LXR linux/arch/x86/mm/testmmiotrace.c

   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