AMU: Add plat interface to select which group 1 counters to enable

A new platform macro `PLAT_AMU_GROUP1_COUNTERS_MASK` controls which
group 1 counters should be enabled. The maximum number of group 1
counters supported by AMUv1 is 16 so the mask can be at most 0xffff.
If the platform does not define this mask, no group 1 counters are
enabled.

A related platform macro `PLAT_AMU_GROUP1_NR_COUNTERS` is used by
generic code to allocate an array to save and restore the counters on
CPU suspend.

Change-Id: I6d135badf4846292de931a43bb563077f42bb47b
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>
diff --git a/include/lib/extensions/amu.h b/include/lib/extensions/amu.h
index bbefe8f..2ecbea5 100644
--- a/include/lib/extensions/amu.h
+++ b/include/lib/extensions/amu.h
@@ -7,9 +7,28 @@
 #ifndef __AMU_H__
 #define __AMU_H__
 
-/* Enable all group 0 counters */
+#include <sys/cdefs.h> /* for CASSERT() */
+#include <cassert.h>
+#include <platform_def.h>
+
+/* All group 0 counters */
 #define AMU_GROUP0_COUNTERS_MASK	0xf
 
+#ifdef PLAT_AMU_GROUP1_COUNTERS_MASK
+#define AMU_GROUP1_COUNTERS_MASK	PLAT_AMU_GROUP1_COUNTERS_MASK
+#else
+#define AMU_GROUP1_COUNTERS_MASK	0
+#endif
+
+#ifdef PLAT_AMU_GROUP1_NR_COUNTERS
+#define AMU_GROUP1_NR_COUNTERS		PLAT_AMU_GROUP1_NR_COUNTERS
+#else
+#define AMU_GROUP1_NR_COUNTERS		0
+#endif
+
+CASSERT(AMU_GROUP1_COUNTERS_MASK <= 0xffff, invalid_amu_group1_counters_mask);
+CASSERT(AMU_GROUP1_NR_COUNTERS <= 16, invalid_amu_group1_nr_counters);
+
 void amu_enable(int el2_unused);
 
 #endif /* __AMU_H__ */