devtime.c revision 993:bc33dc3beeea 
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 <asm/page.h>
38#include <linux/netdevice.h>
39
40#ifdef __i386__
41#include <asm/processor.h>
42#include <asm/msr.h>
43#endif
44
45#define DRIVER_AUTHOR "Ali Saidi"
46#define DRIVER_DESC   "Interface to time uncacachable read and writes to device registers"
47#define DRIVER_VER    "0.1"
48
49static unsigned long devCnt, devSum, devSsq;
50static char *dataAddr = NULL;
51static int count = 0;
52
53static inline uint32_t cycleCounter(uint32_t dep);
54
55static int __init devtime_start(void)
56{
57    uint64_t addr;
58    uint32_t t1, t2;
59    uint32_t trash;
60    int x;
61
62    struct net_device *dev;
63
64
65    printk("Devtime Driver Version %s Loaded...\n", DRIVER_VER);
66
67    if (dataAddr != 0 && count != 0) {
68        addr = simple_strtoull(dataAddr, NULL, 0);
69
70        devSum = 0;
71        devCnt = count;
72
73        addr = ioremap(addr, PAGE_SIZE);
74        /**
75         * Make sure that the remapping actually worked. On alpha we have
76         * linear addressing, so its not a problem. But it can fail in x86
77         * if physical memory is mapped to this address.
78         */
79        if (addr) {
80            printk("Preparing to read %#llx %d times.\n", addr, count);
81
82            t1 = cycleCounter(trash);
83            for (x = 0; x < count; x++) {
84                trash = readl(addr);
85                t2 = cycleCounter(trash);
86                devSum += t2 - t1;
87                t1 = t2;
88            }
89
90            /**
91             * Unmap the address.
92             */
93            iounmap(addr);
94
95            printk("Read Address %#llx %ld times. Average latency %ld.\n",
96                   addr, devCnt, devSum/devCnt);
97        }
98        else
99            printk("Unable to remap address. Please try again later.\n");
100    } else {
101        dev = dev_get_by_name("eth0");
102        if (dev) {
103            printk("Eth0: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n",
104                   dev->mem_start, dev->mem_end, dev->base_addr);
105            dev_put(dev);
106        }
107        dev = 0;
108        dev = dev_get_by_name("eth1");
109        if (dev) {
110            printk("Eth1: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n",
111                   dev->mem_start, dev->mem_end, dev->base_addr);
112            dev_put(dev);
113        }
114
115        printk("Required information not supplied.\n");
116    }
117
118    return 0;
119}
120
121#ifdef __i386__
122
123static inline uint32_t cycleCounter(uint32_t dep)
124{
125    uint32_t time;
126    cpuid_eax(0);
127    rdtscl(time);
128    cpuid_eax(0);
129    return time;
130}
131
132#elif __alpha__
133
134inline uint32_t cycleCounter(uint32_t dep)
135{
136    uint32_t res;
137    asm volatile ("rpcc %0, %1" : "=r"(res) : "r" (dep) : "memory");
138    return res;
139}
140#else
141#error Architecture NOT SUPPORTE
142#endif
143
144static void __exit devtime_end(void)
145{
146    printk("Devtime Driver Version %s Unloaded...\n", DRIVER_VER);
147}
148
149
150module_init(devtime_start);
151module_exit(devtime_end);
152
153MODULE_LICENSE("BSD");
154MODULE_AUTHOR(DRIVER_AUTHOR);
155MODULE_DESCRIPTION(DRIVER_DESC);
156module_param(dataAddr, charp, 0);
157module_param(count, int, 0);
158