[PATCH v5 2/4] powerpc/85xx: add hardware automatically enter altivec idle state
From: Dongsheng Wang <hidden>
Date: 2013-10-15 09:29:29
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: Wang Dongsheng <redacted> Each core's AltiVec unit may be placed into a power savings mode by turning off power to the unit. Core hardware will automatically power down the AltiVec unit after no AltiVec instructions have executed in N cycles. The AltiVec power-control is triggered by hardware. Signed-off-by: Wang Dongsheng <redacted> --- *v3: Assembly code instead of C code. *v2: Remove: delete setup_idle_hw_governor function. delete "Fix erratum" for rev1. Move: move setup_* into __setup/restore_cpu_e6500. arch/powerpc/kernel/cpu_setup_fsl_booke.S | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)
diff --git a/arch/powerpc/kernel/cpu_setup_fsl_booke.S b/arch/powerpc/kernel/cpu_setup_fsl_booke.S
index bfb18c7..4789056 100644
--- a/arch/powerpc/kernel/cpu_setup_fsl_booke.S
+++ b/arch/powerpc/kernel/cpu_setup_fsl_booke.S@@ -53,11 +53,31 @@ _GLOBAL(__e500_dcache_setup) isync blr +/* + * FIXME - we haven't yet done testing to determine a reasonable default + * value for AV_WAIT_IDLE_BIT. + */ +#define AV_WAIT_IDLE_BIT 50 /* 1ms, TB frequency is 41.66MHZ */ +_GLOBAL(setup_altivec_idle) + mfspr r3, SPRN_PWRMGTCR0 + + /* Enable Altivec Idle */ + oris r3, r3, PWRMGTCR0_AV_IDLE_PD_EN@h + li r11, AV_WAIT_IDLE_BIT + + /* Set Automatic AltiVec Idle Count */ + rlwimi r3, r11, PWRMGTCR0_AV_IDLE_CNT_SHIFT, PWRMGTCR0_AV_IDLE_CNT + + mtspr SPRN_PWRMGTCR0, r3 + + blr + _GLOBAL(__setup_cpu_e6500) mflr r6 #ifdef CONFIG_PPC64 bl .setup_altivec_ivors #endif + bl setup_altivec_idle bl __setup_cpu_e5500 mtlr r6 blr
@@ -119,6 +139,7 @@ _GLOBAL(__setup_cpu_e5500) _GLOBAL(__restore_cpu_e6500) mflr r5 bl .setup_altivec_ivors + bl .setup_altivec_idle bl __restore_cpu_e5500 mtlr r5 blr
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1.8.0