diff options
Diffstat (limited to 'arch/arm/mach-omap2/sleep33xx.S')
| -rw-r--r-- | arch/arm/mach-omap2/sleep33xx.S | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/sleep33xx.S b/arch/arm/mach-omap2/sleep33xx.S new file mode 100644 index 0000000000..3bfd8b5e03 --- /dev/null +++ b/arch/arm/mach-omap2/sleep33xx.S @@ -0,0 +1,262 @@ +/* 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 |