1 files changed, 82 insertions, 2 deletions

diff --git a/arch/mips/kernel/reset.c b/arch/mips/kernel/reset.c
index 07fc5244aed4..e7ce07b3e79b 100644
--- a/arch/mips/kernel/reset.c
+++ b/arch/mips/kernel/reset.c
@@ -11,7 +11,11 @@
 #include <linux/pm.h>
 #include <linux/types.h>
 #include <linux/reboot.h>
+#include <linux/delay.h>
 
+#include <asm/compiler.h>
+#include <asm/idle.h>
+#include <asm/mipsregs.h>
 #include <asm/reboot.h>
 
 /*
@@ -25,20 +29,96 @@ void (*pm_power_off)(void);
 
 EXPORT_SYMBOL(pm_power_off);
 
+static void machine_hang(void)
+{
+	/*
+	 * We're hanging the system so we don't want to be interrupted anymore.
+	 * Any interrupt handlers that ran would at best be useless & at worst
+	 * go awry because the system isn't in a functional state.
+	 */
+	local_irq_disable();
+
+	/*
+	 * Mask all interrupts, giving us a better chance of remaining in the
+	 * low power wait state.
+	 */
+	clear_c0_status(ST0_IM);
+
+	while (true) {
+		if (cpu_has_mips_r) {
+			/*
+			 * We know that the wait instruction is supported so
+			 * make use of it directly, leaving interrupts
+			 * disabled.
+			 */
+			asm volatile(
+				".set	push\n\t"
+				".set	" MIPS_ISA_ARCH_LEVEL "\n\t"
+				"wait\n\t"
+				".set	pop");
+		} else if (cpu_wait) {
+			/*
+			 * Try the cpu_wait() callback. This isn't ideal since
+			 * it'll re-enable interrupts, but that ought to be
+			 * harmless given that they're all masked.
+			 */
+			cpu_wait();
+			local_irq_disable();
+		} else {
+			/*
+			 * We're going to burn some power running round the
+			 * loop, but we don't really have a choice. This isn't
+			 * a path we should expect to run for long during
+			 * typical use anyway.
+			 */
+		}
+
+		/*
+		 * In most modern MIPS CPUs interrupts will cause the wait
+		 * instruction to graduate even when disabled, and in some
+		 * cases even when masked. In order to prevent a timer
+		 * interrupt from continuously taking us out of the low power
+		 * wait state, we clear any pending timer interrupt here.
+		 */
+		if (cpu_has_counter)
+			write_c0_compare(0);
+	}
+}
+
 void machine_restart(char *command)
 {
 	if (_machine_restart)
 		_machine_restart(command);
+
+#ifdef CONFIG_SMP
+	preempt_disable();
+	smp_send_stop();
+#endif
+	do_kernel_restart(command);
+	mdelay(1000);
+	pr_emerg("Reboot failed -- System halted\n");
+	machine_hang();
 }
 
 void machine_halt(void)
 {
 	if (_machine_halt)
 		_machine_halt();
+
+#ifdef CONFIG_SMP
+	preempt_disable();
+	smp_send_stop();
+#endif
+	machine_hang();
 }
 
 void machine_power_off(void)
 {
-	if (pm_power_off)
-		pm_power_off();
+	do_kernel_power_off();
+
+#ifdef CONFIG_SMP
+	preempt_disable();
+	smp_send_stop();
+#endif
+	machine_hang();
 }