diff options
Diffstat (limited to 'drivers/char/hfmodem/refclock.c')
| -rw-r--r-- | drivers/char/hfmodem/refclock.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/char/hfmodem/refclock.c b/drivers/char/hfmodem/refclock.c new file mode 100644 index 000000000..6617673ca --- /dev/null +++ b/drivers/char/hfmodem/refclock.c @@ -0,0 +1,189 @@ +/*****************************************************************************/ + +/* + * 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> + +/* --------------------------------------------------------------------- */ + +/* + * 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)) +{ + unsigned long flags; + unsigned long fl1; + union { + struct { + unsigned int ebx, edx, ecx; + } r; + unsigned char s[13]; + } id; + unsigned int eax; + unsigned int x86_capability; + + save_flags(flags); + flags |= 0x200000; + restore_flags(flags); + save_flags(flags); + fl1 = flags; + flags &= ~0x200000; + restore_flags(flags); + save_flags(flags); + if (!(fl1 & 0x200000) || (flags & 0x200000)) { + printk(KERN_WARNING "%s: cpu does not support CPUID\n", hfmodem_drvname); + return; + } + __asm__ ("cpuid" : "=a" (eax), "=b" (id.r.ebx), "=c" (id.r.ecx), "=d" (id.r.edx) : + "0" (0)); + id.s[12] = 0; + if (eax < 1) { + printk(KERN_WARNING "%s: cpu (vendor string %s) does not support capability " + "list\n", hfmodem_drvname, id.s); + return; + } + printk(KERN_INFO "%s: cpu: vendor string %s ", hfmodem_drvname, id.s); + __asm__ ("cpuid" : "=a" (eax), "=d" (x86_capability) : "0" (1) : "ebx", "ecx"); + printk("fam %d mdl %d step %d cap 0x%x\n", (eax >> 8) & 15, (eax >> 4) & 15, eax & 15, + x86_capability); + if (x86_capability & 0x10) + 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); +} + +/* --------------------------------------------------------------------- */ |