arch/riscv/kernel/cpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Regents of the University of California
   4  */
   5
   6 #include <linux/init.h>
   7 #include <linux/seq_file.h>
   8 #include <linux/of.h>
   9 #include <asm/smp.h>
  10
  11 /*
  12  * Returns the hart ID of the given device tree node, or -ENODEV if the node
  13  * isn't an enabled and valid RISC-V hart node.
  14  */
  15 int riscv_of_processor_hartid(struct device_node *node)
  16 {
  17         const char *isa;
  18         u32 hart;
  19
  20         if (!of_device_is_compatible(node, "riscv")) {
  21                 pr_warn("Found incompatible CPU\n");
  22                 return -ENODEV;
  23         }
  24
  25         if (of_property_read_u32(node, "reg", &hart)) {
  26                 pr_warn("Found CPU without hart ID\n");
  27                 return -ENODEV;
  28         }
  29
  30         if (!of_device_is_available(node)) {
  31                 pr_info("CPU with hartid=%d is not available\n", hart);
  32                 return -ENODEV;
  33         }
  34
  35         if (of_property_read_string(node, "riscv,isa", &isa)) {
  36                 pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
  37                 return -ENODEV;
  38         }
  39         if (isa[0] != 'r' || isa[1] != 'v') {
  40                 pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
  41                 return -ENODEV;
  42         }
  43
  44         return hart;
  45 }
  46
  47 /*
  48  * Find hart ID of the CPU DT node under which given DT node falls.
  49  *
  50  * To achieve this, we walk up the DT tree until we find an active
  51  * RISC-V core (HART) node and extract the cpuid from it.
  52  */
  53 int riscv_of_parent_hartid(struct device_node *node)
  54 {
  55         for (; node; node = node->parent) {
  56                 if (of_device_is_compatible(node, "riscv"))
  57                         return riscv_of_processor_hartid(node);
  58         }
  59
  60         return -1;
  61 }
  62
  63 #ifdef CONFIG_PROC_FS
  64
  65 static void print_isa(struct seq_file *f, const char *isa)
  66 {
  67         /* Print the entire ISA as it is */
  68         seq_puts(f, "isa\t\t: ");
  69         seq_write(f, isa, strlen(isa));
  70         seq_puts(f, "\n");
  71 }
  72
  73 static void print_mmu(struct seq_file *f, const char *mmu_type)
  74 {
  75 #if defined(CONFIG_32BIT)
  76         if (strcmp(mmu_type, "riscv,sv32") != 0)
  77                 return;
  78 #elif defined(CONFIG_64BIT)
  79         if (strcmp(mmu_type, "riscv,sv39") != 0 &&
  80             strcmp(mmu_type, "riscv,sv48") != 0)
  81                 return;
  82 #endif
  83
  84         seq_printf(f, "mmu\t\t: %s\n", mmu_type+6);
  85 }
  86
  87 static void *c_start(struct seq_file *m, loff_t *pos)
  88 {
  89         *pos = cpumask_next(*pos - 1, cpu_online_mask);
  90         if ((*pos) < nr_cpu_ids)
  91                 return (void *)(uintptr_t)(1 + *pos);
  92         return NULL;
  93 }
  94
  95 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
  96 {
  97         (*pos)++;
  98         return c_start(m, pos);
  99 }
 100
 101 static void c_stop(struct seq_file *m, void *v)
 102 {
 103 }
 104
 105 static int c_show(struct seq_file *m, void *v)
 106 {
 107         unsigned long cpu_id = (unsigned long)v - 1;
 108         struct device_node *node = of_get_cpu_node(cpu_id, NULL);
 109         const char *compat, *isa, *mmu;
 110
 111         seq_printf(m, "processor\t: %lu\n", cpu_id);
 112         seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
 113         if (!of_property_read_string(node, "riscv,isa", &isa))
 114                 print_isa(m, isa);
 115         if (!of_property_read_string(node, "mmu-type", &mmu))
 116                 print_mmu(m, mmu);
 117         if (!of_property_read_string(node, "compatible", &compat)
 118             && strcmp(compat, "riscv"))
 119                 seq_printf(m, "uarch\t\t: %s\n", compat);
 120         seq_puts(m, "\n");
 121         of_node_put(node);
 122
 123         return 0;
 124 }
 125
 126 const struct seq_operations cpuinfo_op = {
 127         .start  = c_start,
 128         .next   = c_next,
 129         .stop   = c_stop,
 130         .show   = c_show
 131 };
 132
 133 #endif /* CONFIG_PROC_FS */