cregit-Linux how code gets into the kernel

Release 4.7 arch/cris/arch-v10/kernel/fasttimer.c

/*
 * linux/arch/cris/kernel/fasttimer.c
 *
 * Fast timers for ETRAX100/ETRAX100LX
 *
 * Copyright (C) 2000-2007 Axis Communications AB, Lund, Sweden
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>

#include <asm/segment.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/delay.h>

#include <arch/svinto.h>
#include <asm/fasttimer.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>



#define DEBUG_LOG_INCLUDED

#define FAST_TIMER_LOG
/* #define FAST_TIMER_TEST */


#define FAST_TIMER_SANITY_CHECKS

#ifdef FAST_TIMER_SANITY_CHECKS

static int sanity_failed;
#endif


#define D1(x)

#define D2(x)

#define DP(x)


static unsigned int fast_timer_running;

static unsigned int fast_timers_added;

static unsigned int fast_timers_started;

static unsigned int fast_timers_expired;

static unsigned int fast_timers_deleted;

static unsigned int fast_timer_is_init;

static unsigned int fast_timer_ints;


struct fast_timer *fast_timer_list = NULL;

#ifdef DEBUG_LOG_INCLUDED

#define DEBUG_LOG_MAX 128

static const char * debug_log_string[DEBUG_LOG_MAX];

static unsigned long debug_log_value[DEBUG_LOG_MAX];

static unsigned int debug_log_cnt;

static unsigned int debug_log_cnt_wrapped;


#define DEBUG_LOG(string, value) \
{ \
  unsigned long log_flags; \
  local_irq_save(log_flags); \
  debug_log_string[debug_log_cnt] = (string); \
  debug_log_value[debug_log_cnt] = (unsigned long)(value); \
  if (++debug_log_cnt >= DEBUG_LOG_MAX) \
  { \
    debug_log_cnt = debug_log_cnt % DEBUG_LOG_MAX; \
    debug_log_cnt_wrapped = 1; \
  } \
  local_irq_restore(log_flags); \
}
#else

#define DEBUG_LOG(string, value)
#endif


/* The frequencies for index = clkselx number in R_TIMER_CTRL */

#define NUM_TIMER_FREQ 15

#define MAX_USABLE_TIMER_FREQ 7

#define MAX_DELAY_US  853333L

const unsigned long timer_freq_100[NUM_TIMER_FREQ] =
{
  3,   /* 0 3333 - 853333 us */
  6,   /* 1 1666 - 426666 us */
  12,  /* 2  833 - 213333 us */
  24,  /* 3  416 - 106666 us */
  48,  /* 4  208 -  53333 us */
  96,  /* 5  104 -  26666 us */
  192, /* 6   52 -  13333 us */
  384, /* 7   26 -   6666 us */
  576,
  1152,
  2304,
  4608,
  9216,
  18432,
  62500,
  /* 15 = cascade */
};

#define NUM_TIMER_STATS 16
#ifdef FAST_TIMER_LOG

struct fast_timer timer_added_log[NUM_TIMER_STATS];

struct fast_timer timer_started_log[NUM_TIMER_STATS];

struct fast_timer timer_expired_log[NUM_TIMER_STATS];
#endif


int timer_div_settings[NUM_TIMER_STATS];

int timer_freq_settings[NUM_TIMER_STATS];

int timer_delay_settings[NUM_TIMER_STATS];

/* Not true gettimeofday, only checks the jiffies (uptime) + useconds */

inline void do_gettimeofday_fast(struct fasttime_t *tv) { tv->tv_jiff = jiffies; tv->tv_usec = GET_JIFFIES_USEC(); }

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inline int fasttime_cmp(struct fasttime_t *t0, struct fasttime_t *t1) { /* Compare jiffies. Takes care of wrapping */ if (time_before(t0->tv_jiff, t1->tv_jiff)) return -1; else if (time_after(t0->tv_jiff, t1->tv_jiff)) return 1; /* Compare us */ if (t0->tv_usec < t1->tv_usec) return -1; else if (t0->tv_usec > t1->tv_usec) return 1; return 0; }

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inline void start_timer1(unsigned long delay_us) { int freq_index = 0; /* This is the lowest resolution */ unsigned long upper_limit = MAX_DELAY_US; unsigned long div; /* Start/Restart the timer to the new shorter value */ /* t = 1/freq = 1/19200 = 53us * T=div*t, div = T/t = delay_us*freq/1000000 */ #if 1 /* Adaptive timer settings */ while (delay_us < upper_limit && freq_index < MAX_USABLE_TIMER_FREQ) { freq_index++; upper_limit >>= 1; /* Divide by 2 using shift */ } if (freq_index > 0) { freq_index--; } #else freq_index = 6; #endif div = delay_us * timer_freq_100[freq_index]/10000; if (div < 2) { /* Maybe increase timer freq? */ div = 2; } if (div > 255) { div = 0; /* This means 256, the max the timer takes */ /* If a longer timeout than the timer can handle is used, * then we must restart it when it goes off. */ } timer_div_settings[fast_timers_started % NUM_TIMER_STATS] = div; timer_freq_settings[fast_timers_started % NUM_TIMER_STATS] = freq_index; timer_delay_settings[fast_timers_started % NUM_TIMER_STATS] = delay_us; D1(printk(KERN_DEBUG "start_timer1 : %d us freq: %i div: %i\n", delay_us, freq_index, div)); /* Clear timer1 irq */ *R_IRQ_MASK0_CLR = IO_STATE(R_IRQ_MASK0_CLR, timer1, clr); /* Set timer values */ *R_TIMER_CTRL = r_timer_ctrl_shadow = (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, timerdiv1) & ~IO_MASK(R_TIMER_CTRL, tm1) & ~IO_MASK(R_TIMER_CTRL, clksel1)) | IO_FIELD(R_TIMER_CTRL, timerdiv1, div) | IO_STATE(R_TIMER_CTRL, tm1, stop_ld) | IO_FIELD(R_TIMER_CTRL, clksel1, freq_index ); /* 6=c19k2Hz */ /* Ack interrupt */ *R_TIMER_CTRL = r_timer_ctrl_shadow | IO_STATE(R_TIMER_CTRL, i1, clr); /* Start timer */ *R_TIMER_CTRL = r_timer_ctrl_shadow = (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, tm1)) | IO_STATE(R_TIMER_CTRL, tm1, run); /* Enable timer1 irq */ *R_IRQ_MASK0_SET = IO_STATE(R_IRQ_MASK0_SET, timer1, set); fast_timers_started++; fast_timer_running = 1; }

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/* In version 1.4 this function takes 27 - 50 us */
void start_one_shot_timer(struct fast_timer *t, fast_timer_function_type *function, unsigned long data, unsigned long delay_us, const char *name) { unsigned long flags; struct fast_timer *tmp; D1(printk("sft %s %d us\n", name, delay_us)); local_irq_save(flags); do_gettimeofday_fast(&t->tv_set); tmp = fast_timer_list; #ifdef FAST_TIMER_SANITY_CHECKS /* Check so this is not in the list already... */ while (tmp != NULL) { if (tmp == t) { printk(KERN_WARNING "timer name: %s data: " "0x%08lX already in list!\n", name, data); sanity_failed++; goto done; } else tmp = tmp->next; } tmp = fast_timer_list; #endif t->delay_us = delay_us; t->function = function; t->data = data; t->name = name; t->tv_expires.tv_usec = t->tv_set.tv_usec + delay_us % 1000000; t->tv_expires.tv_jiff = t->tv_set.tv_jiff + delay_us / 1000000 / HZ; if (t->tv_expires.tv_usec > 1000000) { t->tv_expires.tv_usec -= 1000000; t->tv_expires.tv_jiff += HZ; } #ifdef FAST_TIMER_LOG timer_added_log[fast_timers_added % NUM_TIMER_STATS] = *t; #endif fast_timers_added++; /* Check if this should timeout before anything else */ if (tmp == NULL || fasttime_cmp(&t->tv_expires, &tmp->tv_expires) < 0) { /* Put first in list and modify the timer value */ t->prev = NULL; t->next = fast_timer_list; if (fast_timer_list) { fast_timer_list->prev = t; } fast_timer_list = t; #ifdef FAST_TIMER_LOG timer_started_log[fast_timers_started % NUM_TIMER_STATS] = *t; #endif start_timer1(delay_us); } else { /* Put in correct place in list */ while (tmp->next && fasttime_cmp(&t->tv_expires, &tmp->next->tv_expires) > 0) { tmp = tmp->next; } /* Insert t after tmp */ t->prev = tmp; t->next = tmp->next; if (tmp->next) { tmp->next->prev = t; } tmp->next = t; } D2(printk("start_one_shot_timer: %d us done\n", delay_us)); done: local_irq_restore(flags); }

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/* start_one_shot_timer */
static inline int fast_timer_pending (const struct fast_timer * t) { return (t->next != NULL) || (t->prev != NULL) || (t == fast_timer_list); }

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static inline int detach_fast_timer (struct fast_timer *t) { struct fast_timer *next, *prev; if (!fast_timer_pending(t)) return 0; next = t->next; prev = t->prev; if (next) next->prev = prev; if (prev) prev->next = next; else fast_timer_list = next; fast_timers_deleted++; return 1; }

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int del_fast_timer(struct fast_timer * t) { unsigned long flags; int ret; local_irq_save(flags); ret = detach_fast_timer(t); t->next = t->prev = NULL; local_irq_restore(flags); return ret; }

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/* del_fast_timer */ /* Interrupt routines or functions called in interrupt context */ /* Timer 1 interrupt handler */
static irqreturn_t timer1_handler(int irq, void *dev_id) { struct fast_timer *t; unsigned long flags; /* We keep interrupts disabled not only when we modify the * fast timer list, but any time we hold a reference to a * timer in the list, since del_fast_timer may be called * from (another) interrupt context. Thus, the only time * when interrupts are enabled is when calling the timer * callback function. */ local_irq_save(flags); /* Clear timer1 irq */ *R_IRQ_MASK0_CLR = IO_STATE(R_IRQ_MASK0_CLR, timer1, clr); /* First stop timer, then ack interrupt */ /* Stop timer */ *R_TIMER_CTRL = r_timer_ctrl_shadow = (r_timer_ctrl_shadow & ~IO_MASK(R_TIMER_CTRL, tm1)) | IO_STATE(R_TIMER_CTRL, tm1, stop_ld); /* Ack interrupt */ *R_TIMER_CTRL = r_timer_ctrl_shadow | IO_STATE(R_TIMER_CTRL, i1, clr); fast_timer_running = 0; fast_timer_ints++; t = fast_timer_list; while (t) { struct fasttime_t tv; fast_timer_function_type *f; unsigned long d; /* Has it really expired? */ do_gettimeofday_fast(&tv); D1(printk(KERN_DEBUG "t: %is %06ius\n", tv.tv_jiff, tv.tv_usec)); if (fasttime_cmp(&t->tv_expires, &tv) <= 0) { /* Yes it has expired */ #ifdef FAST_TIMER_LOG timer_expired_log[fast_timers_expired % NUM_TIMER_STATS] = *t; #endif fast_timers_expired++; /* Remove this timer before call, since it may reuse the timer */ if (t->prev) { t->prev->next = t->next; } else { fast_timer_list = t->next; } if (t->next) { t->next->prev = t->prev; } t->prev = NULL; t->next = NULL; /* Save function callback data before enabling * interrupts, since the timer may be removed and * we don't know how it was allocated * (e.g. ->function and ->data may become overwritten * after deletion if the timer was stack-allocated). */ f = t->function; d = t->data; if (f != NULL) { /* Run callback with interrupts enabled. */ local_irq_restore(flags); f(d); local_irq_save(flags); } else DEBUG_LOG("!timer1 %i function==NULL!\n", fast_timer_ints); } else { /* Timer is to early, let's set it again using the normal routines */ D1(printk(".\n")); } if ((t = fast_timer_list) != NULL) { /* Start next timer.. */ long us = 0; struct fasttime_t tv; do_gettimeofday_fast(&tv); /* time_after_eq takes care of wrapping */ if (time_after_eq(t->tv_expires.tv_jiff, tv.tv_jiff)) us = ((t->tv_expires.tv_jiff - tv.tv_jiff) * 1000000 / HZ + t->tv_expires.tv_usec - tv.tv_usec); if (us > 0) { if (!fast_timer_running) { #ifdef FAST_TIMER_LOG timer_started_log[fast_timers_started % NUM_TIMER_STATS] = *t; #endif start_timer1(us); } break; } else { /* Timer already expired, let's handle it better late than never. * The normal loop handles it */ D1(printk("e! %d\n", us)); } } } local_irq_restore(flags); if (!t) { D1(printk("t1 stop!\n")); } return IRQ_HANDLED; }

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static void wake_up_func(unsigned long data) { wait_queue_head_t *sleep_wait_p = (wait_queue_head_t *)data; wake_up(sleep_wait_p); }

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/* Useful API */
void schedule_usleep(unsigned long us) { struct fast_timer t; wait_queue_head_t sleep_wait; init_waitqueue_head(&sleep_wait); D1(printk("schedule_usleep(%d)\n", us)); start_one_shot_timer(&t, wake_up_func, (unsigned long)&sleep_wait, us, "usleep"); /* Uninterruptible sleep on the fast timer. (The condition is somewhat * redundant since the timer is what wakes us up.) */ wait_event(sleep_wait, !fast_timer_pending(&t)); D1(printk("done schedule_usleep(%d)\n", us)); }

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#ifdef CONFIG_PROC_FS /* This value is very much based on testing */ #define BIG_BUF_SIZE (500 + NUM_TIMER_STATS * 300)
static int proc_fasttimer_show(struct seq_file *m, void *v) { unsigned long flags; int i = 0; int num_to_show; struct fasttime_t tv; struct fast_timer *t, *nextt; do_gettimeofday_fast(&tv); seq_printf(m, "Fast timers added: %i\n", fast_timers_added); seq_printf(m, "Fast timers started: %i\n", fast_timers_started); seq_printf(m, "Fast timer interrupts: %i\n", fast_timer_ints); seq_printf(m, "Fast timers expired: %i\n", fast_timers_expired); seq_printf(m, "Fast timers deleted: %i\n", fast_timers_deleted); seq_printf(m, "Fast timer running: %s\n", fast_timer_running ? "yes" : "no"); seq_printf(m, "Current time: %lu.%06lu\n", (unsigned long)tv.tv_jiff, (unsigned long)tv.tv_usec); #ifdef FAST_TIMER_SANITY_CHECKS seq_printf(m, "Sanity failed: %i\n", sanity_failed); #endif seq_putc(m, '\n'); #ifdef DEBUG_LOG_INCLUDED { int end_i = debug_log_cnt; i = 0; if (debug_log_cnt_wrapped) i = debug_log_cnt; while (i != end_i || debug_log_cnt_wrapped) { seq_printf(m, debug_log_string[i], debug_log_value[i]); if (seq_has_overflowed(m)) return 0; i = (i+1) % DEBUG_LOG_MAX; } } seq_putc(m, '\n'); #endif num_to_show = (fast_timers_started < NUM_TIMER_STATS ? fast_timers_started: NUM_TIMER_STATS); seq_printf(m, "Timers started: %i\n", fast_timers_started); for (i = 0; i < num_to_show; i++) { int cur = (fast_timers_started - i - 1) % NUM_TIMER_STATS; #if 1 //ndef FAST_TIMER_LOG seq_printf(m, "div: %i freq: %i delay: %i\n", timer_div_settings[cur], timer_freq_settings[cur], timer_delay_settings[cur]); #endif #ifdef FAST_TIMER_LOG t = &timer_started_log[cur]; seq_printf(m, "%-14s s: %6lu.%06lu e: %6lu.%06lu d: %6li us data: 0x%08lX\n", t->name, (unsigned long)t->tv_set.tv_jiff, (unsigned long)t->tv_set.tv_usec, (unsigned long)t->tv_expires.tv_jiff, (unsigned long)t->tv_expires.tv_usec, t->delay_us, t->data); if (seq_has_overflowed(m)) return 0; #endif } seq_putc(m, '\n'); #ifdef FAST_TIMER_LOG num_to_show = (fast_timers_added < NUM_TIMER_STATS ? fast_timers_added: NUM_TIMER_STATS); seq_printf(m, "Timers added: %i\n", fast_timers_added); for (i = 0; i < num_to_show; i++) { t = &timer_added_log[(fast_timers_added - i - 1) % NUM_TIMER_STATS]; seq_printf(m, "%-14s s: %6lu.%06lu e: %6lu.%06lu d: %6li us data: 0x%08lX\n", t->name, (unsigned long)t->tv_set.tv_jiff, (unsigned long)t->tv_set.tv_usec, (unsigned long)t->tv_expires.tv_jiff, (unsigned long)t->tv_expires.tv_usec, t->delay_us, t->data); if (seq_has_overflowed(m)) return 0; } seq_putc(m, '\n'); num_to_show = (fast_timers_expired < NUM_TIMER_STATS ? fast_timers_expired: NUM_TIMER_STATS); seq_printf(m, "Timers expired: %i\n", fast_timers_expired); for (i = 0; i < num_to_show; i++) { t = &timer_expired_log[(fast_timers_expired - i - 1) % NUM_TIMER_STATS]; seq_printf(m, "%-14s s: %6lu.%06lu e: %6lu.%06lu d: %6li us data: 0x%08lX\n", t->name, (unsigned long)t->tv_set.tv_jiff, (unsigned long)t->tv_set.tv_usec, (unsigned long)t->tv_expires.tv_jiff, (unsigned long)t->tv_expires.tv_usec, t->delay_us, t->data); if (seq_has_overflowed(m)) return 0; } seq_putc(m, '\n'); #endif seq_puts(m, "Active timers:\n"); local_irq_save(flags); t = fast_timer_list; while (t) { nextt = t->next; local_irq_restore(flags); seq_printf(m, "%-14s s: %6lu.%06lu e: %6lu.%06lu d: %6li us data: 0x%08lX\n", t->name, (unsigned long)t->tv_set.tv_jiff, (unsigned long)t->tv_set.tv_usec, (unsigned long)t->tv_expires.tv_jiff, (unsigned long)t->tv_expires.tv_usec, t->delay_us, t->data); if (seq_has_overflowed(m)) return 0; local_irq_save(flags); if (t->next != nextt) printk(KERN_WARNING "timer removed!\n"); t = nextt; } local_irq_restore(flags); return 0; }

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static int proc_fasttimer_open(struct inode *inode, struct file *file) { return single_open_size(file, proc_fasttimer_show, PDE_DATA(inode), BIG_BUF_SIZE); }

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static const struct file_operations proc_fasttimer_fops = { .open = proc_fasttimer_open, .read = seq_read, .llseek = seq_lseek, .release = single_release, }; #endif /* PROC_FS */ #ifdef FAST_TIMER_TEST static volatile unsigned long i = 0; static volatile int num_test_timeout = 0; static struct fast_timer tr[10]; static int exp_num[10]; static struct fasttime_t tv_exp[100];
static void test_timeout(unsigned long data) { do_gettimeofday_fast(&tv_exp[data]); exp_num[data] = num_test_timeout; num_test_timeout++; }

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static void test_timeout1(unsigned long data) { do_gettimeofday_fast(&tv_exp[data]); exp_num[data] = num_test_timeout; if (data < 7) { start_one_shot_timer(&tr[i], test_timeout1, i, 1000, "timeout1"); i++; } num_test_timeout++; }

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DP( static char buf0[2000]; static char buf1[2000]; static char buf2[2000]; static char buf3[2000]; static char buf4[2000]; ); static char buf5[6000]; static int j_u[1000];
static void fast_timer_test(void) { int prev_num; int j; struct fasttime_t tv, tv0, tv1, tv2; printk("fast_timer_test() start\n"); do_gettimeofday_fast(&tv); for (j = 0; j < 1000; j++) { j_u[j] = GET_JIFFIES_USEC(); } for (j = 0; j < 100; j++) { do_gettimeofday_fast(&tv_exp[j]); } printk(KERN_DEBUG "fast_timer_test() %is %06i\n", tv.tv_jiff, tv.tv_usec); for (j = 0; j < 1000; j++) { printk("%i %i %i %i %i\n",j_u[j], j_u[j+1], j_u[j+2], j_u[