Patchwork [V4,2/6] ARM: imx: add suspend in ocram support on i.mx6q

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Submitter Anson Huang
Date Jan. 13, 2014, 11:53 a.m.
Message ID <1389614031-7253-2-git-send-email-b20788@freescale.com>
Download mbox | patch
Permalink /patch/309810/
State New
Headers show

Comments

Anson Huang - Jan. 13, 2014, 11:53 a.m.
When system enter suspend, we can set the DDR IO
to high-Z state to save DDR IO's power, this operation
can save many power(from ~26mA@1.5V to ~15mA@1.5V,
measured on i.MX6Q/DL SabreSD board, R25) of DDR IO. To
achieve that, we need to copy the suspend code to ocram
and run the low level hardware related code(set DDR IO
to high-Z) in ocram.

If there is no ocram space available, then system will
still do suspend in DDR, hence no DDR IO will be set
to high-Z.

The OCRAM usage layout is as below,

ocram suspend region:
Russell King - ARM Linux - Jan. 13, 2014, 12:44 p.m.
On Mon, Jan 13, 2014 at 07:53:47PM +0800, Anson Huang wrote:
>  #ifdef CONFIG_PM
> +void imx6_suspend(void);

So, imx6_suspend() takes no arguments.

> +static int (*imx6_suspend_in_ocram_fn)(void __iomem *ocram_vbase);

Oh, it takes one argument.

> +		/*
> +		 * call low level suspend function in ocram,
> +		 * as we need to float DDR IO.
> +		 */
> +		local_flush_tlb_all();
> +		imx6_suspend_in_ocram_fn(suspend_ocram_base);

Yes, definitely takes one argument...

> +	imx6_suspend_in_ocram_fn = (void *)fncpy(
> +		suspend_ocram_base + sizeof(*pm_info),
> +		&imx6_suspend,
> +		MX6Q_SUSPEND_OCRAM_SIZE - sizeof(*pm_info));

This cast here is needed to work around the above confusion.

> +ENTRY(imx6_suspend)
> +	ldr	r1, [r0, #PM_INFO_PBASE_OFFSET]
> +	ldr	r2, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
> +	ldr	r3, [r0, #PM_INFO_CPU_TYPE_OFFSET]
> +	ldr	r4, [r0, #PM_INFO_PM_INFO_SIZE_OFFSET]

Yes, definitely takes one argument.

If you fix the prototype for imx6_suspend, you don't need to cast the
result of fncpy().  Casts should always be avoided where possible.
Shawn Guo - Jan. 13, 2014, 2:19 p.m.
On Mon, Jan 13, 2014 at 12:44:45PM +0000, Russell King - ARM Linux wrote:
> On Mon, Jan 13, 2014 at 07:53:47PM +0800, Anson Huang wrote:
> >  #ifdef CONFIG_PM
> > +void imx6_suspend(void);
> 
> So, imx6_suspend() takes no arguments.
> 
> > +static int (*imx6_suspend_in_ocram_fn)(void __iomem *ocram_vbase);
> 
> Oh, it takes one argument.

Great catch.

Anson,

The return type of imx6_suspend() and imx6_suspend_in_ocram_fn should be
aligned too.

Shawn

> 
> > +		/*
> > +		 * call low level suspend function in ocram,
> > +		 * as we need to float DDR IO.
> > +		 */
> > +		local_flush_tlb_all();
> > +		imx6_suspend_in_ocram_fn(suspend_ocram_base);
> 
> Yes, definitely takes one argument...
> 
> > +	imx6_suspend_in_ocram_fn = (void *)fncpy(
> > +		suspend_ocram_base + sizeof(*pm_info),
> > +		&imx6_suspend,
> > +		MX6Q_SUSPEND_OCRAM_SIZE - sizeof(*pm_info));
> 
> This cast here is needed to work around the above confusion.
> 
> > +ENTRY(imx6_suspend)
> > +	ldr	r1, [r0, #PM_INFO_PBASE_OFFSET]
> > +	ldr	r2, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
> > +	ldr	r3, [r0, #PM_INFO_CPU_TYPE_OFFSET]
> > +	ldr	r4, [r0, #PM_INFO_PM_INFO_SIZE_OFFSET]
> 
> Yes, definitely takes one argument.
> 
> If you fix the prototype for imx6_suspend, you don't need to cast the
> result of fncpy().  Casts should always be avoided where possible.
> 
> -- 
> FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up.  Estimation
> in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
> Estimate before purchase was "up to 13.2Mbit".

Patch

======================== high address ======================
                              .
                              .
                              .
                              ^
                              ^
                              ^
                      imx6_suspend code
      reserved region(to make imx6_suspend aligned with 8)
             PM_INFO structure(imx6_cpu_pm_info)
======================== low address =======================

Signed-off-by: Anson Huang <b20788@freescale.com>
---
Changes since V3:
    1. Add const to MMDC IO offset array;
    2. Improve for-loop code to save code lines;
    3. Use __aligned to save one variable of pm_info;
    4. Remove unnecessary header files.

 arch/arm/mach-imx/Makefile       |    3 +-
 arch/arm/mach-imx/common.h       |    4 +-
 arch/arm/mach-imx/hardware.h     |    4 +-
 arch/arm/mach-imx/pm-imx6q.c     |  245 +++++++++++++++++++++++++++++-
 arch/arm/mach-imx/suspend-imx6.S |  303 ++++++++++++++++++++++++++++++++++++++
 5 files changed, 552 insertions(+), 7 deletions(-)
 create mode 100644 arch/arm/mach-imx/suspend-imx6.S

diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile
index befcaf5..3d96a45 100644
--- a/arch/arm/mach-imx/Makefile
+++ b/arch/arm/mach-imx/Makefile
@@ -102,7 +102,8 @@  obj-$(CONFIG_SOC_IMX6Q) += clk-imx6q.o mach-imx6q.o
 obj-$(CONFIG_SOC_IMX6SL) += clk-imx6sl.o mach-imx6sl.o
 
 ifeq ($(CONFIG_PM),y)
-obj-$(CONFIG_SOC_IMX6Q) += pm-imx6q.o headsmp.o
+AFLAGS_suspend-imx6.o :=-Wa,-march=armv7-a
+obj-$(CONFIG_SOC_IMX6Q) += pm-imx6q.o headsmp.o suspend-imx6.o
 # i.MX6SL reuses i.MX6Q code
 obj-$(CONFIG_SOC_IMX6SL) += pm-imx6q.o headsmp.o
 endif
diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
index 4f4a95c..7c249e1 100644
--- a/arch/arm/mach-imx/common.h
+++ b/arch/arm/mach-imx/common.h
@@ -1,5 +1,5 @@ 
 /*
- * Copyright 2004-2013 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2004-2014 Freescale Semiconductor, Inc. All Rights Reserved.
  */
 
 /*
@@ -145,10 +145,12 @@  void imx_cpu_die(unsigned int cpu);
 int imx_cpu_kill(unsigned int cpu);
 
 #ifdef CONFIG_PM
+void imx6_suspend(void);
 void imx6q_pm_init(void);
 void imx6q_pm_set_ccm_base(void __iomem *base);
 void imx5_pm_init(void);
 #else
+static inline void imx6_suspend(void) {}
 static inline void imx6q_pm_init(void) {}
 static inline void imx6q_pm_set_ccm_base(void __iomem *base) {}
 static inline void imx5_pm_init(void) {}
diff --git a/arch/arm/mach-imx/hardware.h b/arch/arm/mach-imx/hardware.h
index a3b0b04..abf43bb 100644
--- a/arch/arm/mach-imx/hardware.h
+++ b/arch/arm/mach-imx/hardware.h
@@ -1,5 +1,5 @@ 
 /*
- * Copyright 2004-2007 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Copyright 2004-2007, 2014 Freescale Semiconductor, Inc. All Rights Reserved.
  * Copyright 2008 Juergen Beisert, kernel@pengutronix.de
  *
  * This program is free software; you can redistribute it and/or
@@ -20,7 +20,9 @@ 
 #ifndef __ASM_ARCH_MXC_HARDWARE_H__
 #define __ASM_ARCH_MXC_HARDWARE_H__
 
+#ifndef __ASSEMBLY__
 #include <asm/io.h>
+#endif
 #include <asm/sizes.h>
 
 #define addr_in_module(addr, mod) \
diff --git a/arch/arm/mach-imx/pm-imx6q.c b/arch/arm/mach-imx/pm-imx6q.c
index d45acc0..42ac301 100644
--- a/arch/arm/mach-imx/pm-imx6q.c
+++ b/arch/arm/mach-imx/pm-imx6q.c
@@ -1,5 +1,5 @@ 
 /*
- * Copyright 2011-2013 Freescale Semiconductor, Inc.
+ * Copyright 2011-2014 Freescale Semiconductor, Inc.
  * Copyright 2011 Linaro Ltd.
  *
  * The code contained herein is licensed under the GNU General Public
@@ -14,16 +14,19 @@ 
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/irq.h>
+#include <linux/genalloc.h>
 #include <linux/mfd/syscon.h>
 #include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_platform.h>
 #include <linux/regmap.h>
 #include <linux/suspend.h>
 #include <asm/cacheflush.h>
+#include <asm/fncpy.h>
 #include <asm/proc-fns.h>
 #include <asm/suspend.h>
-#include <asm/hardware/cache-l2x0.h>
+#include <asm/tlb.h>
 
 #include "common.h"
 #include "hardware.h"
@@ -58,7 +61,66 @@ 
 #define CGPR				0x64
 #define BM_CGPR_INT_MEM_CLK_LPM		(0x1 << 17)
 
+#define MX6Q_SUSPEND_OCRAM_SIZE		0x1000
+#define MX6_MAX_MMDC_IO_NUM		33
+
 static void __iomem *ccm_base;
+static void __iomem *suspend_ocram_base;
+static int (*imx6_suspend_in_ocram_fn)(void __iomem *ocram_vbase);
+
+/*
+ * suspend ocram space layout:
+ * ======================== high address ======================
+ *                              .
+ *                              .
+ *                              .
+ *                              ^
+ *                              ^
+ *                              ^
+ *                      imx6_suspend code
+ *      reserved region(to make imx6_suspend aligned with 8)
+ *              PM_INFO structure(imx6_cpu_pm_info)
+ * ======================== low address =======================
+ */
+
+struct imx6_pm_base {
+	phys_addr_t pbase;
+	void __iomem *vbase;
+};
+
+static const u32 imx6q_mmdc_io_dsm_offset[] __initconst = {
+	0x5ac, 0x5b4, 0x528, 0x520, /* DQM0 ~ DQM3 */
+	0x514, 0x510, 0x5bc, 0x5c4, /* DQM4 ~ DQM7 */
+	0x56c, 0x578, 0x588, 0x594, /* CAS, RAS, SDCLK_0, SDCLK_1 */
+	0x5a8, 0x5b0, 0x524, 0x51c, /* SDQS0 ~ SDQS3 */
+	0x518, 0x50c, 0x5b8, 0x5c0, /* SDQS4 ~ SDQS7 */
+	0x784, 0x788, 0x794, 0x79c, /* GPR_B0DS ~ GPR_B3DS */
+	0x7a0, 0x7a4, 0x7a8, 0x748, /* GPR_B4DS ~ GPR_B7DS */
+	0x59c, 0x5a0, 0x750, 0x774, /* SODT0, SODT1, DDRMODE_CTL, DDRMODE */
+	0x74c			    /* GPR_ADDS */
+};
+
+/*
+ * This structure is for passing necessary data for low level ocram
+ * suspend code(arch/arm/mach-imx/suspend-imx6.S), if this struct
+ * definition is changed, the offset definition in
+ * arch/arm/mach-imx/suspend-imx6.S must be also changed accordingly,
+ * otherwise, the suspend to ocram fucntion will be broken!
+ */
+struct imx6_cpu_pm_info {
+	phys_addr_t pbase; /* The physical address of pm_info. */
+	phys_addr_t resume_addr; /* The physical resume address for asm code */
+	u32 cpu_type;
+	u32 pm_info_size; /* Size of pm_info. */
+	struct imx6_pm_base mmdc_base;
+	struct imx6_pm_base src_base;
+	struct imx6_pm_base iomuxc_base;
+	struct imx6_pm_base ccm_base;
+	struct imx6_pm_base gpc_base;
+	struct imx6_pm_base l2_base;
+	u32 mmdc_io_num; /* Number of MMDC IOs which need saved/restored. */
+	u32 mmdc_io_val[MX6_MAX_MMDC_IO_NUM][2]; /* To save offset and value */
+} __aligned(8);
 
 void imx6q_set_int_mem_clk_lpm(void)
 {
@@ -177,7 +239,17 @@  int imx6q_set_lpm(enum mxc_cpu_pwr_mode mode)
 
 static int imx6q_suspend_finish(unsigned long val)
 {
-	cpu_do_idle();
+	if (!imx6_suspend_in_ocram_fn) {
+		cpu_do_idle();
+	} else {
+		/*
+		 * call low level suspend function in ocram,
+		 * as we need to float DDR IO.
+		 */
+		local_flush_tlb_all();
+		imx6_suspend_in_ocram_fn(suspend_ocram_base);
+	}
+
 	return 0;
 }
 
@@ -187,7 +259,12 @@  static int imx6q_pm_enter(suspend_state_t state)
 	case PM_SUSPEND_MEM:
 		imx6q_set_lpm(STOP_POWER_OFF);
 		imx6q_enable_wb(true);
-		imx6q_enable_rbc(true);
+		/*
+		 * For suspend into ocram, asm code already take care of
+		 * RBC setting, so we do NOT need to do that here.
+		 */
+		if (!imx6_suspend_in_ocram_fn)
+			imx6q_enable_rbc(true);
 		imx_gpc_pre_suspend();
 		imx_anatop_pre_suspend();
 		imx_set_cpu_jump(0, v7_cpu_resume);
@@ -218,12 +295,172 @@  void __init imx6q_pm_set_ccm_base(void __iomem *base)
 	ccm_base = base;
 }
 
+static int __init imx6_pm_get_base(struct imx6_pm_base *base,
+				const char *compat)
+{
+	struct device_node *node;
+	struct resource res;
+	int ret = 0;
+
+	node = of_find_compatible_node(NULL, NULL, compat);
+	if (!node) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	ret = of_address_to_resource(node, 0, &res);
+	if (ret)
+		goto put_node;
+
+	base->pbase = res.start;
+	base->vbase = ioremap(res.start, resource_size(&res));
+	if (!base->vbase)
+		ret = -ENOMEM;
+
+put_node:
+	of_node_put(node);
+out:
+	return ret;
+}
+
+static int __init imx6q_ocram_suspend_init(void)
+{
+	phys_addr_t ocram_pbase;
+	struct device_node *node;
+	struct platform_device *pdev;
+	struct imx6_cpu_pm_info *pm_info;
+	struct gen_pool *ocram_pool;
+	unsigned long ocram_base;
+	int i, ret = 0;
+	const u32 *mmdc_offset_array = NULL;
+
+	node = of_find_compatible_node(NULL, NULL, "mmio-sram");
+	if (!node) {
+		pr_warn("%s: failed to find ocram node!\n", __func__);
+		return -ENODEV;
+	}
+
+	pdev = of_find_device_by_node(node);
+	if (!pdev) {
+		pr_warn("%s: failed to find ocram device!\n", __func__);
+		ret = -ENODEV;
+		goto put_node;
+	}
+
+	ocram_pool = dev_get_gen_pool(&pdev->dev);
+	if (!ocram_pool) {
+		pr_warn("%s: ocram pool unavailable!\n", __func__);
+		ret = -ENODEV;
+		goto put_node;
+	}
+
+	ocram_base = gen_pool_alloc(ocram_pool, MX6Q_SUSPEND_OCRAM_SIZE);
+	if (!ocram_base) {
+		pr_warn("%s: unable to alloc ocram!\n", __func__);
+		ret = -ENOMEM;
+		goto put_node;
+	}
+
+	ocram_pbase = gen_pool_virt_to_phys(ocram_pool, ocram_base);
+
+	suspend_ocram_base = __arm_ioremap_exec(ocram_pbase,
+		MX6Q_SUSPEND_OCRAM_SIZE, false);
+
+	pm_info = suspend_ocram_base;
+	pm_info->pbase = ocram_pbase;
+	pm_info->resume_addr = virt_to_phys(v7_cpu_resume);
+	pm_info->pm_info_size = sizeof(*pm_info);
+
+	/*
+	 * ccm physical address is not used by asm code currently,
+	 * so get ccm virtual address directly, as we already have
+	 * it from ccm driver.
+	 */
+	pm_info->ccm_base.vbase = ccm_base;
+
+	ret = imx6_pm_get_base(&pm_info->mmdc_base, "fsl,mmdc");
+	if (ret) {
+		pr_warn("%s: failed to get mmdc base %d!\n", __func__, ret);
+		goto put_node;
+	}
+
+	ret = imx6_pm_get_base(&pm_info->src_base, "fsl,src");
+	if (ret) {
+		pr_warn("%s: failed to get src base %d!\n", __func__, ret);
+		goto src_map_failed;
+	}
+
+	ret = imx6_pm_get_base(&pm_info->iomuxc_base, "fsl,iomuxc");
+	if (ret) {
+		pr_warn("%s: failed to get iomuxc base %d!\n", __func__, ret);
+		goto iomuxc_map_failed;
+	}
+
+	ret = imx6_pm_get_base(&pm_info->gpc_base, "fsl,gpc");
+	if (ret) {
+		pr_warn("%s: failed to get gpc base %d!\n", __func__, ret);
+		goto gpc_map_failed;
+	}
+
+	ret = imx6_pm_get_base(&pm_info->l2_base, "arm,pl310-cache");
+	if (ret) {
+		pr_warn("%s: failed to get pl310-cache base %d!\n",
+			__func__, ret);
+		goto pl310_cache_map_failed;
+	}
+
+	if (cpu_is_imx6q()) {
+		pm_info->cpu_type = MXC_CPU_IMX6Q;
+		pm_info->mmdc_io_num = ARRAY_SIZE(imx6q_mmdc_io_dsm_offset);
+		mmdc_offset_array = imx6q_mmdc_io_dsm_offset;
+	}
+
+	if (!mmdc_offset_array) {
+		pr_warn("%s: unsupported platform!\n", __func__);
+		goto pl310_cache_map_failed;
+	}
+
+	for (i = 0; i < pm_info->mmdc_io_num; i++) {
+		pm_info->mmdc_io_val[i][0] =
+			mmdc_offset_array[i];
+		pm_info->mmdc_io_val[i][1] =
+			readl_relaxed(*(&pm_info->iomuxc_base.vbase) +
+			mmdc_offset_array[i]);
+	}
+
+	imx6_suspend_in_ocram_fn = (void *)fncpy(
+		suspend_ocram_base + sizeof(*pm_info),
+		&imx6_suspend,
+		MX6Q_SUSPEND_OCRAM_SIZE - sizeof(*pm_info));
+
+	goto put_node;
+
+pl310_cache_map_failed:
+	iounmap(&pm_info->gpc_base.vbase);
+gpc_map_failed:
+	iounmap(&pm_info->iomuxc_base.vbase);
+iomuxc_map_failed:
+	iounmap(&pm_info->src_base.vbase);
+src_map_failed:
+	iounmap(&pm_info->mmdc_base.vbase);
+put_node:
+	of_node_put(node);
+
+	return ret;
+}
+
 void __init imx6q_pm_init(void)
 {
 	struct regmap *gpr;
+	int ret;
 
 	WARN_ON(!ccm_base);
 
+	ret = imx6q_ocram_suspend_init();
+	if (ret)
+		pr_warn("%s: failed to initialize ocram suspend %d!\n",
+			__func__, ret);
+
 	/*
 	 * This is for SW workaround step #1 of ERR007265, see comments
 	 * in imx6q_set_lpm for details of this errata.
diff --git a/arch/arm/mach-imx/suspend-imx6.S b/arch/arm/mach-imx/suspend-imx6.S
new file mode 100644
index 0000000..0800033
--- /dev/null
+++ b/arch/arm/mach-imx/suspend-imx6.S
@@ -0,0 +1,303 @@ 
+/*
+ * Copyright 2014 Freescale Semiconductor, Inc.
+ *
+ * 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/linkage.h>
+#include <asm/hardware/cache-l2x0.h>
+#include "hardware.h"
+
+/*
+ * ==================== low level suspend ====================
+ *
+ * Better to follow below rules to use ARM registers:
+ * r0: pm_info structure address;
+ * r1 ~ r5: for saving pm_info members;
+ * r6 ~ r10: free registers;
+ * r11: io base address.
+ *
+ * suspend ocram space layout:
+ * ======================== high address ======================
+ *                              .
+ *                              .
+ *                              .
+ *                              ^
+ *                              ^
+ *                              ^
+ *                      imx6_suspend code
+ *      reserved region(to make imx6_suspend aligned with 8)
+ *              PM_INFO structure(imx6_cpu_pm_info)
+ * ======================== low address =======================
+ */
+
+/*
+ * Below offsets are based on struct imx6_cpu_pm_info
+ * which defined in arch/arm/mach-imx/pm-imx6q.c, this
+ * structure contains necessary pm info for low level
+ * suspend related code.
+ */
+#define PM_INFO_PBASE_OFFSET			0x0
+#define PM_INFO_RESUME_ADDR_OFFSET		0x4
+#define PM_INFO_CPU_TYPE_OFFSET			0x8
+#define PM_INFO_PM_INFO_SIZE_OFFSET		0xC
+#define PM_INFO_MX6Q_MMDC_P_OFFSET		0x10
+#define PM_INFO_MX6Q_MMDC_V_OFFSET		0x14
+#define PM_INFO_MX6Q_SRC_P_OFFSET		0x18
+#define PM_INFO_MX6Q_SRC_V_OFFSET		0x1C
+#define PM_INFO_MX6Q_IOMUXC_P_OFFSET		0x20
+#define PM_INFO_MX6Q_IOMUXC_V_OFFSET		0x24
+#define PM_INFO_MX6Q_CCM_P_OFFSET		0x28
+#define PM_INFO_MX6Q_CCM_V_OFFSET		0x2C
+#define PM_INFO_MX6Q_GPC_P_OFFSET		0x30
+#define PM_INFO_MX6Q_GPC_V_OFFSET		0x34
+#define PM_INFO_MX6Q_L2_P_OFFSET		0x38
+#define PM_INFO_MX6Q_L2_V_OFFSET		0x3C
+#define PM_INFO_MMDC_IO_NUM_OFFSET		0x40
+#define PM_INFO_MMDC_IO_VAL_OFFSET		0x44
+
+#define MX6Q_SRC_GPR1	0x20
+#define MX6Q_SRC_GPR2	0x24
+#define MX6Q_MMDC_MAPSR	0x404
+#define MX6Q_GPC_IMR1	0x08
+#define MX6Q_GPC_IMR2	0x0c
+#define MX6Q_GPC_IMR3	0x10
+#define MX6Q_GPC_IMR4	0x14
+#define MX6Q_CCM_CCR	0x0
+
+	.align 3
+
+	.macro  sync_l2_cache
+
+	/* sync L2 cache to drain L2's buffers to DRAM. */
+#ifdef CONFIG_CACHE_L2X0
+	ldr	r11, [r0, #PM_INFO_MX6Q_L2_V_OFFSET]
+	mov	r6, #0x0
+	str	r6, [r11, #L2X0_CACHE_SYNC]
+1:
+	ldr	r6, [r11, #L2X0_CACHE_SYNC]
+	ands	r6, r6, #0x1
+	bne	1b
+#endif
+	.endm
+
+ENTRY(imx6_suspend)
+	ldr	r1, [r0, #PM_INFO_PBASE_OFFSET]
+	ldr	r2, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
+	ldr	r3, [r0, #PM_INFO_CPU_TYPE_OFFSET]
+	ldr	r4, [r0, #PM_INFO_PM_INFO_SIZE_OFFSET]
+
+	/*
+	 * counting the resume address in iram
+	 * to set it in SRC register.
+	 */
+	ldr	r6, =imx6_suspend
+	ldr	r7, =resume
+	sub	r7, r7, r6
+	add	r8, r1, r4
+	add	r9, r8, r7
+
+	/*
+	 * make sure TLB contain the addr we want,
+	 * as we will access them after MMDC IO floated.
+	 */
+
+	ldr	r11, [r0, #PM_INFO_MX6Q_CCM_V_OFFSET]
+	ldr	r6, [r11, #0x0]
+	ldr	r11, [r0, #PM_INFO_MX6Q_GPC_V_OFFSET]
+	ldr	r6, [r11, #0x0]
+
+	/* use r11 to store the IO address */
+	ldr	r11, [r0, #PM_INFO_MX6Q_SRC_V_OFFSET]
+	/* store physical resume addr and pm_info address. */
+	str	r9, [r11, #MX6Q_SRC_GPR1]
+	str	r1, [r11, #MX6Q_SRC_GPR2]
+
+	/* need to sync L2 cache before DSM. */
+	sync_l2_cache
+
+	ldr	r11, [r0, #PM_INFO_MX6Q_MMDC_V_OFFSET]
+	/*
+	 * put DDR explicitly into self-refresh and
+	 * disable automatic power savings.
+	 */
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	orr	r7, r7, #0x1
+	str	r7, [r11, #MX6Q_MMDC_MAPSR]
+
+	/* make the DDR explicitly enter self-refresh. */
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	orr	r7, r7, #(1 << 21)
+	str	r7, [r11, #MX6Q_MMDC_MAPSR]
+
+poll_dvfs_set_1:
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	ands	r7, r7, #(1 << 25)
+	beq	poll_dvfs_set_1
+
+	ldr	r11, [r0, #PM_INFO_MX6Q_IOMUXC_V_OFFSET]
+	ldr	r6, =0x0
+	ldr	r7, [r0, #PM_INFO_MMDC_IO_NUM_OFFSET]
+	ldr	r8, =PM_INFO_MMDC_IO_VAL_OFFSET
+set_mmdc_io_lpm:
+	ldr	r9, [r0, r8]
+	str	r6, [r11, r9]
+	add	r8, r8, #0x8
+	sub	r7, r7, #0x1
+	cmp     r7, #0x0
+	bne	set_mmdc_io_lpm
+
+	/*
+	 * mask all GPC interrupts before
+	 * enabling the RBC counters to
+	 * avoid the counter starting too
+	 * early if an interupt is already
+	 * pending.
+	 */
+	ldr	r11, [r0, #PM_INFO_MX6Q_GPC_V_OFFSET]
+	ldr	r6, [r11, #MX6Q_GPC_IMR1]
+	ldr	r7, [r11, #MX6Q_GPC_IMR2]
+	ldr	r8, [r11, #MX6Q_GPC_IMR3]
+	ldr	r9, [r11, #MX6Q_GPC_IMR4]
+
+	ldr	r10, =0xffffffff
+	str	r10, [r11, #MX6Q_GPC_IMR1]
+	str	r10, [r11, #MX6Q_GPC_IMR2]
+	str	r10, [r11, #MX6Q_GPC_IMR3]
+	str	r10, [r11, #MX6Q_GPC_IMR4]
+
+	/*
+	 * enable the RBC bypass counter here
+	 * to hold off the interrupts. RBC counter
+	 * = 32 (1ms), Minimum RBC delay should be
+	 * 400us for the analog LDOs to power down.
+	 */
+	ldr	r11, [r0, #PM_INFO_MX6Q_CCM_V_OFFSET]
+	ldr	r10, [r11, #MX6Q_CCM_CCR]
+	bic	r10, r10, #(0x3f << 21)
+	orr	r10, r10, #(0x20 << 21)
+	str	r10, [r11, #MX6Q_CCM_CCR]
+
+	/* enable the counter. */
+	ldr	r10, [r11, #MX6Q_CCM_CCR]
+	orr	r10, r10, #(0x1 << 27)
+	str	r10, [r11, #MX6Q_CCM_CCR]
+
+	/* unmask all the GPC interrupts. */
+	ldr	r11, [r0, #PM_INFO_MX6Q_GPC_V_OFFSET]
+	str	r6, [r11, #MX6Q_GPC_IMR1]
+	str	r7, [r11, #MX6Q_GPC_IMR2]
+	str	r8, [r11, #MX6Q_GPC_IMR3]
+	str	r9, [r11, #MX6Q_GPC_IMR4]
+
+	/*
+	 * now delay for a short while (3usec)
+	 * ARM is at 1GHz at this point
+	 * so a short loop should be enough.
+	 * this delay is required to ensure that
+	 * the RBC counter can start counting in
+	 * case an interrupt is already pending
+	 * or in case an interrupt arrives just
+	 * as ARM is about to assert DSM_request.
+	 */
+	ldr     r6, =2000
+rbc_loop:
+	sub     r6, r6, #0x1
+	cmp     r6, #0x0
+	bne     rbc_loop
+
+	/* Zzz, enter stop mode */
+	wfi
+	nop
+	nop
+	nop
+	nop
+
+	/*
+	 * run to here means there is pending
+	 * wakeup source, system should auto
+	 * resume, we need to restore MMDC IO first
+	 */
+	ldr	r11, [r0, #PM_INFO_MX6Q_IOMUXC_V_OFFSET]
+	ldr	r6, [r0, #PM_INFO_MMDC_IO_NUM_OFFSET]
+	ldr	r7, =PM_INFO_MMDC_IO_VAL_OFFSET
+restore_mmdc_io:
+	ldr	r8, [r0, r7]
+	add	r7, r7, #0x4
+	ldr	r9, [r0, r7]
+	add	r7, r7, #0x4
+	str	r9, [r11, r8]
+	sub	r6, r6, #0x1
+	cmp     r6, #0x0
+	bne	restore_mmdc_io
+
+	ldr	r11, [r0, #PM_INFO_MX6Q_MMDC_V_OFFSET]
+	/* let DDR out of self-refresh. */
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	bic	r7, r7, #(1 << 21)
+	str	r7, [r11, #MX6Q_MMDC_MAPSR]
+
+poll_dvfs_clear_2:
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	ands	r7, r7, #(1 << 25)
+	bne     poll_dvfs_clear_2
+	/* enable DDR auto power saving */
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	bic	r7, r7, #0x1
+	str	r7, [r11, #MX6Q_MMDC_MAPSR]
+	/* return to suspend finish */
+	mov	pc, lr
+
+resume:
+	/* invalidate L1 I-cache first */
+	mov     r6, #0x0
+	mcr     p15, 0, r6, c7, c5, 0
+	mcr     p15, 0, r6, c7, c5, 0
+	mcr     p15, 0, r6, c7, c5, 6
+	/* enable the Icache and branch prediction */
+	mov     r6, #0x1800
+	mcr     p15, 0, r6, c1, c0, 0
+	isb
+
+	/* get physical resume address from pm_info. */
+	ldr	lr, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
+	/* clear core0's entry and parameter */
+	ldr	r11, [r0, #PM_INFO_MX6Q_SRC_P_OFFSET]
+	mov	r7, #0
+	str	r7, [r11, #MX6Q_SRC_GPR1]
+	str	r7, [r11, #MX6Q_SRC_GPR2]
+
+	ldr	r11, [r0, #PM_INFO_MX6Q_IOMUXC_P_OFFSET]
+	ldr	r6, [r0, #PM_INFO_MMDC_IO_NUM_OFFSET]
+	ldr	r7, =PM_INFO_MMDC_IO_VAL_OFFSET
+dsm_restore_mmdc_io:
+	ldr	r8, [r0, r7]
+	add	r7, r7, #0x4
+	ldr	r9, [r0, r7]
+	add	r7, r7, #0x4
+	str	r9, [r11, r8]
+	sub	r6, r6, #0x1
+	cmp     r6, #0x0
+	bne	dsm_restore_mmdc_io
+
+	ldr	r11, [r0, #PM_INFO_MX6Q_MMDC_P_OFFSET]
+	/* let DDR out of self-refresh */
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	bic	r7, r7, #(1 << 21)
+	str	r7, [r11, #MX6Q_MMDC_MAPSR]
+
+poll_dvfs_clear_1:
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	ands	r7, r7, #(1 << 25)
+	bne	poll_dvfs_clear_1
+	/* enable DDR auto power saving */
+	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
+	bic	r7, r7, #0x1
+	str	r7, [r11, #MX6Q_MMDC_MAPSR]
+	mov	pc, lr
+ENDPROC(imx6_suspend)