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![Dave Gerlach](/assets/img/avatar_default.png)
Certain SoCs like Texas Instruments AM335x and AM437x require parts of the EMIF PM code to run late in the suspend sequence from SRAM, such as saving and restoring the EMIF context and placing the memory into self-refresh. One requirement for these SoCs to suspend and enter its lowest power mode, called DeepSleep0, is that the PER power domain must be shut off. Because the EMIF (DDR Controller) resides within this power domain, it will lose context during a suspend operation, so we must save it so we can restore once we resume. However, we cannot execute this code from external memory, as it is not available at this point, so the code must be executed late in the suspend path from SRAM. This patch introduces a ti-emif-sram driver that includes several functions written in ARM ASM that are relocatable so the PM SRAM code can use them. It also allocates a region of writable SRAM to be used by the code running in the executable region of SRAM to save and restore the EMIF context. It can export a table containing the absolute addresses of the available PM functions so that other SRAM code can branch to them. This code is required for suspend/resume on AM335x and AM437x to work. In addition to this, to be able to share data structures between C and the ti-emif-sram-pm assembly code, we can automatically generate all of the C struct member offsets and sizes as macros by processing emif-asm-offsets.c into assembly code and then extracting the relevant data as is done for the generated platform asm-offsets.h files. Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by: Dave Gerlach <d-gerlach@ti.com> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
334 lines
9.9 KiB
ArmAsm
334 lines
9.9 KiB
ArmAsm
/*
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* Low level PM code for TI EMIF
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*
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* Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com/
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* Dave Gerlach
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation version 2.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <generated/ti-emif-asm-offsets.h>
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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#include <asm/memory.h>
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#include "emif.h"
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#define EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES 0x00a0
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#define EMIF_POWER_MGMT_SR_TIMER_MASK 0x00f0
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#define EMIF_POWER_MGMT_SELF_REFRESH_MODE 0x0200
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#define EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK 0x0700
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#define EMIF_SDCFG_TYPE_DDR2 0x2 << SDRAM_TYPE_SHIFT
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#define EMIF_STATUS_READY 0x4
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#define AM43XX_EMIF_PHY_CTRL_REG_COUNT 0x120
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#define EMIF_AM437X_REGISTERS 0x1
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.arm
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.align 3
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ENTRY(ti_emif_sram)
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/*
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* void ti_emif_save_context(void)
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*
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* Used during suspend to save the context of all required EMIF registers
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* to local memory if the EMIF is going to lose context during the sleep
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* transition. Operates on the VIRTUAL address of the EMIF.
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*/
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ENTRY(ti_emif_save_context)
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stmfd sp!, {r4 - r11, lr} @ save registers on stack
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adr r4, ti_emif_pm_sram_data
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ldr r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
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ldr r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
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/* Save EMIF configuration */
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ldr r1, [r0, #EMIF_SDRAM_CONFIG]
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str r1, [r2, #EMIF_SDCFG_VAL_OFFSET]
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ldr r1, [r0, #EMIF_SDRAM_REFRESH_CONTROL]
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str r1, [r2, #EMIF_REF_CTRL_VAL_OFFSET]
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ldr r1, [r0, #EMIF_SDRAM_TIMING_1]
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str r1, [r2, #EMIF_TIMING1_VAL_OFFSET]
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ldr r1, [r0, #EMIF_SDRAM_TIMING_2]
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str r1, [r2, #EMIF_TIMING2_VAL_OFFSET]
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ldr r1, [r0, #EMIF_SDRAM_TIMING_3]
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str r1, [r2, #EMIF_TIMING3_VAL_OFFSET]
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ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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str r1, [r2, #EMIF_PMCR_VAL_OFFSET]
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ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
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str r1, [r2, #EMIF_PMCR_SHDW_VAL_OFFSET]
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ldr r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
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str r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
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ldr r1, [r0, #EMIF_DDR_PHY_CTRL_1]
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str r1, [r2, #EMIF_DDR_PHY_CTLR_1_OFFSET]
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ldr r1, [r0, #EMIF_COS_CONFIG]
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str r1, [r2, #EMIF_COS_CONFIG_OFFSET]
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ldr r1, [r0, #EMIF_PRIORITY_TO_CLASS_OF_SERVICE_MAPPING]
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str r1, [r2, #EMIF_PRIORITY_TO_COS_MAPPING_OFFSET]
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ldr r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_1_MAPPING]
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str r1, [r2, #EMIF_CONNECT_ID_SERV_1_MAP_OFFSET]
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ldr r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_2_MAPPING]
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str r1, [r2, #EMIF_CONNECT_ID_SERV_2_MAP_OFFSET]
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ldr r1, [r0, #EMIF_OCP_CONFIG]
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str r1, [r2, #EMIF_OCP_CONFIG_VAL_OFFSET]
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ldr r5, [r4, #EMIF_PM_CONFIG_OFFSET]
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cmp r5, #EMIF_SRAM_AM43_REG_LAYOUT
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bne emif_skip_save_extra_regs
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ldr r1, [r0, #EMIF_READ_WRITE_LEVELING_RAMP_CONTROL]
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str r1, [r2, #EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET]
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ldr r1, [r0, #EMIF_READ_WRITE_EXECUTION_THRESHOLD]
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str r1, [r2, #EMIF_RD_WR_EXEC_THRESH_OFFSET]
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ldr r1, [r0, #EMIF_LPDDR2_NVM_TIMING]
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str r1, [r2, #EMIF_LPDDR2_NVM_TIM_OFFSET]
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ldr r1, [r0, #EMIF_LPDDR2_NVM_TIMING_SHDW]
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str r1, [r2, #EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET]
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ldr r1, [r0, #EMIF_DLL_CALIB_CTRL]
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str r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_OFFSET]
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ldr r1, [r0, #EMIF_DLL_CALIB_CTRL_SHDW]
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str r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET]
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/* Loop and save entire block of emif phy regs */
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mov r5, #0x0
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add r4, r2, #EMIF_EXT_PHY_CTRL_VALS_OFFSET
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add r3, r0, #EMIF_EXT_PHY_CTRL_1
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ddr_phy_ctrl_save:
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ldr r1, [r3, r5]
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str r1, [r4, r5]
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add r5, r5, #0x4
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cmp r5, #AM43XX_EMIF_PHY_CTRL_REG_COUNT
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bne ddr_phy_ctrl_save
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emif_skip_save_extra_regs:
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ldmfd sp!, {r4 - r11, pc} @ restore regs and return
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ENDPROC(ti_emif_save_context)
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/*
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* void ti_emif_restore_context(void)
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*
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* Used during resume to restore the context of all required EMIF registers
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* from local memory after the EMIF has lost context during a sleep transition.
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* Operates on the PHYSICAL address of the EMIF.
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*/
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ENTRY(ti_emif_restore_context)
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adr r4, ti_emif_pm_sram_data
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ldr r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
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ldr r2, [r4, #EMIF_PM_REGS_PHYS_OFFSET]
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/* Config EMIF Timings */
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ldr r1, [r2, #EMIF_DDR_PHY_CTLR_1_OFFSET]
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str r1, [r0, #EMIF_DDR_PHY_CTRL_1]
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str r1, [r0, #EMIF_DDR_PHY_CTRL_1_SHDW]
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ldr r1, [r2, #EMIF_TIMING1_VAL_OFFSET]
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str r1, [r0, #EMIF_SDRAM_TIMING_1]
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str r1, [r0, #EMIF_SDRAM_TIMING_1_SHDW]
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ldr r1, [r2, #EMIF_TIMING2_VAL_OFFSET]
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str r1, [r0, #EMIF_SDRAM_TIMING_2]
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str r1, [r0, #EMIF_SDRAM_TIMING_2_SHDW]
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ldr r1, [r2, #EMIF_TIMING3_VAL_OFFSET]
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str r1, [r0, #EMIF_SDRAM_TIMING_3]
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str r1, [r0, #EMIF_SDRAM_TIMING_3_SHDW]
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ldr r1, [r2, #EMIF_REF_CTRL_VAL_OFFSET]
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str r1, [r0, #EMIF_SDRAM_REFRESH_CONTROL]
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str r1, [r0, #EMIF_SDRAM_REFRESH_CTRL_SHDW]
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ldr r1, [r2, #EMIF_PMCR_VAL_OFFSET]
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str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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ldr r1, [r2, #EMIF_PMCR_SHDW_VAL_OFFSET]
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str r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
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ldr r1, [r2, #EMIF_COS_CONFIG_OFFSET]
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str r1, [r0, #EMIF_COS_CONFIG]
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ldr r1, [r2, #EMIF_PRIORITY_TO_COS_MAPPING_OFFSET]
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str r1, [r0, #EMIF_PRIORITY_TO_CLASS_OF_SERVICE_MAPPING]
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ldr r1, [r2, #EMIF_CONNECT_ID_SERV_1_MAP_OFFSET]
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str r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_1_MAPPING]
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ldr r1, [r2, #EMIF_CONNECT_ID_SERV_2_MAP_OFFSET]
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str r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_2_MAPPING]
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ldr r1, [r2, #EMIF_OCP_CONFIG_VAL_OFFSET]
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str r1, [r0, #EMIF_OCP_CONFIG]
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ldr r5, [r4, #EMIF_PM_CONFIG_OFFSET]
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cmp r5, #EMIF_SRAM_AM43_REG_LAYOUT
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bne emif_skip_restore_extra_regs
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ldr r1, [r2, #EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET]
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str r1, [r0, #EMIF_READ_WRITE_LEVELING_RAMP_CONTROL]
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ldr r1, [r2, #EMIF_RD_WR_EXEC_THRESH_OFFSET]
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str r1, [r0, #EMIF_READ_WRITE_EXECUTION_THRESHOLD]
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ldr r1, [r2, #EMIF_LPDDR2_NVM_TIM_OFFSET]
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str r1, [r0, #EMIF_LPDDR2_NVM_TIMING]
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ldr r1, [r2, #EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET]
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str r1, [r0, #EMIF_LPDDR2_NVM_TIMING_SHDW]
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ldr r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_OFFSET]
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str r1, [r0, #EMIF_DLL_CALIB_CTRL]
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ldr r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET]
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str r1, [r0, #EMIF_DLL_CALIB_CTRL_SHDW]
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ldr r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
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str r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
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/* Loop and restore entire block of emif phy regs */
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mov r5, #0x0
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/* Load ti_emif_regs_amx3 + EMIF_EXT_PHY_CTRL_VALS_OFFSET for address
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* to phy register save space
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*/
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add r3, r2, #EMIF_EXT_PHY_CTRL_VALS_OFFSET
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add r4, r0, #EMIF_EXT_PHY_CTRL_1
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ddr_phy_ctrl_restore:
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ldr r1, [r3, r5]
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str r1, [r4, r5]
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add r5, r5, #0x4
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cmp r5, #AM43XX_EMIF_PHY_CTRL_REG_COUNT
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bne ddr_phy_ctrl_restore
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emif_skip_restore_extra_regs:
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/*
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* Output impedence calib needed only for DDR3
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* but since the initial state of this will be
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* disabled for DDR2 no harm in restoring the
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* old configuration
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*/
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ldr r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
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str r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
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/* Write to sdcfg last for DDR2 only */
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ldr r1, [r2, #EMIF_SDCFG_VAL_OFFSET]
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and r2, r1, #SDRAM_TYPE_MASK
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cmp r2, #EMIF_SDCFG_TYPE_DDR2
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streq r1, [r0, #EMIF_SDRAM_CONFIG]
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mov pc, lr
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ENDPROC(ti_emif_restore_context)
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/*
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* void ti_emif_enter_sr(void)
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*
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* Programs the EMIF to tell the SDRAM to enter into self-refresh
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* mode during a sleep transition. Operates on the VIRTUAL address
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* of the EMIF.
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*/
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ENTRY(ti_emif_enter_sr)
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stmfd sp!, {r4 - r11, lr} @ save registers on stack
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adr r4, ti_emif_pm_sram_data
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ldr r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
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ldr r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
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ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
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orr r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE
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str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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ldmfd sp!, {r4 - r11, pc} @ restore regs and return
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ENDPROC(ti_emif_enter_sr)
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/*
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* void ti_emif_exit_sr(void)
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*
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* Programs the EMIF to tell the SDRAM to exit self-refresh mode
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* after a sleep transition. Operates on the PHYSICAL address of
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* the EMIF.
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*/
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ENTRY(ti_emif_exit_sr)
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adr r4, ti_emif_pm_sram_data
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ldr r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
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ldr r2, [r4, #EMIF_PM_REGS_PHYS_OFFSET]
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/*
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* Toggle EMIF to exit refresh mode:
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* if EMIF lost context, PWR_MGT_CTRL is currently 0, writing disable
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* (0x0), wont do diddly squat! so do a toggle from SR(0x2) to disable
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* (0x0) here.
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* *If* EMIF did not lose context, nothing broken as we write the same
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* value(0x2) to reg before we write a disable (0x0).
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*/
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ldr r1, [r2, #EMIF_PMCR_VAL_OFFSET]
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bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
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orr r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE
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str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
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str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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/* Wait for EMIF to become ready */
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1: ldr r1, [r0, #EMIF_STATUS]
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tst r1, #EMIF_STATUS_READY
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beq 1b
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mov pc, lr
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ENDPROC(ti_emif_exit_sr)
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/*
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* void ti_emif_abort_sr(void)
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*
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* Disables self-refresh after a failed transition to a low-power
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* state so the kernel can jump back to DDR and follow abort path.
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* Operates on the VIRTUAL address of the EMIF.
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*/
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ENTRY(ti_emif_abort_sr)
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stmfd sp!, {r4 - r11, lr} @ save registers on stack
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adr r4, ti_emif_pm_sram_data
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ldr r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
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ldr r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
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ldr r1, [r2, #EMIF_PMCR_VAL_OFFSET]
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bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
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str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
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/* Wait for EMIF to become ready */
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1: ldr r1, [r0, #EMIF_STATUS]
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tst r1, #EMIF_STATUS_READY
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beq 1b
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ldmfd sp!, {r4 - r11, pc} @ restore regs and return
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ENDPROC(ti_emif_abort_sr)
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.align 3
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ENTRY(ti_emif_pm_sram_data)
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.space EMIF_PM_DATA_SIZE
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ENTRY(ti_emif_sram_sz)
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.word . - ti_emif_save_context
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