Commit dc06010c authored by Cornelia Huck's avatar Cornelia Huck Committed by Linus Torvalds

[PATCH] s390: cio documentation update

Update documentation of the common I/O layer:
- Add MSS-specific example.
- Add more information on ccwgroup devices.
- Add channel path type attribute.
- Fix typo.
Signed-off-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3ba1998e
......@@ -16,10 +16,12 @@ devices/
- 0.0.0000/0.0.0815/
- 0.0.0001/0.0.4711/
- 0.0.0002/
- 0.1.0000/0.1.1234/
...
In this example, device 0815 is accessed via subchannel 0, device 4711 via
subchannel 1, and subchannel 2 is a non-I/O subchannel.
In this example, device 0815 is accessed via subchannel 0 in subchannel set 0,
device 4711 via subchannel 1 in subchannel set 0, and subchannel 2 is a non-I/O
subchannel. Device 1234 is accessed via subchannel 0 in subchannel set 1.
You should address a ccw device via its bus id (e.g. 0.0.4711); the device can
be found under bus/ccw/devices/.
......@@ -97,7 +99,7 @@ is not available to the device driver.
Each driver should declare in a MODULE_DEVICE_TABLE into which CU types/models
and/or device types/models it is interested. This information can later be found
found in the struct ccw_device_id fields:
in the struct ccw_device_id fields:
struct ccw_device_id {
__u16 match_flags;
......@@ -208,6 +210,11 @@ Each ccwgroup device also provides an 'ungroup' attribute to destroy the device
again (only when offline). This is a generic ccwgroup mechanism (the driver does
not need to implement anything beyond normal removal routines).
A ccw device which is a member of a ccwgroup device carries a pointer to the
ccwgroup device in the driver_data of its device struct. This field must not be
touched by the driver - it should use the ccwgroup device's driver_data for its
private data.
To implement a ccwgroup driver, please refer to include/asm/ccwgroup.h. Keep in
mind that most drivers will need to implement both a ccwgroup and a ccw driver
(unless you have a meta ccw driver, like cu3088 for lcs and ctc).
......@@ -230,6 +237,8 @@ status - Can be 'online' or 'offline'.
a channel path the user knows to be online, but the machine hasn't
created a machine check for.
type - The physical type of the channel path.
3. System devices
-----------------
......
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