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// SPDX-License-Identifier: GPL-2.0-only
/*
* HSM extension and cpu_ops implementation.
*
* Copyright (c) 2020 Western Digital Corporation or its affiliates.
*/
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/sched/task_stack.h>
#include <asm/cpu_ops.h>
#include <asm/cpu_ops_sbi.h>
#include <asm/sbi.h>
#include <asm/smp.h>
extern char secondary_start_sbi[];
const struct cpu_operations cpu_ops_sbi;
/*
* Ordered booting via HSM brings one cpu at a time. However, cpu hotplug can
* be invoked from multiple threads in parallel. Define a per cpu data
* to handle that.
*/
DEFINE_PER_CPU(struct sbi_hart_boot_data, boot_data);
static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
unsigned long priv)
{
struct sbiret ret;
ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
hartid, saddr, priv, 0, 0, 0);
if (ret.error)
return sbi_err_map_linux_errno(ret.error);
else
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
static int sbi_hsm_hart_stop(void)
{
struct sbiret ret;
ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0);
if (ret.error)
return sbi_err_map_linux_errno(ret.error);
else
return 0;
}
static int sbi_hsm_hart_get_status(unsigned long hartid)
{
struct sbiret ret;
ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS,
hartid, 0, 0, 0, 0, 0);
if (ret.error)
return sbi_err_map_linux_errno(ret.error);
else
return ret.value;
}
#endif
static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle)
{
unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
int hartid = cpuid_to_hartid_map(cpuid);
unsigned long hsm_data;
struct sbi_hart_boot_data *bdata = &per_cpu(boot_data, cpuid);
/* Make sure tidle is updated */
smp_mb();
bdata->task_ptr = tidle;
bdata->stack_ptr = task_stack_page(tidle) + THREAD_SIZE;
/* Make sure boot data is updated */
smp_mb();
hsm_data = __pa(bdata);
return sbi_hsm_hart_start(hartid, boot_addr, hsm_data);
}
static int sbi_cpu_prepare(unsigned int cpuid)
{
if (!cpu_ops_sbi.cpu_start) {
pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
return -ENODEV;
}
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
static int sbi_cpu_disable(unsigned int cpuid)
{
if (!cpu_ops_sbi.cpu_stop)
return -EOPNOTSUPP;
return 0;
}
static void sbi_cpu_stop(void)
{
int ret;
ret = sbi_hsm_hart_stop();
pr_crit("Unable to stop the cpu %u (%d)\n", smp_processor_id(), ret);
}
static int sbi_cpu_is_stopped(unsigned int cpuid)
{
int rc;
int hartid = cpuid_to_hartid_map(cpuid);
rc = sbi_hsm_hart_get_status(hartid);
if (rc == SBI_HSM_HART_STATUS_STOPPED)
return 0;
return rc;
}
#endif
const struct cpu_operations cpu_ops_sbi = {
.name = "sbi",
.cpu_prepare = sbi_cpu_prepare,
.cpu_start = sbi_cpu_start,
#ifdef CONFIG_HOTPLUG_CPU
.cpu_disable = sbi_cpu_disable,
.cpu_stop = sbi_cpu_stop,
.cpu_is_stopped = sbi_cpu_is_stopped,
#endif
};
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