aboutsummaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/timers/common.c
diff options
context:
space:
mode:
authorJames Bottomley <jejb@mulgrave.il.steeleye.com>2006-06-28 14:06:39 -0400
committerJames Bottomley <jejb@mulgrave.il.steeleye.com>2006-06-28 14:06:39 -0400
commitf28e71617ddaf2483e3e5c5237103484a303743f (patch)
tree67627d2d8ddbf6a4449371e9261d796c013b1fa1 /arch/i386/kernel/timers/common.c
parentdc6a78f1af10d28fb8c395034ae1e099b85c05b0 (diff)
parenta39727f212426b9d5f9267b3318a2afaf9922d3b (diff)
Merge ../linux-2.6/
Conflicts: drivers/scsi/aacraid/comminit.c Fixed up by removing the now renamed CONFIG_IOMMU option from aacraid Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Diffstat (limited to 'arch/i386/kernel/timers/common.c')
-rw-r--r--arch/i386/kernel/timers/common.c172
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 8163fe0cf1f0..000000000000
--- a/arch/i386/kernel/timers/common.c
+++ /dev/null
@@ -1,172 +0,0 @@
1/*
2 * Common functions used across the timers go here
3 */
4
5#include <linux/init.h>
6#include <linux/timex.h>
7#include <linux/errno.h>
8#include <linux/jiffies.h>
9#include <linux/module.h>
10
11#include <asm/io.h>
12#include <asm/timer.h>
13#include <asm/hpet.h>
14
15#include "mach_timer.h"
16
17/* ------ Calibrate the TSC -------
18 * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset().
19 * Too much 64-bit arithmetic here to do this cleanly in C, and for
20 * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2)
21 * output busy loop as low as possible. We avoid reading the CTC registers
22 * directly because of the awkward 8-bit access mechanism of the 82C54
23 * device.
24 */
25
26#define CALIBRATE_TIME (5 * 1000020/HZ)
27
28unsigned long calibrate_tsc(void)
29{
30 mach_prepare_counter();
31
32 {
33 unsigned long startlow, starthigh;
34 unsigned long endlow, endhigh;
35 unsigned long count;
36
37 rdtsc(startlow,starthigh);
38 mach_countup(&count);
39 rdtsc(endlow,endhigh);
40
41
42 /* Error: ECTCNEVERSET */
43 if (count <= 1)
44 goto bad_ctc;
45
46 /* 64-bit subtract - gcc just messes up with long longs */
47 __asm__("subl %2,%0\n\t"
48 "sbbl %3,%1"
49 :"=a" (endlow), "=d" (endhigh)
50 :"g" (startlow), "g" (starthigh),
51 "0" (endlow), "1" (endhigh));
52
53 /* Error: ECPUTOOFAST */
54 if (endhigh)
55 goto bad_ctc;
56
57 /* Error: ECPUTOOSLOW */
58 if (endlow <= CALIBRATE_TIME)
59 goto bad_ctc;
60
61 __asm__("divl %2"
62 :"=a" (endlow), "=d" (endhigh)
63 :"r" (endlow), "0" (0), "1" (CALIBRATE_TIME));
64
65 return endlow;
66 }
67
68 /*
69 * The CTC wasn't reliable: we got a hit on the very first read,
70 * or the CPU was so fast/slow that the quotient wouldn't fit in
71 * 32 bits..
72 */
73bad_ctc:
74 return 0;
75}
76
77#ifdef CONFIG_HPET_TIMER
78/* ------ Calibrate the TSC using HPET -------
79 * Return 2^32 * (1 / (TSC clocks per usec)) for getting the CPU freq.
80 * Second output is parameter 1 (when non NULL)
81 * Set 2^32 * (1 / (tsc per HPET clk)) for delay_hpet().
82 * calibrate_tsc() calibrates the processor TSC by comparing
83 * it to the HPET timer of known frequency.
84 * Too much 64-bit arithmetic here to do this cleanly in C
85 */
86#define CALIBRATE_CNT_HPET (5 * hpet_tick)
87#define CALIBRATE_TIME_HPET (5 * KERNEL_TICK_USEC)
88
89unsigned long __devinit calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr)
90{
91 unsigned long tsc_startlow, tsc_starthigh;
92 unsigned long tsc_endlow, tsc_endhigh;
93 unsigned long hpet_start, hpet_end;
94 unsigned long result, remain;
95
96 hpet_start = hpet_readl(HPET_COUNTER);
97 rdtsc(tsc_startlow, tsc_starthigh);
98 do {
99 hpet_end = hpet_readl(HPET_COUNTER);
100 } while ((hpet_end - hpet_start) < CALIBRATE_CNT_HPET);
101 rdtsc(tsc_endlow, tsc_endhigh);
102
103 /* 64-bit subtract - gcc just messes up with long longs */
104 __asm__("subl %2,%0\n\t"
105 "sbbl %3,%1"
106 :"=a" (tsc_endlow), "=d" (tsc_endhigh)
107 :"g" (tsc_startlow), "g" (tsc_starthigh),
108 "0" (tsc_endlow), "1" (tsc_endhigh));
109
110 /* Error: ECPUTOOFAST */
111 if (tsc_endhigh)
112 goto bad_calibration;
113
114 /* Error: ECPUTOOSLOW */
115 if (tsc_endlow <= CALIBRATE_TIME_HPET)
116 goto bad_calibration;
117
118 ASM_DIV64_REG(result, remain, tsc_endlow, 0, CALIBRATE_TIME_HPET);
119 if (remain > (tsc_endlow >> 1))
120 result++; /* rounding the result */
121
122 if (tsc_hpet_quotient_ptr) {
123 unsigned long tsc_hpet_quotient;
124
125 ASM_DIV64_REG(tsc_hpet_quotient, remain, tsc_endlow, 0,
126 CALIBRATE_CNT_HPET);
127 if (remain > (tsc_endlow >> 1))
128 tsc_hpet_quotient++; /* rounding the result */
129 *tsc_hpet_quotient_ptr = tsc_hpet_quotient;
130 }
131
132 return result;
133bad_calibration:
134 /*
135 * the CPU was so fast/slow that the quotient wouldn't fit in
136 * 32 bits..
137 */
138 return 0;
139}
140#endif
141
142
143unsigned long read_timer_tsc(void)
144{
145 unsigned long retval;
146 rdtscl(retval);
147 return retval;
148}
149
150
151/* calculate cpu_khz */
152void init_cpu_khz(void)
153{
154 if (cpu_has_tsc) {
155 unsigned long tsc_quotient = calibrate_tsc();
156 if (tsc_quotient) {
157 /* report CPU clock rate in Hz.
158 * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
159 * clock/second. Our precision is about 100 ppm.
160 */
161 { unsigned long eax=0, edx=1000;
162 __asm__("divl %2"
163 :"=a" (cpu_khz), "=d" (edx)
164 :"r" (tsc_quotient),
165 "0" (eax), "1" (edx));
166 printk("Detected %u.%03u MHz processor.\n",
167 cpu_khz / 1000, cpu_khz % 1000);
168 }
169 }
170 }
171}
172
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-26 12:00:29 -0500