arch/arm/mach-imx/suspend-imx6.S - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  * Copyright 2014 Freescale Semiconductor, Inc.
  */

 #include <linux/linkage.h>
 #include <asm/assembler.h>
 #include <asm/asm-offsets.h>
 #include <asm/hardware/cache-l2x0.h>
 #include "hardware.h"

 .arch armv7-a

 /*
  * ==================== low level suspend ====================
  *
  * Better to follow below rules to use ARM registers:
  * r0: pm_info structure address;
  * r1 ~ r4: for saving pm_info members;
  * r5 ~ r10: free registers;
  * r11: io base address.
  *
  * suspend ocram space layout:
  * ======================== high address ======================
  *                              .
  *                              .
  *                              .
  *                              ^
  *                              ^
  *                              ^
  *                      imx6_suspend code
  *              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_DDR_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_MMDC_MPDGCTRL0	0x83c
 #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
 	.arm

 	.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]
 	teq	r11, #0
 	beq	6f
 	mov	r6, #0x0
 	str	r6, [r11, #L2X0_CACHE_SYNC]
 1:
 	ldr	r6, [r11, #L2X0_CACHE_SYNC]
 	ands	r6, r6, #0x1
 	bne	1b
 6:
 #endif

 	.endm

 	.macro	resume_mmdc

 	/* restore MMDC IO */
 	cmp	r5, #0x0
 	ldreq	r11, [r0, #PM_INFO_MX6Q_IOMUXC_V_OFFSET]
 	ldrne	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
 	add	r7, r7, r0
 1:
 	ldr	r8, [r7], #0x4
 	ldr	r9, [r7], #0x4
 	str	r9, [r11, r8]
 	subs	r6, r6, #0x1
 	bne	1b

 	cmp	r5, #0x0
 	ldreq	r11, [r0, #PM_INFO_MX6Q_MMDC_V_OFFSET]
 	ldrne	r11, [r0, #PM_INFO_MX6Q_MMDC_P_OFFSET]

 	cmp	r3, #IMX_DDR_TYPE_LPDDR2
 	bne	4f

 	/* reset read FIFO, RST_RD_FIFO */
 	ldr	r7, =MX6Q_MMDC_MPDGCTRL0
 	ldr	r6, [r11, r7]
 	orr     r6, r6, #(1 << 31)
 	str	r6, [r11, r7]
 2:
 	ldr	r6, [r11, r7]
 	ands	r6, r6, #(1 << 31)
 	bne	2b

 	/* reset FIFO a second time */
 	ldr	r6, [r11, r7]
 	orr     r6, r6, #(1 << 31)
 	str	r6, [r11, r7]
 3:
 	ldr	r6, [r11, r7]
 	ands	r6, r6, #(1 << 31)
 	bne	3b
 4:
 	/* let DDR out of self-refresh */
 	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
 	bic	r7, r7, #(1 << 21)
 	str	r7, [r11, #MX6Q_MMDC_MAPSR]
 5:
 	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
 	ands	r7, r7, #(1 << 25)
 	bne	5b

 	/* enable DDR auto power saving */
 	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
 	bic	r7, r7, #0x1
 	str	r7, [r11, #MX6Q_MMDC_MAPSR]

 	.endm

 ENTRY(imx6_suspend)
 	ldr	r1, [r0, #PM_INFO_PBASE_OFFSET]
 	ldr	r2, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
 	ldr	r3, [r0, #PM_INFO_DDR_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]
 	ldr	r11, [r0, #PM_INFO_MX6Q_IOMUXC_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:
 	ldr	r7, [r11, #MX6Q_MMDC_MAPSR]
 	ands	r7, r7, #(1 << 25)
 	beq	poll_dvfs_set

 	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
 	add	r8, r8, r0
 	/* LPDDR2's last 3 IOs need special setting */
 	cmp	r3, #IMX_DDR_TYPE_LPDDR2
 	subeq	r7, r7, #0x3
 set_mmdc_io_lpm:
 	ldr	r9, [r8], #0x8
 	str	r6, [r11, r9]
 	subs	r7, r7, #0x1
 	bne	set_mmdc_io_lpm

 	cmp 	r3, #IMX_DDR_TYPE_LPDDR2
 	bne	set_mmdc_io_lpm_done
 	ldr	r6, =0x1000
 	ldr	r9, [r8], #0x8
 	str	r6, [r11, r9]
 	ldr	r9, [r8], #0x8
 	str	r6, [r11, r9]
 	ldr	r6, =0x80000
 	ldr	r9, [r8]
 	str	r6, [r11, r9]
 set_mmdc_io_lpm_done:

 	/*
 	 * 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:
 	subs	r6, r6, #0x1
 	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
 	 */
 	mov	r5, #0x0
 	resume_mmdc

 	/* return to suspend finish */
 	ret	lr

 resume:
 	/* invalidate L1 I-cache first */
 	mov     r6, #0x0
 	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, #0x0
 	str	r7, [r11, #MX6Q_SRC_GPR1]
 	str	r7, [r11, #MX6Q_SRC_GPR2]

 	ldr	r3, [r0, #PM_INFO_DDR_TYPE_OFFSET]
 	mov	r5, #0x1
 	resume_mmdc

 	ret	lr
 ENDPROC(imx6_suspend)
	/* SPDX-License-Identifier: GPL-2.0-or-later */
	/*
	* Copyright 2014 Freescale Semiconductor, Inc.
	*/

	#include <linux/linkage.h>
	#include <asm/assembler.h>
	#include <asm/asm-offsets.h>
	#include <asm/hardware/cache-l2x0.h>
	#include "hardware.h"

	.arch armv7-a

	/*
	* ==================== low level suspend ====================
	*
	* Better to follow below rules to use ARM registers:
	* r0: pm_info structure address;
	* r1 ~ r4: for saving pm_info members;
	* r5 ~ r10: free registers;
	* r11: io base address.
	*
	* suspend ocram space layout:
	* ======================== high address ======================
	* .
	* .
	* .
	* ^
	* ^
	* ^
	* imx6_suspend code
	* 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_DDR_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_MMDC_MPDGCTRL0 0x83c
	#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
	.arm

	.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]
	teq r11, #0
	beq 6f
	mov r6, #0x0
	str r6, [r11, #L2X0_CACHE_SYNC]
	1:
	ldr r6, [r11, #L2X0_CACHE_SYNC]
	ands r6, r6, #0x1
	bne 1b
	6:
	#endif

	.endm

	.macro resume_mmdc

	/* restore MMDC IO */
	cmp r5, #0x0
	ldreq r11, [r0, #PM_INFO_MX6Q_IOMUXC_V_OFFSET]
	ldrne 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
	add r7, r7, r0
	1:
	ldr r8, [r7], #0x4
	ldr r9, [r7], #0x4
	str r9, [r11, r8]
	subs r6, r6, #0x1
	bne 1b

	cmp r5, #0x0
	ldreq r11, [r0, #PM_INFO_MX6Q_MMDC_V_OFFSET]
	ldrne r11, [r0, #PM_INFO_MX6Q_MMDC_P_OFFSET]

	cmp r3, #IMX_DDR_TYPE_LPDDR2
	bne 4f

	/* reset read FIFO, RST_RD_FIFO */
	ldr r7, =MX6Q_MMDC_MPDGCTRL0
	ldr r6, [r11, r7]
	orr r6, r6, #(1 << 31)
	str r6, [r11, r7]
	2:
	ldr r6, [r11, r7]
	ands r6, r6, #(1 << 31)
	bne 2b

	/* reset FIFO a second time */
	ldr r6, [r11, r7]
	orr r6, r6, #(1 << 31)
	str r6, [r11, r7]
	3:
	ldr r6, [r11, r7]
	ands r6, r6, #(1 << 31)
	bne 3b
	4:
	/* let DDR out of self-refresh */
	ldr r7, [r11, #MX6Q_MMDC_MAPSR]
	bic r7, r7, #(1 << 21)
	str r7, [r11, #MX6Q_MMDC_MAPSR]
	5:
	ldr r7, [r11, #MX6Q_MMDC_MAPSR]
	ands r7, r7, #(1 << 25)
	bne 5b

	/* enable DDR auto power saving */
	ldr r7, [r11, #MX6Q_MMDC_MAPSR]
	bic r7, r7, #0x1
	str r7, [r11, #MX6Q_MMDC_MAPSR]

	.endm

	ENTRY(imx6_suspend)
	ldr r1, [r0, #PM_INFO_PBASE_OFFSET]
	ldr r2, [r0, #PM_INFO_RESUME_ADDR_OFFSET]
	ldr r3, [r0, #PM_INFO_DDR_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]
	ldr r11, [r0, #PM_INFO_MX6Q_IOMUXC_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:
	ldr r7, [r11, #MX6Q_MMDC_MAPSR]
	ands r7, r7, #(1 << 25)
	beq poll_dvfs_set

	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
	add r8, r8, r0
	/* LPDDR2's last 3 IOs need special setting */
	cmp r3, #IMX_DDR_TYPE_LPDDR2
	subeq r7, r7, #0x3
	set_mmdc_io_lpm:
	ldr r9, [r8], #0x8
	str r6, [r11, r9]
	subs r7, r7, #0x1
	bne set_mmdc_io_lpm

	cmp r3, #IMX_DDR_TYPE_LPDDR2
	bne set_mmdc_io_lpm_done
	ldr r6, =0x1000
	ldr r9, [r8], #0x8
	str r6, [r11, r9]
	ldr r9, [r8], #0x8
	str r6, [r11, r9]
	ldr r6, =0x80000
	ldr r9, [r8]
	str r6, [r11, r9]
	set_mmdc_io_lpm_done:

	/*
	* 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:
	subs r6, r6, #0x1
	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
	*/
	mov r5, #0x0
	resume_mmdc

	/* return to suspend finish */
	ret lr

	resume:
	/* invalidate L1 I-cache first */
	mov r6, #0x0
	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, #0x0
	str r7, [r11, #MX6Q_SRC_GPR1]
	str r7, [r11, #MX6Q_SRC_GPR2]

	ldr r3, [r0, #PM_INFO_DDR_TYPE_OFFSET]
	mov r5, #0x1
	resume_mmdc

	ret lr
	ENDPROC(imx6_suspend)