ARCv2: ioremap: Support dynamic peripheral address space

The peripheral address space is architectural address window which is
uncached and typically used to wire up peripherals.

For ARC700 cores (ARCompact ISA based) this was fixed to 1GB region
0xC000_0000 - 0xFFFF_FFFF.

For ARCv2 based HS38 cores the start address is flexible and can be
0xC, 0xD, 0xE, 0xF 000_000 by programming AUX_NON_VOLATILE_LIMIT reg
(typically done in bootloader)

Further in cas of PAE, the physical address can extend beyond 4GB so
need to confine this check, otherwise all pages beyond 4GB will be
treated as uncached

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

arch/arc/kernel/setup.c

@@ -91,11 +91,9 @@ static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
 
 static void read_arc_build_cfg_regs(void)
 {
-	struct bcr_perip uncached_space;
 	struct bcr_timer timer;
 	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);
@@ -108,14 +106,6 @@ 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);
-        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);
 
 	cpu->extn.norm = read_aux_reg(ARC_REG_NORM_BCR) > 1 ? 1 : 0; /* 2,3 */
@@ -288,8 +278,8 @@ static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
 	FIX_PTR(cpu);
 
 	n += scnprintf(buf + n, len - n,
-		       "Vector Table\t: %#x\nUncached Base\t: %#x\n",
-		       cpu->vec_base, ARC_UNCACHED_ADDR_SPACE);
+		       "Vector Table\t: %#x\nUncached Base\t: %#lx\n",
+		       cpu->vec_base, perip_base);
 
 	if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
 		n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",