armv8: add cpu core helper functions

Add helper functions to identify different armv8 variants.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Cc: Stefano Babic <sbabic@denx.de>

diff --git a/arch/arm/include/asm/armv8/cpu.h b/arch/arm/include/asm/armv8/cpu.h
new file mode 100644 (file)
index 0000000..40d54dc
--- /dev/null
+++ b/arch/arm/include/asm/armv8/cpu.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright 2018 NXP
+ */
+
+#define MIDR_PARTNUM_CORTEX_A35        0xD04
+#define MIDR_PARTNUM_CORTEX_A53        0xD03
+#define MIDR_PARTNUM_CORTEX_A72        0xD08
+#define MIDR_PARTNUM_SHIFT     0x4
+#define MIDR_PARTNUM_MASK      (0xFFF << 0x4)
+
+static inline unsigned int read_midr(void)
+{
+       unsigned long val;
+
+       asm volatile("mrs %0, midr_el1" : "=r" (val));
+
+       return val;
+}
+
+#define is_cortex_a35() (((read_midr() & MIDR_PARTNUM_MASK) >> \
+                        MIDR_PARTNUM_SHIFT) == MIDR_PARTNUM_CORTEX_A35)
+#define is_cortex_a53() (((read_midr() & MIDR_PARTNUM_MASK) >> \
+                        MIDR_PARTNUM_SHIFT) == MIDR_PARTNUM_CORTEX_A53)
+#define is_cortex_a72() (((read_midr() & MIDR_PARTNUM_MASK) >>\
+                        MIDR_PARTNUM_SHIFT) == MIDR_PARTNUM_CORTEX_A72)