ARM: mx51: Add support for low power suspend on MX51

Adds initial low power suspend functionality to MX51.
Supports "mem" and "standby" modes.

Tested on mx51-babbage.

Signed-off-by: Dinh Nguyen <Dinh.Nguyen@freescale.com>
Tested-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 74 insertions, 0 deletions

diff --git a/arch/arm/mach-mx5/Makefile b/arch/arm/mach-mx5/Makefile
index df67fefdc6cb..383e7cd3fbcb 100644
--- a/arch/arm/mach-mx5/Makefile
+++ b/arch/arm/mach-mx5/Makefile
@@ -6,6 +6,7 @@
 obj-y   := cpu.o mm.o clock-mx51-mx53.o devices.o ehci.o system.o
 obj-$(CONFIG_SOC_IMX50) += mm-mx50.o
 
+obj-$(CONFIG_PM) += pm-imx5.o
 obj-$(CONFIG_CPU_FREQ_IMX)    += cpu_op-mx51.o
 obj-$(CONFIG_MACH_MX51_BABBAGE) += board-mx51_babbage.o
 obj-$(CONFIG_MACH_MX51_3DS) += board-mx51_3ds.o
diff --git a/arch/arm/mach-mx5/pm-imx5.c b/arch/arm/mach-mx5/pm-imx5.c
new file mode 100644
index 000000000000..e4529af0da72
--- /dev/null
+++ b/arch/arm/mach-mx5/pm-imx5.c
@@ -0,0 +1,73 @@
+/*
+ *  Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+#include <linux/suspend.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/err.h>
+#include <asm/cacheflush.h>
+#include <asm/tlbflush.h>
+#include <mach/system.h>
+#include "crm_regs.h"
+
+static struct clk *gpc_dvfs_clk;
+
+static int mx5_suspend_enter(suspend_state_t state)
+{
+        clk_enable(gpc_dvfs_clk);
+        switch (state) {
+        case PM_SUSPEND_MEM:
+                mx5_cpu_lp_set(STOP_POWER_OFF);
+                break;
+        case PM_SUSPEND_STANDBY:
+                mx5_cpu_lp_set(WAIT_UNCLOCKED_POWER_OFF);
+                break;
+        default:
+                return -EINVAL;
+        }
+
+        if (state == PM_SUSPEND_MEM) {
+                local_flush_tlb_all();
+                flush_cache_all();
+
+                /*clear the EMPGC0/1 bits */
+                __raw_writel(0, MXC_SRPG_EMPGC0_SRPGCR);
+                __raw_writel(0, MXC_SRPG_EMPGC1_SRPGCR);
+        }
+        cpu_do_idle();
+        clk_disable(gpc_dvfs_clk);
+
+        return 0;
+}
+
+static int mx5_pm_valid(suspend_state_t state)
+{
+        return (state > PM_SUSPEND_ON && state <= PM_SUSPEND_MAX);
+}
+
+static const struct platform_suspend_ops mx5_suspend_ops = {
+        .valid = mx5_pm_valid,
+        .enter = mx5_suspend_enter,
+};
+
+static int __init mx5_pm_init(void)
+{
+        if (gpc_dvfs_clk == NULL)
+                gpc_dvfs_clk = clk_get(NULL, "gpc_dvfs");
+
+        if (!IS_ERR(gpc_dvfs_clk)) {
+                if (cpu_is_mx51())
+                        suspend_set_ops(&mx5_suspend_ops);
+        } else
+                return -EPERM;
+
+        return 0;
+}
+device_initcall(mx5_pm_init);