1 Linux for the Q40 1 Linux for the Q40
2 ================= 2 =================
3 3
4 You may try http://www.geocities.com/SiliconVa 4 You may try http://www.geocities.com/SiliconValley/Bay/2602/ for
5 some up to date information. Booter and other 5 some up to date information. Booter and other tools will be also
6 available from this place or http://ftp.uni-er 6 available from this place or http://ftp.uni-erlangen.de/pub/unix/Linux/680x0/q40/
7 and mirrors. 7 and mirrors.
8 8
9 Hints to documentation usually refer to the li 9 Hints to documentation usually refer to the linux source tree in
10 /usr/src/linux/Documentation unless URL given. 10 /usr/src/linux/Documentation unless URL given.
11 11
12 It seems IRQ unmasking can't be safely done on 12 It seems IRQ unmasking can't be safely done on a Q40. IRQ probing
13 is not implemented - do not try it! (See below 13 is not implemented - do not try it! (See below)
14 14
15 For a list of kernel command-line options read 15 For a list of kernel command-line options read the documentation for the
16 particular device drivers. 16 particular device drivers.
17 17
18 The floppy imposes a very high interrupt load 18 The floppy imposes a very high interrupt load on the CPU, approx 30K/s.
19 When something blocks interrupts (HD) it will 19 When something blocks interrupts (HD) it will lose some of them, so far
20 this is not known to have caused any data loss 20 this is not known to have caused any data loss. On highly loaded systems
21 it can make the floppy very slow or practicall 21 it can make the floppy very slow or practically stop. Other Q40 OS' simply
22 poll the floppy for this reason - something th 22 poll the floppy for this reason - something that can't be done in Linux.
23 Only possible cure is getting a 82072 controll 23 Only possible cure is getting a 82072 controller with fifo instead of
24 the 8272A. 24 the 8272A.
25 25
26 drivers used by the Q40, apart from the very o 26 drivers used by the Q40, apart from the very obvious (console etc.):
27 drivers/char/q40_keyb.c # use 27 drivers/char/q40_keyb.c # use PC keymaps for national keyboards
28 serial.c # norm 28 serial.c # normal PC driver - any speed
29 lp.c # prin 29 lp.c # printer driver
30 genrtc.c # RTC 30 genrtc.c # RTC
31 char/joystick/* # most 31 char/joystick/* # most of this should work, not
32 # in d 32 # in default config.in
33 block/floppy.c # norm 33 block/floppy.c # normal PC driver, DMA emu in asm/floppy.h
34 # and 34 # and arch/m68k/kernel/entry.S
35 # see 35 # see drivers/block/README.fd
36 ata/pata_falcon.c 36 ata/pata_falcon.c
37 net/ne.c 37 net/ne.c
38 video/q40fb.c 38 video/q40fb.c
39 parport/* 39 parport/*
40 sound/dmasound_core.c 40 sound/dmasound_core.c
41 dmasound_q40.c 41 dmasound_q40.c
42 42
43 Various other PC drivers can be enabled simply 43 Various other PC drivers can be enabled simply by adding them to
44 arch/m68k/config.in, especially 8 bit devices 44 arch/m68k/config.in, especially 8 bit devices should be without any
45 problems. For cards using 16bit io/mem more ca 45 problems. For cards using 16bit io/mem more care is required, like
46 checking byte order issues, hacking memcpy_*_i 46 checking byte order issues, hacking memcpy_*_io etc.
47 47
48 48
49 Debugging 49 Debugging
50 ========= 50 =========
51 51
52 Upon startup the kernel will usually output "A 52 Upon startup the kernel will usually output "ABCQGHIJ" into the SRAM,
53 preceded by the booter signature. This is a tr 53 preceded by the booter signature. This is a trace just in case something
54 went wrong during earliest setup stages of hea 54 went wrong during earliest setup stages of head.S.
55 **Changed** to preserve SRAM contents by defau 55 **Changed** to preserve SRAM contents by default, this is only done when
56 requested - SRAM must start with '%LX$' signat 56 requested - SRAM must start with '%LX$' signature to do this. '-d' option
57 to 'lxx' loader enables this. 57 to 'lxx' loader enables this.
58 58
59 SRAM can also be used as additional console de 59 SRAM can also be used as additional console device, use debug=mem.
60 This will save kernel startup msgs into SRAM, 60 This will save kernel startup msgs into SRAM, the screen will display
61 only the penguin - and shell prompt if it gets 61 only the penguin - and shell prompt if it gets that far..
62 Unfortunately only 2000 bytes are available. 62 Unfortunately only 2000 bytes are available.
63 63
64 Serial console works and can also be used for 64 Serial console works and can also be used for debugging, see loader_txt
65 65
66 Most problems seem to be caused by fawlty or b 66 Most problems seem to be caused by fawlty or badly configured io-cards or
67 hard drives anyway. 67 hard drives anyway.
68 Make sure to configure the parallel port as SP 68 Make sure to configure the parallel port as SPP and remove IRQ/DMA jumpers
69 for first testing. The Q40 does not support DM 69 for first testing. The Q40 does not support DMA and may have trouble with
70 parallel ports version of interrupts. 70 parallel ports version of interrupts.
71 71
72 72
73 Q40 Hardware Description 73 Q40 Hardware Description
74 ======================== 74 ========================
75 75
76 This is just an overview, see asm-m68k/* for d 76 This is just an overview, see asm-m68k/* for details ask if you have any
77 questions. 77 questions.
78 78
79 The Q40 consists of a 68040@40 MHz, 1MB video 79 The Q40 consists of a 68040@40 MHz, 1MB video RAM, up to 32MB RAM, AT-style
80 keyboard interface, 1 Programmable LED, 2x8bit 80 keyboard interface, 1 Programmable LED, 2x8bit DACs and up to 1MB ROM, 1MB
81 shadow ROM. 81 shadow ROM.
82 The Q60 has any of 68060 or 68LC060 and up to 82 The Q60 has any of 68060 or 68LC060 and up to 128 MB RAM.
83 83
84 Most interfacing like floppy, IDE, serial and 84 Most interfacing like floppy, IDE, serial and parallel ports is done via ISA
85 slots. The ISA io and mem range is mapped (spa 85 slots. The ISA io and mem range is mapped (sparse&byteswapped!) into separate
86 regions of the memory. 86 regions of the memory.
87 The main interrupt register IIRQ_REG will indi 87 The main interrupt register IIRQ_REG will indicate whether an IRQ was internal
88 or from some ISA devices, EIRQ_REG can disting 88 or from some ISA devices, EIRQ_REG can distinguish up to 8 ISA IRQs.
89 89
90 The Q40 custom chip is programmable to provide 90 The Q40 custom chip is programmable to provide 2 periodic timers:
91 - 50 or 200 Hz - level 2, !!THIS CAN'T 91 - 50 or 200 Hz - level 2, !!THIS CAN'T BE DISABLED!!
92 - 10 or 20 KHz - level 4, used for dma 92 - 10 or 20 KHz - level 4, used for dma-sound
93 93
94 Linux uses the 200 Hz interrupt for timer and 94 Linux uses the 200 Hz interrupt for timer and beep by default.
95 95
96 96
97 Interrupts 97 Interrupts
98 ========== 98 ==========
99 99
100 q40 master chip handles only a subset of level 100 q40 master chip handles only a subset of level triggered interrupts.
101 101
102 Linux has some requirements wrt interrupt arch 102 Linux has some requirements wrt interrupt architecture, these are
103 to my knowledge: 103 to my knowledge:
104 (a) interrupt handler must not be reen 104 (a) interrupt handler must not be reentered even when sti() is called
105 from within handler 105 from within handler
106 (b) working enable/disable_irq 106 (b) working enable/disable_irq
107 107
108 Luckily these requirements are only important 108 Luckily these requirements are only important for drivers shared
109 with other architectures - ide,serial,parallel 109 with other architectures - ide,serial,parallel, ethernet.
110 q40ints.c now contains a trivial hack for (a), 110 q40ints.c now contains a trivial hack for (a), (b) is more difficult
111 because only irq's 4-15 can be disabled - and 111 because only irq's 4-15 can be disabled - and only all of them at once.
112 Thus disable_irq() can effectively block the m 112 Thus disable_irq() can effectively block the machine if the driver goes
113 asleep. 113 asleep.
114 One thing to keep in mind when hacking around 114 One thing to keep in mind when hacking around the interrupt code is
115 that there is no way to find out which IRQ cau 115 that there is no way to find out which IRQ caused a request, [EI]IRQ_REG
116 displays current state of the various IRQ line 116 displays current state of the various IRQ lines.
117 117
118 Keyboard 118 Keyboard
119 ======== 119 ========
120 120
121 q40 receives AT make/break codes from the keyb 121 q40 receives AT make/break codes from the keyboard, these are translated to
122 the PC scancodes x86 Linux uses. So by theory 122 the PC scancodes x86 Linux uses. So by theory every national keyboard should
123 work just by loading the appropriate x86 keyta 123 work just by loading the appropriate x86 keytable - see any national-HOWTO.
124 124
125 Unfortunately the AT->PC translation isn't qui 125 Unfortunately the AT->PC translation isn't quite trivial and even worse, my
126 documentation of it is absolutely minimal - th 126 documentation of it is absolutely minimal - thus some exotic keys may not
127 behave exactly as expected. 127 behave exactly as expected.
128 128
129 There is still hope that it can be fixed compl 129 There is still hope that it can be fixed completely though. If you encounter
130 problems, email me ideally this: 130 problems, email me ideally this:
131 - exact keypress/release sequence 131 - exact keypress/release sequence
132 - 'showkey -s' run on q40, non-X sessi 132 - 'showkey -s' run on q40, non-X session
133 - 'showkey -s' run on a PC, non-X sess 133 - 'showkey -s' run on a PC, non-X session
134 - AT codes as displayed by the q40 deb 134 - AT codes as displayed by the q40 debugging ROM
135 btw if the showkey output from PC and Q40 does 135 btw if the showkey output from PC and Q40 doesn't differ then you have some
136 classic configuration problem - don't send me 136 classic configuration problem - don't send me anything in this case
137 137
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