the IRQ-line of IDE port 1. 
69	
70	$f41-$f7f	mirror of $f40
71	
72	$f80		read only, Byte-access: Bit 7 shows the 
73			level of the IRQ-line of IDE port 2. 
74			(Catweasel only!)
75	
76	$f81-$fbf	mirror of $f80
77	
78	$fc0		write-only: Writing any value to this
79			register enables IRQs to be passed from the 
80			IDE ports to the Zorro bus. This mechanism 
81			has been implemented to be compatible with 
82			harddisks that are either defective or have
83			a buggy firmware and pull the IRQ line up 
84			while starting up. If interrupts would 
85			always be passed to the bus, the computer 
86			might not start up. Once enabled, this flag 
87			can not be disabled again. The level of the 
88			flag can not be determined by software 
89			(what for? Write to me if it's necessary!).
90	
91	$fc1-$fff	mirror of $fc0
92	
93	$1000-$ffff	Buddha-Rom with offset $1000 in the rom
94			chip. The addresses $0 to $fff of the rom 
95			chip cannot be read. Rom is Byte-wide and
96			mapped to even addresses.
97	
98	The  IDE ports issue an INT2.  You can read the level of the
99	IRQ-lines  of  the  IDE-ports by reading from the three (two
100	for  Buddha-only)  registers  $f00, $f40 and $f80.  This way
101	more  than one I/O request can be handled and you can easily
102	determine  what  driver  has  to serve the INT2.  Buddha and
103	Catweasel  expansion  boards  can issue an INT6.  A separate
104	memory  map  is available for the I/O module and the sysop's
105	I/O module.
106	
107	The IDE ports are fed by the address lines A2 to A4, just as
108	the  Amiga  1200  and  Amiga  4000  IDE ports are.  This way
109	existing  drivers  can be easily ported to Buddha.  A move.l
110	polls  two  words  out of the same address of IDE port since
111	every  word  is  mirrored  once.  movem is not possible, but
112	it's  not  necessary  either,  because  you can only speedup
113	68000  systems  with  this  technique.   A 68020 system with
114	fastmem is faster with move.l.
115	
116	If you're using the mirrored registers of the IDE-ports with
117	A6=1,  the Buddha doesn't care about the speed that you have
118	selected  in  the  speed  register (see further down).  With
119	A6=1  (for example $840 for port 0, register set 0), a 780ns
120	access  is being made.  These registers should be used for a
121	command   access   to  the  harddisk/CD-Rom,  since  command
122	accesses  are Byte-wide and have to be made slower according
123	to the ATA-X3T9 manual.
124	
125	Now  for the speed-register:  The register is byte-wide, and
126	only  the  upper  three  bits are used (Bits 7 to 5).  Bit 4
127	must  always  be set to 1 to be compatible with later Buddha
128	versions  (if  I'll  ever  update this one).  I presume that
129	I'll  never use the lower four bits, but they have to be set
130	to 1 by definition.
131	  The  values in this table have to be shifted 5 bits to the
132	left and or'd with $1f (this sets the lower 5 bits).
133	
134	All  the timings have in common:  Select and IOR/IOW rise at
135	the  same  time.   IOR  and  IOW have a propagation delay of
136	about  30ns  to  the clocks on the Zorro bus, that's why the
137	values  are no multiple of 71.  One clock-cycle is 71ns long
138	(exactly 70,5 at 14,18 Mhz on PAL systems).
139	
140	value 0 (Default after reset)
141	
142	497ns Select (7 clock cycles) , IOR/IOW after 172ns (2 clock cycles)
143	(same timing as the Amiga 1200 does on it's IDE port without
144	accelerator card)
145	
146	value 1
147	
148	639ns Select (9 clock cycles), IOR/IOW after 243ns (3 clock cycles)
149	
150	value 2
151	
152	781ns Select (11 clock cycles), IOR/IOW after 314ns (4 clock cycles)
153	
154	value 3
155	
156	355ns Select (5 clock cycles), IOR/IOW after 101ns (1 clock cycle)
157	
158	value 4
159	
160	355ns Select (5 clock cycles), IOR/IOW after 172ns (2 clock cycles)
161	
162	value 5
163	
164	355ns Select (5 clock cycles), IOR/IOW after 243ns (3 clock cycles)
165	
166	value 6
167	
168	1065ns Select (15 clock cycles), IOR/IOW after 314ns (4 clock cycles)
169	
170	value 7
171	
172	355ns Select, (5 clock cycles), IOR/IOW after 101ns (1 clock cycle)
173	
174	When accessing IDE registers with A6=1 (for example $84x),
175	the timing will always be mode 0 8-bit compatible, no matter
176	what you have selected in the speed register:
177	
178	781ns select, IOR/IOW after 4 clock cycles (=314ns) aktive. 
179	
180	All  the  timings with a very short select-signal (the 355ns
181	fast  accesses)  depend  on the accelerator card used in the
182	system:  Sometimes two more clock cycles are inserted by the
183	bus  interface,  making  the  whole access 497ns long.  This
184	doesn't  affect  the  reliability  of the controller nor the
185	performance  of  the  card,  since  this doesn't happen very
186	often.
187	
188	All  the  timings  are  calculated  and  only  confirmed  by
189	measurements  that allowed me to count the clock cycles.  If
190	the  system  is clocked by an oscillator other than 28,37516
191	Mhz  (for  example  the  NTSC-frequency  28,63636 Mhz), each
192	clock  cycle is shortened to a bit less than 70ns (not worth
193	mentioning).   You  could think of a small performance boost
194	by  overclocking  the  system,  but  you would either need a
195	multisync  monitor,  or  a  graphics card, and your internal
196	diskdrive would go crazy, that's why you shouldn't tune your
197	Amiga this way.
198	
199	Giving  you  the  possibility  to  write  software  that  is
200	compatible  with both the Buddha and the Catweasel Z-II, The
201	Buddha  acts  just  like  a  Catweasel  Z-II  with no device
202	connected  to  the  third  IDE-port.   The IRQ-register $f80
203	always  shows a "no IRQ here" on the Buddha, and accesses to
204	the  third  IDE  port  are  going into data's Nirwana on the
205	Buddha.
206	
207				    Jens Schönfeld february 19th, 1997
208						updated may 27th, 1997
209				     eMail: sysop@nostlgic.tng.oche.de
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