diff options
Diffstat (limited to 'arch/i386/kernel/timers/common.c')
| -rw-r--r-- | arch/i386/kernel/timers/common.c | 172 |
1 files changed, 0 insertions, 172 deletions
diff --git a/arch/i386/kernel/timers/common.c b/arch/i386/kernel/timers/common.c deleted file mode 100644 index 8163fe0..0000000 --- a/arch/i386/kernel/timers/common.c +++ /dev/null @@ -1,172 +0,0 @@ -/* - * Common functions used across the timers go here - */ - -#include <linux/init.h> -#include <linux/timex.h> -#include <linux/errno.h> -#include <linux/jiffies.h> -#include <linux/module.h> - -#include <asm/io.h> -#include <asm/timer.h> -#include <asm/hpet.h> - -#include "mach_timer.h" - -/* ------ Calibrate the TSC ------- - * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset(). - * Too much 64-bit arithmetic here to do this cleanly in C, and for - * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2) - * output busy loop as low as possible. We avoid reading the CTC registers - * directly because of the awkward 8-bit access mechanism of the 82C54 - * device. - */ - -#define CALIBRATE_TIME (5 * 1000020/HZ) - -unsigned long calibrate_tsc(void) -{ - mach_prepare_counter(); - - { - unsigned long startlow, starthigh; - unsigned long endlow, endhigh; - unsigned long count; - - rdtsc(startlow,starthigh); - mach_countup(&count); - rdtsc(endlow,endhigh); - - - /* Error: ECTCNEVERSET */ - if (count <= 1) - goto bad_ctc; - - /* 64-bit subtract - gcc just messes up with long longs */ - __asm__("subl %2,%0\n\t" - "sbbl %3,%1" - :"=a" (endlow), "=d" (endhigh) - :"g" (startlow), "g" (starthigh), - "0" (endlow), "1" (endhigh)); - - /* Error: ECPUTOOFAST */ - if (endhigh) - goto bad_ctc; - - /* Error: ECPUTOOSLOW */ - if (endlow <= CALIBRATE_TIME) - goto bad_ctc; - - __asm__("divl %2" - :"=a" (endlow), "=d" (endhigh) - :"r" (endlow), "0" (0), "1" (CALIBRATE_TIME)); - - return endlow; - } - - /* - * The CTC wasn't reliable: we got a hit on the very first read, - * or the CPU was so fast/slow that the quotient wouldn't fit in - * 32 bits.. - */ -bad_ctc: - return 0; -} - -#ifdef CONFIG_HPET_TIMER -/* ------ Calibrate the TSC using HPET ------- - * Return 2^32 * (1 / (TSC clocks per usec)) for getting the CPU freq. - * Second output is parameter 1 (when non NULL) - * Set 2^32 * (1 / (tsc per HPET clk)) for delay_hpet(). - * calibrate_tsc() calibrates the processor TSC by comparing - * it to the HPET timer of known frequency. - * Too much 64-bit arithmetic here to do this cleanly in C - */ -#define CALIBRATE_CNT_HPET (5 * hpet_tick) -#define CALIBRATE_TIME_HPET (5 * KERNEL_TICK_USEC) - -unsigned long __devinit calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr) -{ - unsigned long tsc_startlow, tsc_starthigh; - unsigned long tsc_endlow, tsc_endhigh; - unsigned long hpet_start, hpet_end; - unsigned long result, remain; - - hpet_start = hpet_readl(HPET_COUNTER); - rdtsc(tsc_startlow, tsc_starthigh); - do { - hpet_end = hpet_readl(HPET_COUNTER); - } while ((hpet_end - hpet_start) < CALIBRATE_CNT_HPET); - rdtsc(tsc_endlow, tsc_endhigh); - - /* 64-bit subtract - gcc just messes up with long longs */ - __asm__("subl %2,%0\n\t" - "sbbl %3,%1" - :"=a" (tsc_endlow), "=d" (tsc_endhigh) - :"g" (tsc_startlow), "g" (tsc_starthigh), - "0" (tsc_endlow), "1" (tsc_endhigh)); - - /* Error: ECPUTOOFAST */ - if (tsc_endhigh) - goto bad_calibration; - - /* Error: ECPUTOOSLOW */ - if (tsc_endlow <= CALIBRATE_TIME_HPET) - goto bad_calibration; - - ASM_DIV64_REG(result, remain, tsc_endlow, 0, CALIBRATE_TIME_HPET); - if (remain > (tsc_endlow >> 1)) - result++; /* rounding the result */ - - if (tsc_hpet_quotient_ptr) { - unsigned long tsc_hpet_quotient; - - ASM_DIV64_REG(tsc_hpet_quotient, remain, tsc_endlow, 0, - CALIBRATE_CNT_HPET); - if (remain > (tsc_endlow >> 1)) - tsc_hpet_quotient++; /* rounding the result */ - *tsc_hpet_quotient_ptr = tsc_hpet_quotient; - } - - return result; -bad_calibration: - /* - * the CPU was so fast/slow that the quotient wouldn't fit in - * 32 bits.. - */ - return 0; -} -#endif - - -unsigned long read_timer_tsc(void) -{ - unsigned long retval; - rdtscl(retval); - return retval; -} - - -/* calculate cpu_khz */ -void init_cpu_khz(void) -{ - if (cpu_has_tsc) { - unsigned long tsc_quotient = calibrate_tsc(); - if (tsc_quotient) { - /* report CPU clock rate in Hz. - * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) = - * clock/second. Our precision is about 100 ppm. - */ - { unsigned long eax=0, edx=1000; - __asm__("divl %2" - :"=a" (cpu_khz), "=d" (edx) - :"r" (tsc_quotient), - "0" (eax), "1" (edx)); - printk("Detected %u.%03u MHz processor.\n", - cpu_khz / 1000, cpu_khz % 1000); - } - } - } -} - |
