drivers/gicv3: use mpidr to probe GICR for current CPU

In function gicv3_rdistif_probe(), line #1322 implies
gicv3_driver_data->mpidr_to_core_pos() may be null, but the original
code uses this interface to get current CPU index unconditionally.

It is better to use MPIDR to probe GICR which does not depend on
gicv3_driver_data->mpidr_to_core_pos().
Signed-off-by: Heyi Guo <guoheyi@linux.alibaba.com>
Change-Id: I64add055385040fe0a56b977e2299608e2309a6e

drivers/arm/gic/v3/gicv3_main.c

 /*
- * Copyright (c) 2015-2020, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -1299,8 +1299,8 @@ unsigned int gicv3_set_pmr(unsigned int mask)
  ******************************************************************************/
 int gicv3_rdistif_probe(const uintptr_t gicr_frame)
 {
-	u_register_t mpidr;
-	unsigned int proc_num, proc_self;
+	u_register_t mpidr, mpidr_self;
+	unsigned int proc_num;
 	uint64_t typer_val;
 	uintptr_t rdistif_base;
 	bool gicr_frame_found = false;
@@ -1314,18 +1314,18 @@ int gicv3_rdistif_probe(const uintptr_t gicr_frame)
 	assert((read_sctlr_el3() & SCTLR_C_BIT) != 0U);
 #endif /* !__aarch64__ */
 
-	proc_self = gicv3_driver_data->mpidr_to_core_pos(read_mpidr_el1());
+	mpidr_self = read_mpidr_el1() & MPIDR_AFFINITY_MASK;
 	rdistif_base = gicr_frame;
 	do {
 		typer_val = gicr_read_typer(rdistif_base);
-		if (gicv3_driver_data->mpidr_to_core_pos != NULL) {
 		mpidr = mpidr_from_gicr_typer(typer_val);
+		if (gicv3_driver_data->mpidr_to_core_pos != NULL) {
 			proc_num = gicv3_driver_data->mpidr_to_core_pos(mpidr);
 		} else {
 			proc_num = (unsigned int)(typer_val >>
 				TYPER_PROC_NUM_SHIFT) & TYPER_PROC_NUM_MASK;
 		}
-		if (proc_num == proc_self) {
+		if (mpidr == mpidr_self) {
 			/* The base address doesn't need to be initialized on
 			 * every warm boot.
 			 */