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