cpu.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2012 Regents of the University of California
*/
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/of.h>
#include <asm/smp.h>
/*
* Returns the hart ID of the given device tree node, or -ENODEV if the node
* isn't an enabled and valid RISC-V hart node.
*/
int riscv_of_processor_hartid(struct device_node *node)
{
const char *isa;
u32 hart;
if (!of_device_is_compatible(node, "riscv")) {
pr_warn("Found incompatible CPU\n");
return -ENODEV;
}
if (of_property_read_u32(node, "reg", &hart)) {
pr_warn("Found CPU without hart ID\n");
return -ENODEV;
}
if (!of_device_is_available(node)) {
pr_info("CPU with hartid=%d is not available\n", hart);
return -ENODEV;
}
if (of_property_read_string(node, "riscv,isa", &isa)) {
pr_warn("CPU with hartid=%d has no \"riscv,isa\" property\n", hart);
return -ENODEV;
}
if (isa[0] != 'r' || isa[1] != 'v') {
pr_warn("CPU with hartid=%d has an invalid ISA of \"%s\"\n", hart, isa);
return -ENODEV;
}
return hart;
}
/*
* Find hart ID of the CPU DT node under which given DT node falls.
*
* To achieve this, we walk up the DT tree until we find an active
* RISC-V core (HART) node and extract the cpuid from it.
*/
int riscv_of_parent_hartid(struct device_node *node)
{
for (; node; node = node->parent) {
if (of_device_is_compatible(node, "riscv"))
return riscv_of_processor_hartid(node);
}
return -1;
}
#ifdef CONFIG_PROC_FS
static void print_isa(struct seq_file *f, const char *isa)
{
/* Print the entire ISA as it is */
seq_puts(f, "isa\t\t: ");
seq_write(f, isa, strlen(isa));
seq_puts(f, "\n");
}
static void print_mmu(struct seq_file *f, const char *mmu_type)
{
#if defined(CONFIG_32BIT)
if (strcmp(mmu_type, "riscv,sv32") != 0)
return;
#elif defined(CONFIG_64BIT)
if (strcmp(mmu_type, "riscv,sv39") != 0 &&
strcmp(mmu_type, "riscv,sv48") != 0)
return;
#endif
seq_printf(f, "mmu\t\t: %s\n", mmu_type+6);
}
static void *c_start(struct seq_file *m, loff_t *pos)
{
*pos = cpumask_next(*pos - 1, cpu_online_mask);
if ((*pos) < nr_cpu_ids)
return (void *)(uintptr_t)(1 + *pos);
return NULL;
}
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
(*pos)++;
return c_start(m, pos);
}
static void c_stop(struct seq_file *m, void *v)
{
}
static int c_show(struct seq_file *m, void *v)
{
unsigned long cpu_id = (unsigned long)v - 1;
struct device_node *node = of_get_cpu_node(cpu_id, NULL);
const char *compat, *isa, *mmu;
seq_printf(m, "processor\t: %lu\n", cpu_id);
seq_printf(m, "hart\t\t: %lu\n", cpuid_to_hartid_map(cpu_id));
if (!of_property_read_string(node, "riscv,isa", &isa))
print_isa(m, isa);
if (!of_property_read_string(node, "mmu-type", &mmu))
print_mmu(m, mmu);
if (!of_property_read_string(node, "compatible", &compat)
&& strcmp(compat, "riscv"))
seq_printf(m, "uarch\t\t: %s\n", compat);
seq_puts(m, "\n");
of_node_put(node);
return 0;
}
const struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = c_show
};
#endif /* CONFIG_PROC_FS */