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/*****************************************************************************/
/*
* refclock.c -- Linux soundcard HF FSK driver,
* Reference clock routines.
*
* Copyright (C) 1997 Thomas Sailer (sailer@ife.ee.ethz.ch)
* Swiss Federal Institute of Technology (ETH), Electronics Lab
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
*/
/*****************************************************************************/
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/hfmodem.h>
#include <asm/processor.h>
/* --------------------------------------------------------------------- */
/*
* currently this module is supposed to support both module styles, i.e.
* the old one present up to about 2.1.9, and the new one functioning
* starting with 2.1.21. The reason is I have a kit allowing to compile
* this module also under 2.0.x which was requested by several people.
* This will go in 2.2
*/
#include <linux/version.h>
#if LINUX_VERSION_CODE >= 0x20123
#include <linux/init.h>
#else
#define __init
#define __initdata
#define __initfunc(x) x
#endif
/* --------------------------------------------------------------------- */
/*
* command line params
*/
static unsigned int scale_tvusec = 1UL<<24;
#ifdef __i386__
static unsigned int scale_rdtsc = 0;
static int rdtsc_ok = 1;
#endif /* __i386__ */
/* --------------------------------------------------------------------- */
#ifdef __i386__
__initfunc(static void i386_capability(void))
{
if (boot_cpu_data.x86_capability & X86_FEATURE_TSC)
rdtsc_ok = 1;
else
printk(KERN_INFO "%s: cpu does not support the rdtsc instruction\n", hfmodem_drvname);
}
#endif /* __i386__ */
/* --------------------------------------------------------------------- */
__initfunc(void hfmodem_refclock_probe(void))
{
#ifdef __i386__
if (rdtsc_ok) {
rdtsc_ok = 0;
i386_capability();
if (rdtsc_ok) {
unsigned int tmp0, tmp1, tmp2, tmp3;
__asm__("rdtsc" : "=a" (tmp0), "=d" (tmp1));
__asm__("rdtsc" : "=a" (tmp2), "=d" (tmp3));
if (tmp0 == tmp2 && tmp1 == tmp3) {
rdtsc_ok = 0;
printk(KERN_WARNING "%s: rdtsc unusable, does not change\n",
hfmodem_drvname);
}
}
}
printk(KERN_INFO "%s: using %s as timing source\n", hfmodem_drvname,
rdtsc_ok ? "rdtsc" : "gettimeofday");
#endif /* __i386__ */
}
/* --------------------------------------------------------------------- */
void hfmodem_refclock_init(struct hfmodem_state *dev)
{
struct timeval tv;
dev->clk.lasttime = 0;
#ifdef __i386__
if (rdtsc_ok) {
__asm__("rdtsc;" : "=&d" (dev->clk.starttime_hi), "=&a" (dev->clk.starttime_lo));
return;
}
#endif /* __i386__ */
do_gettimeofday(&tv);
dev->clk.last_tvusec = tv.tv_usec;
dev->clk.time_cnt = 0;
}
/* --------------------------------------------------------------------- */
hfmodem_time_t hfmodem_refclock_current(struct hfmodem_state *dev, hfmodem_time_t expected, int exp_valid)
{
struct timeval tv;
hfmodem_time_t curtime;
long diff;
#ifdef __i386__
if (rdtsc_ok) {
unsigned int tmp0, tmp1;
unsigned int tmp2, tmp3;
__asm__("rdtsc;\n\t"
"subl %2,%%eax\n\t"
"sbbl %3,%%edx\n\t" : "=&a" (tmp0), "=&d" (tmp1)
: "m" (dev->clk.starttime_lo), "m" (dev->clk.starttime_hi) : "ax", "dx");
__asm__("mull %1" : "=d" (tmp2) : "m" (scale_rdtsc), "a" (tmp0) : "ax");
__asm__("mull %1" : "=a" (tmp3) : "m" (scale_rdtsc), "a" (tmp1) : "dx");
curtime = tmp2 + tmp3;
goto time_known;
}
#endif /* __i386__ */
do_gettimeofday(&tv);
dev->clk.time_cnt += (unsigned)(1000000 + tv.tv_usec - dev->clk.last_tvusec) % 1000000;
dev->clk.last_tvusec = tv.tv_usec;
curtime = (dev->clk.time_cnt * scale_tvusec) >> 24;
time_known:
if (exp_valid && abs(diff = (curtime - dev->clk.lasttime - expected)) >= 1000)
printk(KERN_DEBUG "%s: refclock adjustment %ld more than 1ms\n",
hfmodem_drvname, diff);
return (dev->clk.lasttime = curtime);
}
/* --------------------------------------------------------------------- */
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