![Olof Johansson](/assets/img/avatar_default.png)
Without this patch, on an idle system I get: cpu-power-0:21.638 cpu-power-1:27.102 cpu-power-2:29.343 cpu-power-3:25.784 Total: 103.8W With this patch: cpu-power-0:11.730 cpu-power-1:17.185 cpu-power-2:18.547 cpu-power-3:17.528 Total: 65.0W If I lower HZ to 100, I can get it as low as: cpu-power-0:10.938 cpu-power-1:16.021 cpu-power-2:17.245 cpu-power-3:16.145 Total: 60.2W Another (older) Quad G5 went from 54W to 39W at HZ=250. Coming back out of Deep Nap takes 40-70 cycles longer than coming back from just Nap (which already takes quite a while). I don't think it'll be a performance issue (interrupt latency on an idle system), but in case someone does measurements feel free to report them. Signed-off-by: Olof Johansson <olof@lixom.net> Acked-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
193 lines
3.6 KiB
ArmAsm
193 lines
3.6 KiB
ArmAsm
/*
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* This file contains low level CPU setup functions.
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* Copyright (C) 2003 Benjamin Herrenschmidt (benh@kernel.crashing.org)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <asm/processor.h>
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#include <asm/page.h>
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#include <asm/cputable.h>
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#include <asm/ppc_asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/cache.h>
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_GLOBAL(__cpu_preinit_ppc970)
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/* Do nothing if not running in HV mode */
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mfmsr r0
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rldicl. r0,r0,4,63
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beqlr
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/* Make sure HID4:rm_ci is off before MMU is turned off, that large
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* pages are enabled with HID4:61 and clear HID5:DCBZ_size and
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* HID5:DCBZ32_ill
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*/
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li r0,0
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mfspr r3,SPRN_HID4
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rldimi r3,r0,40,23 /* clear bit 23 (rm_ci) */
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rldimi r3,r0,2,61 /* clear bit 61 (lg_pg_en) */
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sync
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mtspr SPRN_HID4,r3
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isync
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sync
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mfspr r3,SPRN_HID5
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rldimi r3,r0,6,56 /* clear bits 56 & 57 (DCBZ*) */
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sync
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mtspr SPRN_HID5,r3
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isync
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sync
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/* Setup some basic HID1 features */
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mfspr r0,SPRN_HID1
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li r3,0x1200 /* enable i-fetch cacheability */
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sldi r3,r3,44 /* and prefetch */
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or r0,r0,r3
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mtspr SPRN_HID1,r0
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mtspr SPRN_HID1,r0
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isync
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/* Clear HIOR */
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li r0,0
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sync
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mtspr SPRN_HIOR,0 /* Clear interrupt prefix */
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isync
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blr
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/* Definitions for the table use to save CPU states */
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#define CS_HID0 0
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#define CS_HID1 8
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#define CS_HID4 16
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#define CS_HID5 24
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#define CS_SIZE 32
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.data
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.balign L1_CACHE_BYTES,0
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cpu_state_storage:
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.space CS_SIZE
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.balign L1_CACHE_BYTES,0
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.text
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_GLOBAL(__setup_cpu_ppc970)
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/* Do nothing if not running in HV mode */
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mfmsr r0
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rldicl. r0,r0,4,63
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beqlr
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mfspr r0,SPRN_HID0
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li r11,5 /* clear DOZE and SLEEP */
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rldimi r0,r11,52,8 /* set NAP and DPM */
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li r11,0
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rldimi r0,r11,32,31 /* clear EN_ATTN */
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b load_hids /* Jump to shared code */
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_GLOBAL(__setup_cpu_ppc970MP)
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/* Do nothing if not running in HV mode */
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mfmsr r0
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rldicl. r0,r0,4,63
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beqlr
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mfspr r0,SPRN_HID0
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li r11,0x15 /* clear DOZE and SLEEP */
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rldimi r0,r11,52,6 /* set DEEPNAP, NAP and DPM */
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li r11,0
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rldimi r0,r11,32,31 /* clear EN_ATTN */
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load_hids:
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mtspr SPRN_HID0,r0
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mfspr r0,SPRN_HID0
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mfspr r0,SPRN_HID0
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mfspr r0,SPRN_HID0
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mfspr r0,SPRN_HID0
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mfspr r0,SPRN_HID0
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mfspr r0,SPRN_HID0
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sync
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isync
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/* Save away cpu state */
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LOAD_REG_IMMEDIATE(r5,cpu_state_storage)
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/* Save HID0,1,4 and 5 */
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mfspr r3,SPRN_HID0
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std r3,CS_HID0(r5)
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mfspr r3,SPRN_HID1
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std r3,CS_HID1(r5)
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mfspr r3,SPRN_HID4
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std r3,CS_HID4(r5)
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mfspr r3,SPRN_HID5
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std r3,CS_HID5(r5)
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blr
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/* Called with no MMU context (typically MSR:IR/DR off) to
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* restore CPU state as backed up by the previous
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* function. This does not include cache setting
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*/
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_GLOBAL(__restore_cpu_ppc970)
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/* Do nothing if not running in HV mode */
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mfmsr r0
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rldicl. r0,r0,4,63
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beqlr
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LOAD_REG_IMMEDIATE(r5,cpu_state_storage)
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/* Before accessing memory, we make sure rm_ci is clear */
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li r0,0
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mfspr r3,SPRN_HID4
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rldimi r3,r0,40,23 /* clear bit 23 (rm_ci) */
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sync
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mtspr SPRN_HID4,r3
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isync
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sync
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/* Clear interrupt prefix */
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li r0,0
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sync
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mtspr SPRN_HIOR,0
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isync
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/* Restore HID0 */
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ld r3,CS_HID0(r5)
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sync
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isync
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mtspr SPRN_HID0,r3
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mfspr r3,SPRN_HID0
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mfspr r3,SPRN_HID0
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mfspr r3,SPRN_HID0
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mfspr r3,SPRN_HID0
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mfspr r3,SPRN_HID0
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mfspr r3,SPRN_HID0
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sync
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isync
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/* Restore HID1 */
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ld r3,CS_HID1(r5)
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sync
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isync
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mtspr SPRN_HID1,r3
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mtspr SPRN_HID1,r3
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sync
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isync
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/* Restore HID4 */
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ld r3,CS_HID4(r5)
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sync
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isync
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mtspr SPRN_HID4,r3
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sync
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isync
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/* Restore HID5 */
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ld r3,CS_HID5(r5)
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sync
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isync
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mtspr SPRN_HID5,r3
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sync
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isync
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blr
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