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linux/arch/arm/mach-imx/suspend-imx6.S
Shawn Guo 59d05b5183 ARM: imx: fix TLB missing of IOMUXC base address during suspend 
After the suspend routine running in OCRAM puts DDR into self-refresh,
it will access IOMUXC block to float DDR IO for power saving.  A TLB
missing of IOMUXC base address may happen in this case, and triggers an
access to DDR, and thus hangs the system.

The failure is discovered by running suspend/resume on a Cubox-i board.
Though the issue is not Cubox-i specific, it can be hit the on the board
quite easily with the 3.15 or 3.16 kernel.

Fix the issue with a dummy access to IOMUXC block at the beginning of
suspend routine, so that the address translation can be filled into TLB
before DDR is put into self-refresh.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>
Cc: <stable@vger.kernel.org>
Acked-by: Anson Huang <Anson.Huang@freescale.com>
2014-08-18 11:38:33 +08:00

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/*
* 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/assembler.h>
#include <asm/asm-offsets.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 ~ 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_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_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
.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
.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, #MXC_CPU_IMX6SL
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_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]
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
/* i.MX6SL's last 3 IOs need special setting */
cmp r3, #MXC_CPU_IMX6SL
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, #MXC_CPU_IMX6SL
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_CPU_TYPE_OFFSET]
mov r5, #0x1
resume_mmdc
ret lr
ENDPROC(imx6_suspend)
/*
* The following code must assume it is running from physical address
* where absolute virtual addresses to the data section have to be
* turned into relative ones.
*/
ENTRY(v7_cpu_resume)
bl v7_invalidate_l1
#ifdef CONFIG_CACHE_L2X0
bl l2c310_early_resume
#endif
b cpu_resume
ENDPROC(v7_cpu_resume)
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