X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=Documentation%2Fs390%2Fdriver-model.txt;fp=Documentation%2Fs390%2Fdriver-model.txt;h=e938c442277dc0ecd1b05002ba9167abbedd914c;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=df09758bf3fe1619df2b57118b5bb60a12c754a8;hpb=76828883507a47dae78837ab5dec5a5b4513c667;p=linux-2.6.git

diff --git a/Documentation/s390/driver-model.txt b/Documentation/s390/driver-model.txt
index df09758bf..e938c4422 100644
--- a/Documentation/s390/driver-model.txt
+++ b/Documentation/s390/driver-model.txt
@@ -16,10 +16,19 @@ devices/
            - 0.0.0000/0.0.0815/
 	   - 0.0.0001/0.0.4711/
 	   - 0.0.0002/
+	   - 0.1.0000/0.1.1234/
 	   ...
+	   - defunct/
 
-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.
+
+The subchannel named 'defunct' does not represent any real subchannel on the
+system; it is a pseudo subchannel where disconnnected ccw devices are moved to
+if they are displaced by another ccw device becoming operational on their
+former subchannel. The ccw devices will be moved again to a proper subchannel
+if they become operational again on that subchannel.
 
 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 +106,7 @@ 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;	
@@ -155,7 +164,7 @@ notify: This function is called by the common I/O layer for some state changes
 	* In online state, device detached (CIO_GONE) or last path gone
 	  (CIO_NO_PATH). The driver must return !0 to keep the device; for
 	  return code 0, the device will be deleted as usual (also when no
-	  notify function is registerd). If the driver wants to keep the
+	  notify function is registered). If the driver wants to keep the
 	  device, it is moved into disconnected state.
 	* In disconnected state, device operational again (CIO_OPER). The
 	  common I/O layer performs some sanity checks on device number and
@@ -208,6 +217,11 @@ 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 +244,11 @@ 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.
+
+shared - Whether the channel path is shared.
+
+cmg - The channel measurement group.
 
 3. System devices
 -----------------
@@ -253,7 +272,7 @@ attribute 'online' which can be 0 or 1.
 -----------
 
 The netiucv driver creates an attribute 'connection' under
-bus/iucv/drivers/netiucv. Piping to this attibute creates a new netiucv
+bus/iucv/drivers/netiucv. Piping to this attribute creates a new netiucv
 connection to the specified host.
 
 Netiucv connections show up under devices/iucv/ as "netiucv<ifnum>". The interface