RISC-V: ACPI: cpu: Enable cpuinfo for ACPI systems

On ACPI based platforms, few details like ISA need to be read
from the ACPI table. Enable cpuinfo on ACPI based systems.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>

arch/riscv/kernel/cpu.c

@@ -3,6 +3,7 @@
  * Copyright (C) 2012 Regents of the University of California
  */
 
+#include <linux/acpi.h>
 #include <linux/cpu.h>
 #include <linux/init.h>
 #include <linux/seq_file.h>
@@ -231,26 +232,48 @@ static void c_stop(struct seq_file *m, void *v)
 {
 }
 
+#ifdef CONFIG_ACPI
+void acpi_print_hart_info(struct seq_file *m,
+			  unsigned long cpu)
+{
+	char isa[256];
+
+	if(!acpi_get_riscv_isa(cpu, isa))
+		print_isa(m, isa);
+
+}
+#endif
+
 static int c_show(struct seq_file *m, void *v)
 {
 	unsigned long cpu_id = (unsigned long)v - 1;
-	struct device_node *node = of_get_cpu_node(cpu_id, NULL);
 	struct riscv_cpuinfo *ci = per_cpu_ptr(&riscv_cpuinfo, cpu_id);
+	struct device_node *node;
 	const char *compat, *isa;
 
 	seq_printf(m, "processor\t: %lu\n", cpu_id);
 	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
-	if (!of_property_read_string(node, "riscv,isa", &isa))
-		print_isa(m, isa);
+
+	if (acpi_disabled) {
+		node = of_get_cpu_node(cpu_id, NULL);
+		if (!of_property_read_string(node, "riscv,isa", &isa))
+			print_isa(m, isa);
+		if (!of_property_read_string(node, "compatible", &compat)
+		    && strcmp(compat, "riscv"))
+			seq_printf(m, "uarch\t\t: %s\n", compat);
+		of_node_put(node);
+	}
+#ifdef CONFIG_ACPI
+	else {
+		acpi_print_hart_info(m, cpu_id);
+	}
+#endif
+
 	print_mmu(m);
-	if (!of_property_read_string(node, "compatible", &compat)
-	    && strcmp(compat, "riscv"))
-		seq_printf(m, "uarch\t\t: %s\n", compat);
 	seq_printf(m, "mvendorid\t: 0x%lx\n", ci->mvendorid);
 	seq_printf(m, "marchid\t\t: 0x%lx\n", ci->marchid);
 	seq_printf(m, "mimpid\t\t: 0x%lx\n", ci->mimpid);
 	seq_puts(m, "\n");
-	of_node_put(node);
 
 	return 0;
 }