ARC: boot log: refactor printing abt features not captured in BCRs

On older arc700 cores, some of the features configured were not present
in Build config registers. To print about them at boot, we just use the
Kconfig option i.e. whether linux is built to use them or not.
So yes this seems bogus, but what else can be done. Moreover if linux is
booting with these enabled, then the Kconfig info is a good indicator
anyways.

Over time these "hacks" accumulated in read_arc_build_cfg_regs() as well
as arc_cpu_mumbojumbo(). so refactor and move all of those in a single
place: read_arc_build_cfg_regs(). This causes some code redcution too:

| bloat-o-meter2 arch/arc/kernel/setup.o.0 arch/arc/kernel/setup.o.1
| add/remove: 0/0 grow/shrink: 2/1 up/down: 64/-132 (-68)
| function                                     old     new   delta
| setup_processor                              610     670     +60
| cpuinfo_arc700                                76      80      +4
| arc_cpu_mumbojumbo                           752     620    -132
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/include/asm/arcregs.h

@@ -349,6 +349,7 @@ struct cpuinfo_arc {
 	struct cpuinfo_arc_bpu bpu;
 	struct bcr_identity core;
 	struct bcr_isa isa;
+	const char *details;
 	unsigned int vec_base;
 	struct cpuinfo_arc_ccm iccm, dccm;
 	struct {

arch/arc/kernel/setup.c

@@ -40,6 +40,20 @@ struct task_struct *_current_task[NR_CPUS];	/* For stack switching */
 
 struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];
 
+static const struct cpuinfo_data arc_cpu_tbl[] = {
+#ifdef CONFIG_ISA_ARCOMPACT
+	{ {0x20, "ARC 600"      }, 0x2F},
+	{ {0x30, "ARC 700"      }, 0x33},
+	{ {0x34, "ARC 700 R4.10"}, 0x34},
+	{ {0x35, "ARC 700 R4.11"}, 0x35},
+#else
+	{ {0x50, "ARC HS38 R2.0"}, 0x51},
+	{ {0x52, "ARC HS38 R2.1"}, 0x52},
+	{ {0x53, "ARC HS38 R3.0"}, 0x53},
+#endif
+	{ {0x00, NULL		} }
+};
+
 static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
 {
 	if (is_isa_arcompact()) {
@@ -92,11 +106,24 @@ static void read_arc_build_cfg_regs(void)
 	struct bcr_timer timer;
 	struct bcr_generic bcr;
 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
+	const struct cpuinfo_data *tbl;
+
 	FIX_PTR(cpu);
 
 	READ_BCR(AUX_IDENTITY, cpu->core);
 	READ_BCR(ARC_REG_ISA_CFG_BCR, cpu->isa);
 
+	for (tbl = &arc_cpu_tbl[0]; tbl->info.id != 0; tbl++) {
+		if ((cpu->core.family >= tbl->info.id) &&
+		    (cpu->core.family <= tbl->up_range)) {
+			cpu->details = tbl->info.str;
+			break;
+		}
+	}
+
+	if (tbl->info.id == 0)
+		cpu->details = "UNKNOWN";
+
 	READ_BCR(ARC_REG_TIMERS_BCR, timer);
 	cpu->extn.timer0 = timer.t0;
 	cpu->extn.timer1 = timer.t1;
@@ -160,64 +187,34 @@ static void read_arc_build_cfg_regs(void)
 	cpu->extn.rtt = bcr.ver ? 1 : 0;
 
 	cpu->extn.debug = cpu->extn.ap | cpu->extn.smart | cpu->extn.rtt;
-}
 
-static const struct cpuinfo_data arc_cpu_tbl[] = {
-#ifdef CONFIG_ISA_ARCOMPACT
-	{ {0x20, "ARC 600"      }, 0x2F},
-	{ {0x30, "ARC 700"      }, 0x33},
-	{ {0x34, "ARC 700 R4.10"}, 0x34},
-	{ {0x35, "ARC 700 R4.11"}, 0x35},
-#else
-	{ {0x50, "ARC HS38 R2.0"}, 0x51},
-	{ {0x52, "ARC HS38 R2.1"}, 0x52},
-	{ {0x53, "ARC HS38 R3.0"}, 0x53},
-#endif
-	{ {0x00, NULL		} }
-};
+	/* some hacks for lack of feature BCR info in old ARC700 cores */
+	if (is_isa_arcompact()) {
+		if (!cpu->isa.ver)	/* ISA BCR absent, use Kconfig info */
+			cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
+		else
+			cpu->isa.atomic = cpu->isa.atomic1;
 
+		cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
+	}
+}
 
 static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
 {
 	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
 	struct bcr_identity *core = &cpu->core;
-	const struct cpuinfo_data *tbl;
-	char *isa_nm;
-	int i, be, atomic;
-	int n = 0;
+	int i, n = 0;
 
 	FIX_PTR(cpu);
 
-	if (is_isa_arcompact()) {
-		isa_nm = "ARCompact";
-		be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);
-
-		atomic = cpu->isa.atomic1;
-		if (!cpu->isa.ver)	/* ISA BCR absent, use Kconfig info */
-			atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
-	} else {
-		isa_nm = "ARCv2";
-		be = cpu->isa.be;
-		atomic = cpu->isa.atomic;
-	}
-
 	n += scnprintf(buf + n, len - n,
 		       "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
 		       core->family, core->cpu_id, core->chip_id);
 
-	for (tbl = &arc_cpu_tbl[0]; tbl->info.id != 0; tbl++) {
-		if ((core->family >= tbl->info.id) &&
-		    (core->family <= tbl->up_range)) {
-			n += scnprintf(buf + n, len - n,
-				       "processor [%d]\t: %s (%s ISA) %s\n",
-				       cpu_id, tbl->info.str, isa_nm,
-				       IS_AVAIL1(be, "[Big-Endian]"));
-			break;
-		}
-	}
-
-	if (tbl->info.id == 0)
-		n += scnprintf(buf + n, len - n, "UNKNOWN ARC Processor\n");
+	n += scnprintf(buf + n, len - n, "processor [%d]\t: %s (%s ISA) %s\n",
+		       cpu_id, cpu->details,
+		       is_isa_arcompact() ? "ARCompact" : "ARCv2",
+		       IS_AVAIL1(cpu->isa.be, "[Big-Endian]"));
 
 	n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s\nISA Extn\t: ",
 		       IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
@@ -226,7 +223,7 @@ static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
 				 CONFIG_ARC_HAS_RTC));
 
 	n += i = scnprintf(buf + n, len - n, "%s%s%s%s%s",
-			   IS_AVAIL2(atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
+			   IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
 			   IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
 			   IS_AVAIL1(cpu->isa.unalign, "unalign (not used)"));