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-rw-r--r--arch/arm/mach-omap2/sleep33xx.S262
1 files changed, 262 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/sleep33xx.S b/arch/arm/mach-omap2/sleep33xx.S
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index 000000000..ac3d0b363
--- /dev/null
+++ b/arch/arm/mach-omap2/sleep33xx.S
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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/memory.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