| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * 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) |
| */ |
| |
| #include <linux/threads.h> |
| #include <asm/reg.h> |
| #include <asm/page.h> |
| #include <asm/cputable.h> |
| #include <asm/thread_info.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/feature-fixups.h> |
| |
| .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 |
| |
| /* 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) |
| 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) |
| lwz r8,TI_LOCAL_FLAGS(r2) /* set napping bit */ |
| ori r8,r8,_TLF_NAPPING /* so when we take an exception */ |
| stw r8,TI_LOCAL_FLAGS(r2) /* it will return to our caller */ |
| mfmsr r7 |
| ori r7,r7,MSR_EE |
| oris r7,r7,MSR_POW@h |
| 1: sync |
| mtmsr r7 |
| isync |
| b 1b |
| |
| /* |
| * Return from NAP/DOZE mode, restore some CPU specific registers, |
| * R11 points to the exception frame. We have to preserve r10. |
| */ |
| _GLOBAL(power_save_ppc32_restore) |
| lwz r9,_LINK(r11) /* interrupted in ppc6xx_idle: */ |
| stw r9,_NIP(r11) /* make it do a blr */ |
| |
| #ifdef CONFIG_SMP |
| lwz r11,TASK_CPU(r2) /* get cpu number * 4 */ |
| slwi r11,r11,2 |
| #else |
| li r11,0 |
| #endif |
| /* Todo make sure all these are in the same page |
| * and load r11 (@ha part + CPU offset) only once |
| */ |
| BEGIN_FTR_SECTION |
| mfspr r9,SPRN_HID0 |
| andis. r9,r9,HID0_NAP@h |
| beq 1f |
| addis r9, r11, nap_save_msscr0@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@ha |
| lwz r9,nap_save_hid1@l(r9) |
| mtspr SPRN_HID1, r9 |
| END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX) |
| blr |
| _ASM_NOKPROBE_SYMBOL(power_save_ppc32_restore) |
| |
| .data |
| |
| _GLOBAL(nap_save_msscr0) |
| .space 4*NR_CPUS |
| |
| _GLOBAL(nap_save_hid1) |
| .space 4*NR_CPUS |
| |
| _GLOBAL(powersave_lowspeed) |
| .long 0 |
