4 You may try http://www.geocities.com/SiliconValley/Bay/2602/ for
5 some up to date information. Booter and other tools will be also
6 available from this place or http://ftp.uni-erlangen.de/pub/unix/Linux/680x0/q40/
9 Hints to documentation usually refer to the linux source tree in
10 /usr/src/linux/Documentation unless URL given.
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)
15 For a list of kernel command-line options read the documentation for the
16 particular device drivers.
18 The floppy imposes a very high interrupt load on the CPU, approx 30K/s.
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. On highly loaded systems
21 it can make the floppy very slow or practically stop. Other Q40 OS' simply
22 poll the floppy for this reason - something that can't be done in Linux.
23 Only possible cure is getting a 82072 controller with fifo instead of
26 drivers used by the Q40, apart from the very obvious (console etc.):
27 drivers/char/q40_keyb.c # use PC keymaps for national keyboards
28 serial.c # normal PC driver - any speed
31 char/joystick/* # most of this should work, not
32 # in default config.in
33 block/floppy.c # normal PC driver, DMA emu in asm/floppy.h
34 # and arch/m68k/kernel/entry.S
35 # see drivers/block/README.fd
43 Various other PC drivers can be enabled simply by adding them to
44 arch/m68k/config.in, especially 8 bit devices should be without any
45 problems. For cards using 16bit io/mem more care is required, like
46 checking byte order issues, hacking memcpy_*_io etc.
52 Upon startup the kernel will usually output "ABCQGHIJ" into the SRAM,
53 preceded by the booter signature. This is a trace just in case something
54 went wrong during earliest setup stages of head.S.
55 **Changed** to preserve SRAM contents by default, this is only done when
56 requested - SRAM must start with '%LX$' signature to do this. '-d' option
57 to 'lxx' loader enables this.
59 SRAM can also be used as additional console device, use debug=mem.
60 This will save kernel startup msgs into SRAM, the screen will display
61 only the penguin - and shell prompt if it gets that far..
62 Unfortunately only 2000 bytes are available.
64 Serial console works and can also be used for debugging, see loader_txt
66 Most problems seem to be caused by fawlty or badly configured io-cards or
68 Make sure to configure the parallel port as SPP and remove IRQ/DMA jumpers
69 for first testing. The Q40 does not support DMA and may have trouble with
70 parallel ports version of interrupts.
73 Q40 Hardware Description
74 ========================
76 This is just an overview, see asm-m68k/* for details ask if you have any
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 DACs and up to 1MB ROM, 1MB
82 The Q60 has any of 68060 or 68LC060 and up to 128 MB RAM.
84 Most interfacing like floppy, IDE, serial and parallel ports is done via ISA
85 slots. The ISA io and mem range is mapped (sparse&byteswapped!) into separate
86 regions of the memory.
87 The main interrupt register IIRQ_REG will indicate whether an IRQ was internal
88 or from some ISA devices, EIRQ_REG can distinguish up to 8 ISA IRQs.
90 The Q40 custom chip is programmable to provide 2 periodic timers:
91 - 50 or 200 Hz - level 2, !!THIS CAN'T BE DISABLED!!
92 - 10 or 20 KHz - level 4, used for dma-sound
94 Linux uses the 200 Hz interrupt for timer and beep by default.
100 q40 master chip handles only a subset of level triggered interrupts.
102 Linux has some requirements wrt interrupt architecture, these are
104 (a) interrupt handler must not be reentered even when sti() is called
106 (b) working enable/disable_irq
108 Luckily these requirements are only important for drivers shared
109 with other architectures - ide,serial,parallel, ethernet.
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 only all of them at once.
112 Thus disable_irq() can effectively block the machine if the driver goes
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 caused a request, [EI]IRQ_REG
116 displays current state of the various IRQ lines.
121 q40 receives AT make/break codes from the keyboard, these are translated to
122 the PC scancodes x86 Linux uses. So by theory every national keyboard should
123 work just by loading the appropriate x86 keytable - see any national-HOWTO.
125 Unfortunately the AT->PC translation isn't quite trivial and even worse, my
126 documentation of it is absolutely minimal - thus some exotic keys may not
127 behave exactly as expected.
129 There is still hope that it can be fixed completely though. If you encounter
130 problems, email me ideally this:
131 - exact keypress/release sequence
132 - 'showkey -s' run on q40, non-X session
133 - 'showkey -s' run on a PC, non-X session
134 - AT codes as displayed by the q40 debugging ROM
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 anything in this case