1/*
  2 * Copyright (C) 2012 Regents of the University of California
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful,
  9 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 11 *   GNU General Public License for more details.
 12 */
 13
 14#include <linux/init.h>
 15#include <linux/seq_file.h>
 16#include <linux/of.h>
 17
 18/* Return -1 if not a valid hart */
 19int riscv_of_processor_hart(struct device_node *node)
 20{
 21	const char *isa, *status;
 22	u32 hart;
 23
 24	if (!of_device_is_compatible(node, "riscv")) {
 25		pr_warn("Found incompatible CPU\n");
 26		return -(ENODEV);
 27	}
 28
 29	if (of_property_read_u32(node, "reg", &hart)) {
 30		pr_warn("Found CPU without hart ID\n");
 31		return -(ENODEV);
 32	}
 33	if (hart >= NR_CPUS) {
 34		pr_info("Found hart ID %d, which is above NR_CPUs.  Disabling this hart\n", hart);
 35		return -(ENODEV);
 36	}
 37
 38	if (of_property_read_string(node, "status", &status)) {
 39		pr_warn("CPU with hartid=%d has no \"status\" property\n", hart);
 40		return -(ENODEV);
 41	}
 42	if (strcmp(status, "okay")) {
 43		pr_info("CPU with hartid=%d has a non-okay status of \"%s\"\n", hart, status);
 44		return -(ENODEV);
 45	}
 46
 47	if (of_property_read_string(node, "riscv,isa", &isa)) {
 48		pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
 49		return -(ENODEV);
 50	}
 51	if (isa[0] != 'r' || isa[1] != 'v') {
 52		pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
 53		return -(ENODEV);
 54	}
 55
 56	return hart;
 57}
 58
 59#ifdef CONFIG_PROC_FS
 60
 61static void *c_start(struct seq_file *m, loff_t *pos)
 62{
 63	*pos = cpumask_next(*pos - 1, cpu_online_mask);
 64	if ((*pos) < nr_cpu_ids)
 65		return (void *)(uintptr_t)(1 + *pos);
 66	return NULL;
 67}
 68
 69static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 70{
 71	(*pos)++;
 72	return c_start(m, pos);
 73}
 74
 75static void c_stop(struct seq_file *m, void *v)
 76{
 77}
 78
 79static int c_show(struct seq_file *m, void *v)
 80{
 81	unsigned long hart_id = (unsigned long)v - 1;
 82	struct device_node *node = of_get_cpu_node(hart_id, NULL);
 83	const char *compat, *isa, *mmu;
 84
 85	seq_printf(m, "hart\t: %lu\n", hart_id);
 86	if (!of_property_read_string(node, "riscv,isa", &isa)
 87	    && isa[0] == 'r'
 88	    && isa[1] == 'v')
 89		seq_printf(m, "isa\t: %s\n", isa);
 90	if (!of_property_read_string(node, "mmu-type", &mmu)
 91	    && !strncmp(mmu, "riscv,", 6))
 92		seq_printf(m, "mmu\t: %s\n", mmu+6);
 93	if (!of_property_read_string(node, "compatible", &compat)
 94	    && strcmp(compat, "riscv"))
 95		seq_printf(m, "uarch\t: %s\n", compat);
 96	seq_puts(m, "\n");
 97
 98	return 0;
 99}
100
101const struct seq_operations cpuinfo_op = {
102	.start	= c_start,
103	.next	= c_next,
104	.stop	= c_stop,
105	.show	= c_show
106};
107
108#endif /* CONFIG_PROC_FS */