1 Linux for the Q40
2 =================
3
4 You may try http://www.geocities.com/SiliconVa
5 some up to date information. Booter and other
6 available from this place or http://ftp.uni-er
7 and mirrors.
8
9 Hints to documentation usually refer to the li
10 /usr/src/linux/Documentation unless URL given.
11
12 It seems IRQ unmasking can't be safely done on
13 is not implemented - do not try it! (See below
14
15 For a list of kernel command-line options read
16 particular device drivers.
17
18 The floppy imposes a very high interrupt load
19 When something blocks interrupts (HD) it will
20 this is not known to have caused any data loss
21 it can make the floppy very slow or practicall
22 poll the floppy for this reason - something th
23 Only possible cure is getting a 82072 controll
24 the 8272A.
25
26 drivers used by the Q40, apart from the very o
27 drivers/char/q40_keyb.c # use
28 serial.c # norm
29 lp.c # prin
30 genrtc.c # RTC
31 char/joystick/* # most
32 # in d
33 block/floppy.c # norm
34 # and
35 # see
36 ata/pata_falcon.c
37 net/ne.c
38 video/q40fb.c
39 parport/*
40 sound/dmasound_core.c
41 dmasound_q40.c
42
43 Various other PC drivers can be enabled simply
44 arch/m68k/config.in, especially 8 bit devices
45 problems. For cards using 16bit io/mem more ca
46 checking byte order issues, hacking memcpy_*_i
47
48
49 Debugging
50 =========
51
52 Upon startup the kernel will usually output "A
53 preceded by the booter signature. This is a tr
54 went wrong during earliest setup stages of hea
55 **Changed** to preserve SRAM contents by defau
56 requested - SRAM must start with '%LX$' signat
57 to 'lxx' loader enables this.
58
59 SRAM can also be used as additional console de
60 This will save kernel startup msgs into SRAM,
61 only the penguin - and shell prompt if it gets
62 Unfortunately only 2000 bytes are available.
63
64 Serial console works and can also be used for
65
66 Most problems seem to be caused by fawlty or b
67 hard drives anyway.
68 Make sure to configure the parallel port as SP
69 for first testing. The Q40 does not support DM
70 parallel ports version of interrupts.
71
72
73 Q40 Hardware Description
74 ========================
75
76 This is just an overview, see asm-m68k/* for d
77 questions.
78
79 The Q40 consists of a 68040@40 MHz, 1MB video
80 keyboard interface, 1 Programmable LED, 2x8bit
81 shadow ROM.
82 The Q60 has any of 68060 or 68LC060 and up to
83
84 Most interfacing like floppy, IDE, serial and
85 slots. The ISA io and mem range is mapped (spa
86 regions of the memory.
87 The main interrupt register IIRQ_REG will indi
88 or from some ISA devices, EIRQ_REG can disting
89
90 The Q40 custom chip is programmable to provide
91 - 50 or 200 Hz - level 2, !!THIS CAN'T
92 - 10 or 20 KHz - level 4, used for dma
93
94 Linux uses the 200 Hz interrupt for timer and
95
96
97 Interrupts
98 ==========
99
100 q40 master chip handles only a subset of level
101
102 Linux has some requirements wrt interrupt arch
103 to my knowledge:
104 (a) interrupt handler must not be reen
105 from within handler
106 (b) working enable/disable_irq
107
108 Luckily these requirements are only important
109 with other architectures - ide,serial,parallel
110 q40ints.c now contains a trivial hack for (a),
111 because only irq's 4-15 can be disabled - and
112 Thus disable_irq() can effectively block the m
113 asleep.
114 One thing to keep in mind when hacking around
115 that there is no way to find out which IRQ cau
116 displays current state of the various IRQ line
117
118 Keyboard
119 ========
120
121 q40 receives AT make/break codes from the keyb
122 the PC scancodes x86 Linux uses. So by theory
123 work just by loading the appropriate x86 keyta
124
125 Unfortunately the AT->PC translation isn't qui
126 documentation of it is absolutely minimal - th
127 behave exactly as expected.
128
129 There is still hope that it can be fixed compl
130 problems, email me ideally this:
131 - exact keypress/release sequence
132 - 'showkey -s' run on q40, non-X sessi
133 - 'showkey -s' run on a PC, non-X sess
134 - AT codes as displayed by the q40 deb
135 btw if the showkey output from PC and Q40 does
136 classic configuration problem - don't send me
137
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