diff options
Diffstat (limited to 'arch/arm64/kernel/acpi_parking_protocol.c')
| -rw-r--r-- | arch/arm64/kernel/acpi_parking_protocol.c | 142 |
1 files changed, 142 insertions, 0 deletions
diff --git a/arch/arm64/kernel/acpi_parking_protocol.c b/arch/arm64/kernel/acpi_parking_protocol.c new file mode 100644 index 000000000..98a20e587 --- /dev/null +++ b/arch/arm64/kernel/acpi_parking_protocol.c @@ -0,0 +1,142 @@ +/* + * ARM64 ACPI Parking Protocol implementation + * + * Authors: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> + * Mark Salter <msalter@redhat.com> + * + * 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 <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(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 +}; |