[S390] cio: update documentation.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 24 insertions, 28 deletions

diff --git a/Documentation/s390/cds.txt b/Documentation/s390/cds.txt
index d80e5733827d..32a96cc39215 100644
--- a/Documentation/s390/cds.txt
+++ b/Documentation/s390/cds.txt
@@ -174,14 +174,10 @@ read_dev_chars() - Read Device Characteristics
 
 This routine returns the characteristics for the device specified.
 
-The function is meant to be called with an irq handler in place; that is,
+The function is meant to be called with the device already enabled; that is,
 at earliest during set_online() processing.
 
-While the request is processed synchronously, the device interrupt
-handler is called for final ending status. In case of error situations the
-interrupt handler may recover appropriately. The device irq handler can
-recognize the corresponding interrupts by the interruption parameter be
-0x00524443. The ccw_device must not be locked prior to calling read_dev_chars().
+The ccw_device must not be locked prior to calling read_dev_chars().
 
 The function may be called enabled or disabled.
 
@@ -410,26 +406,7 @@ individual flag meanings.
 
 Usage Notes :
 
-Prior to call ccw_device_start() the device driver must assure disabled state,
-i.e. the I/O mask value in the PSW must be disabled. This can be accomplished
-by calling local_save_flags( flags). The current PSW flags are preserved and
-can be restored by local_irq_restore( flags) at a later time.
-
-If the device driver violates this rule while running in a uni-processor
-environment an interrupt might be presented prior to the ccw_device_start()
-routine returning to the device driver main path. In this case we will end in a
-deadlock situation as the interrupt handler will try to obtain the irq
-lock the device driver still owns (see below) !
-
-The driver must assure to hold the device specific lock. This can be
-accomplished by
-
-(i)  spin_lock(get_ccwdev_lock(cdev)), or
-(ii) spin_lock_irqsave(get_ccwdev_lock(cdev), flags)
-
-Option (i) should be used if the calling routine is running disabled for
-I/O interrupts (see above) already. Option (ii) obtains the device gate und
-puts the CPU into I/O disabled state by preserving the current PSW flags.
+ccw_device_start() must be called disabled and with the ccw device lock held.
 
 The device driver is allowed to issue the next ccw_device_start() call from
 within its interrupt handler already. It is not required to schedule a
@@ -488,7 +465,7 @@ int ccw_device_resume(struct ccw_device *cdev);
 
 cdev - ccw_device the resume operation is requested for
 
-The resume_IO() function returns:
+The ccw_device_resume() function returns:
 
         0  - suspended channel program is resumed
 -EBUSY     - status pending
@@ -507,6 +484,8 @@ a long-running channel program or the device might require to initially issue
 a halt subchannel (HSCH) I/O command. For those purposes the ccw_device_halt()
 command is provided.
 
+ccw_device_halt() must be called disabled and with the ccw device lock held.
+
 int ccw_device_halt(struct ccw_device *cdev,
                     unsigned long intparm);
 
@@ -517,7 +496,7 @@ intparm : interruption parameter; value is only used if no I/O
 
 The ccw_device_halt() function returns :
 
-      0 - successful completion or request successfully initiated
+      0 - request successfully initiated
 -EBUSY  - the device is currently busy, or status pending.
 -ENODEV - cdev invalid.
 -EINVAL - The device is not operational or the ccw device is not online.
@@ -533,6 +512,23 @@ can then perform an appropriate action. Prior to interrupt of an outstanding
 read to a network device (with or without PCI flag) a ccw_device_halt()
 is required to end the pending operation.
 
+ccw_device_clear() - Terminage I/O Request Processing
+
+In order to terminate all I/O processing at the subchannel, the clear subchannel
+(CSCH) command is used. It can be issued via ccw_device_clear().
+
+ccw_device_clear() must be called disabled and with the ccw device lock held.
+
+int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm);
+
+cdev:    ccw_device the clear operation is requested for
+intparm: interruption parameter (see ccw_device_halt())
+
+The ccw_device_clear() function returns:
+
+      0 - request successfully initiated
+-ENODEV - cdev invalid
+-EINVAL - The device is not operational or the ccw device is not online.
 
 Miscellaneous Support Routines