[MIPS] Qemu system shutdown support

Signed-off-by: Thiemo Seufer <ths@networkno.de>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/qemu/Makefile

@@ -2,6 +2,6 @@
 # Makefile for Qemu specific kernel interface routines under Linux.
 #
 
-obj-y		= q-firmware.o q-irq.o q-mem.o q-setup.o
+obj-y		= q-firmware.o q-irq.o q-mem.o q-setup.o q-reset.o
 
 obj-$(CONFIG_SMP) += q-smp.o

arch/mips/qemu/q-reset.c

@@ -0,0 +1,34 @@
+#include <linux/config.h>
+
+#include <asm/io.h>
+#include <asm/reboot.h>
+#include <asm/cacheflush.h>
+#include <asm/qemu.h>
+
+static void qemu_machine_restart(char *command)
+{
+	volatile unsigned int *reg = (unsigned int *)QEMU_RESTART_REG;
+
+	set_c0_status(ST0_BEV | ST0_ERL);
+	change_c0_config(CONF_CM_CMASK, CONF_CM_UNCACHED);
+	flush_cache_all();
+	write_c0_wired(0);
+	*reg = 42;
+	while (1)
+		cpu_wait();
+}
+
+static void qemu_machine_halt(void)
+{
+	volatile unsigned int *reg = (unsigned int *)QEMU_HALT_REG;
+
+	*reg = 42;
+	while (1)
+		cpu_wait();
+}
+
+void qemu_reboot_setup(void)
+{
+	_machine_restart = qemu_machine_restart;
+	_machine_halt = qemu_machine_halt;
+}

arch/mips/qemu/q-setup.c

@@ -2,6 +2,8 @@
 #include <asm/io.h>
 #include <asm/time.h>
 
+extern void qemu_reboot_setup(void);
+
 #define QEMU_PORT_BASE 0xb4000000
 
 const char *get_system_type(void)
@@ -22,4 +24,6 @@ void __init plat_setup(void)
 {
 	set_io_port_base(QEMU_PORT_BASE);
 	board_timer_setup = qemu_timer_setup;
+
+	qemu_reboot_setup();
 }

include/asm-mips/qemu.h

@@ -21,4 +21,10 @@
  */
 #define QEMU_C0_COUNTER_CLOCK	100000000
 
+/*
+ * Magic qemu system control location.
+ */
+#define QEMU_RESTART_REG	0xBFBF0000
+#define QEMU_HALT_REG		0xBFBF0004
+
 #endif /* __ASM_QEMU_H */