i.MX27: add suspend to RAM support

Signed-off-by: Eric Bénard <eric@eukrea.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

arch/arm/mach-mx2/Makefile

@@ -8,7 +8,7 @@ obj-y	:=  devices.o serial.o
 
 obj-$(CONFIG_MACH_MX21) += clock_imx21.o mm-imx21.o
 
-obj-$(CONFIG_MACH_MX27) += cpu_imx27.o
+obj-$(CONFIG_MACH_MX27) += cpu_imx27.o pm-imx27.o
 obj-$(CONFIG_MACH_MX27) += clock_imx27.o mm-imx27.o
 
 obj-$(CONFIG_MACH_MX21ADS) += mach-mx21ads.o

arch/arm/mach-mx2/pm-imx27.c

+/*
+ * i.MX27 Power Management Routines
+ *
+ * Based on Freescale's BSP
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License.
+ */
+
+#include <linux/kernel.h>
+#include <linux/suspend.h>
+#include <linux/io.h>
+#include <mach/system.h>
+#include <mach/mx27.h>
+
+static int mx27_suspend_enter(suspend_state_t state)
+{
+	u32 cscr;
+	switch (state) {
+	case PM_SUSPEND_MEM:
+		/* Clear MPEN and SPEN to disable MPLL/SPLL */
+		cscr = __raw_readl(MX27_IO_ADDRESS(MX27_CCM_BASE_ADDR));
+		cscr &= 0xFFFFFFFC;
+		__raw_writel(cscr, MX27_IO_ADDRESS(MX27_CCM_BASE_ADDR));
+		/* Executes WFI */
+		arch_idle();
+		break;
+
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static struct platform_suspend_ops mx27_suspend_ops = {
+	.enter = mx27_suspend_enter,
+	.valid = suspend_valid_only_mem,
+};
+
+static int __init mx27_pm_init(void)
+{
+	suspend_set_ops(&mx27_suspend_ops);
+	return 0;
+}
+
+device_initcall(mx27_pm_init);