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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Low level suspend code for AM33XX SoCs
*
* Copyright (C) 2012-2018 Texas Instruments Incorporated - https://www.ti.com/
* Dave Gerlach, Vaibhav Bedia
*/
#include <linux/linkage.h>
#include <linux/platform_data/pm33xx.h>
#include <linux/ti-emif-sram.h>
#include <asm/assembler.h>
#include <asm/page.h>
#include "iomap.h"
#include "cm33xx.h"
#include "pm-asm-offsets.h"
#define AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED 0x00030000
#define AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE 0x0003
#define AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE 0x0002
/* replicated define because linux/bitops.h cannot be included in assembly */
#define BIT(nr) (1 << (nr))
.arm
.arch armv7-a
.align 3
ENTRY(am33xx_do_wfi)
stmfd sp!, {r4 - r11, lr} @ save registers on stack
/* Save wfi_flags arg to data space */
mov r4, r0
adr r3, am33xx_pm_ro_sram_data
ldr r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
str r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
/* Only flush cache is we know we are losing MPU context */
tst r4, #WFI_FLAG_FLUSH_CACHE
beq cache_skip_flush
/*
* Flush all data from the L1 and L2 data cache before disabling
* SCTLR.C bit.
*/
ldr r1, kernel_flush
blx r1
/*
* Clear the SCTLR.C bit to prevent further data cache
* allocation. Clearing SCTLR.C would make all the data accesses
* strongly ordered and would not hit the cache.
*/
mrc p15, 0, r0, c1, c0, 0
bic r0, r0, #(1 << 2) @ Disable the C bit
mcr p15, 0, r0, c1, c0, 0
isb
/*
* Invalidate L1 and L2 data cache.
*/
ldr r1, kernel_flush
blx r1
adr r3, am33xx_pm_ro_sram_data
ldr r2, [r3, #AMX3_PM_RO_SRAM_DATA_VIRT_OFFSET]
ldr r4, [r2, #AMX3_PM_WFI_FLAGS_OFFSET]
cache_skip_flush:
/* Check if we want self refresh */
tst r4, #WFI_FLAG_SELF_REFRESH
beq emif_skip_enter_sr
adr r9, am33xx_emif_sram_table
ldr r3, [r9, #EMIF_PM_ENTER_SR_OFFSET]
blx r3
emif_skip_enter_sr:
/* Only necessary if PER is losing context */
tst r4, #WFI_FLAG_SAVE_EMIF
beq emif_skip_save
ldr r3, [r9, #EMIF_PM_SAVE_CONTEXT_OFFSET]
blx r3
emif_skip_save:
/* Only can disable EMIF if we have entered self refresh */
tst r4, #WFI_FLAG_SELF_REFRESH
beq emif_skip_disable
/* Disable EMIF */
ldr r1, virt_emif_clkctrl
ldr r2, [r1]
bic r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
str r2, [r1]
ldr r1, virt_emif_clkctrl
wait_emif_disable:
ldr r2, [r1]
mov r3, #AM33XX_CM_CLKCTRL_MODULESTATE_DISABLED
cmp r2, r3
bne wait_emif_disable
emif_skip_disable:
tst r4, #WFI_FLAG_WAKE_M3
beq wkup_m3_skip
/*
* For the MPU WFI to be registered as an interrupt
* to WKUP_M3, MPU_CLKCTRL.MODULEMODE needs to be set
* to DISABLED
*/
ldr r1, virt_mpu_clkctrl
ldr r2, [r1]
bic r2, r2, #AM33XX_CM_CLKCTRL_MODULEMODE_DISABLE
str r2, [r1]
wkup_m3_skip:
/*
* Execute an ISB instruction to ensure that all of the
* CP15 register changes have been committed.
*/
isb
/*
* Execute a barrier instruction to ensure that all cache,
* TLB and branch predictor maintenance operations issued
* have completed.
*/
dsb
dmb
/*
* Execute a WFI instruction and wait until the
* STANDBYWFI output is asserted to indicate that the
* CPU is in idle and low power state. CPU can specualatively
* prefetch the instructions so add NOPs after WFI. Thirteen
* NOPs as per Cortex-A8 pipeline.
*/
wfi
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
nop
/* We come here in case of an abort due to a late interrupt */
/* Set MPU_CLKCTRL.MODULEMODE back to ENABLE */
ldr r1, virt_mpu_clkctrl
mov r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
str r2, [r1]
/* Re-enable EMIF */
ldr r1, virt_emif_clkctrl
mov r2, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
str r2, [r1]
wait_emif_enable:
ldr r3, [r1]
cmp r2, r3
bne wait_emif_enable
/* Only necessary if PER is losing context */
tst r4, #WFI_FLAG_SELF_REFRESH
beq emif_skip_exit_sr_abt
adr r9, am33xx_emif_sram_table
ldr r1, [r9, #EMIF_PM_ABORT_SR_OFFSET]
blx r1
emif_skip_exit_sr_abt:
tst r4, #WFI_FLAG_FLUSH_CACHE
beq cache_skip_restore
/*
* Set SCTLR.C bit to allow data cache allocation
*/
mrc p15, 0, r0, c1, c0, 0
orr r0, r0, #(1 << 2) @ Enable the C bit
mcr p15, 0, r0, c1, c0, 0
isb
cache_skip_restore:
/* Let the suspend code know about the abort */
mov r0, #1
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
ENDPROC(am33xx_do_wfi)
.align
ENTRY(am33xx_resume_offset)
.word . - am33xx_do_wfi
ENTRY(am33xx_resume_from_deep_sleep)
/* Re-enable EMIF */
ldr r0, phys_emif_clkctrl
mov r1, #AM33XX_CM_CLKCTRL_MODULEMODE_ENABLE
str r1, [r0]
wait_emif_enable1:
ldr r2, [r0]
cmp r1, r2
bne wait_emif_enable1
adr r9, am33xx_emif_sram_table
ldr r1, [r9, #EMIF_PM_RESTORE_CONTEXT_OFFSET]
blx r1
ldr r1, [r9, #EMIF_PM_EXIT_SR_OFFSET]
blx r1
resume_to_ddr:
/* We are back. Branch to the common CPU resume routine */
mov r0, #0
ldr pc, resume_addr
ENDPROC(am33xx_resume_from_deep_sleep)
/*
* Local variables
*/
.align
kernel_flush:
.word v7_flush_dcache_all
virt_mpu_clkctrl:
.word AM33XX_CM_MPU_MPU_CLKCTRL
virt_emif_clkctrl:
.word AM33XX_CM_PER_EMIF_CLKCTRL
phys_emif_clkctrl:
.word (AM33XX_CM_BASE + AM33XX_CM_PER_MOD + \
AM33XX_CM_PER_EMIF_CLKCTRL_OFFSET)
.align 3
/* DDR related defines */
am33xx_emif_sram_table:
.space EMIF_PM_FUNCTIONS_SIZE
ENTRY(am33xx_pm_sram)
.word am33xx_do_wfi
.word am33xx_do_wfi_sz
.word am33xx_resume_offset
.word am33xx_emif_sram_table
.word am33xx_pm_ro_sram_data
resume_addr:
.word cpu_resume - PAGE_OFFSET + 0x80000000
.align 3
ENTRY(am33xx_pm_ro_sram_data)
.space AMX3_PM_RO_SRAM_DATA_SIZE
ENTRY(am33xx_do_wfi_sz)
.word . - am33xx_do_wfi
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