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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/arm64/kernel/acpi_parking_protocol.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--arch/arm64/kernel/acpi_parking_protocol.c132
1 files changed, 132 insertions, 0 deletions
diff --git a/arch/arm64/kernel/acpi_parking_protocol.c b/arch/arm64/kernel/acpi_parking_protocol.c
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index 000000000..b1990e38a
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+++ b/arch/arm64/kernel/acpi_parking_protocol.c
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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(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
+};