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-rw-r--r--arch/ppc/kernel/temp.c271
1 files changed, 0 insertions, 271 deletions
diff --git a/arch/ppc/kernel/temp.c b/arch/ppc/kernel/temp.c
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index 26bd8ea35a4e..000000000000
--- a/arch/ppc/kernel/temp.c
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1/*
2 * temp.c Thermal management for cpu's with Thermal Assist Units
3 *
4 * Written by Troy Benjegerdes <hozer@drgw.net>
5 *
6 * TODO:
7 * dynamic power management to limit peak CPU temp (using ICTC)
8 * calibration???
9 *
10 * Silly, crazy ideas: use cpu load (from scheduler) and ICTC to extend battery
11 * life in portables, and add a 'performance/watt' metric somewhere in /proc
12 */
13
14#include <linux/config.h>
15#include <linux/errno.h>
16#include <linux/jiffies.h>
17#include <linux/kernel.h>
18#include <linux/param.h>
19#include <linux/string.h>
20#include <linux/mm.h>
21#include <linux/interrupt.h>
22#include <linux/init.h>
23
24#include <asm/io.h>
25#include <asm/reg.h>
26#include <asm/nvram.h>
27#include <asm/cache.h>
28#include <asm/8xx_immap.h>
29#include <asm/machdep.h>
30
31static struct tau_temp
32{
33 int interrupts;
34 unsigned char low;
35 unsigned char high;
36 unsigned char grew;
37} tau[NR_CPUS];
38
39struct timer_list tau_timer;
40
41#undef DEBUG
42
43/* TODO: put these in a /proc interface, with some sanity checks, and maybe
44 * dynamic adjustment to minimize # of interrupts */
45/* configurable values for step size and how much to expand the window when
46 * we get an interrupt. These are based on the limit that was out of range */
47#define step_size 2 /* step size when temp goes out of range */
48#define window_expand 1 /* expand the window by this much */
49/* configurable values for shrinking the window */
50#define shrink_timer 2*HZ /* period between shrinking the window */
51#define min_window 2 /* minimum window size, degrees C */
52
53void set_thresholds(unsigned long cpu)
54{
55#ifdef CONFIG_TAU_INT
56 /*
57 * setup THRM1,
58 * threshold, valid bit, enable interrupts, interrupt when below threshold
59 */
60 mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | THRM1_TIE | THRM1_TID);
61
62 /* setup THRM2,
63 * threshold, valid bit, enable interrupts, interrupt when above threshhold
64 */
65 mtspr (SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V | THRM1_TIE);
66#else
67 /* same thing but don't enable interrupts */
68 mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | THRM1_TID);
69 mtspr(SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V);
70#endif
71}
72
73void TAUupdate(int cpu)
74{
75 unsigned thrm;
76
77#ifdef DEBUG
78 printk("TAUupdate ");
79#endif
80
81 /* if both thresholds are crossed, the step_sizes cancel out
82 * and the window winds up getting expanded twice. */
83 if((thrm = mfspr(SPRN_THRM1)) & THRM1_TIV){ /* is valid? */
84 if(thrm & THRM1_TIN){ /* crossed low threshold */
85 if (tau[cpu].low >= step_size){
86 tau[cpu].low -= step_size;
87 tau[cpu].high -= (step_size - window_expand);
88 }
89 tau[cpu].grew = 1;
90#ifdef DEBUG
91 printk("low threshold crossed ");
92#endif
93 }
94 }
95 if((thrm = mfspr(SPRN_THRM2)) & THRM1_TIV){ /* is valid? */
96 if(thrm & THRM1_TIN){ /* crossed high threshold */
97 if (tau[cpu].high <= 127-step_size){
98 tau[cpu].low += (step_size - window_expand);
99 tau[cpu].high += step_size;
100 }
101 tau[cpu].grew = 1;
102#ifdef DEBUG
103 printk("high threshold crossed ");
104#endif
105 }
106 }
107
108#ifdef DEBUG
109 printk("grew = %d\n", tau[cpu].grew);
110#endif
111
112#ifndef CONFIG_TAU_INT /* tau_timeout will do this if not using interrupts */
113 set_thresholds(cpu);
114#endif
115
116}
117
118#ifdef CONFIG_TAU_INT
119/*
120 * TAU interrupts - called when we have a thermal assist unit interrupt
121 * with interrupts disabled
122 */
123
124void TAUException(struct pt_regs * regs)
125{
126 int cpu = smp_processor_id();
127
128 irq_enter();
129 tau[cpu].interrupts++;
130
131 TAUupdate(cpu);
132
133 irq_exit();
134}
135#endif /* CONFIG_TAU_INT */
136
137static void tau_timeout(void * info)
138{
139 int cpu;
140 unsigned long flags;
141 int size;
142 int shrink;
143
144 /* disabling interrupts *should* be okay */
145 local_irq_save(flags);
146 cpu = smp_processor_id();
147
148#ifndef CONFIG_TAU_INT
149 TAUupdate(cpu);
150#endif
151
152 size = tau[cpu].high - tau[cpu].low;
153 if (size > min_window && ! tau[cpu].grew) {
154 /* do an exponential shrink of half the amount currently over size */
155 shrink = (2 + size - min_window) / 4;
156 if (shrink) {
157 tau[cpu].low += shrink;
158 tau[cpu].high -= shrink;
159 } else { /* size must have been min_window + 1 */
160 tau[cpu].low += 1;
161#if 1 /* debug */
162 if ((tau[cpu].high - tau[cpu].low) != min_window){
163 printk(KERN_ERR "temp.c: line %d, logic error\n", __LINE__);
164 }
165#endif
166 }
167 }
168
169 tau[cpu].grew = 0;
170
171 set_thresholds(cpu);
172
173 /*
174 * Do the enable every time, since otherwise a bunch of (relatively)
175 * complex sleep code needs to be added. One mtspr every time
176 * tau_timeout is called is probably not a big deal.
177 *
178 * Enable thermal sensor and set up sample interval timer
179 * need 20 us to do the compare.. until a nice 'cpu_speed' function
180 * call is implemented, just assume a 500 mhz clock. It doesn't really
181 * matter if we take too long for a compare since it's all interrupt
182 * driven anyway.
183 *
184 * use a extra long time.. (60 us @ 500 mhz)
185 */
186 mtspr(SPRN_THRM3, THRM3_SITV(500*60) | THRM3_E);
187
188 local_irq_restore(flags);
189}
190
191static void tau_timeout_smp(unsigned long unused)
192{
193
194 /* schedule ourselves to be run again */
195 mod_timer(&tau_timer, jiffies + shrink_timer) ;
196 on_each_cpu(tau_timeout, NULL, 1, 0);
197}
198
199/*
200 * setup the TAU
201 *
202 * Set things up to use THRM1 as a temperature lower bound, and THRM2 as an upper bound.
203 * Start off at zero
204 */
205
206int tau_initialized = 0;
207
208void __init TAU_init_smp(void * info)
209{
210 unsigned long cpu = smp_processor_id();
211
212 /* set these to a reasonable value and let the timer shrink the
213 * window */
214 tau[cpu].low = 5;
215 tau[cpu].high = 120;
216
217 set_thresholds(cpu);
218}
219
220int __init TAU_init(void)
221{
222 /* We assume in SMP that if one CPU has TAU support, they
223 * all have it --BenH
224 */
225 if (!cpu_has_feature(CPU_FTR_TAU)) {
226 printk("Thermal assist unit not available\n");
227 tau_initialized = 0;
228 return 1;
229 }
230
231
232 /* first, set up the window shrinking timer */
233 init_timer(&tau_timer);
234 tau_timer.function = tau_timeout_smp;
235 tau_timer.expires = jiffies + shrink_timer;
236 add_timer(&tau_timer);
237
238 on_each_cpu(TAU_init_smp, NULL, 1, 0);
239
240 printk("Thermal assist unit ");
241#ifdef CONFIG_TAU_INT
242 printk("using interrupts, ");
243#else
244 printk("using timers, ");
245#endif
246 printk("shrink_timer: %d jiffies\n", shrink_timer);
247 tau_initialized = 1;
248
249 return 0;
250}
251
252__initcall(TAU_init);
253
254/*
255 * return current temp
256 */
257
258u32 cpu_temp_both(unsigned long cpu)
259{
260 return ((tau[cpu].high << 16) | tau[cpu].low);
261}
262
263int cpu_temp(unsigned long cpu)
264{
265 return ((tau[cpu].high + tau[cpu].low) / 2);
266}
267
268int tau_interrupts(unsigned long cpu)
269{
270 return (tau[cpu].interrupts);
271}
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