sleep.S
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/*
* Low-level PXA250/210 sleep/wakeUp support
*
* Initial SA1110 code:
* Copyright (c) 2001 Cliff Brake <cbrake@accelent.com>
*
* Adapted for PXA by Nicolas Pitre:
* Copyright (c) 2002 Monta Vista Software, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <mach/hardware.h>
#include <mach/smemc.h>
#include <mach/pxa2xx-regs.h>
#define MDREFR_KDIV 0x200a4000 // all banks
#define CCCR_SLEEP 0x00000107 // L=7 2N=2 A=0 PPDIS=0 CPDIS=0
.text
#ifdef CONFIG_PXA3xx
/*
* pxa3xx_finish_suspend() - forces CPU into sleep state (S2D3C4)
*/
ENTRY(pxa3xx_finish_suspend)
mov r0, #0x06 @ S2D3C4 mode
mcr p14, 0, r0, c7, c0, 0 @ enter sleep
20: b 20b @ waiting for sleep
#endif /* CONFIG_PXA3xx */
#ifdef CONFIG_PXA27x
/*
* pxa27x_finish_suspend()
*
* Forces CPU into sleep state.
*
* r0 = value for PWRMODE M field for desired sleep state
*/
ENTRY(pxa27x_finish_suspend)
@ Put the processor to sleep
@ (also workaround for sighting 28071)
@ prepare value for sleep mode
mov r1, r0 @ sleep mode
@ prepare pointer to physical address 0 (virtual mapping in generic.c)
mov r2, #UNCACHED_PHYS_0
@ prepare SDRAM refresh settings
ldr r4, =MDREFR
ldr r5, [r4]
@ enable SDRAM self-refresh mode
orr r5, r5, #MDREFR_SLFRSH
@ set SDCLKx divide-by-2 bits (this is part of a workaround for Errata 50)
ldr r6, =MDREFR_KDIV
orr r5, r5, r6
@ Intel PXA270 Specification Update notes problems sleeping
@ with core operating above 91 MHz
@ (see Errata 50, ...processor does not exit from sleep...)
ldr r6, =CCCR
ldr r8, [r6] @ keep original value for resume
ldr r7, =CCCR_SLEEP @ prepare CCCR sleep value
mov r0, #0x2 @ prepare value for CLKCFG
@ align execution to a cache line
b pxa_cpu_do_suspend
#endif
#ifdef CONFIG_PXA25x
/*
* pxa25x_finish_suspend()
*
* Forces CPU into sleep state.
*
* r0 = value for PWRMODE M field for desired sleep state
*/
ENTRY(pxa25x_finish_suspend)
@ prepare value for sleep mode
mov r1, r0 @ sleep mode
@ prepare pointer to physical address 0 (virtual mapping in generic.c)
mov r2, #UNCACHED_PHYS_0
@ prepare SDRAM refresh settings
ldr r4, =MDREFR
ldr r5, [r4]
@ enable SDRAM self-refresh mode
orr r5, r5, #MDREFR_SLFRSH
@ Intel PXA255 Specification Update notes problems
@ about suspending with PXBus operating above 133MHz
@ (see Errata 31, GPIO output signals, ... unpredictable in sleep
@
@ We keep the change-down close to the actual suspend on SDRAM
@ as possible to eliminate messing about with the refresh clock
@ as the system will restore with the original speed settings
@
@ Ben Dooks, 13-Sep-2004
ldr r6, =CCCR
ldr r8, [r6] @ keep original value for resume
@ ensure x1 for run and turbo mode with memory clock
bic r7, r8, #CCCR_M_MASK | CCCR_N_MASK
orr r7, r7, #(1<<5) | (2<<7)
@ check that the memory frequency is within limits
and r14, r7, #CCCR_L_MASK
teq r14, #1
bicne r7, r7, #CCCR_L_MASK
orrne r7, r7, #1 @@ 99.53MHz
@ get ready for the change
@ note, turbo is not preserved over sleep so there is no
@ point in preserving it here. we save it on the stack with the
@ other CP registers instead.
mov r0, #0
mcr p14, 0, r0, c6, c0, 0
orr r0, r0, #2 @ initiate change bit
b pxa_cpu_do_suspend
#endif
.ltorg
.align 5
pxa_cpu_do_suspend:
@ All needed values are now in registers.
@ These last instructions should be in cache
@ initiate the frequency change...
str r7, [r6]
mcr p14, 0, r0, c6, c0, 0
@ restore the original cpu speed value for resume
str r8, [r6]
@ need 6 13-MHz cycles before changing PWRMODE
@ just set frequency to 91-MHz... 6*91/13 = 42
mov r0, #42
10: subs r0, r0, #1
bne 10b
@ Do not reorder...
@ Intel PXA270 Specification Update notes problems performing
@ external accesses after SDRAM is put in self-refresh mode
@ (see Errata 39 ...hangs when entering self-refresh mode)
@ force address lines low by reading at physical address 0
ldr r3, [r2]
@ put SDRAM into self-refresh
str r5, [r4]
@ enter sleep mode
mcr p14, 0, r1, c7, c0, 0 @ PWRMODE
20: b 20b @ loop waiting for sleep