sh: machine_ops based reboot support.

This provides a machine_ops-based reboot interface loosely cloned from
x86, and converts the native sh32 and sh64 cases over to it.

Necessary both for tying in SMP support and also enabling platforms like
SDK7786 to add support for their microcontroller-based power managers.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/reboot.c

@@ -0,0 +1,98 @@
+#include <linux/pm.h>
+#include <linux/kexec.h>
+#include <linux/kernel.h>
+#include <linux/reboot.h>
+#include <linux/module.h>
+#ifdef CONFIG_SUPERH32
+#include <asm/watchdog.h>
+#endif
+#include <asm/addrspace.h>
+#include <asm/reboot.h>
+#include <asm/system.h>
+
+void (*pm_power_off)(void);
+EXPORT_SYMBOL(pm_power_off);
+
+#ifdef CONFIG_SUPERH32
+static void watchdog_trigger_immediate(void)
+{
+	sh_wdt_write_cnt(0xFF);
+	sh_wdt_write_csr(0xC2);
+}
+#endif
+
+static void native_machine_restart(char * __unused)
+{
+	local_irq_disable();
+
+	/* Address error with SR.BL=1 first. */
+	trigger_address_error();
+
+#ifdef CONFIG_SUPERH32
+	/* If that fails or is unsupported, go for the watchdog next. */
+	watchdog_trigger_immediate();
+#endif
+
+	/*
+	 * Give up and sleep.
+	 */
+	while (1)
+		cpu_sleep();
+}
+
+static void native_machine_shutdown(void)
+{
+	smp_send_stop();
+}
+
+static void native_machine_power_off(void)
+{
+	if (pm_power_off)
+		pm_power_off();
+}
+
+static void native_machine_halt(void)
+{
+	/* stop other cpus */
+	machine_shutdown();
+
+	/* stop this cpu */
+	stop_this_cpu(NULL);
+}
+
+struct machine_ops machine_ops = {
+	.power_off	= native_machine_power_off,
+	.shutdown	= native_machine_shutdown,
+	.restart	= native_machine_restart,
+	.halt		= native_machine_halt,
+#ifdef CONFIG_KEXEC
+	.crash_shutdown = native_machine_crash_shutdown,
+#endif
+};
+
+void machine_power_off(void)
+{
+	machine_ops.power_off();
+}
+
+void machine_shutdown(void)
+{
+	machine_ops.shutdown();
+}
+
+void machine_restart(char *cmd)
+{
+	machine_ops.restart(cmd);
+}
+
+void machine_halt(void)
+{
+	machine_ops.halt();
+}
+
+#ifdef CONFIG_KEXEC
+void machine_crash_shutdown(struct pt_regs *regs)
+{
+	machine_ops.crash_shutdown(regs);
+}
+#endif