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 */
  19 int 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
  61 static 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
  69 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  70 {
  71         (*pos)++;
  72         return c_start(m, pos);
  73 }
  74
  75 static void c_stop(struct seq_file *m, void *v)
  76 {
  77 }
  78
  79 static 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
 101 const 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 */