1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * This file contains the power_save function for 6xx & 7xxx CPUs 4 * rewritten in assembler 5 * 6 * Warning ! This code assumes that if your machine has a 750fx 7 * it will have PLL 1 set to low speed mode (used during NAP/DOZE). 8 * if this is not the case some additional changes will have to 9 * be done to check a runtime var (a bit like powersave-nap) 10 */ 11 12#include <linux/threads.h> 13#include <asm/reg.h> 14#include <asm/page.h> 15#include <asm/cputable.h> 16#include <asm/thread_info.h> 17#include <asm/ppc_asm.h> 18#include <asm/asm-offsets.h> 19#include <asm/feature-fixups.h> 20 21 .text 22 23/* 24 * Init idle, called at early CPU setup time from head.S for each CPU 25 * Make sure no rest of NAP mode remains in HID0, save default 26 * values for some CPU specific registers. Called with r24 27 * containing CPU number and r3 reloc offset 28 */ 29_GLOBAL(init_idle_6xx) 30BEGIN_FTR_SECTION 31 mfspr r4,SPRN_HID0 32 rlwinm r4,r4,0,10,8 /* Clear NAP */ 33 mtspr SPRN_HID0, r4 34 b 1f 35END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) 36 blr 371: 38 slwi r5,r24,2 39 add r5,r5,r3 40BEGIN_FTR_SECTION 41 mfspr r4,SPRN_MSSCR0 42 addis r6,r5, nap_save_msscr0@ha 43 stw r4,nap_save_msscr0@l(r6) 44END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) 45BEGIN_FTR_SECTION 46 mfspr r4,SPRN_HID1 47 addis r6,r5,nap_save_hid1@ha 48 stw r4,nap_save_hid1@l(r6) 49END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) 50 blr 51 52/* 53 * Here is the power_save_6xx function. This could eventually be 54 * split into several functions & changing the function pointer 55 * depending on the various features. 56 */ 57_GLOBAL(ppc6xx_idle) 58 /* Check if we can nap or doze, put HID0 mask in r3 59 */ 60 lis r3, 0 61BEGIN_FTR_SECTION 62 lis r3,HID0_DOZE@h 63END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) 64BEGIN_FTR_SECTION 65 /* We must dynamically check for the NAP feature as it 66 * can be cleared by CPU init after the fixups are done 67 */ 68 lis r4,cur_cpu_spec@ha 69 lwz r4,cur_cpu_spec@l(r4) 70 lwz r4,CPU_SPEC_FEATURES(r4) 71 andi. r0,r4,CPU_FTR_CAN_NAP 72 beq 1f 73 /* Now check if user or arch enabled NAP mode */ 74 lis r4,powersave_nap@ha 75 lwz r4,powersave_nap@l(r4) 76 cmpwi 0,r4,0 77 beq 1f 78 lis r3,HID0_NAP@h 791: 80END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP) 81 cmpwi 0,r3,0 82 beqlr 83 84 /* Some pre-nap cleanups needed on some CPUs */ 85 andis. r0,r3,HID0_NAP@h 86 beq 2f 87BEGIN_FTR_SECTION 88 /* Disable L2 prefetch on some 745x and try to ensure 89 * L2 prefetch engines are idle. As explained by errata 90 * text, we can't be sure they are, we just hope very hard 91 * that well be enough (sic !). At least I noticed Apple 92 * doesn't even bother doing the dcbf's here... 93 */ 94 mfspr r4,SPRN_MSSCR0 95 rlwinm r4,r4,0,0,29 96 sync 97 mtspr SPRN_MSSCR0,r4 98 sync 99 isync 100 lis r4,KERNELBASE@h 101 dcbf 0,r4 102 dcbf 0,r4 103 dcbf 0,r4 104 dcbf 0,r4 105END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) 1062: 107BEGIN_FTR_SECTION 108 /* Go to low speed mode on some 750FX */ 109 lis r4,powersave_lowspeed@ha 110 lwz r4,powersave_lowspeed@l(r4) 111 cmpwi 0,r4,0 112 beq 1f 113 mfspr r4,SPRN_HID1 114 oris r4,r4,0x0001 115 mtspr SPRN_HID1,r4 1161: 117END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) 118 119 /* Go to NAP or DOZE now */ 120 mfspr r4,SPRN_HID0 121 lis r5,(HID0_NAP|HID0_SLEEP)@h 122BEGIN_FTR_SECTION 123 oris r5,r5,HID0_DOZE@h 124END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE) 125 andc r4,r4,r5 126 or r4,r4,r3 127BEGIN_FTR_SECTION 128 oris r4,r4,HID0_DPM@h /* that should be done once for all */ 129END_FTR_SECTION_IFCLR(CPU_FTR_NO_DPM) 130 mtspr SPRN_HID0,r4 131BEGIN_FTR_SECTION 132 DSSALL 133 sync 134END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC) 135 lwz r8,TI_LOCAL_FLAGS(r2) /* set napping bit */ 136 ori r8,r8,_TLF_NAPPING /* so when we take an exception */ 137 stw r8,TI_LOCAL_FLAGS(r2) /* it will return to our caller */ 138 mfmsr r7 139 ori r7,r7,MSR_EE 140 oris r7,r7,MSR_POW@h 1411: sync 142 mtmsr r7 143 isync 144 b 1b 145 146/* 147 * Return from NAP/DOZE mode, restore some CPU specific registers, 148 * we are called with DR/IR still off and r2 containing physical 149 * address of current. R11 points to the exception frame (physical 150 * address). We have to preserve r10. 151 */ 152_GLOBAL(power_save_ppc32_restore) 153 lwz r9,_LINK(r11) /* interrupted in ppc6xx_idle: */ 154 stw r9,_NIP(r11) /* make it do a blr */ 155 156#ifdef CONFIG_SMP 157 lwz r11,TASK_CPU(r2) /* get cpu number * 4 */ 158 slwi r11,r11,2 159#else 160 li r11,0 161#endif 162 /* Todo make sure all these are in the same page 163 * and load r11 (@ha part + CPU offset) only once 164 */ 165BEGIN_FTR_SECTION 166 mfspr r9,SPRN_HID0 167 andis. r9,r9,HID0_NAP@h 168 beq 1f 169#ifdef CONFIG_VMAP_STACK 170 addis r9, r11, nap_save_msscr0@ha 171#else 172 addis r9,r11,(nap_save_msscr0-KERNELBASE)@ha 173#endif 174 lwz r9,nap_save_msscr0@l(r9) 175 mtspr SPRN_MSSCR0, r9 176 sync 177 isync 1781: 179END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR) 180BEGIN_FTR_SECTION 181#ifdef CONFIG_VMAP_STACK 182 addis r9, r11, nap_save_hid1@ha 183#else 184 addis r9,r11,(nap_save_hid1-KERNELBASE)@ha 185#endif 186 lwz r9,nap_save_hid1@l(r9) 187 mtspr SPRN_HID1, r9 188END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) 189 b transfer_to_handler_cont 190_ASM_NOKPROBE_SYMBOL(power_save_ppc32_restore) 191 192 .data 193 194_GLOBAL(nap_save_msscr0) 195 .space 4*NR_CPUS 196 197_GLOBAL(nap_save_hid1) 198 .space 4*NR_CPUS 199 200_GLOBAL(powersave_lowspeed) 201 .long 0 202