powerpc/pseries: Device tree should only be updated once after suspend/migrate

The current code makes rtas calls for update-nodes, activate-firmware and then
update-nodes again. The FW provides the same data for both update-nodes calls.
As a result a proc entry exists error is reported for the second update while
adding device nodes.

This patch makes a single rtas call for update-nodes after activating the FW.
It also add rtas_busy delay for the activate-firmware rtas call.

Signed-off-by: Haren Myneni <hbabu@us.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc/pseries: Update dynamic cache nodes for suspend/resume operation

pHyp can change cache nodes for suspend/resume operation. Currently the
device tree is updated by drmgr in userspace after all non boot CPUs are
enabled. Hence, we do not modify the cache list based on the latest cache
nodes. Also we do not remove cache entries for the primary CPU.

This patch removes the cache list for the boot CPU, updates the device tree
before enabling nonboot CPUs and adds cache list for the boot cpu.

This patch also has the side effect that older versions of drmgr will
perform a second device tree update from userspace. While this is a
redundant waste of a couple cycles it is harmless since firmware returns the
same data for the subsequent update-nodes/properties rtas calls.

Signed-off-by: Haren Myneni <hbabu@us.ibm.com>
Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
powerpc/pseries: Expose in kernel device tree update to drmgr

Traditionally it has been drmgr's responsibilty to update the device tree
through the /proc/ppc64/ofdt interface after a suspend/resume operation.
This patchset however has modified suspend/resume ops to preform an update
entirely in the kernel during the resume. Therefore, a mechanism is required
to expose that information to drmgr.

This patch adds a show function to the "hibernate" attribute that returns 1
if the kernel performs a device tree update after the resume and 0 otherwise.
This allows newer versions of drmgr to avoid doing a second unnecessary
device tree update.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>