diff options
author | Dave Jones <davej@redhat.com> | 2006-04-18 17:19:55 -0500 |
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committer | Dave Jones <davej@redhat.com> | 2006-04-18 17:19:55 -0500 |
commit | f1f76afd71e0f17af9a35fcb649f4bab53304a4d (patch) | |
tree | a56257b13a0eda4a9b7e950c3b85adad16341b80 /arch/powerpc/kernel/tau_6xx.c | |
parent | 530515a06f90c0831732709efee4a99497bd2b7c (diff) | |
parent | 385910f2b275a636238f70844f1b6da9fda6f2da (diff) |
Merge ../linus
Diffstat (limited to 'arch/powerpc/kernel/tau_6xx.c')
-rw-r--r-- | arch/powerpc/kernel/tau_6xx.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/tau_6xx.c b/arch/powerpc/kernel/tau_6xx.c new file mode 100644 index 00000000000..26bd8ea35a4 --- /dev/null +++ b/arch/powerpc/kernel/tau_6xx.c @@ -0,0 +1,271 @@ +/* + * temp.c Thermal management for cpu's with Thermal Assist Units + * + * Written by Troy Benjegerdes <hozer@drgw.net> + * + * TODO: + * dynamic power management to limit peak CPU temp (using ICTC) + * calibration??? + * + * Silly, crazy ideas: use cpu load (from scheduler) and ICTC to extend battery + * life in portables, and add a 'performance/watt' metric somewhere in /proc + */ + +#include <linux/config.h> +#include <linux/errno.h> +#include <linux/jiffies.h> +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/init.h> + +#include <asm/io.h> +#include <asm/reg.h> +#include <asm/nvram.h> +#include <asm/cache.h> +#include <asm/8xx_immap.h> +#include <asm/machdep.h> + +static struct tau_temp +{ + int interrupts; + unsigned char low; + unsigned char high; + unsigned char grew; +} tau[NR_CPUS]; + +struct timer_list tau_timer; + +#undef DEBUG + +/* TODO: put these in a /proc interface, with some sanity checks, and maybe + * dynamic adjustment to minimize # of interrupts */ +/* configurable values for step size and how much to expand the window when + * we get an interrupt. These are based on the limit that was out of range */ +#define step_size 2 /* step size when temp goes out of range */ +#define window_expand 1 /* expand the window by this much */ +/* configurable values for shrinking the window */ +#define shrink_timer 2*HZ /* period between shrinking the window */ +#define min_window 2 /* minimum window size, degrees C */ + +void set_thresholds(unsigned long cpu) +{ +#ifdef CONFIG_TAU_INT + /* + * setup THRM1, + * threshold, valid bit, enable interrupts, interrupt when below threshold + */ + mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | THRM1_TIE | THRM1_TID); + + /* setup THRM2, + * threshold, valid bit, enable interrupts, interrupt when above threshhold + */ + mtspr (SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V | THRM1_TIE); +#else + /* same thing but don't enable interrupts */ + mtspr(SPRN_THRM1, THRM1_THRES(tau[cpu].low) | THRM1_V | THRM1_TID); + mtspr(SPRN_THRM2, THRM1_THRES(tau[cpu].high) | THRM1_V); +#endif +} + +void TAUupdate(int cpu) +{ + unsigned thrm; + +#ifdef DEBUG + printk("TAUupdate "); +#endif + + /* if both thresholds are crossed, the step_sizes cancel out + * and the window winds up getting expanded twice. */ + if((thrm = mfspr(SPRN_THRM1)) & THRM1_TIV){ /* is valid? */ + if(thrm & THRM1_TIN){ /* crossed low threshold */ + if (tau[cpu].low >= step_size){ + tau[cpu].low -= step_size; + tau[cpu].high -= (step_size - window_expand); + } + tau[cpu].grew = 1; +#ifdef DEBUG + printk("low threshold crossed "); +#endif + } + } + if((thrm = mfspr(SPRN_THRM2)) & THRM1_TIV){ /* is valid? */ + if(thrm & THRM1_TIN){ /* crossed high threshold */ + if (tau[cpu].high <= 127-step_size){ + tau[cpu].low += (step_size - window_expand); + tau[cpu].high += step_size; + } + tau[cpu].grew = 1; +#ifdef DEBUG + printk("high threshold crossed "); +#endif + } + } + +#ifdef DEBUG + printk("grew = %d\n", tau[cpu].grew); +#endif + +#ifndef CONFIG_TAU_INT /* tau_timeout will do this if not using interrupts */ + set_thresholds(cpu); +#endif + +} + +#ifdef CONFIG_TAU_INT +/* + * TAU interrupts - called when we have a thermal assist unit interrupt + * with interrupts disabled + */ + +void TAUException(struct pt_regs * regs) +{ + int cpu = smp_processor_id(); + + irq_enter(); + tau[cpu].interrupts++; + + TAUupdate(cpu); + + irq_exit(); +} +#endif /* CONFIG_TAU_INT */ + +static void tau_timeout(void * info) +{ + int cpu; + unsigned long flags; + int size; + int shrink; + + /* disabling interrupts *should* be okay */ + local_irq_save(flags); + cpu = smp_processor_id(); + +#ifndef CONFIG_TAU_INT + TAUupdate(cpu); +#endif + + size = tau[cpu].high - tau[cpu].low; + if (size > min_window && ! tau[cpu].grew) { + /* do an exponential shrink of half the amount currently over size */ + shrink = (2 + size - min_window) / 4; + if (shrink) { + tau[cpu].low += shrink; + tau[cpu].high -= shrink; + } else { /* size must have been min_window + 1 */ + tau[cpu].low += 1; +#if 1 /* debug */ + if ((tau[cpu].high - tau[cpu].low) != min_window){ + printk(KERN_ERR "temp.c: line %d, logic error\n", __LINE__); + } +#endif + } + } + + tau[cpu].grew = 0; + + set_thresholds(cpu); + + /* + * Do the enable every time, since otherwise a bunch of (relatively) + * complex sleep code needs to be added. One mtspr every time + * tau_timeout is called is probably not a big deal. + * + * Enable thermal sensor and set up sample interval timer + * need 20 us to do the compare.. until a nice 'cpu_speed' function + * call is implemented, just assume a 500 mhz clock. It doesn't really + * matter if we take too long for a compare since it's all interrupt + * driven anyway. + * + * use a extra long time.. (60 us @ 500 mhz) + */ + mtspr(SPRN_THRM3, THRM3_SITV(500*60) | THRM3_E); + + local_irq_restore(flags); +} + +static void tau_timeout_smp(unsigned long unused) +{ + + /* schedule ourselves to be run again */ + mod_timer(&tau_timer, jiffies + shrink_timer) ; + on_each_cpu(tau_timeout, NULL, 1, 0); +} + +/* + * setup the TAU + * + * Set things up to use THRM1 as a temperature lower bound, and THRM2 as an upper bound. + * Start off at zero + */ + +int tau_initialized = 0; + +void __init TAU_init_smp(void * info) +{ + unsigned long cpu = smp_processor_id(); + + /* set these to a reasonable value and let the timer shrink the + * window */ + tau[cpu].low = 5; + tau[cpu].high = 120; + + set_thresholds(cpu); +} + +int __init TAU_init(void) +{ + /* We assume in SMP that if one CPU has TAU support, they + * all have it --BenH + */ + if (!cpu_has_feature(CPU_FTR_TAU)) { + printk("Thermal assist unit not available\n"); + tau_initialized = 0; + return 1; + } + + + /* first, set up the window shrinking timer */ + init_timer(&tau_timer); + tau_timer.function = tau_timeout_smp; + tau_timer.expires = jiffies + shrink_timer; + add_timer(&tau_timer); + + on_each_cpu(TAU_init_smp, NULL, 1, 0); + + printk("Thermal assist unit "); +#ifdef CONFIG_TAU_INT + printk("using interrupts, "); +#else + printk("using timers, "); +#endif + printk("shrink_timer: %d jiffies\n", shrink_timer); + tau_initialized = 1; + + return 0; +} + +__initcall(TAU_init); + +/* + * return current temp + */ + +u32 cpu_temp_both(unsigned long cpu) +{ + return ((tau[cpu].high << 16) | tau[cpu].low); +} + +int cpu_temp(unsigned long cpu) +{ + return ((tau[cpu].high + tau[cpu].low) / 2); +} + +int tau_interrupts(unsigned long cpu) +{ + return (tau[cpu].interrupts); +} |