1 files changed, 108 insertions, 0 deletions
diff --git a/arch/riscv/kernel/cpu.c b/arch/riscv/kernel/cpu.c
new file mode 100644
index 000000000000..ca6c81e54e37
--- /dev/null
+++ b/arch/riscv/kernel/cpu.c
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2012 Regents of the University of California
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/seq_file.h>
+#include <linux/of.h>
+
+/* Return -1 if not a valid hart */
+int riscv_of_processor_hart(struct device_node *node)
+{
+	const char *isa, *status;
+	u32 hart;
+
+	if (!of_device_is_compatible(node, "riscv")) {
+		pr_warn("Found incompatible CPU\n");
+		return -(ENODEV);
+	}
+
+	if (of_property_read_u32(node, "reg", &hart)) {
+		pr_warn("Found CPU without hart ID\n");
+		return -(ENODEV);
+	}
+	if (hart >= NR_CPUS) {
+		pr_info("Found hart ID %d, which is above NR_CPUs.  Disabling this hart\n", hart);
+		return -(ENODEV);
+	}
+
+	if (of_property_read_string(node, "status", &status)) {
+		pr_warn("CPU with hartid=%d has no \"status\" property\n", hart);
+		return -(ENODEV);
+	}
+	if (strcmp(status, "okay")) {
+		pr_info("CPU with hartid=%d has a non-okay status of \"%s\"\n", hart, status);
+		return -(ENODEV);
+	}
+
+	if (of_property_read_string(node, "riscv,isa", &isa)) {
+		pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
+		return -(ENODEV);
+	}
+	if (isa[0] != 'r' || isa[1] != 'v') {
+		pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
+		return -(ENODEV);
+	}
+
+	return hart;
+}
+
+#ifdef CONFIG_PROC_FS
+
+static void *c_start(struct seq_file *m, loff_t *pos)
+{
+	*pos = cpumask_next(*pos - 1, cpu_online_mask);
+	if ((*pos) < nr_cpu_ids)
+		return (void *)(uintptr_t)(1 + *pos);
+	return NULL;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	(*pos)++;
+	return c_start(m, pos);
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+static int c_show(struct seq_file *m, void *v)
+{
+	unsigned long hart_id = (unsigned long)v - 1;
+	struct device_node *node = of_get_cpu_node(hart_id, NULL);
+	const char *compat, *isa, *mmu;
+
+	seq_printf(m, "hart\t: %lu\n", hart_id);
+	if (!of_property_read_string(node, "riscv,isa", &isa)
+	    && isa[0] == 'r'
+	    && isa[1] == 'v')
+		seq_printf(m, "isa\t: %s\n", isa);
+	if (!of_property_read_string(node, "mmu-type", &mmu)
+	    && !strncmp(mmu, "riscv,", 6))
+		seq_printf(m, "mmu\t: %s\n", mmu+6);
+	if (!of_property_read_string(node, "compatible", &compat)
+	    && strcmp(compat, "riscv"))
+		seq_printf(m, "uarch\t: %s\n", compat);
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+const struct seq_operations cpuinfo_op = {
+	.start	= c_start,
+	.next	= c_next,
+	.stop	= c_stop,
+	.show	= c_show
+};
+
+#endif /* CONFIG_PROC_FS */