linux-sg2042/arch/riscv/kernel/cpu.c

109 lines
2.8 KiB
C

/*
* Copyright (C) 2012 Regents of the University of California
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/of.h>
/* Return -1 if not a valid hart */
int riscv_of_processor_hart(struct device_node *node)
{
const char *isa, *status;
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 (hart >= NR_CPUS) {
pr_info("Found hart ID %d, which is above NR_CPUs. Disabling this hart\n", hart);
return -(ENODEV);
}
if (of_property_read_string(node, "status", &status)) {
pr_warn("CPU with hartid=%d has no \"status\" property\n", hart);
return -(ENODEV);
}
if (strcmp(status, "okay")) {
pr_info("CPU with hartid=%d has a non-okay status of \"%s\"\n", hart, status);
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;
}
#ifdef CONFIG_PROC_FS
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 hart_id = (unsigned long)v - 1;
struct device_node *node = of_get_cpu_node(hart_id, NULL);
const char *compat, *isa, *mmu;
seq_printf(m, "hart\t: %lu\n", hart_id);
if (!of_property_read_string(node, "riscv,isa", &isa)
&& isa[0] == 'r'
&& isa[1] == 'v')
seq_printf(m, "isa\t: %s\n", isa);
if (!of_property_read_string(node, "mmu-type", &mmu)
&& !strncmp(mmu, "riscv,", 6))
seq_printf(m, "mmu\t: %s\n", mmu+6);
if (!of_property_read_string(node, "compatible", &compat)
&& strcmp(compat, "riscv"))
seq_printf(m, "uarch\t: %s\n", compat);
seq_puts(m, "\n");
return 0;
}
const struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = c_show
};
#endif /* CONFIG_PROC_FS */