diff options
Diffstat (limited to 'arch/ppc/kernel/idle_6xx.S')
| -rw-r--r-- | arch/ppc/kernel/idle_6xx.S | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/arch/ppc/kernel/idle_6xx.S b/arch/ppc/kernel/idle_6xx.S new file mode 100644 index 00000000000..25d009c75f7 --- /dev/null +++ b/arch/ppc/kernel/idle_6xx.S @@ -0,0 +1,233 @@ +/* + * This file contains the power_save function for 6xx & 7xxx CPUs + * rewritten in assembler + * + * Warning ! This code assumes that if your machine has a 750fx + * it will have PLL 1 set to low speed mode (used during NAP/DOZE). + * if this is not the case some additional changes will have to + * be done to check a runtime var (a bit like powersave-nap) + * + * 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; either version + * 2 of the License, or (at your option) any later version. + */ + +#include <linux/config.h> +#include <linux/threads.h> +#include <asm/processor.h> +#include <asm/page.h> +#include <asm/cputable.h> +#include <asm/thread_info.h> +#include <asm/ppc_asm.h> +#include <asm/offsets.h> + +#undef DEBUG + + .text + +/* + * Init idle, called at early CPU setup time from head.S for each CPU + * Make sure no rest of NAP mode remains in HID0, save default + * values for some CPU specific registers. Called with r24 + * containing CPU number and r3 reloc offset + */ +_GLOBAL(init_idle_6xx) +BEGIN_FTR_SECTION + mfspr r4,SPRN_HID0 + rlwinm r4,r4,0,10,8 /* Clear NAP */ + mtspr SPRN_HID0, r4 + b 1f +END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) + blr +1: + slwi r5,r24,2 + add r5,r5,r3 +BEGIN_FTR_SECTION + mfspr r4,SPRN_MSSCR0 + addis r6,r5, nap_save_msscr0@ha + stw r4,nap_save_msscr0@l(r6) +END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) +BEGIN_FTR_SECTION + mfspr r4,SPRN_HID1 + addis r6,r5,nap_save_hid1@ha + stw r4,nap_save_hid1@l(r6) +END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) + blr + +/* + * Here is the power_save_6xx function. This could eventually be + * split into several functions & changing the function pointer + * depending on the various features. + */ +_GLOBAL(ppc6xx_idle) + /* Check if we can nap or doze, put HID0 mask in r3 + */ + lis r3, 0 +BEGIN_FTR_SECTION + lis r3,HID0_DOZE@h +END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) +BEGIN_FTR_SECTION + /* We must dynamically check for the NAP feature as it + * can be cleared by CPU init after the fixups are done + */ + lis r4,cur_cpu_spec@ha + lwz r4,cur_cpu_spec@l(r4) + lwz r4,CPU_SPEC_FEATURES(r4) + andi. r0,r4,CPU_FTR_CAN_NAP + beq 1f + /* Now check if user or arch enabled NAP mode */ + lis r4,powersave_nap@ha + lwz r4,powersave_nap@l(r4) + cmpwi 0,r4,0 + beq 1f + lis r3,HID0_NAP@h +1: +END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) + cmpwi 0,r3,0 + beqlr + + /* Clear MSR:EE */ + mfmsr r7 + rlwinm r0,r7,0,17,15 + mtmsr r0 + + /* Check current_thread_info()->flags */ + rlwinm r4,r1,0,0,18 + lwz r4,TI_FLAGS(r4) + andi. r0,r4,_TIF_NEED_RESCHED + beq 1f + mtmsr r7 /* out of line this ? */ + blr +1: + /* Some pre-nap cleanups needed on some CPUs */ + andis. r0,r3,HID0_NAP@h + beq 2f +BEGIN_FTR_SECTION + /* Disable L2 prefetch on some 745x and try to ensure + * L2 prefetch engines are idle. As explained by errata + * text, we can't be sure they are, we just hope very hard + * that well be enough (sic !). At least I noticed Apple + * doesn't even bother doing the dcbf's here... + */ + mfspr r4,SPRN_MSSCR0 + rlwinm r4,r4,0,0,29 + sync + mtspr SPRN_MSSCR0,r4 + sync + isync + lis r4,KERNELBASE@h + dcbf 0,r4 + dcbf 0,r4 + dcbf 0,r4 + dcbf 0,r4 +END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) +#ifdef DEBUG + lis r6,nap_enter_count@ha + lwz r4,nap_enter_count@l(r6) + addi r4,r4,1 + stw r4,nap_enter_count@l(r6) +#endif +2: +BEGIN_FTR_SECTION + /* Go to low speed mode on some 750FX */ + lis r4,powersave_lowspeed@ha + lwz r4,powersave_lowspeed@l(r4) + cmpwi 0,r4,0 + beq 1f + mfspr r4,SPRN_HID1 + oris r4,r4,0x0001 + mtspr SPRN_HID1,r4 +1: +END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) + + /* Go to NAP or DOZE now */ + mfspr r4,SPRN_HID0 + lis r5,(HID0_NAP|HID0_SLEEP)@h +BEGIN_FTR_SECTION + oris r5,r5,HID0_DOZE@h +END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) + andc r4,r4,r5 + or r4,r4,r3 +BEGIN_FTR_SECTION + oris r4,r4,HID0_DPM@h /* that should be done once for all */ +END_FTR_SECTION_IFCLR(CPU_FTR_NO_DPM) + mtspr SPRN_HID0,r4 +BEGIN_FTR_SECTION + DSSALL + sync +END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) + ori r7,r7,MSR_EE /* Could be ommited (already set) */ + oris r7,r7,MSR_POW@h + sync + isync + mtmsr r7 + isync + sync + blr + +/* + * Return from NAP/DOZE mode, restore some CPU specific registers, + * we are called with DR/IR still off and r2 containing physical + * address of current. + */ +_GLOBAL(power_save_6xx_restore) + mfspr r11,SPRN_HID0 + rlwinm. r11,r11,0,10,8 /* Clear NAP & copy NAP bit !state to cr1 EQ */ + cror 4*cr1+eq,4*cr0+eq,4*cr0+eq +BEGIN_FTR_SECTION + rlwinm r11,r11,0,9,7 /* Clear DOZE */ +END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) + mtspr SPRN_HID0, r11 + +#ifdef DEBUG + beq cr1,1f + lis r11,(nap_return_count-KERNELBASE)@ha + lwz r9,nap_return_count@l(r11) + addi r9,r9,1 + stw r9,nap_return_count@l(r11) +1: +#endif + + rlwinm r9,r1,0,0,18 + tophys(r9,r9) + lwz r11,TI_CPU(r9) + slwi r11,r11,2 + /* Todo make sure all these are in the same page + * and load r22 (@ha part + CPU offset) only once + */ +BEGIN_FTR_SECTION + beq cr1,1f + addis r9,r11,(nap_save_msscr0-KERNELBASE)@ha + lwz r9,nap_save_msscr0@l(r9) + mtspr SPRN_MSSCR0, r9 + sync + isync +1: +END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) +BEGIN_FTR_SECTION + addis r9,r11,(nap_save_hid1-KERNELBASE)@ha + lwz r9,nap_save_hid1@l(r9) + mtspr SPRN_HID1, r9 +END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) + b transfer_to_handler_cont + + .data + +_GLOBAL(nap_save_msscr0) + .space 4*NR_CPUS + +_GLOBAL(nap_save_hid1) + .space 4*NR_CPUS + +_GLOBAL(powersave_nap) + .long 0 +_GLOBAL(powersave_lowspeed) + .long 0 + +#ifdef DEBUG +_GLOBAL(nap_enter_count) + .space 4 +_GLOBAL(nap_return_count) + .space 4 +#endif |