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// SPDX-License-Identifier: GPL-2.0-only
/*
* ARM64 ACPI Parking Protocol implementation
*
* Authors: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
* Mark Salter <msalter@redhat.com>
*/
#include <linux/acpi.h>
#include <linux/mm.h>
#include <linux/types.h>
#include <asm/cpu_ops.h>
struct parking_protocol_mailbox {
__le32 cpu_id;
__le32 reserved;
__le64 entry_point;
};
struct cpu_mailbox_entry {
struct parking_protocol_mailbox __iomem *mailbox;
phys_addr_t mailbox_addr;
u8 version;
u8 gic_cpu_id;
};
static struct cpu_mailbox_entry cpu_mailbox_entries[NR_CPUS];
void __init acpi_set_mailbox_entry(int cpu,
struct acpi_madt_generic_interrupt *p)
{
struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
cpu_entry->mailbox_addr = p->parked_address;
cpu_entry->version = p->parking_version;
cpu_entry->gic_cpu_id = p->cpu_interface_number;
}
bool acpi_parking_protocol_valid(int cpu)
{
struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
return cpu_entry->mailbox_addr && cpu_entry->version;
}
static int acpi_parking_protocol_cpu_init(unsigned int cpu)
{
pr_debug("%s: ACPI parked addr=%llx\n", __func__,
cpu_mailbox_entries[cpu].mailbox_addr);
return 0;
}
static int acpi_parking_protocol_cpu_prepare(unsigned int cpu)
{
return 0;
}
static int acpi_parking_protocol_cpu_boot(unsigned int cpu)
{
struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
struct parking_protocol_mailbox __iomem *mailbox;
u32 cpu_id;
/*
* Map mailbox memory with attribute device nGnRE (ie ioremap -
* this deviates from the parking protocol specifications since
* the mailboxes are required to be mapped nGnRnE; the attribute
* discrepancy is harmless insofar as the protocol specification
* is concerned).
* If the mailbox is mistakenly allocated in the linear mapping
* by FW ioremap will fail since the mapping will be prevented
* by the kernel (it clashes with the linear mapping attributes
* specifications).
*/
mailbox = ioremap(cpu_entry->mailbox_addr, sizeof(*mailbox));
if (!mailbox)
return -EIO;
cpu_id = readl_relaxed(&mailbox->cpu_id);
/*
* Check if firmware has set-up the mailbox entry properly
* before kickstarting the respective cpu.
*/
if (cpu_id != ~0U) {
iounmap(mailbox);
return -ENXIO;
}
/*
* stash the mailbox address mapping to use it for further FW
* checks in the postboot method
*/
cpu_entry->mailbox = mailbox;
/*
* We write the entry point and cpu id as LE regardless of the
* native endianness of the kernel. Therefore, any boot-loaders
* that read this address need to convert this address to the
* Boot-Loader's endianness before jumping.
*/
writeq_relaxed(__pa_symbol(function_nocfi(secondary_entry)),
&mailbox->entry_point);
writel_relaxed(cpu_entry->gic_cpu_id, &mailbox->cpu_id);
arch_send_wakeup_ipi_mask(cpumask_of(cpu));
return 0;
}
static void acpi_parking_protocol_cpu_postboot(void)
{
int cpu = smp_processor_id();
struct cpu_mailbox_entry *cpu_entry = &cpu_mailbox_entries[cpu];
struct parking_protocol_mailbox __iomem *mailbox = cpu_entry->mailbox;
u64 entry_point;
entry_point = readq_relaxed(&mailbox->entry_point);
/*
* Check if firmware has cleared the entry_point as expected
* by the protocol specification.
*/
WARN_ON(entry_point);
}
const struct cpu_operations acpi_parking_protocol_ops = {
.name = "parking-protocol",
.cpu_init = acpi_parking_protocol_cpu_init,
.cpu_prepare = acpi_parking_protocol_cpu_prepare,
.cpu_boot = acpi_parking_protocol_cpu_boot,
.cpu_postboot = acpi_parking_protocol_cpu_postboot
};
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