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-rw-r--r--arch/powerpc/kernel/idle_6xx.S233
1 files changed, 233 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle_6xx.S b/arch/powerpc/kernel/idle_6xx.S
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1/*
2 * This file contains the power_save function for 6xx & 7xxx CPUs
3 * rewritten in assembler
4 *
5 * Warning ! This code assumes that if your machine has a 750fx
6 * it will have PLL 1 set to low speed mode (used during NAP/DOZE).
7 * if this is not the case some additional changes will have to
8 * be done to check a runtime var (a bit like powersave-nap)
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
14 */
15
16#include <linux/config.h>
17#include <linux/threads.h>
18#include <asm/processor.h>
19#include <asm/page.h>
20#include <asm/cputable.h>
21#include <asm/thread_info.h>
22#include <asm/ppc_asm.h>
23#include <asm/asm-offsets.h>
24
25#undef DEBUG
26
27 .text
28
29/*
30 * Init idle, called at early CPU setup time from head.S for each CPU
31 * Make sure no rest of NAP mode remains in HID0, save default
32 * values for some CPU specific registers. Called with r24
33 * containing CPU number and r3 reloc offset
34 */
35_GLOBAL(init_idle_6xx)
36BEGIN_FTR_SECTION
37 mfspr r4,SPRN_HID0
38 rlwinm r4,r4,0,10,8 /* Clear NAP */
39 mtspr SPRN_HID0, r4
40 b 1f
41END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
42 blr
431:
44 slwi r5,r24,2
45 add r5,r5,r3
46BEGIN_FTR_SECTION
47 mfspr r4,SPRN_MSSCR0
48 addis r6,r5, nap_save_msscr0@ha
49 stw r4,nap_save_msscr0@l(r6)
50END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR)
51BEGIN_FTR_SECTION
52 mfspr r4,SPRN_HID1
53 addis r6,r5,nap_save_hid1@ha
54 stw r4,nap_save_hid1@l(r6)
55END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX)
56 blr
57
58/*
59 * Here is the power_save_6xx function. This could eventually be
60 * split into several functions & changing the function pointer
61 * depending on the various features.
62 */
63_GLOBAL(ppc6xx_idle)
64 /* Check if we can nap or doze, put HID0 mask in r3
65 */
66 lis r3, 0
67BEGIN_FTR_SECTION
68 lis r3,HID0_DOZE@h
69END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
70BEGIN_FTR_SECTION
71 /* We must dynamically check for the NAP feature as it
72 * can be cleared by CPU init after the fixups are done
73 */
74 lis r4,cur_cpu_spec@ha
75 lwz r4,cur_cpu_spec@l(r4)
76 lwz r4,CPU_SPEC_FEATURES(r4)
77 andi. r0,r4,CPU_FTR_CAN_NAP
78 beq 1f
79 /* Now check if user or arch enabled NAP mode */
80 lis r4,powersave_nap@ha
81 lwz r4,powersave_nap@l(r4)
82 cmpwi 0,r4,0
83 beq 1f
84 lis r3,HID0_NAP@h
851:
86END_FTR_SECTION_IFSET(CPU_FTR_CAN_NAP)
87 cmpwi 0,r3,0
88 beqlr
89
90 /* Clear MSR:EE */
91 mfmsr r7
92 rlwinm r0,r7,0,17,15
93 mtmsr r0
94
95 /* Check current_thread_info()->flags */
96 rlwinm r4,r1,0,0,18
97 lwz r4,TI_FLAGS(r4)
98 andi. r0,r4,_TIF_NEED_RESCHED
99 beq 1f
100 mtmsr r7 /* out of line this ? */
101 blr
1021:
103 /* Some pre-nap cleanups needed on some CPUs */
104 andis. r0,r3,HID0_NAP@h
105 beq 2f
106BEGIN_FTR_SECTION
107 /* Disable L2 prefetch on some 745x and try to ensure
108 * L2 prefetch engines are idle. As explained by errata
109 * text, we can't be sure they are, we just hope very hard
110 * that well be enough (sic !). At least I noticed Apple
111 * doesn't even bother doing the dcbf's here...
112 */
113 mfspr r4,SPRN_MSSCR0
114 rlwinm r4,r4,0,0,29
115 sync
116 mtspr SPRN_MSSCR0,r4
117 sync
118 isync
119 lis r4,KERNELBASE@h
120 dcbf 0,r4
121 dcbf 0,r4
122 dcbf 0,r4
123 dcbf 0,r4
124END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR)
125#ifdef DEBUG
126 lis r6,nap_enter_count@ha
127 lwz r4,nap_enter_count@l(r6)
128 addi r4,r4,1
129 stw r4,nap_enter_count@l(r6)
130#endif
1312:
132BEGIN_FTR_SECTION
133 /* Go to low speed mode on some 750FX */
134 lis r4,powersave_lowspeed@ha
135 lwz r4,powersave_lowspeed@l(r4)
136 cmpwi 0,r4,0
137 beq 1f
138 mfspr r4,SPRN_HID1
139 oris r4,r4,0x0001
140 mtspr SPRN_HID1,r4
1411:
142END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX)
143
144 /* Go to NAP or DOZE now */
145 mfspr r4,SPRN_HID0
146 lis r5,(HID0_NAP|HID0_SLEEP)@h
147BEGIN_FTR_SECTION
148 oris r5,r5,HID0_DOZE@h
149END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
150 andc r4,r4,r5
151 or r4,r4,r3
152BEGIN_FTR_SECTION
153 oris r4,r4,HID0_DPM@h /* that should be done once for all */
154END_FTR_SECTION_IFCLR(CPU_FTR_NO_DPM)
155 mtspr SPRN_HID0,r4
156BEGIN_FTR_SECTION
157 DSSALL
158 sync
159END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
160 ori r7,r7,MSR_EE /* Could be ommited (already set) */
161 oris r7,r7,MSR_POW@h
162 sync
163 isync
164 mtmsr r7
165 isync
166 sync
167 blr
168
169/*
170 * Return from NAP/DOZE mode, restore some CPU specific registers,
171 * we are called with DR/IR still off and r2 containing physical
172 * address of current.
173 */
174_GLOBAL(power_save_6xx_restore)
175 mfspr r11,SPRN_HID0
176 rlwinm. r11,r11,0,10,8 /* Clear NAP & copy NAP bit !state to cr1 EQ */
177 cror 4*cr1+eq,4*cr0+eq,4*cr0+eq
178BEGIN_FTR_SECTION
179 rlwinm r11,r11,0,9,7 /* Clear DOZE */
180END_FTR_SECTION_IFSET(CPU_FTR_CAN_DOZE)
181 mtspr SPRN_HID0, r11
182
183#ifdef DEBUG
184 beq cr1,1f
185 lis r11,(nap_return_count-KERNELBASE)@ha
186 lwz r9,nap_return_count@l(r11)
187 addi r9,r9,1
188 stw r9,nap_return_count@l(r11)
1891:
190#endif
191
192 rlwinm r9,r1,0,0,18
193 tophys(r9,r9)
194 lwz r11,TI_CPU(r9)
195 slwi r11,r11,2
196 /* Todo make sure all these are in the same page
197 * and load r22 (@ha part + CPU offset) only once
198 */
199BEGIN_FTR_SECTION
200 beq cr1,1f
201 addis r9,r11,(nap_save_msscr0-KERNELBASE)@ha
202 lwz r9,nap_save_msscr0@l(r9)
203 mtspr SPRN_MSSCR0, r9
204 sync
205 isync
2061:
207END_FTR_SECTION_IFSET(CPU_FTR_NAP_DISABLE_L2_PR)
208BEGIN_FTR_SECTION
209 addis r9,r11,(nap_save_hid1-KERNELBASE)@ha
210 lwz r9,nap_save_hid1@l(r9)
211 mtspr SPRN_HID1, r9
212END_FTR_SECTION_IFSET(CPU_FTR_DUAL_PLL_750FX)
213 b transfer_to_handler_cont
214
215 .data
216
217_GLOBAL(nap_save_msscr0)
218 .space 4*NR_CPUS
219
220_GLOBAL(nap_save_hid1)
221 .space 4*NR_CPUS
222
223_GLOBAL(powersave_nap)
224 .long 0
225_GLOBAL(powersave_lowspeed)
226 .long 0
227
228#ifdef DEBUG
229_GLOBAL(nap_enter_count)
230 .space 4
231_GLOBAL(nap_return_count)
232 .space 4
233#endif
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