|
在WinCE中，有3种方式可以使系统进入休眠：
1、用户在开始菜单选择挂起
2、用户短按电源键，请求系统进入休眠（需要电源按键驱动的支持，比如设为长按关机，短按休眠）
3、用户长时间无操作，系统状态由POWER_STATE_ON转为POWER_STATE_USERIDLE，POWER_STATE_IDLE状态，最后进入POWER_STATE_SUSPEND即休眠状态
休眠之前，对于支持电源管理的驱动，系统会调用此驱动的XXX_PowerDown接口关闭设备电源，之后系统会调用OEMPowerOff接口，进入休眠。
OEMPowerOFF位于SMDK2440A/Src/Common/Power/off.c文件中，不要被它的名字迷惑了，它不仅负责休眠，唤醒后恢复也在它的内部实现，它的执行流程如下：
1、调用BSPPowerOFF，关闭休眠时不必要的设备电源，如USB
2、保存当前GPIO和LCD控制器等信息在内存中
3、设置GPIO为低功耗状态，关闭LCD等设备
4、调用OALCPUPowerOff，SDRAM进入自刷新模式，关闭CPU，等待中断唤醒
5、恢复保存在内存中的GPIO和LCD控制器等信息
6、调用BSPPowerOn打开相关设备电源，然后返回
在这个过程中，最容易出问题的部分在OALCPUPowerOff部分，这要从2440的休眠模式说起。
2440需要提供两路独立电源，一路电源给CPU及其内部逻辑供电，另一路电源单独给唤醒逻辑供电。当2440进入休眠时，CPU及其内部逻辑的这一路供电将会停止，仅保留唤醒逻辑的供电。唤醒逻辑支持EINT0-15和RTC中断，如果休眠期间产生这些中断，系统将恢复对CPU的供电并唤醒CPU。
由于CPU在休眠期间是掉电的，所以它唤醒后将会从地址0x00000000开始执行指令，也就是说，这时候CPU已经脱离了WinCE的执行空间，运行的是BootLoader！
BootLoader执行后，首先执行一些必要的初始化工作，如设置系统时钟等，然后检查GSTATUS2[1]位，如果被设置为1，表明系统是从睡眠中恢复的，BootLoader将跳过通常的启动流程，恢复对SDRAM的供电，然后从SDRAM恢复睡眠前保存下来的数据，包括唤醒地址，然后转到唤醒地址执行，返回WinCE的执行空间。
下面通过代码来详细这个过程(SMDK2440A/SRC/OAL/OALLIB/startup.s)：
;; OALCPUPowerOff调用入口
LEAF_ENTRY OALCPUPowerOff
; 1. Push SVC state onto our stack
stmdb sp!, {r4-r12}
stmdb sp!, {lr}
; 2. Save MMU & CPU Register to RAM
;; 注意：这里SLEEPDATA_BASE_VIRTUAL使用的是虚拟地址，其映射的物理地址必须和BootLoader中设定的一致
ldr r3, =SLEEPDATA_BASE_VIRTUAL ; base of Sleep mode storage
ldr r2, =Awake_address ; store Virtual return address
str r2, [r3], #4
mrc p15, 0, r2, c1, c0, 0 ; load r2 with MMU Control
ldr r0, =MMU_CTL_MASK ; mask off the undefined bits
bic r2, r2, r0
str r2, [r3], #4 ; store MMU Control data
mrc p15, 0, r2, c2, c0, 0 ; load r2 with TTB address.
ldr r0, =MMU_TTB_MASK ; mask off the undefined bits
bic r2, r2, r0
str r2, [r3], #4 ; store TTB address
mrc p15, 0, r2, c3, c0, 0 ; load r2 with domain access control.
str r2, [r3], #4 ; store domain access control
str sp, [r3], #4 ; store SVC stack pointer
mrs r2, spsr
str r2, [r3], #4 ; store SVC status register
mov r1, #Mode_FIQ:OR:I_Bit:OR:F_Bit ; Enter FIQ mode, no interrupts
msr cpsr, r1
mrs r2, spsr
stmia r3!, {r2, r8-r12, sp, lr} ; store the FIQ mode registers
mov r1, #Mode_ABT:OR:I_Bit:OR:F_Bit ; Enter ABT mode, no interrupts
msr cpsr, r1
mrs r0, spsr
stmia r3!, {r0, sp, lr} ; store the ABT mode Registers
mov r1, #Mode_IRQ:OR:I_Bit:OR:F_Bit ; Enter IRQ mode, no interrupts
msr cpsr, r1
mrs r0, spsr
stmia r3!, {r0, sp, lr} ; store the IRQ Mode Registers
mov r1, #Mode_UND:OR:I_Bit:OR:F_Bit ; Enter UND mode, no interrupts
msr cpsr, r1
mrs r0, spsr
stmia r3!, {r0, sp, lr} ; store the UND mode Registers
mov r1, #Mode_SYS:OR:I_Bit:OR:F_Bit ; Enter SYS mode, no interrupts
msr cpsr, r1
stmia r3!, {sp, lr} ; store the SYS mode Registers
mov r1, #Mode_SVC:OR:I_Bit:OR:F_Bit ; Back to SVC mode, no interrupts
msr cpsr, r1
; 3. do Checksum on the Sleepdata
ldr r3, =SLEEPDATA_BASE_VIRTUAL ; get pointer to SLEEPDATA
ldr r2, =0x0
ldr r0, =(SLEEPDATA_SIZE-1) ; get size of data structure (in words)
30
ldr r1, [r3], #4
and r1, r1, #0x1
mov r1, r1, ROR #31
add r2, r2, r1
subs r0, r0, #1
bne %b30
;; 保存数据的校验和放在GSTATUS3中，BootLoader中需要进行校验，只有校验正确才会返回WinCE，否则按冷启动的流程走
ldr r0, =vGPIOBASE
str r2, [r0, #oGSTATUS3] ; Store in Power Manager Scratch pad register
; 4. Interrupt Disable
ldr r0, =vINTBASE
mvn r2, #0
str r2, [r0, #oINTMSK]
str r2, [r0, #oSRCPND]
str r2, [r0, #oINTPND]
;; 5. Cache Flush
bl OALClearUTLB
bl OALFlushICache
ldr r0, = (DCACHE_LINES_PER_SET - 1)
ldr r1, = (DCACHE_NUM_SETS - 1)
ldr r2, = DCACHE_SET_INDEX_BIT
ldr r3, = DCACHE_LINE_SIZE
bl OALFlushDCache
; 6. Setting Wakeup External Interrupt(EINT0,1) Mode
ldr r0, =vGPIOBASE
ldr r1, =0x550a
str r1, [r0, #oGPFCON]
; 7. Go to Power-Off Mode
ldr r0, =vMISCCR ; hit the TLB
ldr r0, [r0]
ldr r0, =vCLKCON
ldr r0, [r0]
;; 内存进入自刷新模式，CPU掉电后保持内容
ldr r0, =vREFRESH
ldr r1, [r0] ; r1=rREFRESH
orr r1, r1, #(1 << 22)
ldr r2, =vMISCCR
ldr r3, [r2]
orr r3, r3, #(7<<17) ; Make sure that SCLK0:SCLK->0, SCLK1:SCLK->0, SCKE=L during boot-up
bic r3, r3, #(7<<20)
orr r3, r3, #(6<<20)
ldr r4, =vCLKCON
ldr r5, =0x1ffff8 ; Power Off Mode
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Sometimes it is not working in cache mode. So I modify to jump to ROM area.
;
;;; ldr r6, =0x92000000 ; make address to 0x9200 0020
;;; add r6, r6, #0x20 ;
;;; mov pc, r6 ; jump to Power off code in ROM
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
b SelfRefreshAndPowerOff
ALIGN 32 ; for I-Cache Line(32Byte, 8 Word)
;; 关闭CPU
SelfRefreshAndPowerOff ; run with Instruction Cache's code
str r1, [r0] ; Enable SDRAM self-refresh
str r3, [r2] ; MISCCR Setting
str r5, [r4] ; Power Off !!
b .
;; OALCPUPowerOff调用入口
LEAF_ENTRY OALCPUPowerOff
; 1. Push SVC state onto our stack
stmdb sp!, {r4-r12}
stmdb sp!, {lr}
; 2. Save MMU & CPU Register to RAM
;; 注意：这里SLEEPDATA_BASE_VIRTUAL使用的是虚拟地址，其映射的物理地址必须和BootLoader中设定的一致
ldr r3, =SLEEPDATA_BASE_VIRTUAL ; base of Sleep mode storage
ldr r2, =Awake_address ; store Virtual return address
str r2, [r3], #4
mrc p15, 0, r2, c1, c0, 0 ; load r2 with MMU Control
ldr r0, =MMU_CTL_MASK ; mask off the undefined bits
bic r2, r2, r0
str r2, [r3], #4 ; store MMU Control data
mrc p15, 0, r2, c2, c0, 0 ; load r2 with TTB address.
ldr r0, =MMU_TTB_MASK ; mask off the undefined bits
bic r2, r2, r0
str r2, [r3], #4 ; store TTB address
mrc p15, 0, r2, c3, c0, 0 ; load r2 with domain access control.
str r2, [r3], #4 ; store domain access control
str sp, [r3], #4 ; store SVC stack pointer
mrs r2, spsr
str r2, [r3], #4 ; store SVC status register
mov r1, #Mode_FIQ:OR:I_Bit:OR:F_Bit ; Enter FIQ mode, no interrupts
msr cpsr, r1
mrs r2, spsr
stmia r3!, {r2, r8-r12, sp, lr} ; store the FIQ mode registers
mov r1, #Mode_ABT:OR:I_Bit:OR:F_Bit ; Enter ABT mode, no interrupts
msr cpsr, r1
mrs r0, spsr
stmia r3!, {r0, sp, lr} ; store the ABT mode Registers
mov r1, #Mode_IRQ:OR:I_Bit:OR:F_Bit ; Enter IRQ mode, no interrupts
msr cpsr, r1
mrs r0, spsr
stmia r3!, {r0, sp, lr} ; store the IRQ Mode Registers
mov r1, #Mode_UND:OR:I_Bit:OR:F_Bit ; Enter UND mode, no interrupts
msr cpsr, r1
mrs r0, spsr
stmia r3!, {r0, sp, lr} ; store the UND mode Registers
mov r1, #Mode_SYS:OR:I_Bit:OR:F_Bit ; Enter SYS mode, no interrupts
msr cpsr, r1
stmia r3!, {sp, lr} ; store the SYS mode Registers
mov r1, #Mode_SVC:OR:I_Bit:OR:F_Bit ; Back to SVC mode, no interrupts
msr cpsr, r1
; 3. do Checksum on the Sleepdata
ldr r3, =SLEEPDATA_BASE_VIRTUAL ; get pointer to SLEEPDATA
ldr r2, =0x0
ldr r0, =(SLEEPDATA_SIZE-1) ; get size of data structure (in words)
30
ldr r1, [r3], #4
and r1, r1, #0x1
mov r1, r1, ROR #31
add r2, r2, r1
subs r0, r0, #1
bne %b30
;; 保存数据的校验和放在GSTATUS3中，BootLoader中需要进行校验，只有校验正确才会返回WinCE，否则按冷启动的流程走
ldr r0, =vGPIOBASE
str r2, [r0, #oGSTATUS3] ; Store in Power Manager Scratch pad register
; 4. Interrupt Disable
ldr r0, =vINTBASE
mvn r2, #0
str r2, [r0, #oINTMSK]
str r2, [r0, #oSRCPND]
str r2, [r0, #oINTPND]
;; 5. Cache Flush
bl OALClearUTLB
bl OALFlushICache
ldr r0, = (DCACHE_LINES_PER_SET - 1)
ldr r1, = (DCACHE_NUM_SETS - 1)
ldr r2, = DCACHE_SET_INDEX_BIT
ldr r3, = DCACHE_LINE_SIZE
bl OALFlushDCache
; 6. Setting Wakeup External Interrupt(EINT0,1) Mode
ldr r0, =vGPIOBASE
ldr r1, =0x550a
str r1, [r0, #oGPFCON]
; 7. Go to Power-Off Mode
ldr r0, =vMISCCR ; hit the TLB
ldr r0, [r0]
ldr r0, =vCLKCON
ldr r0, [r0]
;; 内存进入自刷新模式，CPU掉电后保持内容
ldr r0, =vREFRESH
ldr r1, [r0] ; r1=rREFRESH
orr r1, r1, #(1 << 22)
ldr r2, =vMISCCR
ldr r3, [r2]
orr r3, r3, #(7<<17) ; Make sure that SCLK0:SCLK->0, SCLK1:SCLK->0, SCKE=L during boot-up
bic r3, r3, #(7<<20)
orr r3, r3, #(6<<20)
ldr r4, =vCLKCON
ldr r5, =0x1ffff8 ; Power Off Mode
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Sometimes it is not working in cache mode. So I modify to jump to ROM area.
;
;;; ldr r6, =0x92000000 ; make address to 0x9200 0020
;;; add r6, r6, #0x20 ;
;;; mov pc, r6 ; jump to Power off code in ROM
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
b SelfRefreshAndPowerOff
ALIGN 32 ; for I-Cache Line(32Byte, 8 Word)
;; 关闭CPU
SelfRefreshAndPowerOff ; run with Instruction Cache's code
str r1, [r0] ; Enable SDRAM self-refresh
str r3, [r2] ; MISCCR Setting
str r5, [r4] ; Power Off !!
b .
下面是BootLoader中唤醒部分的代码：
;Check if the boot is caused by the wake-up from SLEEP mode.
ldr r1,=GSTATUS2
ldr r0,[r1]
tst r0,#0x2
;In case of the wake-up from SLEEP mode, go to SLEEP_WAKEUP handler.
bne WAKEUP_SLEEP
WAKEUP_SLEEP
;Release SCLKn after wake-up from the SLEEP mode.
ldr r1,=MISCCR
ldr r0,[r1]
bic r0,r0,#(7<<17) ;SCLK0:0->SCLK, SCLK1:0->SCLK, SCKE:0->=SCKE.
str r0,[r1]
;Set memory control registers
ldr r0,=SMRDATA
ldr r1,=BWSCON ;BWSCON Address
add r2, r0, #52 ;End address of SMRDATA
0
ldr r3, [r0], #4
str r3, [r1], #4
cmp r2, r0
bne %B0
mov r1,#256
0 subs r1,r1,#1 ;1) wait until the SelfRefresh is released.
bne %B0
;------------------------------------------------------------------------------
; Recover Process : Starting Point
;
; 1. Checksum Calculation saved Data
;; 这里的SLEEPDATA_BASE_PHYSICAL，必须上面的虚拟地址SLEEPDATA_BASE_VIRTUAL映射到相同的物理内存
ldr r5, =SLEEPDATA_BASE_PHYSICAL ; pointer to physical address of reserved Sleep mode info data structure
mov r3, r5 ; pointer for checksum calculation
ldr r2, =0x0
ldr r0, =(SLEEPDATA_SIZE-1) ; get size of data structure to do checksum on
50
ldr r1, [r3], #4 ; pointer to SLEEPDATA
and r1, r1, #0x1
mov r1, r1, ROR #31
add r2, r2, r1
subs r0, r0, #1 ; dec the count
bne %b50 ; loop till done
;; 检查校验和，如果不匹配，说明内存中保存的数据有问题，按冷启动执行
ldr r0,=GSTATUS3
ldr r3, [r0] ; get the Sleep data checksum from the Power Manager Scratch pad register
cmp r2, r3 ; compare to what we saved before going to sleep
bne BringUpWinCE ; bad news - do a cold boot
; 2. MMU Enable
ldr r10, [r5, #SleepState_MMUDOMAIN] ; load the MMU domain access info
ldr r9, [r5, #SleepState_MMUTTB] ; load the MMU TTB info
ldr r8, [r5, #SleepState_MMUCTL] ; load the MMU control info
ldr r7, [r5, #SleepState_WakeAddr ] ; load the LR address
nop
nop
nop
nop
nop
; if software reset
mov r1, #0
teq r1, r7
bne %f60
b BringUpWinCE
; wakeup routine
60 mcr p15, 0, r10, c3, c0, 0 ; setup access to domain 0
mcr p15, 0, r9, c2, c0, 0 ; PT address
mcr p15, 0, r0, c8, c7, 0 ; flush I+D TLBs
mcr p15, 0, r8, c1, c0, 0 ; restore MMU control
; 3. Jump to Kernel Image's fw.s (Awake_address)
mov pc, r7 ; jump to new VA (back up Power management stack)
nop
BringUpWinCE
; bad news, data lose, bring up wince again
mov r0, #2
ldr r1, =GSTATUS2
str r0, [r1]
本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/noodies/archive/2009/09/10/4538382.aspx |
转播
