aboutsummaryrefslogtreecommitdiffstats
path: root/arch/ppc64/kernel/idle.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/ppc64/kernel/idle.c')
-rw-r--r--arch/ppc64/kernel/idle.c283
1 files changed, 14 insertions, 269 deletions
diff --git a/arch/ppc64/kernel/idle.c b/arch/ppc64/kernel/idle.c
index bdf13b4dc1c8..954395d42636 100644
--- a/arch/ppc64/kernel/idle.c
+++ b/arch/ppc64/kernel/idle.c
@@ -20,109 +20,18 @@
20#include <linux/kernel.h> 20#include <linux/kernel.h>
21#include <linux/smp.h> 21#include <linux/smp.h>
22#include <linux/cpu.h> 22#include <linux/cpu.h>
23#include <linux/module.h>
24#include <linux/sysctl.h> 23#include <linux/sysctl.h>
25#include <linux/smp.h>
26 24
27#include <asm/system.h> 25#include <asm/system.h>
28#include <asm/processor.h> 26#include <asm/processor.h>
29#include <asm/mmu.h>
30#include <asm/cputable.h> 27#include <asm/cputable.h>
31#include <asm/time.h> 28#include <asm/time.h>
32#include <asm/iSeries/HvCall.h>
33#include <asm/iSeries/ItLpQueue.h>
34#include <asm/plpar_wrappers.h>
35#include <asm/systemcfg.h> 29#include <asm/systemcfg.h>
30#include <asm/machdep.h>
36 31
37extern void power4_idle(void); 32extern void power4_idle(void);
38 33
39static int (*idle_loop)(void); 34int default_idle(void)
40
41#ifdef CONFIG_PPC_ISERIES
42static unsigned long maxYieldTime = 0;
43static unsigned long minYieldTime = 0xffffffffffffffffUL;
44
45static inline void process_iSeries_events(void)
46{
47 asm volatile ("li 0,0x5555; sc" : : : "r0", "r3");
48}
49
50static void yield_shared_processor(void)
51{
52 unsigned long tb;
53 unsigned long yieldTime;
54
55 HvCall_setEnabledInterrupts(HvCall_MaskIPI |
56 HvCall_MaskLpEvent |
57 HvCall_MaskLpProd |
58 HvCall_MaskTimeout);
59
60 tb = get_tb();
61 /* Compute future tb value when yield should expire */
62 HvCall_yieldProcessor(HvCall_YieldTimed, tb+tb_ticks_per_jiffy);
63
64 yieldTime = get_tb() - tb;
65 if (yieldTime > maxYieldTime)
66 maxYieldTime = yieldTime;
67
68 if (yieldTime < minYieldTime)
69 minYieldTime = yieldTime;
70
71 /*
72 * The decrementer stops during the yield. Force a fake decrementer
73 * here and let the timer_interrupt code sort out the actual time.
74 */
75 get_paca()->lppaca.int_dword.fields.decr_int = 1;
76 process_iSeries_events();
77}
78
79static int iSeries_idle(void)
80{
81 struct paca_struct *lpaca;
82 long oldval;
83
84 /* ensure iSeries run light will be out when idle */
85 ppc64_runlatch_off();
86
87 lpaca = get_paca();
88
89 while (1) {
90 if (lpaca->lppaca.shared_proc) {
91 if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
92 process_iSeries_events();
93 if (!need_resched())
94 yield_shared_processor();
95 } else {
96 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
97
98 if (!oldval) {
99 set_thread_flag(TIF_POLLING_NRFLAG);
100
101 while (!need_resched()) {
102 HMT_medium();
103 if (ItLpQueue_isLpIntPending(lpaca->lpqueue_ptr))
104 process_iSeries_events();
105 HMT_low();
106 }
107
108 HMT_medium();
109 clear_thread_flag(TIF_POLLING_NRFLAG);
110 } else {
111 set_need_resched();
112 }
113 }
114
115 ppc64_runlatch_on();
116 schedule();
117 ppc64_runlatch_off();
118 }
119
120 return 0;
121}
122
123#else
124
125static int default_idle(void)
126{ 35{
127 long oldval; 36 long oldval;
128 unsigned int cpu = smp_processor_id(); 37 unsigned int cpu = smp_processor_id();
@@ -134,7 +43,8 @@ static int default_idle(void)
134 set_thread_flag(TIF_POLLING_NRFLAG); 43 set_thread_flag(TIF_POLLING_NRFLAG);
135 44
136 while (!need_resched() && !cpu_is_offline(cpu)) { 45 while (!need_resched() && !cpu_is_offline(cpu)) {
137 barrier(); 46 ppc64_runlatch_off();
47
138 /* 48 /*
139 * Go into low thread priority and possibly 49 * Go into low thread priority and possibly
140 * low power mode. 50 * low power mode.
@@ -149,6 +59,7 @@ static int default_idle(void)
149 set_need_resched(); 59 set_need_resched();
150 } 60 }
151 61
62 ppc64_runlatch_on();
152 schedule(); 63 schedule();
153 if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING) 64 if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
154 cpu_die(); 65 cpu_die();
@@ -157,127 +68,19 @@ static int default_idle(void)
157 return 0; 68 return 0;
158} 69}
159 70
160#ifdef CONFIG_PPC_PSERIES 71int native_idle(void)
161
162DECLARE_PER_CPU(unsigned long, smt_snooze_delay);
163
164int dedicated_idle(void)
165{ 72{
166 long oldval;
167 struct paca_struct *lpaca = get_paca(), *ppaca;
168 unsigned long start_snooze;
169 unsigned long *smt_snooze_delay = &__get_cpu_var(smt_snooze_delay);
170 unsigned int cpu = smp_processor_id();
171
172 ppaca = &paca[cpu ^ 1];
173
174 while (1) { 73 while (1) {
175 /* 74 ppc64_runlatch_off();
176 * Indicate to the HV that we are idle. Now would be
177 * a good time to find other work to dispatch.
178 */
179 lpaca->lppaca.idle = 1;
180
181 oldval = test_and_clear_thread_flag(TIF_NEED_RESCHED);
182 if (!oldval) {
183 set_thread_flag(TIF_POLLING_NRFLAG);
184 start_snooze = __get_tb() +
185 *smt_snooze_delay * tb_ticks_per_usec;
186 while (!need_resched() && !cpu_is_offline(cpu)) {
187 /*
188 * Go into low thread priority and possibly
189 * low power mode.
190 */
191 HMT_low();
192 HMT_very_low();
193
194 if (*smt_snooze_delay == 0 ||
195 __get_tb() < start_snooze)
196 continue;
197
198 HMT_medium();
199
200 if (!(ppaca->lppaca.idle)) {
201 local_irq_disable();
202
203 /*
204 * We are about to sleep the thread
205 * and so wont be polling any
206 * more.
207 */
208 clear_thread_flag(TIF_POLLING_NRFLAG);
209
210 /*
211 * SMT dynamic mode. Cede will result
212 * in this thread going dormant, if the
213 * partner thread is still doing work.
214 * Thread wakes up if partner goes idle,
215 * an interrupt is presented, or a prod
216 * occurs. Returning from the cede
217 * enables external interrupts.
218 */
219 if (!need_resched())
220 cede_processor();
221 else
222 local_irq_enable();
223 } else {
224 /*
225 * Give the HV an opportunity at the
226 * processor, since we are not doing
227 * any work.
228 */
229 poll_pending();
230 }
231 }
232
233 clear_thread_flag(TIF_POLLING_NRFLAG);
234 } else {
235 set_need_resched();
236 }
237
238 HMT_medium();
239 lpaca->lppaca.idle = 0;
240 schedule();
241 if (cpu_is_offline(cpu) && system_state == SYSTEM_RUNNING)
242 cpu_die();
243 }
244 return 0;
245}
246
247static int shared_idle(void)
248{
249 struct paca_struct *lpaca = get_paca();
250 unsigned int cpu = smp_processor_id();
251
252 while (1) {
253 /*
254 * Indicate to the HV that we are idle. Now would be
255 * a good time to find other work to dispatch.
256 */
257 lpaca->lppaca.idle = 1;
258 75
259 while (!need_resched() && !cpu_is_offline(cpu)) { 76 if (!need_resched())
260 local_irq_disable(); 77 power4_idle();
261 78
262 /* 79 if (need_resched()) {
263 * Yield the processor to the hypervisor. We return if 80 ppc64_runlatch_on();
264 * an external interrupt occurs (which are driven prior 81 schedule();
265 * to returning here) or if a prod occurs from another
266 * processor. When returning here, external interrupts
267 * are enabled.
268 *
269 * Check need_resched() again with interrupts disabled
270 * to avoid a race.
271 */
272 if (!need_resched())
273 cede_processor();
274 else
275 local_irq_enable();
276 } 82 }
277 83
278 HMT_medium();
279 lpaca->lppaca.idle = 0;
280 schedule();
281 if (cpu_is_offline(smp_processor_id()) && 84 if (cpu_is_offline(smp_processor_id()) &&
282 system_state == SYSTEM_RUNNING) 85 system_state == SYSTEM_RUNNING)
283 cpu_die(); 86 cpu_die();
@@ -286,29 +89,10 @@ static int shared_idle(void)
286 return 0; 89 return 0;
287} 90}
288 91
289#endif /* CONFIG_PPC_PSERIES */
290
291static int native_idle(void)
292{
293 while(1) {
294 /* check CPU type here */
295 if (!need_resched())
296 power4_idle();
297 if (need_resched())
298 schedule();
299
300 if (cpu_is_offline(raw_smp_processor_id()) &&
301 system_state == SYSTEM_RUNNING)
302 cpu_die();
303 }
304 return 0;
305}
306
307#endif /* CONFIG_PPC_ISERIES */
308
309void cpu_idle(void) 92void cpu_idle(void)
310{ 93{
311 idle_loop(); 94 BUG_ON(NULL == ppc_md.idle_loop);
95 ppc_md.idle_loop();
312} 96}
313 97
314int powersave_nap; 98int powersave_nap;
@@ -342,42 +126,3 @@ register_powersave_nap_sysctl(void)
342} 126}
343__initcall(register_powersave_nap_sysctl); 127__initcall(register_powersave_nap_sysctl);
344#endif 128#endif
345
346int idle_setup(void)
347{
348 /*
349 * Move that junk to each platform specific file, eventually define
350 * a pSeries_idle for shared processor stuff
351 */
352#ifdef CONFIG_PPC_ISERIES
353 idle_loop = iSeries_idle;
354 return 1;
355#else
356 idle_loop = default_idle;
357#endif
358#ifdef CONFIG_PPC_PSERIES
359 if (systemcfg->platform & PLATFORM_PSERIES) {
360 if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {
361 if (get_paca()->lppaca.shared_proc) {
362 printk(KERN_INFO "Using shared processor idle loop\n");
363 idle_loop = shared_idle;
364 } else {
365 printk(KERN_INFO "Using dedicated idle loop\n");
366 idle_loop = dedicated_idle;
367 }
368 } else {
369 printk(KERN_INFO "Using default idle loop\n");
370 idle_loop = default_idle;
371 }
372 }
373#endif /* CONFIG_PPC_PSERIES */
374#ifndef CONFIG_PPC_ISERIES
375 if (systemcfg->platform == PLATFORM_POWERMAC ||
376 systemcfg->platform == PLATFORM_MAPLE) {
377 printk(KERN_INFO "Using native/NAP idle loop\n");
378 idle_loop = native_idle;
379 }
380#endif /* CONFIG_PPC_ISERIES */
381
382 return 1;
383}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-27 16:41:09 -0500