LXR linux/arch/riscv/kernel/cpu.c

   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 */
 109