devtime.c revision 963:9b3ac57fa611 
1/*
2 * Copyright (c) 2004 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <linux/module.h>
30#include <linux/config.h>
31#include <linux/moduleparam.h>
32#include <linux/init.h>
33#include <linux/fs.h>
34#include <asm/uaccess.h>
35#include <linux/kernel.h>
36#include <asm/io.h>
37#include <linux/netdevice.h>
38
39#ifdef __i386__
40#include <asm/processor.h>
41#include <asm/msr.h>
42#endif
43
44#define DRIVER_AUTHOR "Ali Saidi"
45#define DRIVER_DESC   "Interface to time uncacachable read and writes to device registers"
46#define DRIVER_VER    "0.1"
47
48static unsigned long devCnt, devSum, devSsq;
49static char *dataAddr = NULL;
50static int count = 0;
51
52static inline uint32_t cycleCounter(uint32_t dep);
53
54static int __init devtime_start(void)
55{
56    uint64_t addr;
57        uint32_t t1, t2;
58    uint32_t trash;
59    int x;
60
61    struct net_device *dev;
62
63
64    printk("Devtime Driver Version %s Loaded...\n", DRIVER_VER);
65
66    if ((dataAddr != 0) && (count != 0))
67    {
68        addr = simple_strtoull(dataAddr, NULL, 0);
69
70        devSum = 0;
71        devCnt = count;
72
73        printk("Preparing to read %#llx %d times.\n", addr, count);
74
75        t1 = cycleCounter(trash);
76        for (x=0; x < count; x++)
77        {
78            trash = readl(addr);
79            t2 = cycleCounter(trash);
80            devSum += t2 - t1;
81            t1 = t2;
82        }
83
84        printk("Read Address %#llx %ld times. Average latency %ld.\n", addr, devCnt, devSum/devCnt);
85    } else {
86        dev = dev_get_by_name("eth0");
87        if (dev)
88        {
89            printk("Eth0: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n", dev->mem_start,
90                    dev->mem_end, dev->base_addr);
91            dev_put(dev);
92        }
93        dev = dev_get_by_name("eth1");
94        if (dev)
95        {
96            printk("Eth1: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n", dev->mem_start,
97                    dev->mem_end, dev->base_addr);
98            dev_put(dev);
99        }
100
101
102        printk("Required information not supplied.\n");
103    }
104
105    return 0;
106}
107
108#ifdef __i386__
109
110static inline uint32_t cycleCounter(uint32_t dep)
111{
112    uint32_t time;
113    cpuid_eax(0);
114    rdtscl(time);
115    cpuid_eax(0);
116    return time;
117}
118
119#elif __alpha__
120
121inline uint32_t cycleCounter(uint32_t dep)
122{
123    uint32_t res;
124    asm volatile ("rpcc %0, %1" : "=r"(res) : "r" (dep) : "memory");
125    return res;
126}
127#else
128#error Architecture NOT SUPPORTE
129#endif
130
131static void __exit devtime_end(void) {
132    printk("Devtime Driver Version %s Unloaded...\n", DRIVER_VER);
133}
134
135
136module_init(devtime_start);
137module_exit(devtime_end);
138
139MODULE_LICENSE("BSD");
140MODULE_AUTHOR(DRIVER_AUTHOR);
141MODULE_DESCRIPTION(DRIVER_DESC);
142module_param(dataAddr, charp, 0);
143module_param(count, int, 0);
144