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linux-next/drivers/memory/ti-emif-sram-pm.S
Dave Gerlach 8428e5ad75 memory: ti-emif-sram: introduce relocatable suspend/resume handlers 
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>
2017-12-02 19:27:17 -08:00

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9.9 KiB
ArmAsm
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/*
* Low level PM code for TI EMIF
*
* Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com/
* Dave Gerlach
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <generated/ti-emif-asm-offsets.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/memory.h>
#include "emif.h"
#define EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES 0x00a0
#define EMIF_POWER_MGMT_SR_TIMER_MASK 0x00f0
#define EMIF_POWER_MGMT_SELF_REFRESH_MODE 0x0200
#define EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK 0x0700
#define EMIF_SDCFG_TYPE_DDR2 0x2 << SDRAM_TYPE_SHIFT
#define EMIF_STATUS_READY 0x4
#define AM43XX_EMIF_PHY_CTRL_REG_COUNT 0x120
#define EMIF_AM437X_REGISTERS 0x1
.arm
.align 3
ENTRY(ti_emif_sram)
/*
* void ti_emif_save_context(void)
*
* Used during suspend to save the context of all required EMIF registers
* to local memory if the EMIF is going to lose context during the sleep
* transition. Operates on the VIRTUAL address of the EMIF.
*/
ENTRY(ti_emif_save_context)
stmfd sp!, {r4 - r11, lr} @ save registers on stack
adr r4, ti_emif_pm_sram_data
ldr r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
ldr r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
/* Save EMIF configuration */
ldr r1, [r0, #EMIF_SDRAM_CONFIG]
str r1, [r2, #EMIF_SDCFG_VAL_OFFSET]
ldr r1, [r0, #EMIF_SDRAM_REFRESH_CONTROL]
str r1, [r2, #EMIF_REF_CTRL_VAL_OFFSET]
ldr r1, [r0, #EMIF_SDRAM_TIMING_1]
str r1, [r2, #EMIF_TIMING1_VAL_OFFSET]
ldr r1, [r0, #EMIF_SDRAM_TIMING_2]
str r1, [r2, #EMIF_TIMING2_VAL_OFFSET]
ldr r1, [r0, #EMIF_SDRAM_TIMING_3]
str r1, [r2, #EMIF_TIMING3_VAL_OFFSET]
ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
str r1, [r2, #EMIF_PMCR_VAL_OFFSET]
ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
str r1, [r2, #EMIF_PMCR_SHDW_VAL_OFFSET]
ldr r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
str r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
ldr r1, [r0, #EMIF_DDR_PHY_CTRL_1]
str r1, [r2, #EMIF_DDR_PHY_CTLR_1_OFFSET]
ldr r1, [r0, #EMIF_COS_CONFIG]
str r1, [r2, #EMIF_COS_CONFIG_OFFSET]
ldr r1, [r0, #EMIF_PRIORITY_TO_CLASS_OF_SERVICE_MAPPING]
str r1, [r2, #EMIF_PRIORITY_TO_COS_MAPPING_OFFSET]
ldr r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_1_MAPPING]
str r1, [r2, #EMIF_CONNECT_ID_SERV_1_MAP_OFFSET]
ldr r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_2_MAPPING]
str r1, [r2, #EMIF_CONNECT_ID_SERV_2_MAP_OFFSET]
ldr r1, [r0, #EMIF_OCP_CONFIG]
str r1, [r2, #EMIF_OCP_CONFIG_VAL_OFFSET]
ldr r5, [r4, #EMIF_PM_CONFIG_OFFSET]
cmp r5, #EMIF_SRAM_AM43_REG_LAYOUT
bne emif_skip_save_extra_regs
ldr r1, [r0, #EMIF_READ_WRITE_LEVELING_RAMP_CONTROL]
str r1, [r2, #EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET]
ldr r1, [r0, #EMIF_READ_WRITE_EXECUTION_THRESHOLD]
str r1, [r2, #EMIF_RD_WR_EXEC_THRESH_OFFSET]
ldr r1, [r0, #EMIF_LPDDR2_NVM_TIMING]
str r1, [r2, #EMIF_LPDDR2_NVM_TIM_OFFSET]
ldr r1, [r0, #EMIF_LPDDR2_NVM_TIMING_SHDW]
str r1, [r2, #EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET]
ldr r1, [r0, #EMIF_DLL_CALIB_CTRL]
str r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_OFFSET]
ldr r1, [r0, #EMIF_DLL_CALIB_CTRL_SHDW]
str r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET]
/* Loop and save entire block of emif phy regs */
mov r5, #0x0
add r4, r2, #EMIF_EXT_PHY_CTRL_VALS_OFFSET
add r3, r0, #EMIF_EXT_PHY_CTRL_1
ddr_phy_ctrl_save:
ldr r1, [r3, r5]
str r1, [r4, r5]
add r5, r5, #0x4
cmp r5, #AM43XX_EMIF_PHY_CTRL_REG_COUNT
bne ddr_phy_ctrl_save
emif_skip_save_extra_regs:
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
ENDPROC(ti_emif_save_context)
/*
* void ti_emif_restore_context(void)
*
* Used during resume to restore the context of all required EMIF registers
* from local memory after the EMIF has lost context during a sleep transition.
* Operates on the PHYSICAL address of the EMIF.
*/
ENTRY(ti_emif_restore_context)
adr r4, ti_emif_pm_sram_data
ldr r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
ldr r2, [r4, #EMIF_PM_REGS_PHYS_OFFSET]
/* Config EMIF Timings */
ldr r1, [r2, #EMIF_DDR_PHY_CTLR_1_OFFSET]
str r1, [r0, #EMIF_DDR_PHY_CTRL_1]
str r1, [r0, #EMIF_DDR_PHY_CTRL_1_SHDW]
ldr r1, [r2, #EMIF_TIMING1_VAL_OFFSET]
str r1, [r0, #EMIF_SDRAM_TIMING_1]
str r1, [r0, #EMIF_SDRAM_TIMING_1_SHDW]
ldr r1, [r2, #EMIF_TIMING2_VAL_OFFSET]
str r1, [r0, #EMIF_SDRAM_TIMING_2]
str r1, [r0, #EMIF_SDRAM_TIMING_2_SHDW]
ldr r1, [r2, #EMIF_TIMING3_VAL_OFFSET]
str r1, [r0, #EMIF_SDRAM_TIMING_3]
str r1, [r0, #EMIF_SDRAM_TIMING_3_SHDW]
ldr r1, [r2, #EMIF_REF_CTRL_VAL_OFFSET]
str r1, [r0, #EMIF_SDRAM_REFRESH_CONTROL]
str r1, [r0, #EMIF_SDRAM_REFRESH_CTRL_SHDW]
ldr r1, [r2, #EMIF_PMCR_VAL_OFFSET]
str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
ldr r1, [r2, #EMIF_PMCR_SHDW_VAL_OFFSET]
str r1, [r0, #EMIF_POWER_MANAGEMENT_CTRL_SHDW]
ldr r1, [r2, #EMIF_COS_CONFIG_OFFSET]
str r1, [r0, #EMIF_COS_CONFIG]
ldr r1, [r2, #EMIF_PRIORITY_TO_COS_MAPPING_OFFSET]
str r1, [r0, #EMIF_PRIORITY_TO_CLASS_OF_SERVICE_MAPPING]
ldr r1, [r2, #EMIF_CONNECT_ID_SERV_1_MAP_OFFSET]
str r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_1_MAPPING]
ldr r1, [r2, #EMIF_CONNECT_ID_SERV_2_MAP_OFFSET]
str r1, [r0, #EMIF_CONNECTION_ID_TO_CLASS_OF_SERVICE_2_MAPPING]
ldr r1, [r2, #EMIF_OCP_CONFIG_VAL_OFFSET]
str r1, [r0, #EMIF_OCP_CONFIG]
ldr r5, [r4, #EMIF_PM_CONFIG_OFFSET]
cmp r5, #EMIF_SRAM_AM43_REG_LAYOUT
bne emif_skip_restore_extra_regs
ldr r1, [r2, #EMIF_RD_WR_LEVEL_RAMP_CTRL_OFFSET]
str r1, [r0, #EMIF_READ_WRITE_LEVELING_RAMP_CONTROL]
ldr r1, [r2, #EMIF_RD_WR_EXEC_THRESH_OFFSET]
str r1, [r0, #EMIF_READ_WRITE_EXECUTION_THRESHOLD]
ldr r1, [r2, #EMIF_LPDDR2_NVM_TIM_OFFSET]
str r1, [r0, #EMIF_LPDDR2_NVM_TIMING]
ldr r1, [r2, #EMIF_LPDDR2_NVM_TIM_SHDW_OFFSET]
str r1, [r0, #EMIF_LPDDR2_NVM_TIMING_SHDW]
ldr r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_OFFSET]
str r1, [r0, #EMIF_DLL_CALIB_CTRL]
ldr r1, [r2, #EMIF_DLL_CALIB_CTRL_VAL_SHDW_OFFSET]
str r1, [r0, #EMIF_DLL_CALIB_CTRL_SHDW]
ldr r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
str r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
/* Loop and restore entire block of emif phy regs */
mov r5, #0x0
/* Load ti_emif_regs_amx3 + EMIF_EXT_PHY_CTRL_VALS_OFFSET for address
* to phy register save space
*/
add r3, r2, #EMIF_EXT_PHY_CTRL_VALS_OFFSET
add r4, r0, #EMIF_EXT_PHY_CTRL_1
ddr_phy_ctrl_restore:
ldr r1, [r3, r5]
str r1, [r4, r5]
add r5, r5, #0x4
cmp r5, #AM43XX_EMIF_PHY_CTRL_REG_COUNT
bne ddr_phy_ctrl_restore
emif_skip_restore_extra_regs:
/*
* Output impedence calib needed only for DDR3
* but since the initial state of this will be
* disabled for DDR2 no harm in restoring the
* old configuration
*/
ldr r1, [r2, #EMIF_ZQCFG_VAL_OFFSET]
str r1, [r0, #EMIF_SDRAM_OUTPUT_IMPEDANCE_CALIBRATION_CONFIG]
/* Write to sdcfg last for DDR2 only */
ldr r1, [r2, #EMIF_SDCFG_VAL_OFFSET]
and r2, r1, #SDRAM_TYPE_MASK
cmp r2, #EMIF_SDCFG_TYPE_DDR2
streq r1, [r0, #EMIF_SDRAM_CONFIG]
mov pc, lr
ENDPROC(ti_emif_restore_context)
/*
* void ti_emif_enter_sr(void)
*
* Programs the EMIF to tell the SDRAM to enter into self-refresh
* mode during a sleep transition. Operates on the VIRTUAL address
* of the EMIF.
*/
ENTRY(ti_emif_enter_sr)
stmfd sp!, {r4 - r11, lr} @ save registers on stack
adr r4, ti_emif_pm_sram_data
ldr r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
ldr r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
ldr r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
orr r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE
str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
ENDPROC(ti_emif_enter_sr)
/*
* void ti_emif_exit_sr(void)
*
* Programs the EMIF to tell the SDRAM to exit self-refresh mode
* after a sleep transition. Operates on the PHYSICAL address of
* the EMIF.
*/
ENTRY(ti_emif_exit_sr)
adr r4, ti_emif_pm_sram_data
ldr r0, [r4, #EMIF_PM_BASE_ADDR_PHYS_OFFSET]
ldr r2, [r4, #EMIF_PM_REGS_PHYS_OFFSET]
/*
* Toggle EMIF to exit refresh mode:
* if EMIF lost context, PWR_MGT_CTRL is currently 0, writing disable
* (0x0), wont do diddly squat! so do a toggle from SR(0x2) to disable
* (0x0) here.
* *If* EMIF did not lose context, nothing broken as we write the same
* value(0x2) to reg before we write a disable (0x0).
*/
ldr r1, [r2, #EMIF_PMCR_VAL_OFFSET]
bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
orr r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE
str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
/* Wait for EMIF to become ready */
1: ldr r1, [r0, #EMIF_STATUS]
tst r1, #EMIF_STATUS_READY
beq 1b
mov pc, lr
ENDPROC(ti_emif_exit_sr)
/*
* void ti_emif_abort_sr(void)
*
* Disables self-refresh after a failed transition to a low-power
* state so the kernel can jump back to DDR and follow abort path.
* Operates on the VIRTUAL address of the EMIF.
*/
ENTRY(ti_emif_abort_sr)
stmfd sp!, {r4 - r11, lr} @ save registers on stack
adr r4, ti_emif_pm_sram_data
ldr r0, [r4, #EMIF_PM_BASE_ADDR_VIRT_OFFSET]
ldr r2, [r4, #EMIF_PM_REGS_VIRT_OFFSET]
ldr r1, [r2, #EMIF_PMCR_VAL_OFFSET]
bic r1, r1, #EMIF_POWER_MGMT_SELF_REFRESH_MODE_MASK
str r1, [r0, #EMIF_POWER_MANAGEMENT_CONTROL]
/* Wait for EMIF to become ready */
1: ldr r1, [r0, #EMIF_STATUS]
tst r1, #EMIF_STATUS_READY
beq 1b
ldmfd sp!, {r4 - r11, pc} @ restore regs and return
ENDPROC(ti_emif_abort_sr)
.align 3
ENTRY(ti_emif_pm_sram_data)
.space EMIF_PM_DATA_SIZE
ENTRY(ti_emif_sram_sz)
.word . - ti_emif_save_context
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