diff options
Diffstat (limited to 'arch/powerpc/kernel/idle_6xx.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_6xx.S | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S new file mode 100644 index 0000000000..3c09735636 --- /dev/null +++ b/arch/powerpc/kernel/idle_6xx.S @@ -0,0 +1,191 @@ +/* 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 + PPC_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 |