/*
* 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/config.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/hardware.h>
#include <asm/arch/pxa-regs.h>
#ifdef CONFIG_PXA27x // workaround for Errata 50
#define MDREFR_KDIV 0x200a4000 // all banks
#define CCCR_SLEEP 0x00000107 // L=7 2N=2 A=0 PPDIS=0 CPDIS=0
#endif
.text
/*
* pxa_cpu_suspend()
*
* Forces CPU into sleep state.
*
* r0 = value for PWRMODE M field for desired sleep state
*/
ENTRY(pxa_cpu_suspend)
#ifndef CONFIG_IWMMXT
mra r2, r3, acc0
#endif
stmfd sp!, {r2 - r12, lr} @ save registers on stack
@ get coprocessor registers
mrc p14, 0, r3, c6, c0, 0 @ clock configuration, for turbo mode
mrc p15, 0, r4, c15, c1, 0 @ CP access reg
mrc p15, 0, r5, c13, c0, 0 @ PID
mrc p15, 0, r6, c3, c0, 0 @ domain ID
mrc p15, 0, r7, c2, c0, 0 @ translation table base addr
mrc p15, 0, r8, c1, c1, 0 @ auxiliary control reg
mrc p15, 0, r9, c1, c0, 0 @ control reg
bic r3, r3, #2 @ clear frequency change bit
@ store them plus current virtual stack ptr on stack
mov r10, sp
stmfd sp!, {r3 - r10}
mov r5, r0 @ save sleep mode
@ preserve phys address of stack
mov r0, sp
bl sleep_phys_sp
ldr r1, =sleep_save_sp
str r0, [r1]
@ clean data cache
bl xscale_flush_kern_cache_all
@ Put the processor to sleep
@ (also workaround for sighting 28071)
@ prepare value for sleep mode
mov r1, r5 @ 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
#ifdef CONFIG_PXA27x
@ set SDCLKx divide-by-2 bits (this is part of a workaround for Errata 50)
ldr r6, =MDREFR_KDIV
orr r5, r5, r6
#endif
#ifdef CONFIG_PXA25x
@ 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
#endif
#ifdef CONFIG_PXA27x
@ 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
#endif
@ align execution to a cache line
b 1f
.ltorg
.align 5
1:
@ All needed values are now in registers.
@ These last instructions should be in cache
#if defined(CONFIG_PXA25x) || defined(CONFIG_PXA27x)
@ 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
#endif
@ 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
/*
* cpu_pxa_resume()
*
* entry point from bootloader into kernel during resume
*
* Note: Yes, part of the following code is located into the .data section.
* This is to allow sleep_save_sp to be accessed with a relative load
* while we can't rely on any MMU translation. We could have put
* sleep_save_sp in the .text section as well, but some setups might
* insist on it to be truly read-only.
*/
.data
.align 5
ENTRY(pxa_cpu_resume)
mov r0, #PSR_I_BIT | PSR_F_BIT | SVC_MODE @ set SVC, irqs off
msr cpsr_c, r0
ldr r0, sleep_save_sp @ stack phys addr
ldr r2, =resume_after_mmu @ its absolute virtual address
ldmfd r0, {r3 - r9, sp} @ CP regs + virt stack ptr
mov r1, #0
mcr p15, 0, r1, c8, c7, 0 @ invalidate I & D TLBs
mcr p15, 0, r1, c7, c7, 0 @ invalidate I & D caches, BTB
#ifdef CONFIG_XSCALE_CACHE_ERRATA
bic r9, r9, #0x0004 @ see cpu_xscale_proc_init
#endif
mcr p14, 0, r3, c6, c0, 0 @ clock configuration, turbo mode.
mcr p15, 0, r4, c15, c1, 0 @ CP access reg
mcr p15, 0, r5, c13, c0, 0 @ PID
mcr p15, 0, r6, c3, c0, 0 @ domain ID
mcr p15, 0, r7, c2, c0, 0 @ translation table base addr
mcr p15, 0, r8, c1, c1, 0 @ auxiliary control reg
b resume_turn_on_mmu @ cache align execution
.align 5
resume_turn_on_mmu:
mcr p15, 0, r9, c1, c0, 0 @ turn on MMU, caches, etc.
@ Let us ensure we jump to resume_after_mmu only when the mcr above
@ actually took effect. They call it the "cpwait" operation.
mrc p15, 0, r1, c2, c0, 0 @ queue a dependency on CP15
sub pc, r2, r1, lsr #32 @ jump to virtual addr
nop
nop
nop
sleep_save_sp:
.word 0 @ preserve stack phys ptr here
.text
resume_after_mmu:
#ifdef CONFIG_XSCALE_CACHE_ERRATA
bl cpu_xscale_proc_init
#endif
ldmfd sp!, {r2, r3}
#ifndef CONFIG_IWMMXT
mar acc0, r2, r3
#endif
ldmfd sp!, {r4 - r12, pc} @ return to caller
