44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-only
|
||
|
|
/*
|
||
|
|
* Copyright (c) 2020 Western Digital Corporation or its affiliates.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include <linux/errno.h>
|
||
|
|
#include <linux/of.h>
|
||
|
|
#include <linux/string.h>
|
||
|
|
#include <asm/cpu_ops.h>
|
||
|
|
#include <asm/sbi.h>
|
||
|
|
#include <asm/smp.h>
|
||
|
|
|
||
|
|
const struct cpu_operations cpu_ops_spinwait;
|
||
|
|
|
||
|
|
static int spinwait_cpu_prepare(unsigned int cpuid)
|
||
|
|
{
|
||
|
|
if (!cpu_ops_spinwait.cpu_start) {
|
||
|
|
pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
|
||
|
|
return -ENODEV;
|
||
|
|
}
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static int spinwait_cpu_start(unsigned int cpuid, struct task_struct *tidle)
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* In this protocol, all cpus boot on their own accord. _start
|
||
|
|
* selects the first cpu to boot the kernel and causes the remainder
|
||
|
|
* of the cpus to spin in a loop waiting for their stack pointer to be
|
||
|
|
* setup by that main cpu. Writing to bootdata
|
||
|
|
* (i.e __cpu_up_stack_pointer) signals to the spinning cpus that they
|
||
|
|
* can continue the boot process.
|
||
|
|
*/
|
||
|
|
cpu_update_secondary_bootdata(cpuid, tidle);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
const struct cpu_operations cpu_ops_spinwait = {
|
||
|
|
.name = "spinwait",
|
||
|
|
.cpu_prepare = spinwait_cpu_prepare,
|
||
|
|
.cpu_start = spinwait_cpu_start,
|
||
|
|
};
|