/* * 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 <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