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 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 uint32_t *times;
61 uint32_t num = 0;
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 {
69 addr = simple_strtoull(dataAddr, NULL, 0);
70
71 addr = ioremap(addr, PAGE_SIZE);
72 /**
73 * Make sure that the remapping actually worked. On alpha we have
74 * linear addressing, so its not a problem. But it can fail in x86
75 * if physical memory is mapped to this address.
76 */
77 times = kmalloc(sizeof(uint32_t) * count, GFP_USER);
78 if (!times)
79 {
80 printk("Could not allocate memory... Try again later.\n");
81 return -1;
82 }
83
84 if (addr)
85 {
86 printk("Preparing to read %#llx %d times.\n", addr, count);
87
88 t1 = cycleCounter(trash);
89 for (x=0; x < count; x++)
90 {
91 trash = readl(addr);
92 t2 = cycleCounter(trash);
93 times[num++] = t2 - t1;
94 t1 = t2;
95 }
96
97 /**
98 * Unmap the address.
99 */
100 iounmap(addr);
101
102 printk("Measurements:\n");
103 for (x = 0; x < count; x++)
104 {
105 printk("%d ", times[x]);
106 if (((x+1) % 10) == 0)
107 printk("\n");
108 }
109 printk("\nDone.\n");
110
111
112 }
113 else
114 printk("Unable to remap address. Please try again later.\n");
115 } else {
116 dev = dev_get_by_name("eth0");
117 if (dev)
118 {
119 printk("Eth0: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n", dev->mem_start,
120 dev->mem_end, dev->base_addr);
121 dev_put(dev);
122 }
123 dev = 0;
124 dev = dev_get_by_name("eth1");
125 if (dev)
126 {
127 printk("Eth1: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n", dev->mem_start,
128 dev->mem_end, dev->base_addr);
129 dev_put(dev);
130 }
131
132
133 printk("Required information not supplied.\n");
134 }
135
136 return 0;
137}
138
139#ifdef __i386__
140
141static inline uint32_t cycleCounter(uint32_t dep)
142{
143 uint32_t time;
144 cpuid_eax(0);
145 rdtscl(time);
146 cpuid_eax(0);
147 return time;
148}
149
150#elif __alpha__
151
152inline uint32_t cycleCounter(uint32_t dep)
153{
154 uint32_t res;
155 asm volatile ("rpcc %0, %1" : "=r"(res) : "r" (dep) : "memory");
156 return res;
157}
158#else
159#error Architecture NOT SUPPORTE
160#endif
161
162static void __exit devtime_end(void) {
163 printk("Devtime Driver Version %s Unloaded...\n", DRIVER_VER);
164}
165
166
167module_init(devtime_start);
168module_exit(devtime_end);
169
170MODULE_LICENSE("Dual BSD/GPL");
171MODULE_AUTHOR(DRIVER_AUTHOR);
172MODULE_DESCRIPTION(DRIVER_DESC);
173module_param(dataAddr, charp, 0);
174module_param(count, int, 0);