cregit-Linux how code gets into the kernel

Release 4.7 drivers/sbus/char/bbc_envctrl.c

/* bbc_envctrl.c: UltraSPARC-III environment control driver.
 *
 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net)
 */

#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/kmod.h>
#include <linux/reboot.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/of_device.h>
#include <asm/oplib.h>

#include "bbc_i2c.h"
#include "max1617.h"


#undef ENVCTRL_TRACE

/* WARNING: Making changes to this driver is very dangerous.
 *          If you misprogram the sensor chips they can
 *          cut the power on you instantly.
 */

/* Two temperature sensors exist in the SunBLADE-1000 enclosure.
 * Both are implemented using max1617 i2c devices.  Each max1617
 * monitors 2 temperatures, one for one of the cpu dies and the other
 * for the ambient temperature.
 *
 * The max1617 is capable of being programmed with power-off
 * temperature values, one low limit and one high limit.  These
 * can be controlled independently for the cpu or ambient temperature.
 * If a limit is violated, the power is simply shut off.  The frequency
 * with which the max1617 does temperature sampling can be controlled
 * as well.
 *
 * Three fans exist inside the machine, all three are controlled with
 * an i2c digital to analog converter.  There is a fan directed at the
 * two processor slots, another for the rest of the enclosure, and the
 * third is for the power supply.  The first two fans may be speed
 * controlled by changing the voltage fed to them.  The third fan may
 * only be completely off or on.  The third fan is meant to only be
 * disabled/enabled when entering/exiting the lowest power-saving
 * mode of the machine.
 *
 * An environmental control kernel thread periodically monitors all
 * temperature sensors.  Based upon the samples it will adjust the
 * fan speeds to try and keep the system within a certain temperature
 * range (the goal being to make the fans as quiet as possible without
 * allowing the system to get too hot).
 *
 * If the temperature begins to rise/fall outside of the acceptable
 * operating range, a periodic warning will be sent to the kernel log.
 * The fans will be put on full blast to attempt to deal with this
 * situation.  After exceeding the acceptable operating range by a
 * certain threshold, the kernel thread will shut down the system.
 * Here, the thread is attempting to shut the machine down cleanly
 * before the hardware based power-off event is triggered.
 */

/* These settings are in Celsius.  We use these defaults only
 * if we cannot interrogate the cpu-fru SEEPROM.
 */

struct temp_limits {
	


s8 high_pwroff, high_shutdown, high_warn;
	


s8 low_warn, low_shutdown, low_pwroff;
};


static struct temp_limits cpu_temp_limits[2] = {
	{ 100, 85, 80, 5, -5, -10 },
	{ 100, 85, 80, 5, -5, -10 },
};


static struct temp_limits amb_temp_limits[2] = {
	{ 65, 55, 40, 5, -5, -10 },
	{ 65, 55, 40, 5, -5, -10 },
};

static LIST_HEAD(all_temps);
static LIST_HEAD(all_fans);


#define CPU_FAN_REG	0xf0

#define SYS_FAN_REG	0xf2

#define PSUPPLY_FAN_REG	0xf4


#define FAN_SPEED_MIN	0x0c

#define FAN_SPEED_MAX	0x3f


#define PSUPPLY_FAN_ON	0x1f

#define PSUPPLY_FAN_OFF	0x00


static void set_fan_speeds(struct bbc_fan_control *fp) { /* Put temperatures into range so we don't mis-program * the hardware. */ if (fp->cpu_fan_speed < FAN_SPEED_MIN) fp->cpu_fan_speed = FAN_SPEED_MIN; if (fp->cpu_fan_speed > FAN_SPEED_MAX) fp->cpu_fan_speed = FAN_SPEED_MAX; if (fp->system_fan_speed < FAN_SPEED_MIN) fp->system_fan_speed = FAN_SPEED_MIN; if (fp->system_fan_speed > FAN_SPEED_MAX) fp->system_fan_speed = FAN_SPEED_MAX; #ifdef ENVCTRL_TRACE printk("fan%d: Changed fan speed to cpu(%02x) sys(%02x)\n", fp->index, fp->cpu_fan_speed, fp->system_fan_speed); #endif bbc_i2c_writeb(fp->client, fp->cpu_fan_speed, CPU_FAN_REG); bbc_i2c_writeb(fp->client, fp->system_fan_speed, SYS_FAN_REG); bbc_i2c_writeb(fp->client, (fp->psupply_fan_on ? PSUPPLY_FAN_ON : PSUPPLY_FAN_OFF), PSUPPLY_FAN_REG); }

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static void get_current_temps(struct bbc_cpu_temperature *tp) { tp->prev_amb_temp = tp->curr_amb_temp; bbc_i2c_readb(tp->client, (unsigned char *) &tp->curr_amb_temp, MAX1617_AMB_TEMP); tp->prev_cpu_temp = tp->curr_cpu_temp; bbc_i2c_readb(tp->client, (unsigned char *) &tp->curr_cpu_temp, MAX1617_CPU_TEMP); #ifdef ENVCTRL_TRACE printk("temp%d: cpu(%d C) amb(%d C)\n", tp->index, (int) tp->curr_cpu_temp, (int) tp->curr_amb_temp); #endif }

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static void do_envctrl_shutdown(struct bbc_cpu_temperature *tp) { static int shutting_down = 0; char *type = "???"; s8 val = -1; if (shutting_down != 0) return; if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_shutdown || tp->curr_amb_temp < amb_temp_limits[tp->index].low_shutdown) { type = "ambient"; val = tp->curr_amb_temp; } else if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_shutdown || tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_shutdown) { type = "CPU"; val = tp->curr_cpu_temp; } printk(KERN_CRIT "temp%d: Outside of safe %s " "operating temperature, %d C.\n", tp->index, type, val); printk(KERN_CRIT "kenvctrld: Shutting down the system now.\n"); shutting_down = 1; orderly_poweroff(true); }

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#define WARN_INTERVAL (30 * HZ)
static void analyze_ambient_temp(struct bbc_cpu_temperature *tp, unsigned long *last_warn, int tick) { int ret = 0; if (time_after(jiffies, (*last_warn + WARN_INTERVAL))) { if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_warn) { printk(KERN_WARNING "temp%d: " "Above safe ambient operating temperature, %d C.\n", tp->index, (int) tp->curr_amb_temp); ret = 1; } else if (tp->curr_amb_temp < amb_temp_limits[tp->index].low_warn) { printk(KERN_WARNING "temp%d: " "Below safe ambient operating temperature, %d C.\n", tp->index, (int) tp->curr_amb_temp); ret = 1; } if (ret) *last_warn = jiffies; } else if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_warn || tp->curr_amb_temp < amb_temp_limits[tp->index].low_warn) ret = 1; /* Now check the shutdown limits. */ if (tp->curr_amb_temp >= amb_temp_limits[tp->index].high_shutdown || tp->curr_amb_temp < amb_temp_limits[tp->index].low_shutdown) { do_envctrl_shutdown(tp); ret = 1; } if (ret) { tp->fan_todo[FAN_AMBIENT] = FAN_FULLBLAST; } else if ((tick & (8 - 1)) == 0) { s8 amb_goal_hi = amb_temp_limits[tp->index].high_warn - 10; s8 amb_goal_lo; amb_goal_lo = amb_goal_hi - 3; /* We do not try to avoid 'too cold' events. Basically we * only try to deal with over-heating and fan noise reduction. */ if (tp->avg_amb_temp < amb_goal_hi) { if (tp->avg_amb_temp >= amb_goal_lo) tp->fan_todo[FAN_AMBIENT] = FAN_SAME; else tp->fan_todo[FAN_AMBIENT] = FAN_SLOWER; } else { tp->fan_todo[FAN_AMBIENT] = FAN_FASTER; } } else { tp->fan_todo[FAN_AMBIENT] = FAN_SAME; } }

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static void analyze_cpu_temp(struct bbc_cpu_temperature *tp, unsigned long *last_warn, int tick) { int ret = 0; if (time_after(jiffies, (*last_warn + WARN_INTERVAL))) { if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_warn) { printk(KERN_WARNING "temp%d: " "Above safe CPU operating temperature, %d C.\n", tp->index, (int) tp->curr_cpu_temp); ret = 1; } else if (tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_warn) { printk(KERN_WARNING "temp%d: " "Below safe CPU operating temperature, %d C.\n", tp->index, (int) tp->curr_cpu_temp); ret = 1; } if (ret) *last_warn = jiffies; } else if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_warn || tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_warn) ret = 1; /* Now check the shutdown limits. */ if (tp->curr_cpu_temp >= cpu_temp_limits[tp->index].high_shutdown || tp->curr_cpu_temp < cpu_temp_limits[tp->index].low_shutdown) { do_envctrl_shutdown(tp); ret = 1; } if (ret) { tp->fan_todo[FAN_CPU] = FAN_FULLBLAST; } else if ((tick & (8 - 1)) == 0) { s8 cpu_goal_hi = cpu_temp_limits[tp->index].high_warn - 10; s8 cpu_goal_lo; cpu_goal_lo = cpu_goal_hi - 3; /* We do not try to avoid 'too cold' events. Basically we * only try to deal with over-heating and fan noise reduction. */ if (tp->avg_cpu_temp < cpu_goal_hi) { if (tp->avg_cpu_temp >= cpu_goal_lo) tp->fan_todo[FAN_CPU] = FAN_SAME; else tp->fan_todo[FAN_CPU] = FAN_SLOWER; } else { tp->fan_todo[FAN_CPU] = FAN_FASTER; } } else { tp->fan_todo[FAN_CPU] = FAN_SAME; } }

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static void analyze_temps(struct bbc_cpu_temperature *tp, unsigned long *last_warn) { tp->avg_amb_temp = (s8)((int)((int)tp->avg_amb_temp + (int)tp->curr_amb_temp) / 2); tp->avg_cpu_temp = (s8)((int)((int)tp->avg_cpu_temp + (int)tp->curr_cpu_temp) / 2); analyze_ambient_temp(tp, last_warn, tp->sample_tick); analyze_cpu_temp(tp, last_warn, tp->sample_tick); tp->sample_tick++; }

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static enum fan_action prioritize_fan_action(int which_fan) { struct bbc_cpu_temperature *tp; enum fan_action decision = FAN_STATE_MAX; /* Basically, prioritize what the temperature sensors * recommend we do, and perform that action on all the * fans. */ list_for_each_entry(tp, &all_temps, glob_list) { if (tp->fan_todo[which_fan] == FAN_FULLBLAST) { decision = FAN_FULLBLAST; break; } if (tp->fan_todo[which_fan] == FAN_SAME && decision != FAN_FASTER) decision = FAN_SAME; else if (tp->fan_todo[which_fan] == FAN_FASTER) decision = FAN_FASTER; else if (decision != FAN_FASTER && decision != FAN_SAME && tp->fan_todo[which_fan] == FAN_SLOWER) decision = FAN_SLOWER; } if (decision == FAN_STATE_MAX) decision = FAN_SAME; return decision; }

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static int maybe_new_ambient_fan_speed(struct bbc_fan_control *fp) { enum fan_action decision = prioritize_fan_action(FAN_AMBIENT); int ret; if (decision == FAN_SAME) return 0; ret = 1; if (decision == FAN_FULLBLAST) { if (fp->system_fan_speed >= FAN_SPEED_MAX) ret = 0; else fp->system_fan_speed = FAN_SPEED_MAX; } else { if (decision == FAN_FASTER) { if (fp->system_fan_speed >= FAN_SPEED_MAX) ret = 0; else fp->system_fan_speed += 2; } else { int orig_speed = fp->system_fan_speed; if (orig_speed <= FAN_SPEED_MIN || orig_speed <= (fp->cpu_fan_speed - 3)) ret = 0; else fp->system_fan_speed -= 1; } } return ret; }

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static int maybe_new_cpu_fan_speed(struct bbc_fan_control *fp) { enum fan_action decision = prioritize_fan_action(FAN_CPU); int ret; if (decision == FAN_SAME) return 0; ret = 1; if (decision == FAN_FULLBLAST) { if (fp->cpu_fan_speed >= FAN_SPEED_MAX) ret = 0; else fp->cpu_fan_speed = FAN_SPEED_MAX; } else { if (decision == FAN_FASTER) { if (fp->cpu_fan_speed >= FAN_SPEED_MAX) ret = 0; else { fp->cpu_fan_speed += 2; if (fp->system_fan_speed < (fp->cpu_fan_speed - 3)) fp->system_fan_speed = fp->cpu_fan_speed - 3; } } else { if (fp->cpu_fan_speed <= FAN_SPEED_MIN) ret = 0; else fp->cpu_fan_speed -= 1; } } return ret; }

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static void maybe_new_fan_speeds(struct bbc_fan_control *fp) { int new; new = maybe_new_ambient_fan_speed(fp); new |= maybe_new_cpu_fan_speed(fp); if (new) set_fan_speeds(fp); }

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static void fans_full_blast(void) { struct bbc_fan_control *fp; /* Since we will not be monitoring things anymore, put * the fans on full blast. */ list_for_each_entry(fp, &all_fans, glob_list) { fp->cpu_fan_speed = FAN_SPEED_MAX; fp->system_fan_speed = FAN_SPEED_MAX; fp->psupply_fan_on = 1; set_fan_speeds(fp); } }

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#define POLL_INTERVAL (5 * 1000) static unsigned long last_warning_jiffies; static struct task_struct *kenvctrld_task;
static int kenvctrld(void *__unused) { printk(KERN_INFO "bbc_envctrl: kenvctrld starting...\n"); last_warning_jiffies = jiffies - WARN_INTERVAL; for (;;) { struct bbc_cpu_temperature *tp; struct bbc_fan_control *fp; msleep_interruptible(POLL_INTERVAL); if (kthread_should_stop()) break; list_for_each_entry(tp, &all_temps, glob_list) { get_current_temps(tp); analyze_temps(tp, &last_warning_jiffies); } list_for_each_entry(fp, &all_fans, glob_list) maybe_new_fan_speeds(fp); } printk(KERN_INFO "bbc_envctrl: kenvctrld exiting...\n"); fans_full_blast(); return 0; }

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static void attach_one_temp(struct bbc_i2c_bus *bp, struct platform_device *op, int temp_idx) { struct bbc_cpu_temperature *tp; tp = kzalloc(sizeof(*tp), GFP_KERNEL); if (!tp) return; INIT_LIST_HEAD(&tp->bp_list); INIT_LIST_HEAD(&tp->glob_list); tp->client = bbc_i2c_attach(bp, op); if (!tp->client) { kfree(tp); return; } tp->index = temp_idx; list_add(&tp->glob_list, &all_temps); list_add(&tp->bp_list, &bp->temps); /* Tell it to convert once every 5 seconds, clear all cfg * bits. */ bbc_i2c_writeb(tp->client, 0x00, MAX1617_WR_CFG_BYTE); bbc_i2c_writeb(tp->client, 0x02, MAX1617_WR_CVRATE_BYTE); /* Program the hard temperature limits into the chip. */ bbc_i2c_writeb(tp->client, amb_temp_limits[tp->index].high_pwroff, MAX1617_WR_AMB_HIGHLIM); bbc_i2c_writeb(tp->client, amb_temp_limits[tp->index].low_pwroff, MAX1617_WR_AMB_LOWLIM); bbc_i2c_writeb(tp->client, cpu_temp_limits[tp->index].high_pwroff, MAX1617_WR_CPU_HIGHLIM); bbc_i2c_writeb(tp->client, cpu_temp_limits[tp->index].low_pwroff, MAX1617_WR_CPU_LOWLIM); get_current_temps(tp); tp->prev_cpu_temp = tp->avg_cpu_temp = tp->curr_cpu_temp; tp->prev_amb_temp = tp->avg_amb_temp = tp->curr_amb_temp; tp->fan_todo[FAN_AMBIENT] = FAN_SAME; tp->fan_todo[FAN_CPU] = FAN_SAME; }

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mariusz kozlowskimariusz kozlowski51.94%116.67%
grant likelygrant likely10.39%116.67%
Total258100.00%6100.00%


static void attach_one_fan(struct bbc_i2c_bus *bp, struct platform_device *op, int fan_idx) { struct bbc_fan_control *fp; fp = kzalloc(sizeof(*fp), GFP_KERNEL); if (!fp) return; INIT_LIST_HEAD(&fp->bp_list); INIT_LIST_HEAD(&fp->glob_list); fp->client = bbc_i2c_attach(bp, op); if (!fp->client) { kfree(fp); return; } fp->index = fan_idx; list_add(&fp->glob_list, &all_fans); list_add(&fp->bp_list, &bp->fans); /* The i2c device controlling the fans is write-only. * So the only way to keep track of the current power * level fed to the fans is via software. Choose half * power for cpu/system and 'on' fo the powersupply fan * and set it now. */ fp->psupply_fan_on = 1; fp->cpu_fan_speed = (FAN_SPEED_MAX - FAN_SPEED_MIN) / 2; fp->cpu_fan_speed += FAN_SPEED_MIN; fp->system_fan_speed = (FAN_SPEED_MAX - FAN_SPEED_MIN) / 2; fp->system_fan_speed += FAN_SPEED_MIN; set_fan_speeds(fp); }

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mariusz kozlowskimariusz kozlowski53.07%116.67%
grant likelygrant likely10.61%116.67%
Total163100.00%6100.00%


static void destroy_one_temp(struct bbc_cpu_temperature *tp) { bbc_i2c_detach(tp->client); kfree(tp); }

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static void destroy_all_temps(struct bbc_i2c_bus *bp) { struct bbc_cpu_temperature *tp, *tpos; list_for_each_entry_safe(tp, tpos, &bp->temps, bp_list) { list_del(&tp->bp_list); list_del(&tp->glob_list); destroy_one_temp(tp); } }

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static void destroy_one_fan(struct bbc_fan_control *fp) { bbc_i2c_detach(fp->client); kfree(fp); }

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static void destroy_all_fans(struct bbc_i2c_bus *bp) { struct bbc_fan_control *fp, *fpos; list_for_each_entry_safe(fp, fpos, &bp->fans, bp_list) { list_del(&fp->bp_list); list_del(&fp->glob_list); destroy_one_fan(fp); } }

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int bbc_envctrl_init(struct bbc_i2c_bus *bp) { struct platform_device *op; int temp_index = 0; int fan_index = 0; int devidx = 0; while ((op = bbc_i2c_getdev(bp, devidx++)) != NULL) { if (!strcmp(op->dev.of_node->name, "temperature")) attach_one_temp(bp, op, temp_index++); if (!strcmp(op->dev.of_node->name, "fan-control")) attach_one_fan(bp, op, fan_index++); } if (temp_index != 0 && fan_index != 0) { kenvctrld_task = kthread_run(kenvctrld, NULL, "kenvctrld"); if (IS_ERR(kenvctrld_task)) { int err = PTR_ERR(kenvctrld_task); kenvctrld_task = NULL; destroy_all_temps(bp); destroy_all_fans(bp); return err; } } return 0; }

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david s. millerdavid s. miller4628.75%660.00%
christoph hellwigchristoph hellwig1811.25%110.00%
grant likelygrant likely74.38%220.00%
Total160100.00%10100.00%


void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp) { if (kenvctrld_task) kthread_stop(kenvctrld_task); destroy_all_temps(bp); destroy_all_fans(bp); }

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linus torvaldslinus torvalds1344.83%120.00%
christoph hellwigchristoph hellwig13.45%120.00%
Total29100.00%5100.00%


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linus torvaldslinus torvalds224884.70%15.26%
david s. millerdavid s. miller31912.02%842.11%
christopher alexander tobias schulzechristopher alexander tobias schulze321.21%15.26%
christoph hellwigchristoph hellwig240.90%15.26%
mariusz kozlowskimariusz kozlowski100.38%15.26%
grant likelygrant likely90.34%210.53%
jeremy fitzhardingejeremy fitzhardinge50.19%15.26%
tejun heotejun heo30.11%15.26%
nishanth aravamudannishanth aravamudan20.08%15.26%
steven colesteven cole10.04%15.26%
michael shieldsmichael shields10.04%15.26%
Total2654100.00%19100.00%
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