Zio is "the ultimate I/O framework".  It is being developed on the open
hardware repository at http://www.ohwr.org/projects/zio .

This version is known to compile and run with kernels 2.6.34 onwards.

This README refers to version "beta3", but work is ongoing towards
a stable package. See the TODO file on ohwr for details.

To test zio you need to load the core modules (later, the default
trigger and default buffer will be part of zio-core):

   	insmod zio-core.ko
   	insmod buffers/zio-buf-kmalloc.ko
   	insmod triggers/zio-trig-timer.ko

Drivers can't live without a trigger and a buffer, so the modules above
must be loaded first.

The kmalloc buffer is a simple buffer that hosts a list of data blocks,
for either input or output.

The timer trigger is a kernel-timer based trigger, that fires a block
transfer on a timely basis. You can use the "ms" parameter to set the
inter-block time, in milliseconds (the default is two seconds). You
can also pass the "nsamples" parameter to say how many samples are
acquired at each trigger instance.

With the core in place, you can load a driver:

	insmod drivers/zio-zero.ko

zio-zero has a single channel-set (number 0) with three channels.
They simulate three analog inputs, 8-bits per sample.

     channel 0: returns zero forever
     channel 1: returns random numbers
     channel 2: returns a sawtooth signal (0 to 255 and back)

The char devices are called using device-cset-channel:

    /dev/zzero-0-0-ctrl
    /dev/zzero-0-0-data
    /dev/zzero-0-1-ctrl
    /dev/zzero-0-1-data
    /dev/zzero-0-2-ctrl
    /dev/zzero-0-2-data

(later versions will use a /dev/zio/ directory for all zio files)

To read data you can just cat, or "od -t x1" the data device.
To get control information meta-information) together with data, you
can use the "zio-dump" user-space utility, in this directory.

For example:

    ./zio-dump /dev/zzero-0-2-ctrl /dev/zzero-0-2-data

This is the result with a trigger that uses 2000 as msec and 32
as nsample:

    ./zio-dump /dev/zzero-0-2-ctrl /dev/zzero-0-2-data

    Ctrl: version 0.2, trigger timer, dev zzero, cset 0, chan 2
    Ctrl: seq 1, n 32, size 1, bits 8, flags 01000001 (little-endian)
    Ctrl: stamp 1320403540.084798370 (0)
    Data: 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
    Data: 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f

    Ctrl: version 0.2, trigger timer, dev zzero, cset 0, chan 2
    Ctrl: seq 2, n 32, size 1, bits 8, flags 01000001 (little-endian)
    Ctrl: stamp 1320403542.091093781 (0)
    Data: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
    Data: 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f

    Ctrl: version 0.2, trigger timer, dev zzero, cset 0, chan 2
    Ctrl: seq 3, n 32, size 1, bits 8, flags 01000001 (little-endian)
    Ctrl: stamp 1320403544.084790274 (0)
    Data: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
    Data: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f

zio-dump is able to access several pairs of devices (control and data),
and you can change the trigger and buffer attributes for the cset.

Example:

    echo 500 > /sys/zio/devices/zzero/cset0/trigger/ms-period
    echo 4 > /sys/zio/devices/zzero/cset0/trigger/nsamples
    echo 3 > /sys/zio/devices/zzero/cset0/chan0/buffer/max-buffer-len
    ./zio-dump /dev/zzero-0-*

    Ctrl: version 0.2, trigger timer, dev zzero, cset 0, chan 0
    Ctrl: seq 102, n 4, size 1, bits 8, flags 01000001 (little-endian)
    Ctrl: stamp 4066.519285605 (0)
    Data: 00 00 00 00

    Ctrl: version 0.2, trigger timer, dev zzero, cset 0, chan 1
    Ctrl: seq 102, n 4, size 1, bits 8, flags 01000001 (little-endian)
    Ctrl: stamp 4066.519285605 (0)
    Data: 71 29 a6 53

    Ctrl: version 0.2, trigger timer, dev zzero, cset 0, chan 2
    Ctrl: seq 102, n 4, size 1, bits 8, flags 01000001 (little-endian)
    Ctrl: stamp 4066.519285605 (0)
    Data: 60 61 62 63