[S390] cio: Update documentation.
- read_dev_chars()/read_conf_data() are deprecated. Don't document them, but
advise to issue the channel program from the driver itself.
- Remove some really obsolete and incorrect stuff.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/Documentation/s390/cds.txt b/Documentation/s390/cds.txt
index 05a2b4f..58919d6 100644
--- a/Documentation/s390/cds.txt
+++ b/Documentation/s390/cds.txt
@@ -51,13 +51,8 @@
* The interrupt handlers must be adapted to use a ccw_device as argument.
Moreover, they don't return a devstat, but an irb.
* Before initiating an io, the options must be set via ccw_device_set_options().
-
-read_dev_chars()
- read device characteristics
-
-read_conf_data()
-read_conf_data_lpm()
- read configuration data.
+* Instead of calling read_dev_chars()/read_conf_data(), the driver issues
+ the channel program and handles the interrupt itself.
ccw_device_get_ciw()
get commands from extended sense data.
@@ -130,11 +125,6 @@
has to call every single device driver registered on this IRQ in order to
determine the device driver owning the device that raised the interrupt.
-In order not to introduce a new I/O concept to the common Linux code,
-Linux/390 preserves the IRQ concept and semantically maps the ESA/390
-subchannels to Linux as IRQs. This allows Linux/390 to support up to 64k
-different IRQs, uniquely representing a single device each.
-
Up to kernel 2.4, Linux/390 used to provide interfaces via the IRQ (subchannel).
For internal use of the common I/O layer, these are still there. However,
device drivers should use the new calling interface via the ccw_device only.
@@ -151,9 +141,8 @@
support using the information saved in the struct ccw_device given to them.
This methods implies that Linux/390 doesn't require to probe for free (not
armed) interrupt request lines (IRQs) to drive its devices with. Where
-applicable, the device drivers can use the read_dev_chars() to retrieve device
-characteristics. This can be done without having to request device ownership
-previously.
+applicable, the device drivers can use issue the READ DEVICE CHARACTERISTICS
+ccw to retrieve device characteristics in its online routine.
In order to allow for easy I/O initiation the CDS layer provides a
ccw_device_start() interface that takes a device specific channel program (one
@@ -170,69 +159,6 @@
also covered by ccw_device_halt().
-read_dev_chars() - Read Device Characteristics
-
-This routine returns the characteristics for the device specified.
-
-The function is meant to be called with the device already enabled; that is,
-at earliest during set_online() processing.
-
-The ccw_device must not be locked prior to calling read_dev_chars().
-
-The function may be called enabled or disabled.
-
-int read_dev_chars(struct ccw_device *cdev, void **buffer, int length );
-
-cdev - the ccw_device the information is requested for.
-buffer - pointer to a buffer pointer. The buffer pointer itself
- must contain a valid buffer area.
-length - length of the buffer provided.
-
-The read_dev_chars() function returns :
-
- 0 - successful completion
--ENODEV - cdev invalid
--EINVAL - an invalid parameter was detected, or the function was called early.
--EBUSY - an irrecoverable I/O error occurred or the device is not
- operational.
-
-
-read_conf_data(), read_conf_data_lpm() - Read Configuration Data
-
-Retrieve the device dependent configuration data. Please have a look at your
-device dependent I/O commands for the device specific layout of the node
-descriptor elements. read_conf_data_lpm() will retrieve the configuration data
-for a specific path.
-
-The function is meant to be called with the device already enabled; that is,
-at earliest during set_online() processing.
-
-The function may be called enabled or disabled, but the device must not be
-locked
-
-int read_conf_data(struct ccw_device, void **buffer, int *length);
-int read_conf_data_lpm(struct ccw_device, void **buffer, int *length, __u8 lpm);
-
-cdev - the ccw_device the data is requested for.
-buffer - Pointer to a buffer pointer. The read_conf_data() routine
- will allocate a buffer and initialize the buffer pointer
- accordingly. It's the device driver's responsibility to
- release the kernel memory if no longer needed.
-length - Length of the buffer allocated and retrieved.
-lpm - Logical path mask to be used for retrieving the data. If
- zero the data is retrieved on the next path available.
-
-The read_conf_data() function returns :
- 0 - Successful completion
--ENODEV - cdev invalid.
--EINVAL - An invalid parameter was detected, or the function was called early.
--EIO - An irrecoverable I/O error occurred or the device is
- not operational.
--ENOMEM - The read_conf_data() routine couldn't obtain storage.
--EOPNOTSUPP - The device doesn't support the read configuration
- data command.
-
-
get_ciw() - get command information word
This call enables a device driver to get information about supported commands