1 /*
2 * Written by Pekka Paalanen, 2008-2009 <pq@iki.fi>
3 */
4
5 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
6
7 #include <linux/module.h>
8 #include <linux/io.h>
9 #include <linux/mmiotrace.h>
10
11 static unsigned long mmio_address;
12 module_param_hw(mmio_address, ulong, iomem, 0);
13 MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
14 "(or 8 MB if read_far is non-zero).");
15
16 static unsigned long read_far = 0x400100;
17 module_param(read_far, ulong, 0);
18 MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
19 "(default: 0x400100).");
20
v16(unsigned i)21 static unsigned v16(unsigned i)
22 {
23 return i * 12 + 7;
24 }
25
v32(unsigned i)26 static unsigned v32(unsigned i)
27 {
28 return i * 212371 + 13;
29 }
30
do_write_test(void __iomem * p)31 static void do_write_test(void __iomem *p)
32 {
33 unsigned int i;
34 pr_info("write test.\n");
35 mmiotrace_printk("Write test.\n");
36
37 for (i = 0; i < 256; i++)
38 iowrite8(i, p + i);
39
40 for (i = 1024; i < (5 * 1024); i += 2)
41 iowrite16(v16(i), p + i);
42
43 for (i = (5 * 1024); i < (16 * 1024); i += 4)
44 iowrite32(v32(i), p + i);
45 }
46
do_read_test(void __iomem * p)47 static void do_read_test(void __iomem *p)
48 {
49 unsigned int i;
50 unsigned errs[3] = { 0 };
51 pr_info("read test.\n");
52 mmiotrace_printk("Read test.\n");
53
54 for (i = 0; i < 256; i++)
55 if (ioread8(p + i) != i)
56 ++errs[0];
57
58 for (i = 1024; i < (5 * 1024); i += 2)
59 if (ioread16(p + i) != v16(i))
60 ++errs[1];
61
62 for (i = (5 * 1024); i < (16 * 1024); i += 4)
63 if (ioread32(p + i) != v32(i))
64 ++errs[2];
65
66 mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
67 errs[0], errs[1], errs[2]);
68 }
69
do_read_far_test(void __iomem * p)70 static void do_read_far_test(void __iomem *p)
71 {
72 pr_info("read far test.\n");
73 mmiotrace_printk("Read far test.\n");
74
75 ioread32(p + read_far);
76 }
77
do_test(unsigned long size)78 static void do_test(unsigned long size)
79 {
80 void __iomem *p = ioremap_nocache(mmio_address, size);
81 if (!p) {
82 pr_err("could not ioremap, aborting.\n");
83 return;
84 }
85 mmiotrace_printk("ioremap returned %p.\n", p);
86 do_write_test(p);
87 do_read_test(p);
88 if (read_far && read_far < size - 4)
89 do_read_far_test(p);
90 iounmap(p);
91 }
92
93 /*
94 * Tests how mmiotrace behaves in face of multiple ioremap / iounmaps in
95 * a short time. We had a bug in deferred freeing procedure which tried
96 * to free this region multiple times (ioremap can reuse the same address
97 * for many mappings).
98 */
do_test_bulk_ioremapping(void)99 static void do_test_bulk_ioremapping(void)
100 {
101 void __iomem *p;
102 int i;
103
104 for (i = 0; i < 10; ++i) {
105 p = ioremap_nocache(mmio_address, PAGE_SIZE);
106 if (p)
107 iounmap(p);
108 }
109
110 /* Force freeing. If it will crash we will know why. */
111 synchronize_rcu();
112 }
113
init(void)114 static int __init init(void)
115 {
116 unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
117
118 if (mmio_address == 0) {
119 pr_err("you have to use the module argument mmio_address.\n");
120 pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!\n");
121 return -ENXIO;
122 }
123
124 pr_warning("WARNING: mapping %lu kB @ 0x%08lx in PCI address space, "
125 "and writing 16 kB of rubbish in there.\n",
126 size >> 10, mmio_address);
127 do_test(size);
128 do_test_bulk_ioremapping();
129 pr_info("All done.\n");
130 return 0;
131 }
132
cleanup(void)133 static void __exit cleanup(void)
134 {
135 pr_debug("unloaded.\n");
136 }
137
138 module_init(init);
139 module_exit(cleanup);
140 MODULE_LICENSE("GPL");
141
