SPMD: code/comments cleanup

As a follow-up to bdd2596d4, and related to SPM Dispatcher
EL3 component and SPM Core S-EL2/S-EL1 component: update
with cosmetic and coding rules changes. In addition:
-Add Armv8.4-SecEL2 arch detection helper.
-Add an SPMC context (on current core) get helper.
-Return more meaningful error return codes.
-Remove complexity in few spmd_smc_handler switch-cases.
-Remove unused defines and structures from spmd_private.h

Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I99e642450b0dafb19d3218a2f0e2d3107e8ca3fe
diff --git a/services/std_svc/spmd/spmd_private.h b/services/std_svc/spmd/spmd_private.h
index 0ad35c7..232031b 100644
--- a/services/std_svc/spmd/spmd_private.h
+++ b/services/std_svc/spmd/spmd_private.h
@@ -33,12 +33,6 @@
 #include <services/spci_svc.h>
 #include <stdint.h>
 
-/*
- * Convert a function no. in a FID to a bit position. All function nos. are
- * between 0 and 0x1f
- */
-#define SPCI_FNO_TO_BIT_POS(_fid)	(1 << ((_fid) & U(0x1f)))
-
 typedef enum spmc_state {
 	SPMC_STATE_RESET = 0,
 	SPMC_STATE_IDLE
@@ -60,21 +54,10 @@
 #define SPCI_NS_ENDPOINT_ID		U(0)
 
 /* Mask and shift to check valid secure SPCI Endpoint ID. */
-#define SPMC_SECURE_ID_MASK		0x1
-#define SPMC_SECURE_ID_SHIFT		15
+#define SPMC_SECURE_ID_MASK		U(1)
+#define SPMC_SECURE_ID_SHIFT		U(15)
 
-/*
- * Data structure used by the SPM dispatcher (SPMD) in EL3 to track sequence of
- * SPCI calls from lower ELs.
- *
- * next_smc_bit_map: Per-cpu bit map of SMCs from each world that are expected
- *                   next.
- */
-typedef struct spmd_spci_context {
-	uint32_t next_smc_bit_map[2];
-} spmd_spci_context_t;
-
-/* Functions used to enter/exit a Secure Partition synchronously */
+/* Functions used to enter/exit SPMC synchronously */
 uint64_t spmd_spm_core_sync_entry(spmd_spm_core_context_t *ctx);
 __dead2 void spmd_spm_core_sync_exit(uint64_t rc);
 
@@ -82,6 +65,9 @@
 uint64_t spmd_spm_core_enter(uint64_t *c_rt_ctx);
 void __dead2 spmd_spm_core_exit(uint64_t c_rt_ctx, uint64_t ret);
 
+/* SPMC context on current CPU get helper */
+spmd_spm_core_context_t *spmd_get_context(void);
+
 #endif /* __ASSEMBLER__ */
 
 #endif /* SPMD_PRIVATE_H */