When building a random powerpc kernel I hit this build error:

  arch/powerpc/platforms/powernv/opal-imc.c:130:13: error : assignment
  discards « const » qualifier from pointer target type
  [-Werror=discarded-qualifiers]
     l_cpumask = cpumask_of_node(nid);
             ^

This happens because when CONFIG_NUMA=n cpumask_of_node() returns a
const pointer.

This patch simply adds const to l_cpumask to fix this issue.
Signed-off-by: NCorentin Labbe <clabbe.montjoie@gmail.com>
Reviewed-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Flesh out change log]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Add support to register Nest In-Memory Collection PMU counters.
Patch adds a new device file called "imc-pmu.c" under powerpc/perf
folder to contain all the device PMU functions.

Device tree parser code added to parse the PMU events information
and create sysfs event attributes for the PMU.

Cpumask attribute added along with Cpu hotplug online/offline functions
specific for nest PMU. A new state "CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE"
added for the cpu hotplug callbacks. Error handle path frees the memory
and unregisters the CPU hotplug callbacks.
Signed-off-by: NAnju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: NHemant Kumar <hemant@linux.vnet.ibm.com>
Signed-off-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>

Code to create platform device for the In-Memory Collection (IMC)
counters. Platform devices are created based on the IMC compatibility.
New header file created to contain the data structures and macros
needed for In-Memory Collection (IMC) counter pmu devices.

The device tree for IMC counters starts at the node "imc-counters".
This node contains all the IMC PMU nodes and event nodes for these IMC
PMUs. Device probe() parses the device to locate three possible IMC
device types (Nest/Core/Thread). Function then branch to parse each
unit nodes to populate vital information such as device memory sizes,
event nodes information, base address for reserve memory access (if
any) and so on. Simple bare-minimum shutdown function added which only
"stops" the engines.
Signed-off-by: NAnju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: NHemant Kumar <hemant@linux.vnet.ibm.com>
Signed-off-by: NMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Fix build with CONFIG_PERF_EVENTS=n]
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>