1 files changed, 124 insertions, 0 deletions
diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c
new file mode 100644
index 000000000..29a8e444d
--- /dev/null
+++ b/arch/arm64/kernel/psci.c
@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *
+ * Copyright (C) 2013 ARM Limited
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#define pr_fmt(fmt) "psci: " fmt
+
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/smp.h>
+#include <linux/delay.h>
+#include <linux/psci.h>
+#include <linux/mm.h>
+
+#include <uapi/linux/psci.h>
+
+#include <asm/cpu_ops.h>
+#include <asm/errno.h>
+#include <asm/smp_plat.h>
+
+static int __init cpu_psci_cpu_init(unsigned int cpu)
+{
+	return 0;
+}
+
+static int __init cpu_psci_cpu_prepare(unsigned int cpu)
+{
+	if (!psci_ops.cpu_on) {
+		pr_err("no cpu_on method, not booting CPU%d\n", cpu);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+static int cpu_psci_cpu_boot(unsigned int cpu)
+{
+	phys_addr_t pa_secondary_entry = __pa_symbol(secondary_entry);
+	int err = psci_ops.cpu_on(cpu_logical_map(cpu), pa_secondary_entry);
+	if (err)
+		pr_err("failed to boot CPU%d (%d)\n", cpu, err);
+
+	return err;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static bool cpu_psci_cpu_can_disable(unsigned int cpu)
+{
+	return !psci_tos_resident_on(cpu);
+}
+
+static int cpu_psci_cpu_disable(unsigned int cpu)
+{
+	/* Fail early if we don't have CPU_OFF support */
+	if (!psci_ops.cpu_off)
+		return -EOPNOTSUPP;
+
+	/* Trusted OS will deny CPU_OFF */
+	if (psci_tos_resident_on(cpu))
+		return -EPERM;
+
+	return 0;
+}
+
+static void cpu_psci_cpu_die(unsigned int cpu)
+{
+	/*
+	 * There are no known implementations of PSCI actually using the
+	 * power state field, pass a sensible default for now.
+	 */
+	u32 state = PSCI_POWER_STATE_TYPE_POWER_DOWN <<
+		    PSCI_0_2_POWER_STATE_TYPE_SHIFT;
+
+	psci_ops.cpu_off(state);
+}
+
+static int cpu_psci_cpu_kill(unsigned int cpu)
+{
+	int err;
+	unsigned long start, end;
+
+	if (!psci_ops.affinity_info)
+		return 0;
+	/*
+	 * cpu_kill could race with cpu_die and we can
+	 * potentially end up declaring this cpu undead
+	 * while it is dying. So, try again a few times.
+	 */
+
+	start = jiffies;
+	end = start + msecs_to_jiffies(100);
+	do {
+		err = psci_ops.affinity_info(cpu_logical_map(cpu), 0);
+		if (err == PSCI_0_2_AFFINITY_LEVEL_OFF) {
+			pr_info("CPU%d killed (polled %d ms)\n", cpu,
+				jiffies_to_msecs(jiffies - start));
+			return 0;
+		}
+
+		usleep_range(100, 1000);
+	} while (time_before(jiffies, end));
+
+	pr_warn("CPU%d may not have shut down cleanly (AFFINITY_INFO reports %d)\n",
+			cpu, err);
+	return -ETIMEDOUT;
+}
+#endif
+
+const struct cpu_operations cpu_psci_ops = {
+	.name		= "psci",
+	.cpu_init	= cpu_psci_cpu_init,
+	.cpu_prepare	= cpu_psci_cpu_prepare,
+	.cpu_boot	= cpu_psci_cpu_boot,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_can_disable = cpu_psci_cpu_can_disable,
+	.cpu_disable	= cpu_psci_cpu_disable,
+	.cpu_die	= cpu_psci_cpu_die,
+	.cpu_kill	= cpu_psci_cpu_kill,
+#endif
+};
+