1/* 2 * This file contains the power_save function for 6xx & 7xxx CPUs 3 * rewritten in assembler 4 * 5 * Warning ! This code assumes that if your machine has a 750fx 6 * it will have PLL 1 set to low speed mode (used during NAP/DOZE). 7 * if this is not the case some additional changes will have to 8 * be done to check a runtime var (a bit like powersave-nap) 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16#include <linux/threads.h> 17#include <asm/reg.h> 18#include <asm/page.h> 19#include <asm/cputable.h> 20#include <asm/thread_info.h> 21#include <asm/ppc_asm.h> 22#include <asm/asm-offsets.h> 23#include <asm/feature-fixups.h> 24 25 .text 26 27/* 28 * Init idle, called at early CPU setup time from head.S for each CPU 29 * Make sure no rest of NAP mode remains in HID0, save default 30 * values for some CPU specific registers. Called with r24 31 * containing CPU number and r3 reloc offset 32 */ 33_GLOBAL(init_idle_6xx) 34BEGIN_FTR_SECTION 35 mfspr r4,SPRN_HID0 36 rlwinm r4,r4,0,10,8 /* Clear NAP */ 37 mtspr SPRN_HID0, r4 38 b 1f 39END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) 40 blr 411: 42 slwi r5,r24,2 43 add r5,r5,r3 44BEGIN_FTR_SECTION 45 mfspr r4,SPRN_MSSCR0 46 addis r6,r5, nap_save_msscr0@ha 47 stw r4,nap_save_msscr0@l(r6) 48END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) 49BEGIN_FTR_SECTION 50 mfspr r4,SPRN_HID1 51 addis r6,r5,nap_save_hid1@ha 52 stw r4,nap_save_hid1@l(r6) 53END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) 54 blr 55 56/* 57 * Here is the power_save_6xx function. This could eventually be 58 * split into several functions & changing the function pointer 59 * depending on the various features. 60 */ 61_GLOBAL(ppc6xx_idle) 62 /* Check if we can nap or doze, put HID0 mask in r3 63 */ 64 lis r3, 0 65BEGIN_FTR_SECTION 66 lis r3,HID0_DOZE@h 67END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) 68BEGIN_FTR_SECTION 69 /* We must dynamically check for the NAP feature as it 70 * can be cleared by CPU init after the fixups are done 71 */ 72 lis r4,cur_cpu_spec@ha 73 lwz r4,cur_cpu_spec@l(r4) 74 lwz r4,CPU_SPEC_FEATURES(r4) 75 andi. r0,r4,CPU_FTR_CAN_NAP 76 beq 1f 77 /* Now check if user or arch enabled NAP mode */ 78 lis r4,powersave_nap@ha 79 lwz r4,powersave_nap@l(r4) 80 cmpwi 0,r4,0 81 beq 1f 82 lis r3,HID0_NAP@h 831: 84END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) 85 cmpwi 0,r3,0 86 beqlr 87 88 /* Some pre-nap cleanups needed on some CPUs */ 89 andis. r0,r3,HID0_NAP@h 90 beq 2f 91BEGIN_FTR_SECTION 92 /* Disable L2 prefetch on some 745x and try to ensure 93 * L2 prefetch engines are idle. As explained by errata 94 * text, we can't be sure they are, we just hope very hard 95 * that well be enough (sic !). At least I noticed Apple 96 * doesn't even bother doing the dcbf's here... 97 */ 98 mfspr r4,SPRN_MSSCR0 99 rlwinm r4,r4,0,0,29 100 sync 101 mtspr SPRN_MSSCR0,r4 102 sync 103 isync 104 lis r4,KERNELBASE@h 105 dcbf 0,r4 106 dcbf 0,r4 107 dcbf 0,r4 108 dcbf 0,r4 109END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) 1102: 111BEGIN_FTR_SECTION 112 /* Go to low speed mode on some 750FX */ 113 lis r4,powersave_lowspeed@ha 114 lwz r4,powersave_lowspeed@l(r4) 115 cmpwi 0,r4,0 116 beq 1f 117 mfspr r4,SPRN_HID1 118 oris r4,r4,0x0001 119 mtspr SPRN_HID1,r4 1201: 121END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) 122 123 /* Go to NAP or DOZE now */ 124 mfspr r4,SPRN_HID0 125 lis r5,(HID0_NAP|HID0_SLEEP)@h 126BEGIN_FTR_SECTION 127 oris r5,r5,HID0_DOZE@h 128END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) 129 andc r4,r4,r5 130 or r4,r4,r3 131BEGIN_FTR_SECTION 132 oris r4,r4,HID0_DPM@h /* that should be done once for all */ 133END_FTR_SECTION_IFCLR(CPU_FTR_NO_DPM) 134 mtspr SPRN_HID0,r4 135BEGIN_FTR_SECTION 136 DSSALL 137 sync 138END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) 139 CURRENT_THREAD_INFO(r9, r1) 140 lwz r8,TI_LOCAL_FLAGS(r9) /* set napping bit */ 141 ori r8,r8,_TLF_NAPPING /* so when we take an exception */ 142 stw r8,TI_LOCAL_FLAGS(r9) /* it will return to our caller */ 143 mfmsr r7 144 ori r7,r7,MSR_EE 145 oris r7,r7,MSR_POW@h 1461: sync 147 mtmsr r7 148 isync 149 b 1b 150 151/* 152 * Return from NAP/DOZE mode, restore some CPU specific registers, 153 * we are called with DR/IR still off and r2 containing physical 154 * address of current. R11 points to the exception frame (physical 155 * address). We have to preserve r10. 156 */ 157_GLOBAL(power_save_ppc32_restore) 158 lwz r9,_LINK(r11) /* interrupted in ppc6xx_idle: */ 159 stw r9,_NIP(r11) /* make it do a blr */ 160 161#ifdef CONFIG_SMP 162 CURRENT_THREAD_INFO(r12, r11) 163 lwz r11,TI_CPU(r12) /* get cpu number * 4 */ 164 slwi r11,r11,2 165#else 166 li r11,0 167#endif 168 /* Todo make sure all these are in the same page 169 * and load r11 (@ha part + CPU offset) only once 170 */ 171BEGIN_FTR_SECTION 172 mfspr r9,SPRN_HID0 173 andis. r9,r9,HID0_NAP@h 174 beq 1f 175 addis r9,r11,(nap_save_msscr0-KERNELBASE)@ha 176 lwz r9,nap_save_msscr0@l(r9) 177 mtspr SPRN_MSSCR0, r9 178 sync 179 isync 1801: 181END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) 182BEGIN_FTR_SECTION 183 addis r9,r11,(nap_save_hid1-KERNELBASE)@ha 184 lwz r9,nap_save_hid1@l(r9) 185 mtspr SPRN_HID1, r9 186END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) 187 b transfer_to_handler_cont 188 189 .data 190 191_GLOBAL(nap_save_msscr0) 192 .space 4*NR_CPUS 193 194_GLOBAL(nap_save_hid1) 195 .space 4*NR_CPUS 196 197_GLOBAL(powersave_lowspeed) 198 .long 0 199