[S390] cio: Add docbook comments.

Comment a bunch of function in docbook style and convert existing
comments on structures to docbook.

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

3 files changed, 315 insertions, 57 deletions

diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index b0a18f5176aa..9c3b9ea1e66f 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -152,16 +152,24 @@ __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 	return 0;
 }
 
-/*
- * try to add a new ccwgroup device for one driver
- * argc and argv[] are a list of bus_id's of devices
- * belonging to the driver.
+/**
+ * ccwgroup_create() - create and register a ccw group device
+ * @root: parent device for the new device
+ * @creator_id: identifier of creating driver
+ * @cdrv: ccw driver of slave devices
+ * @argc: number of slave devices
+ * @argv: bus ids of slave devices
+ *
+ * Create and register a new ccw group device as a child of @root. Slave
+ * devices are obtained from the list of bus ids given in @argv[] and must all
+ * belong to @cdrv.
+ * Returns:
+ *  %0 on success and an error code on failure.
+ * Context:
+ *  non-atomic
  */
-int
-ccwgroup_create(struct device *root,
-		unsigned int creator_id,
-		struct ccw_driver *cdrv,
-		int argc, char *argv[])
+int ccwgroup_create(struct device *root, unsigned int creator_id,
+		    struct ccw_driver *cdrv, int argc, char *argv[])
 {
 	struct ccwgroup_device *gdev;
 	int i;
@@ -390,8 +398,13 @@ static struct bus_type ccwgroup_bus_type = {
 	.remove = ccwgroup_remove,
 };
 
-int
-ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
+/**
+ * ccwgroup_driver_register() - register a ccw group driver
+ * @cdriver: driver to be registered
+ *
+ * This function is mainly a wrapper around driver_register().
+ */
+int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 {
 	/* register our new driver with the core */
 	cdriver->driver.bus = &ccwgroup_bus_type;
@@ -406,8 +419,13 @@ __ccwgroup_match_all(struct device *dev, void *data)
 	return 1;
 }
 
-void
-ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
+/**
+ * ccwgroup_driver_unregister() - deregister a ccw group driver
+ * @cdriver: driver to be deregistered
+ *
+ * This function is mainly a wrapper around driver_unregister().
+ */
+void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 {
 	struct device *dev;
 
@@ -427,8 +445,16 @@ ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 	driver_unregister(&cdriver->driver);
 }
 
-int
-ccwgroup_probe_ccwdev(struct ccw_device *cdev)
+/**
+ * ccwgroup_probe_ccwdev() - probe function for slave devices
+ * @cdev: ccw device to be probed
+ *
+ * This is a dummy probe function for ccw devices that are slave devices in
+ * a ccw group device.
+ * Returns:
+ *  always %0
+ */
+int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 {
 	return 0;
 }
@@ -452,8 +478,15 @@ __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 	return NULL;
 }
 
-void
-ccwgroup_remove_ccwdev(struct ccw_device *cdev)
+/**
+ * ccwgroup_remove_ccwdev() - remove function for slave devices
+ * @cdev: ccw device to be removed
+ *
+ * This is a remove function for ccw devices that are slave devices in a ccw
+ * group device. It sets the ccw device offline and also deregisters the
+ * embedding ccw group device.
+ */
+void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 {
 	struct ccwgroup_device *gdev;
 
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index e44d92eac8e9..3943a4fde22a 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -357,8 +357,18 @@ ccw_device_remove_disconnected(struct ccw_device *cdev)
 			      cdev->private->dev_id.devno);
 }
 
-int
-ccw_device_set_offline(struct ccw_device *cdev)
+/**
+ * ccw_device_set_offline() - disable a ccw device for I/O
+ * @cdev: target ccw device
+ *
+ * This function calls the driver's set_offline() function for @cdev, if
+ * given, and then disables @cdev.
+ * Returns:
+ *   %0 on success and a negative error value on failure.
+ * Context:
+ *  enabled, ccw device lock not held
+ */
+int ccw_device_set_offline(struct ccw_device *cdev)
 {
 	int ret;
 
@@ -396,8 +406,19 @@ ccw_device_set_offline(struct ccw_device *cdev)
  	return ret;
 }
 
-int
-ccw_device_set_online(struct ccw_device *cdev)
+/**
+ * ccw_device_set_online() - enable a ccw device for I/O
+ * @cdev: target ccw device
+ *
+ * This function first enables @cdev and then calls the driver's set_online()
+ * function for @cdev, if given. If set_online() returns an error, @cdev is
+ * disabled again.
+ * Returns:
+ *   %0 on success and a negative error value on failure.
+ * Context:
+ *  enabled, ccw device lock not held
+ */
+int ccw_device_set_online(struct ccw_device *cdev)
 {
 	int ret;
 
@@ -1326,8 +1347,19 @@ __ccwdev_check_busid(struct device *dev, void *id)
 }
 
 
-struct ccw_device *
-get_ccwdev_by_busid(struct ccw_driver *cdrv, const char *bus_id)
+/**
+ * get_ccwdev_by_busid() - obtain device from a bus id
+ * @cdrv: driver the device is owned by
+ * @bus_id: bus id of the device to be searched
+ *
+ * This function searches all devices owned by @cdrv for a device with a bus
+ * id matching @bus_id.
+ * Returns:
+ *  If a match is found, its reference count of the found device is increased
+ *  and it is returned; else %NULL is returned.
+ */
+struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
+				       const char *bus_id)
 {
 	struct device *dev;
 	struct device_driver *drv;
@@ -1409,8 +1441,15 @@ struct bus_type ccw_bus_type = {
 	.remove = ccw_device_remove,
 };
 
-int
-ccw_driver_register (struct ccw_driver *cdriver)
+/**
+ * ccw_driver_register() - register a ccw driver
+ * @cdriver: driver to be registered
+ *
+ * This function is mainly a wrapper around driver_register().
+ * Returns:
+ *   %0 on success and a negative error value on failure.
+ */
+int ccw_driver_register(struct ccw_driver *cdriver)
 {
 	struct device_driver *drv = &cdriver->driver;
 
@@ -1420,8 +1459,13 @@ ccw_driver_register (struct ccw_driver *cdriver)
 	return driver_register(drv);
 }
 
-void
-ccw_driver_unregister (struct ccw_driver *cdriver)
+/**
+ * ccw_driver_unregister() - deregister a ccw driver
+ * @cdriver: driver to be deregistered
+ *
+ * This function is mainly a wrapper around driver_unregister().
+ */
+void ccw_driver_unregister(struct ccw_driver *cdriver)
 {
 	driver_unregister(&cdriver->driver);
 }
diff --git a/drivers/s390/cio/device_ops.c b/drivers/s390/cio/device_ops.c
index 14eba854b155..7fd2dadc3297 100644
--- a/drivers/s390/cio/device_ops.c
+++ b/drivers/s390/cio/device_ops.c
@@ -25,6 +25,16 @@
 #include "device.h"
 #include "chp.h"
 
+/**
+ * ccw_device_set_options_mask() - set some options and unset the rest
+ * @cdev: device for which the options are to be set
+ * @flags: options to be set
+ *
+ * All flags specified in @flags are set, all flags not specified in @flags
+ * are cleared.
+ * Returns:
+ *   %0 on success, -%EINVAL on an invalid flag combination.
+ */
 int ccw_device_set_options_mask(struct ccw_device *cdev, unsigned long flags)
 {
        /*
@@ -40,6 +50,15 @@ int ccw_device_set_options_mask(struct ccw_device *cdev, unsigned long flags)
 	return 0;
 }
 
+/**
+ * ccw_device_set_options() - set some options
+ * @cdev: device for which the options are to be set
+ * @flags: options to be set
+ *
+ * All flags specified in @flags are set, the remainder is left untouched.
+ * Returns:
+ *   %0 on success, -%EINVAL if an invalid flag combination would ensue.
+ */
 int ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
 {
        /*
@@ -59,6 +78,13 @@ int ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
 	return 0;
 }
 
+/**
+ * ccw_device_clear_options() - clear some options
+ * @cdev: device for which the options are to be cleared
+ * @flags: options to be cleared
+ *
+ * All flags specified in @flags are cleared, the remainder is left untouched.
+ */
 void ccw_device_clear_options(struct ccw_device *cdev, unsigned long flags)
 {
 	cdev->private->options.fast &= (flags & CCWDEV_EARLY_NOTIFICATION) == 0;
@@ -67,8 +93,22 @@ void ccw_device_clear_options(struct ccw_device *cdev, unsigned long flags)
 	cdev->private->options.force &= (flags & CCWDEV_ALLOW_FORCE) == 0;
 }
 
-int
-ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
+/**
+ * ccw_device_clear() - terminate I/O request processing
+ * @cdev: target ccw device
+ * @intparm: interruption parameter; value is only used if no I/O is
+ *	     outstanding, otherwise the intparm associated with the I/O request
+ *	     is returned
+ *
+ * ccw_device_clear() calls csch on @cdev's subchannel.
+ * Returns:
+ *  %0 on success,
+ *  -%ENODEV on device not operational,
+ *  -%EINVAL on invalid device state.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
 {
 	struct subchannel *sch;
 	int ret;
@@ -89,10 +129,33 @@ ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
 	return ret;
 }
 
-int
-ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
-		     unsigned long intparm, __u8 lpm, __u8 key,
-		     unsigned long flags)
+/**
+ * ccw_device_start_key() - start a s390 channel program with key
+ * @cdev: target ccw device
+ * @cpa: logical start address of channel program
+ * @intparm: user specific interruption parameter; will be presented back to
+ *	     @cdev's interrupt handler. Allows a device driver to associate
+ *	     the interrupt with a particular I/O request.
+ * @lpm: defines the channel path to be used for a specific I/O request. A
+ *	 value of 0 will make cio use the opm.
+ * @key: storage key to be used for the I/O
+ * @flags: additional flags; defines the action to be performed for I/O
+ *	   processing.
+ *
+ * Start a S/390 channel program. When the interrupt arrives, the
+ * IRQ handler is called, either immediately, delayed (dev-end missing,
+ * or sense required) or never (no IRQ handler registered).
+ * Returns:
+ *  %0, if the operation was successful;
+ *  -%EBUSY, if the device is busy, or status pending;
+ *  -%EACCES, if no path specified in @lpm is operational;
+ *  -%ENODEV, if the device is not operational.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
+			 unsigned long intparm, __u8 lpm, __u8 key,
+			 unsigned long flags)
 {
 	struct subchannel *sch;
 	int ret;
@@ -135,11 +198,38 @@ ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
 	return ret;
 }
 
-
-int
-ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
-			     unsigned long intparm, __u8 lpm, __u8 key,
-			     unsigned long flags, int expires)
+/**
+ * ccw_device_start_timeout_key() - start a s390 channel program with timeout and key
+ * @cdev: target ccw device
+ * @cpa: logical start address of channel program
+ * @intparm: user specific interruption parameter; will be presented back to
+ *	     @cdev's interrupt handler. Allows a device driver to associate
+ *	     the interrupt with a particular I/O request.
+ * @lpm: defines the channel path to be used for a specific I/O request. A
+ *	 value of 0 will make cio use the opm.
+ * @key: storage key to be used for the I/O
+ * @flags: additional flags; defines the action to be performed for I/O
+ *	   processing.
+ * @expires: timeout value in jiffies
+ *
+ * Start a S/390 channel program. When the interrupt arrives, the
+ * IRQ handler is called, either immediately, delayed (dev-end missing,
+ * or sense required) or never (no IRQ handler registered).
+ * This function notifies the device driver if the channel program has not
+ * completed during the time specified by @expires. If a timeout occurs, the
+ * channel program is terminated via xsch, hsch or csch, and the device's
+ * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
+ * Returns:
+ *  %0, if the operation was successful;
+ *  -%EBUSY, if the device is busy, or status pending;
+ *  -%EACCES, if no path specified in @lpm is operational;
+ *  -%ENODEV, if the device is not operational.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
+				 unsigned long intparm, __u8 lpm, __u8 key,
+				 unsigned long flags, int expires)
 {
 	int ret;
 
@@ -152,18 +242,67 @@ ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
 	return ret;
 }
 
-int
-ccw_device_start(struct ccw_device *cdev, struct ccw1 *cpa,
-		 unsigned long intparm, __u8 lpm, unsigned long flags)
+/**
+ * ccw_device_start() - start a s390 channel program
+ * @cdev: target ccw device
+ * @cpa: logical start address of channel program
+ * @intparm: user specific interruption parameter; will be presented back to
+ *	     @cdev's interrupt handler. Allows a device driver to associate
+ *	     the interrupt with a particular I/O request.
+ * @lpm: defines the channel path to be used for a specific I/O request. A
+ *	 value of 0 will make cio use the opm.
+ * @flags: additional flags; defines the action to be performed for I/O
+ *	   processing.
+ *
+ * Start a S/390 channel program. When the interrupt arrives, the
+ * IRQ handler is called, either immediately, delayed (dev-end missing,
+ * or sense required) or never (no IRQ handler registered).
+ * Returns:
+ *  %0, if the operation was successful;
+ *  -%EBUSY, if the device is busy, or status pending;
+ *  -%EACCES, if no path specified in @lpm is operational;
+ *  -%ENODEV, if the device is not operational.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_start(struct ccw_device *cdev, struct ccw1 *cpa,
+		     unsigned long intparm, __u8 lpm, unsigned long flags)
 {
 	return ccw_device_start_key(cdev, cpa, intparm, lpm,
 				    PAGE_DEFAULT_KEY, flags);
 }
 
-int
-ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
-			 unsigned long intparm, __u8 lpm, unsigned long flags,
-			 int expires)
+/**
+ * ccw_device_start_timeout() - start a s390 channel program with timeout
+ * @cdev: target ccw device
+ * @cpa: logical start address of channel program
+ * @intparm: user specific interruption parameter; will be presented back to
+ *	     @cdev's interrupt handler. Allows a device driver to associate
+ *	     the interrupt with a particular I/O request.
+ * @lpm: defines the channel path to be used for a specific I/O request. A
+ *	 value of 0 will make cio use the opm.
+ * @flags: additional flags; defines the action to be performed for I/O
+ *	   processing.
+ * @expires: timeout value in jiffies
+ *
+ * Start a S/390 channel program. When the interrupt arrives, the
+ * IRQ handler is called, either immediately, delayed (dev-end missing,
+ * or sense required) or never (no IRQ handler registered).
+ * This function notifies the device driver if the channel program has not
+ * completed during the time specified by @expires. If a timeout occurs, the
+ * channel program is terminated via xsch, hsch or csch, and the device's
+ * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
+ * Returns:
+ *  %0, if the operation was successful;
+ *  -%EBUSY, if the device is busy, or status pending;
+ *  -%EACCES, if no path specified in @lpm is operational;
+ *  -%ENODEV, if the device is not operational.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
+			     unsigned long intparm, __u8 lpm,
+			     unsigned long flags, int expires)
 {
 	return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm,
 					    PAGE_DEFAULT_KEY, flags,
@@ -171,8 +310,23 @@ ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
 }
 
 
-int
-ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
+/**
+ * ccw_device_halt() - halt I/O request processing
+ * @cdev: target ccw device
+ * @intparm: interruption parameter; value is only used if no I/O is
+ *	     outstanding, otherwise the intparm associated with the I/O request
+ *	     is returned
+ *
+ * ccw_device_halt() calls hsch on @cdev's subchannel.
+ * Returns:
+ *  %0 on success,
+ *  -%ENODEV on device not operational,
+ *  -%EINVAL on invalid device state,
+ *  -%EBUSY on device busy or interrupt pending.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
 {
 	struct subchannel *sch;
 	int ret;
@@ -193,8 +347,20 @@ ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
 	return ret;
 }
 
-int
-ccw_device_resume(struct ccw_device *cdev)
+/**
+ * ccw_device_resume() - resume channel program execution
+ * @cdev: target ccw device
+ *
+ * ccw_device_resume() calls rsch on @cdev's subchannel.
+ * Returns:
+ *  %0 on success,
+ *  -%ENODEV on device not operational,
+ *  -%EINVAL on invalid device state,
+ *  -%EBUSY on device busy or interrupt pending.
+ * Context:
+ *  Interrupts disabled, ccw device lock held
+ */
+int ccw_device_resume(struct ccw_device *cdev)
 {
 	struct subchannel *sch;
 
@@ -260,11 +426,21 @@ ccw_device_call_handler(struct ccw_device *cdev)
 	return 1;
 }
 
-/*
- * Search for CIW command in extended sense data.
+/**
+ * ccw_device_get_ciw() - Search for CIW command in extended sense data.
+ * @cdev: ccw device to inspect
+ * @ct: command type to look for
+ *
+ * During SenseID, command information words (CIWs) describing special
+ * commands available to the device may have been stored in the extended
+ * sense data. This function searches for CIWs of a specified command
+ * type in the extended sense data.
+ * Returns:
+ *  %NULL if no extended sense data has been stored or if no CIW of the
+ *  specified command type could be found,
+ *  else a pointer to the CIW of the specified command type.
  */
-struct ciw *
-ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
+struct ciw *ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
 {
 	int ciw_cnt;
 
@@ -276,8 +452,14 @@ ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
 	return NULL;
 }
 
-__u8
-ccw_device_get_path_mask(struct ccw_device *cdev)
+/**
+ * ccw_device_get_path_mask() - get currently available paths
+ * @cdev: ccw device to be queried
+ * Returns:
+ *  %0 if no subchannel for the device is available,
+ *  else the mask of currently available paths for the ccw device's subchannel.
+ */
+__u8 ccw_device_get_path_mask(struct ccw_device *cdev)
 {
 	struct subchannel *sch;
 
@@ -357,8 +539,7 @@ out_unlock:
 	return ret;
 }
 
-void *
-ccw_device_get_chp_desc(struct ccw_device *cdev, int chp_no)
+void *ccw_device_get_chp_desc(struct ccw_device *cdev, int chp_no)
 {
 	struct subchannel *sch;
 	struct chp_id chpid;