linux/arch/arm64/kernel/cpu_ops.c

88 lines
2.1 KiB
C

/*
* CPU kernel entry/exit control
*
* Copyright (C) 2013 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <asm/cpu_ops.h>
#include <asm/smp_plat.h>
#include <linux/errno.h>
#include <linux/of.h>
#include <linux/string.h>
extern const struct cpu_operations smp_spin_table_ops;
extern const struct cpu_operations cpu_psci_ops;
const struct cpu_operations *cpu_ops[NR_CPUS];
static const struct cpu_operations *supported_cpu_ops[] __initconst = {
#ifdef CONFIG_SMP
&smp_spin_table_ops,
&cpu_psci_ops,
#endif
NULL,
};
static const struct cpu_operations * __init cpu_get_ops(const char *name)
{
const struct cpu_operations **ops = supported_cpu_ops;
while (*ops) {
if (!strcmp(name, (*ops)->name))
return *ops;
ops++;
}
return NULL;
}
/*
* Read a cpu's enable method from the device tree and record it in cpu_ops.
*/
int __init cpu_read_ops(struct device_node *dn, int cpu)
{
const char *enable_method = of_get_property(dn, "enable-method", NULL);
if (!enable_method) {
/*
* The boot CPU may not have an enable method (e.g. when
* spin-table is used for secondaries). Don't warn spuriously.
*/
if (cpu != 0)
pr_err("%s: missing enable-method property\n",
dn->full_name);
return -ENOENT;
}
cpu_ops[cpu] = cpu_get_ops(enable_method);
if (!cpu_ops[cpu]) {
pr_warn("%s: unsupported enable-method property: %s\n",
dn->full_name, enable_method);
return -EOPNOTSUPP;
}
return 0;
}
void __init cpu_read_bootcpu_ops(void)
{
struct device_node *dn = of_get_cpu_node(0, NULL);
if (!dn) {
pr_err("Failed to find device node for boot cpu\n");
return;
}
cpu_read_ops(dn, 0);
}