powerpc/powernv: Add IMC OPAL APIs

In-Memory Collection (IMC) counters are performance monitoring
infrastructure. These counters need special sequence of SCOMs to
init/start/stop which is handled by OPAL. And OPAL provides three APIs
to init and control these IMC engines.

OPAL API documentation:
  https://github.com/open-power/skiboot/blob/master/doc/opal-api/opal-imc-counters.rst

Patch updates the kernel side powernv platform code to support the new
OPAL APIs
Signed-off-by: Hemant Kumar <hemant@linux.vnet.ibm.com>
Signed-off-by: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/opal-api.h

@@ -190,7 +190,10 @@
 #define OPAL_NPU_INIT_CONTEXT			146
 #define OPAL_NPU_DESTROY_CONTEXT		147
 #define OPAL_NPU_MAP_LPAR			148
-#define OPAL_LAST				148
+#define OPAL_IMC_COUNTERS_INIT			149
+#define OPAL_IMC_COUNTERS_START			150
+#define OPAL_IMC_COUNTERS_STOP			151
+#define OPAL_LAST				151
 
 /* Device tree flags */
 
@@ -1084,6 +1087,13 @@ enum {
 	XIVE_DUMP_EMU_STATE	= 5,
 };
 
+/* "type" argument options for OPAL_IMC_COUNTERS_* calls */
+enum {
+	OPAL_IMC_COUNTERS_NEST = 1,
+	OPAL_IMC_COUNTERS_CORE = 2,
+};
+
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __OPAL_API_H */

arch/powerpc/include/asm/opal.h

@@ -268,6 +268,11 @@ int64_t opal_xive_free_irq(uint32_t girq);
 int64_t opal_xive_sync(uint32_t type, uint32_t id);
 int64_t opal_xive_dump(uint32_t type, uint32_t id);
 
+int64_t opal_imc_counters_init(uint32_t type, uint64_t address,
+							uint64_t cpu_pir);
+int64_t opal_imc_counters_start(uint32_t type, uint64_t cpu_pir);
+int64_t opal_imc_counters_stop(uint32_t type, uint64_t cpu_pir);
+
 /* Internal functions */
 extern int early_init_dt_scan_opal(unsigned long node, const char *uname,
 				   int depth, void *data);

arch/powerpc/platforms/powernv/opal-wrappers.S

@@ -310,3 +310,6 @@ OPAL_CALL(opal_xive_dump,			OPAL_XIVE_DUMP);
 OPAL_CALL(opal_npu_init_context,		OPAL_NPU_INIT_CONTEXT);
 OPAL_CALL(opal_npu_destroy_context,		OPAL_NPU_DESTROY_CONTEXT);
 OPAL_CALL(opal_npu_map_lpar,			OPAL_NPU_MAP_LPAR);
+OPAL_CALL(opal_imc_counters_init,		OPAL_IMC_COUNTERS_INIT);
+OPAL_CALL(opal_imc_counters_start,		OPAL_IMC_COUNTERS_START);
+OPAL_CALL(opal_imc_counters_stop,		OPAL_IMC_COUNTERS_STOP);