FVP: change the method for translating MPIDR values to a linear indices

x3 will be assigned by the folloing instructions.
So the first instruction is not needed any more.

old method:
  (ClusterId * FVP_MAX_CPUS_PER_CLUSTER)
+ (CPUId * FVP_MAX_PE_PER_CPU)
+ ThreadId

it should be
  (ClusterId * FVP_MAX_CPUS_PER_CLUSTER) * FVP_MAX_PE_PER_CPU
+ (CPUId * FVP_MAX_PE_PER_CPU)
+ ThreadId

which can be simplified as:
(ClusterId * FVP_MAX_CPUS_PER_CLUSTER + CPUId) * FVP_MAX_PE_PER_CPU + ThreadId

Signed-off-by: Wang Feng <feng_feng.wang@spreadtrum.com>

diff --git a/plat/arm/board/fvp/aarch64/fvp_helpers.S b/plat/arm/board/fvp/aarch64/fvp_helpers.S
index 6ea4585154a198340dfe9cdca1664020cafab010..88fcdb1b0981e05c60d103921e4a9476db617eb2 100644 (file)
--- a/plat/arm/board/fvp/aarch64/fvp_helpers.S
+++ b/plat/arm/board/fvp/aarch64/fvp_helpers.S
@@ -178,19 +178,22 @@ func plat_is_my_cpu_primary
        ret
 endfunc plat_is_my_cpu_primary
 
-       /* -----------------------------------------------------
+       /* ---------------------------------------------------------------------
         * unsigned int plat_arm_calc_core_pos(u_register_t mpidr)
         *
         * Function to calculate the core position on FVP.
         *
-        * (ClusterId * FVP_MAX_CPUS_PER_CLUSTER) +
+        * (ClusterId * FVP_MAX_CPUS_PER_CLUSTER * FVP_MAX_PE_PER_CPU) +
         * (CPUId * FVP_MAX_PE_PER_CPU) +
         * ThreadId
-        * -----------------------------------------------------
+        *
+        * which can be simplified as:
+        *
+        * ((ClusterId * FVP_MAX_CPUS_PER_CLUSTER + CPUId) * FVP_MAX_PE_PER_CPU)
+        * + ThreadId
+        * ---------------------------------------------------------------------
         */
 func plat_arm_calc_core_pos
-       mov     x3, x0
-
        /*
         * Check for MT bit in MPIDR. If not set, shift MPIDR to left to make it
         * look as if in a multi-threaded implementation.
@@ -205,9 +208,9 @@ func plat_arm_calc_core_pos
        ubfx    x2, x3, #MPIDR_AFF2_SHIFT, #MPIDR_AFFINITY_BITS
 
        /* Compute linear position */
-       mov     x4, #FVP_MAX_PE_PER_CPU
-       madd    x0, x1, x4, x0
-       mov     x5, #FVP_MAX_CPUS_PER_CLUSTER
-       madd    x0, x2, x5, x0
+       mov     x4, #FVP_MAX_CPUS_PER_CLUSTER
+       madd    x1, x2, x4, x1
+       mov     x5, #FVP_MAX_PE_PER_CPU
+       madd    x0, x1, x5, x0
        ret
 endfunc plat_arm_calc_core_pos