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 */
 15int 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
 49static void print_isa(struct seq_file *f, const char *orig_isa)
 50{
 51	static const char *ext = "mafdcsu";
 52	const char *isa = orig_isa;
 53	const char *e;
 54
 55	/*
 56	 * Linux doesn't support rv32e or rv128i, and we only support booting
 57	 * kernels on harts with the same ISA that the kernel is compiled for.
 58	 */
 59#if defined(CONFIG_32BIT)
 60	if (strncmp(isa, "rv32i", 5) != 0)
 61		return;
 62#elif defined(CONFIG_64BIT)
 63	if (strncmp(isa, "rv64i", 5) != 0)
 64		return;
 65#endif
 66
 67	/* Print the base ISA, as we already know it's legal. */
 68	seq_puts(f, "isa\t\t: ");
 69	seq_write(f, isa, 5);
 70	isa += 5;
 71
 72	/*
 73	 * Check the rest of the ISA string for valid extensions, printing those
 74	 * we find.  RISC-V ISA strings define an order, so we only print the
 75	 * extension bits when they're in order. Hide the supervisor (S)
 76	 * extension from userspace as it's not accessible from there.
 77	 */
 78	for (e = ext; *e != '\0'; ++e) {
 79		if (isa[0] == e[0]) {
 80			if (isa[0] != 's')
 81				seq_write(f, isa, 1);
 82
 83			isa++;
 84		}
 85	}
 86	seq_puts(f, "\n");
 87
 88	/*
 89	 * If we were given an unsupported ISA in the device tree then print
 90	 * a bit of info describing what went wrong.
 91	 */
 92	if (isa[0] != '\0')
 93		pr_info("unsupported ISA \"%s\" in device tree\n", orig_isa);
 94}
 95
 96static void print_mmu(struct seq_file *f, const char *mmu_type)
 97{
 98#if defined(CONFIG_32BIT)
 99	if (strcmp(mmu_type, "riscv,sv32") != 0)
100		return;
101#elif defined(CONFIG_64BIT)
102	if (strcmp(mmu_type, "riscv,sv39") != 0 &&
103	    strcmp(mmu_type, "riscv,sv48") != 0)
104		return;
105#endif
106
107	seq_printf(f, "mmu\t\t: %s\n", mmu_type+6);
108}
109
110static void *c_start(struct seq_file *m, loff_t *pos)
111{
112	*pos = cpumask_next(*pos - 1, cpu_online_mask);
113	if ((*pos) < nr_cpu_ids)
114		return (void *)(uintptr_t)(1 + *pos);
115	return NULL;
116}
117
118static void *c_next(struct seq_file *m, void *v, loff_t *pos)
119{
120	(*pos)++;
121	return c_start(m, pos);
122}
123
124static void c_stop(struct seq_file *m, void *v)
125{
126}
127
128static int c_show(struct seq_file *m, void *v)
129{
130	unsigned long cpu_id = (unsigned long)v - 1;
131	struct device_node *node = of_get_cpu_node(cpu_id, NULL);
132	const char *compat, *isa, *mmu;
133
134	seq_printf(m, "processor\t: %lu\n", cpu_id);
135	seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
136	if (!of_property_read_string(node, "riscv,isa", &isa))
137		print_isa(m, isa);
138	if (!of_property_read_string(node, "mmu-type", &mmu))
139		print_mmu(m, mmu);
140	if (!of_property_read_string(node, "compatible", &compat)
141	    && strcmp(compat, "riscv"))
142		seq_printf(m, "uarch\t\t: %s\n", compat);
143	seq_puts(m, "\n");
144	of_node_put(node);
145
146	return 0;
147}
148
149const struct seq_operations cpuinfo_op = {
150	.start	= c_start,
151	.next	= c_next,
152	.stop	= c_stop,
153	.show	= c_show
154};
155
156#endif /* CONFIG_PROC_FS */