ARCv2: Fix the peripheral address space detection

With HS 2.1 release, the peripheral space register no longer contains
the uncached space specifics, causing the kernel to panic early on.
So read the newer NON VOLATILE AUX register to get that info.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

2 files changed, 10 insertions, 5 deletions

diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 070f58827a5c..c8f57b8449dc 100644
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -89,11 +89,10 @@
 #define ECR_C_BIT_DTLB_LD_MISS          8
 #define ECR_C_BIT_DTLB_ST_MISS          9
 
-
 /* Auxiliary registers */
 #define AUX_IDENTITY            4
 #define AUX_INTR_VEC_BASE       0x25
-
+#define AUX_NON_VOL             0x5e
 
 /*
  * Floating Pt Registers
@@ -240,9 +239,9 @@ struct bcr_extn_xymem {
 
 struct bcr_perip {
 #ifdef CONFIG_CPU_BIG_ENDIAN
-        unsigned int start:8, pad2:8, sz:8, pad:8;
+        unsigned int start:8, pad2:8, sz:8, ver:8;
 #else
-        unsigned int pad:8, sz:8, pad2:8, start:8;
+        unsigned int ver:8, sz:8, pad2:8, start:8;
 #endif
 };
 
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 18cc01591c96..f2f771bd3ede 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -47,6 +47,7 @@ static void read_arc_build_cfg_regs(void)
         struct bcr_perip uncached_space;
         struct bcr_generic bcr;
         struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
+        unsigned long perip_space;
         FIX_PTR(cpu);
 
         READ_BCR(AUX_IDENTITY, cpu->core);
@@ -56,7 +57,12 @@ static void read_arc_build_cfg_regs(void)
         cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
 
         READ_BCR(ARC_REG_D_UNCACH_BCR, uncached_space);
-        BUG_ON((uncached_space.start << 24) != ARC_UNCACHED_ADDR_SPACE);
+        if (uncached_space.ver < 3)
+                perip_space = uncached_space.start << 24;
+        else
+                perip_space = read_aux_reg(AUX_NON_VOL) & 0xF0000000;
+
+        BUG_ON(perip_space != ARC_UNCACHED_ADDR_SPACE);
 
         READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);