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837cd1059a
This patch adds notifications to userspace for two important
conditions of the ap bus:
I) Initial ap bus scan done. This indicates that the initial
scan of all the ap devices (cards, queues) is complete and
ap devices have been build up for all the hardware found.
This condition is signaled with
1) An ap bus change uevent send to userspace with an environment
key/value pair "INITSCAN=done":
# udevadm monitor -k -p
...
KERNEL[97.830919] change /devices/ap (ap)
ACTION=change
DEVPATH=/devices/ap
SUBSYSTEM=ap
INITSCAN=done
SEQNUM=10421
2) A sysfs attribute /sys/bus/ap/scans which shows the
number of completed ap bus scans done since bus init.
So a value of 1 or greater signals that the initial
ap bus scan is complete.
Note: The initial ap bus scan complete condition is fulfilled
and will be signaled even if there was no ap resource found.
II) APQN driver bindings complete. This indicates that all
APQNs have been bound to an zcrypt or alternate device
driver. Only with the help of an device driver an APQN
can be used for crypto load. So the binding complete
condition is the starting point for user space to be
sure all crypto resources on the ap bus are available
for use.
This condition is signaled with
1) An ap bus change uevent send to userspace with an environment
key/value pair "BINDINGS=complete":
# udevadm monitor -k -p
...
KERNEL[97.830975] change /devices/ap (ap)
ACTION=change
DEVPATH=/devices/ap
SUBSYSTEM=ap
BINDINGS=complete
SEQNUM=10422
2) A sysfs attribute /sys/bus/ap/bindings showing
"<nr of bound apqns>/<total nr of apqns> (complete)"
when all available apqns have been bound to device drivers, or
"<nr of bound apqns>/<total nr of apqns>"
when there are some apqns not bound to an device driver.
Note: The binding complete condition is also fulfilled, when
there are no apqns available to bind any device driver. In
this case the binding complete will be signaled AFTER init
scan is done.
Note: This condition may arise multiple times when after
initial scan modifications on the bindings take place. For
example a manual unbind of an APQN switches the binding
complete condition off. When at a later time the unbound APQNs
are bound with an device driver the binding is (again) complete
resulting in another uevent and marking the bindings sysfs
attribute with '(complete)'.
There is also a new function to be used within the kernel:
int ap_wait_init_apqn_bindings_complete(unsigned long timeout)
Interface to wait for the AP bus to have done one initial ap bus
scan and all detected APQNs have been bound to device drivers.
If these both conditions are not fulfilled, this function blocks
on a condition with wait_for_completion_interruptible_timeout().
If these both conditions are fulfilled (before the timeout hits)
the return value is 0. If the timeout (in jiffies) hits instead
-ETIME is returned. On failures negative return values are
returned to the caller. Please note that further unbind/bind
actions after initial binding complete is through do not cause this
function to block again.
Reviewed-by: Ingo Franzki <ifranzki@linux.ibm.com>
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.