xref: /openbmc/linux/arch/riscv/kernel/cpu.c (revision 715f23b6)
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 #ifdef CONFIG_PROC_FS
48 
49 static void print_isa(struct seq_file *f, const char *isa)
50 {
51 	/* Print the entire ISA as it is */
52 	seq_puts(f, "isa\t\t: ");
53 	seq_write(f, isa, strlen(isa));
54 	seq_puts(f, "\n");
55 }
56 
57 static void print_mmu(struct seq_file *f, const char *mmu_type)
58 {
59 #if defined(CONFIG_32BIT)
60 	if (strcmp(mmu_type, "riscv,sv32") != 0)
61 		return;
62 #elif defined(CONFIG_64BIT)
63 	if (strcmp(mmu_type, "riscv,sv39") != 0 &&
64 	    strcmp(mmu_type, "riscv,sv48") != 0)
65 		return;
66 #endif
67 
68 	seq_printf(f, "mmu\t\t: %s\n", mmu_type+6);
69 }
70 
71 static void *c_start(struct seq_file *m, loff_t *pos)
72 {
73 	*pos = cpumask_next(*pos - 1, cpu_online_mask);
74 	if ((*pos) < nr_cpu_ids)
75 		return (void *)(uintptr_t)(1 + *pos);
76 	return NULL;
77 }
78 
79 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
80 {
81 	(*pos)++;
82 	return c_start(m, pos);
83 }
84 
85 static void c_stop(struct seq_file *m, void *v)
86 {
87 }
88 
89 static int c_show(struct seq_file *m, void *v)
90 {
91 	unsigned long cpu_id = (unsigned long)v - 1;
92 	struct device_node *node = of_get_cpu_node(cpu_id, NULL);
93 	const char *compat, *isa, *mmu;
94 
95 	seq_printf(m, "processor\t: %lu\n", cpu_id);
96 	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
97 	if (!of_property_read_string(node, "riscv,isa", &isa))
98 		print_isa(m, isa);
99 	if (!of_property_read_string(node, "mmu-type", &mmu))
100 		print_mmu(m, mmu);
101 	if (!of_property_read_string(node, "compatible", &compat)
102 	    && strcmp(compat, "riscv"))
103 		seq_printf(m, "uarch\t\t: %s\n", compat);
104 	seq_puts(m, "\n");
105 	of_node_put(node);
106 
107 	return 0;
108 }
109 
110 const struct seq_operations cpuinfo_op = {
111 	.start	= c_start,
112 	.next	= c_next,
113 	.stop	= c_stop,
114 	.show	= c_show
115 };
116 
117 #endif /* CONFIG_PROC_FS */
118