diff options
Diffstat (limited to 'libdde_linux26/lib/src/init')
| -rw-r--r-- | libdde_linux26/lib/src/init/calibrate.c | 204 |
1 files changed, 0 insertions, 204 deletions
diff --git a/libdde_linux26/lib/src/init/calibrate.c b/libdde_linux26/lib/src/init/calibrate.c deleted file mode 100644 index 36747582..00000000 --- a/libdde_linux26/lib/src/init/calibrate.c +++ /dev/null @@ -1,204 +0,0 @@ -/* calibrate.c: default delay calibration - * - * Excised from init/main.c - * Copyright (C) 1991, 1992 Linus Torvalds - */ - -#include <linux/jiffies.h> -#include <linux/delay.h> -#include <linux/init.h> -#include <linux/timex.h> -#include <linux/smp.h> -#include <ddekit/timer.h> - -unsigned long loops_per_jiffy = (1<<12); - -unsigned long lpj_fine; -unsigned long preset_lpj; -static int __init lpj_setup(char *str) -{ - preset_lpj = simple_strtoul(str,NULL,0); - return 1; -} - -__setup("lpj=", lpj_setup); - -#ifdef ARCH_HAS_READ_CURRENT_TIMER - -/* This routine uses the read_current_timer() routine and gets the - * loops per jiffy directly, instead of guessing it using delay(). - * Also, this code tries to handle non-maskable asynchronous events - * (like SMIs) - */ -#define DELAY_CALIBRATION_TICKS ((HZ < 100) ? 1 : (HZ/100)) -#define MAX_DIRECT_CALIBRATION_RETRIES 5 - -static unsigned long __cpuinit calibrate_delay_direct(void) -{ - unsigned long pre_start, start, post_start; - unsigned long pre_end, end, post_end; - unsigned long start_jiffies; - unsigned long timer_rate_min, timer_rate_max; - unsigned long good_timer_sum = 0; - unsigned long good_timer_count = 0; - int i; - - /* TODO It's not a very good place to call this function - * as TSC is very platform-dependant but calibrate_delay_direct - * isn't that much. */ - use_tsc_delay (); - - if (read_current_timer(&pre_start) < 0 ) - return 0; - - /* - * A simple loop like - * while ( jiffies < start_jiffies+1) - * start = read_current_timer(); - * will not do. As we don't really know whether jiffy switch - * happened first or timer_value was read first. And some asynchronous - * event can happen between these two events introducing errors in lpj. - * - * So, we do - * 1. pre_start <- When we are sure that jiffy switch hasn't happened - * 2. check jiffy switch - * 3. start <- timer value before or after jiffy switch - * 4. post_start <- When we are sure that jiffy switch has happened - * - * Note, we don't know anything about order of 2 and 3. - * Now, by looking at post_start and pre_start difference, we can - * check whether any asynchronous event happened or not - */ - - for (i = 0; i < MAX_DIRECT_CALIBRATION_RETRIES; i++) { - pre_start = 0; - read_current_timer(&start); - start_jiffies = jiffies; - while (jiffies <= (start_jiffies + 1)) { - pre_start = start; - read_current_timer(&start); - } - read_current_timer(&post_start); - - pre_end = 0; - end = post_start; - while (jiffies <= - (start_jiffies + 1 + DELAY_CALIBRATION_TICKS)) { - pre_end = end; - read_current_timer(&end); - } - read_current_timer(&post_end); - - timer_rate_max = (post_end - pre_start) / - DELAY_CALIBRATION_TICKS; - timer_rate_min = (pre_end - post_start) / - DELAY_CALIBRATION_TICKS; - - /* - * If the upper limit and lower limit of the timer_rate is - * >= 12.5% apart, redo calibration. - */ - if (pre_start != 0 && pre_end != 0 && - (timer_rate_max - timer_rate_min) < (timer_rate_max >> 3)) { - good_timer_count++; - good_timer_sum += timer_rate_max; - } - } - - if (good_timer_count) - return (good_timer_sum/good_timer_count); - - printk(KERN_WARNING "calibrate_delay_direct() failed to get a good " - "estimate for loops_per_jiffy.\nProbably due to long platform interrupts. Consider using \"lpj=\" boot option.\n"); - return 0; -} -#else -static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} -#endif - -/* - * This is the number of bits of precision for the loops_per_jiffy. Each - * bit takes on average 1.5/HZ seconds. This (like the original) is a little - * better than 1% - * For the boot cpu we can skip the delay calibration and assign it a value - * calculated based on the timer frequency. - * For the rest of the CPUs we cannot assume that the timer frequency is same as - * the cpu frequency, hence do the calibration for those. - */ -#define LPS_PREC 8 - -static unsigned long __cpuinit calibrate_delay_estimate(void) -{ - unsigned long ticks, loopbit; - int lps_precision = LPS_PREC; - int loops_per_jiffy; - - loops_per_jiffy = (1<<12); - - while ((loops_per_jiffy <<= 1) != 0) { - /* wait for "start of" clock tick */ - ticks = jiffies; - while (ticks == jiffies) - /* nothing */; - /* Go .. */ - ticks = jiffies; - __delay(loops_per_jiffy); - ticks = jiffies - ticks; - if (ticks) - break; - } - - /* - * Do a binary approximation to get loops_per_jiffy set to - * equal one clock (up to lps_precision bits) - */ - loops_per_jiffy >>= 1; - loopbit = loops_per_jiffy; - while (lps_precision-- && (loopbit >>= 1)) { - loops_per_jiffy |= loopbit; - ticks = jiffies; - while (ticks == jiffies) - /* nothing */; - ticks = jiffies; - __delay(loops_per_jiffy); - if (jiffies != ticks) /* longer than 1 tick */ - loops_per_jiffy &= ~loopbit; - } - return loops_per_jiffy; -} - -#define NRETRIES 3 - -void __cpuinit calibrate_delay(void) -{ - if (preset_lpj) { - loops_per_jiffy = preset_lpj; - printk(KERN_INFO - "Calibrating delay loop (skipped) preset value.. "); - } else if ((smp_processor_id() == 0) && lpj_fine) { - loops_per_jiffy = lpj_fine; - printk(KERN_INFO - "Calibrating delay loop (skipped), " - "value calculated using timer frequency.. "); - } else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) { - printk(KERN_INFO - "Calibrating delay using timer specific routine.. "); - } else { - int i; - unsigned long result; - - printk(KERN_INFO "Calibrating delay loop... "); - loops_per_jiffy = 0; - for (i = 0; i < NRETRIES; i++) { - result = calibrate_delay_estimate(); - if (result > loops_per_jiffy) - loops_per_jiffy = result; - } - - } - printk(KERN_CONT "%lu.%02lu BogoMIPS (lpj=%lu)\n", - loops_per_jiffy/(500000/HZ), - (loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy); -} - -core_initcall(calibrate_delay); |