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 printk("Devtime Driver Version %s Loaded...\n", DRIVER_VER);
65
66 if (dataAddr != 0 && count != 0) {
67 addr = simple_strtoull(dataAddr, NULL, 0);
68
69 addr = ioremap(addr, PAGE_SIZE);
70 /**
71 * Make sure that the remapping actually worked. On alpha we have
72 * linear addressing, so its not a problem. But it can fail in x86
73 * if physical memory is mapped to this address.
74 */
75 times = kmalloc(sizeof(uint32_t) * count, GFP_USER);
76 if (!times) {
77 printk("Could not allocate memory... Try again later.\n");
78 return -1;
79 }
80
81 if (addr) {
82 printk("Preparing to read %#llx %d times.\n", addr, count);
83
84 t1 = cycleCounter(trash);
85 for (x = 0; x < count; x++) {
86 trash = readl(addr);
87 t2 = cycleCounter(trash);
88 times[num++] = t2 - t1;
89 t1 = t2;
90 }
91
92 /**
93 * Unmap the address.
94 */
95 iounmap(addr);
96
97 printk("Measurements:\n");
98 for (x = 0; x < count; x++) {
99 printk("%d ", times[x]);
100 if (((x + 1) % 10) == 0)
101 printk("\n");
102 }
103 printk("\nDone.\n");
104 } else {
105 printk("Unable to remap address. Please try again later.\n");
106 }
107 } else {
108 dev = dev_get_by_name("eth0");
109 if (dev) {
110 printk("Eth0: 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 dev = 0;
115 dev = dev_get_by_name("eth1");
116 if (dev) {
117 printk("Eth1: MemStart: %#lx MemEnd: %#lx I/O Addr: %#lx\n",
118 dev->mem_start, dev->mem_end, dev->base_addr);
119 dev_put(dev);
120 }
121
122 printk("Required information not supplied.\n");
123 }
124
125 return 0;
126}
127
128#ifdef __i386__
129
130static inline uint32_t cycleCounter(uint32_t dep)
131{
132 uint32_t time;
133 cpuid_eax(0);
134 rdtscl(time);
135 cpuid_eax(0);
136 return time;
137}
138
139#elif __alpha__
140
141inline uint32_t cycleCounter(uint32_t dep)
142{
143 uint32_t res;
144 asm volatile ("rpcc %0, %1" : "=r"(res) : "r" (dep) : "memory");
145 return res;
146}
147#else
148#error Architecture NOT SUPPORTE
149#endif
150
151static void __exit devtime_end(void)
152{
153 printk("Devtime Driver Version %s Unloaded...\n", DRIVER_VER);
154}
155
156
157module_init(devtime_start);
158module_exit(devtime_end);
159
160MODULE_LICENSE("Dual BSD/GPL");
161MODULE_AUTHOR(DRIVER_AUTHOR);
162MODULE_DESCRIPTION(DRIVER_DESC);
163module_param(dataAddr, charp, 0);
164module_param(count, int, 0);