qemu/aarch64/plat_helpers.S : calculate the position shift

Rather than re-create this file in multiple qemu variants instead
caclulate the shift needed to convert MPIDR to position.

Add a new PLATFORM_CPU_PER_CLUSTER_SHIFT define in platform_def.h
for both qemu and qemu_sbsa to enable this calculation.
Signed-off-by: Graeme Gregory <graeme@nuviainc.com>
Change-Id: I0e3a86354aa716d95150a3a34b15287cd70c8fd2

plat/qemu/common/aarch64/plat_helpers.S

@@ -32,7 +32,8 @@ endfunc plat_my_core_pos
 func plat_qemu_calc_core_pos
 	and	x1, x0, #MPIDR_CPU_MASK
 	and	x0, x0, #MPIDR_CLUSTER_MASK
-	add	x0, x1, x0, LSR #6
+	add	x0, x1, x0, LSR #(MPIDR_AFFINITY_BITS -\
+				  PLATFORM_CPU_PER_CLUSTER_SHIFT)
 	ret
 endfunc plat_qemu_calc_core_pos
 

plat/qemu/qemu/include/platform_def.h

@@ -24,6 +24,14 @@
 #define PLATFORM_CLUSTER1_CORE_COUNT	U(0)
 #else
 #define PLATFORM_MAX_CPUS_PER_CLUSTER	U(4)
+/*
+ * Define the number of cores per cluster used in calculating core position.
+ * The cluster number is shifted by this value and added to the core ID,
+ * so its value represents log2(cores/cluster).
+ * Default is 2**(2) = 4 cores per cluster.
+ */
+#define PLATFORM_CPU_PER_CLUSTER_SHIFT	U(2)
+
 #define PLATFORM_CLUSTER_COUNT		U(2)
 #define PLATFORM_CLUSTER0_CORE_COUNT	PLATFORM_MAX_CPUS_PER_CLUSTER
 #define PLATFORM_CLUSTER1_CORE_COUNT	PLATFORM_MAX_CPUS_PER_CLUSTER

plat/qemu/qemu_sbsa/include/platform_def.h

@@ -17,6 +17,13 @@
 #define PLATFORM_STACK_SIZE		0x1000
 
 #define PLATFORM_MAX_CPUS_PER_CLUSTER	U(4)
+/*
+ * Define the number of cores per cluster used in calculating core position.
+ * The cluster number is shifted by this value and added to the core ID,
+ * so its value represents log2(cores/cluster).
+ * Default is 2**(2) = 4 cores per cluster.
+ */
+#define PLATFORM_CPU_PER_CLUSTER_SHIFT	U(2)
 #define PLATFORM_CLUSTER_COUNT		U(2)
 #define PLATFORM_CLUSTER0_CORE_COUNT	PLATFORM_MAX_CPUS_PER_CLUSTER
 #define PLATFORM_CLUSTER1_CORE_COUNT	PLATFORM_MAX_CPUS_PER_CLUSTER