diff options
Diffstat (limited to 'arch/ppc/kernel/idle_power4.S')
| -rw-r--r-- | arch/ppc/kernel/idle_power4.S | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/arch/ppc/kernel/idle_power4.S b/arch/ppc/kernel/idle_power4.S new file mode 100644 index 00000000000..73a58ff0390 --- /dev/null +++ b/arch/ppc/kernel/idle_power4.S @@ -0,0 +1,91 @@ +/* + * 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 + * So nothing for now. Called with r24 containing CPU number and r3 + * reloc offset + */ + .globl init_idle_power4 +init_idle_power4: + 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. + */ + .globl power4_idle +power4_idle: +BEGIN_FTR_SECTION + blr +END_FTR_SECTION_IFCLR(CPU_FTR_CAN_NAP) + /* 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 + beqlr + /* Now check if user or arch enabled NAP mode */ + lis r4,powersave_nap@ha + lwz r4,powersave_nap@l(r4) + cmpwi 0,r4,0 + 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: + /* Go to NAP now */ +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 + + .globl powersave_nap +powersave_nap: + .long 0 |