ARM: tango: add Suspend-to-RAM support

Ask firmware to put RAM in self-refresh mode and power system down.

echo mem > /sys/power/state

See Documentation/power/states.txt

Signed-off-by: Marc Gonzalez <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

arch/arm/mach-tango/Makefile

···
 
 obj-y += setup.o smc.o
 obj-$(CONFIG_SMP) += platsmp.o
+obj-$(CONFIG_SUSPEND) += pm.o

arch/arm/mach-tango/pm.c

···
+#include <linux/init.h>
+#include <linux/suspend.h>
+#include <asm/suspend.h>
+#include "smc.h"
+
+static int tango_pm_powerdown(unsigned long arg)
+{
+	tango_suspend(virt_to_phys(cpu_resume));
+
+	return -EIO; /* tango_suspend has failed */
+}
+
+static int tango_pm_enter(suspend_state_t state)
+{
+	if (state == PM_SUSPEND_MEM)
+		return cpu_suspend(0, tango_pm_powerdown);
+
+	return -EINVAL;
+}
+
+static const struct platform_suspend_ops tango_pm_ops = {
+	.enter = tango_pm_enter,
+	.valid = suspend_valid_only_mem,
+};
+
+static int __init tango_pm_init(void)
+{
+	suspend_set_ops(&tango_pm_ops);
+	return 0;
+}
+
+late_initcall(tango_pm_init);

arch/arm/mach-tango/smc.h

···
 #define tango_set_l2_control(val)	tango_smc(val, 0x102)
 #define tango_start_aux_core(val)	tango_smc(val, 0x104)
 #define tango_set_aux_boot_addr(val)	tango_smc(val, 0x105)
+#define tango_suspend(val)		tango_smc(val, 0x120)
 #define tango_aux_core_die(val)		tango_smc(val, 0x121)
 #define tango_aux_core_kill(val)	tango_smc(val, 0x122)