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
11static unsigned long mmio_address;
12module_param(mmio_address, ulong, 0);
13MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
14				"(or 8 MB if read_far is non-zero).");
15
16static unsigned long read_far = 0x400100;
17module_param(read_far, ulong, 0);
18MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
19				"(default: 0x400100).");
20
21static unsigned v16(unsigned i)
22{
23	return i * 12 + 7;
24}
25
26static unsigned v32(unsigned i)
27{
28	return i * 212371 + 13;
29}
30
31static 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
47static 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
70static 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
78static 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 */
99static 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
114static 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
133static void __exit cleanup(void)
134{
135	pr_debug("unloaded.\n");
136}
137
138module_init(init);
139module_exit(cleanup);
140MODULE_LICENSE("GPL");
141