+/*
+ * acpi_idle_kernel is called by the ACPI Platform kext to request the kernel
+ * to idle the boot processor in the deepest C-state for S0 sleep. All slave
+ * processors are expected already to have been offlined in the deepest C-state.
+ *
+ * The contract with ACPI is that although the kernel is called with interrupts
+ * disabled, interrupts may need to be re-enabled to dismiss any pending timer
+ * interrupt. However, the callback function will be called once this has
+ * occurred and interrupts are guaranteed to be disabled at that time,
+ * and to remain disabled during C-state entry, exit (wake) and return
+ * from acpi_idle_kernel.
+ */
+void
+acpi_idle_kernel(acpi_sleep_callback func, void *refcon)
+{
+ boolean_t istate = ml_get_interrupts_enabled();
+
+ kprintf("acpi_idle_kernel, cpu=%d, interrupts %s\n",
+ cpu_number(), istate ? "enabled" : "disabled");
+
+ assert(cpu_number() == master_cpu);
+
+ /* Cancel any pending deadline */
+ setPop(0);
+ while (lapic_is_interrupting(LAPIC_TIMER_VECTOR)) {
+ (void) ml_set_interrupts_enabled(TRUE);
+ setPop(0);
+ ml_set_interrupts_enabled(FALSE);
+ }
+
+ /*
+ * Call back to caller to indicate that interrupts will remain
+ * disabled while we deep idle, wake and return.
+ */
+ func(refcon);
+
+ acpi_idle_abstime = mach_absolute_time();
+
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED, MACH_DEEP_IDLE) | DBG_FUNC_START,
+ acpi_idle_abstime, deep_idle_rebase, 0, 0, 0);
+
+ /*
+ * Disable tracing during S0-sleep
+ * unless overridden by sysctl -w tsc.deep_idle_rebase=0
+ */
+ if (deep_idle_rebase) {
+ save_kdebug_enable = kdebug_enable;
+ kdebug_enable = 0;
+ }
+
+ /*
+ * Call into power-management to enter the lowest C-state.
+ * Note when called on the boot processor this routine will
+ * return directly when awoken.
+ */
+ pmCPUHalt(PM_HALT_SLEEP);
+
+ /*
+ * Get wakeup time relative to the TSC which has progressed.
+ * Then rebase nanotime to reflect time not progressing over sleep
+ * - unless overriden so that tracing can occur during deep_idle.
+ */
+ acpi_wake_abstime = mach_absolute_time();
+ if (deep_idle_rebase) {
+ rtc_sleep_wakeup(acpi_idle_abstime);
+ kdebug_enable = save_kdebug_enable;
+ }
+ acpi_wake_postrebase_abstime = mach_absolute_time();
+ assert(mach_absolute_time() >= acpi_idle_abstime);
+
+ KERNEL_DEBUG_CONSTANT(
+ MACHDBG_CODE(DBG_MACH_SCHED, MACH_DEEP_IDLE) | DBG_FUNC_END,
+ acpi_wake_abstime, acpi_wake_abstime - acpi_idle_abstime, 0, 0, 0);
+
+ /* Like S3 sleep, turn on tracing if trace_wake boot-arg is present */
+ if (kdebug_enable == 0) {
+ if (wake_nkdbufs)
+ kdebug_trace_start(wake_nkdbufs, NULL, TRUE);
+ }
+
+ IOCPURunPlatformActiveActions();
+
+ /* Restart timer interrupts */
+ rtc_timer_start();
+}
+
projects / apple / xnu.git / blobdiff