linux/arch/x86/mm/testmmiotrace.c
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   1/*
   2 * Written by Pekka Paalanen, 2008 <pq@iki.fi>
   3 */
   4#include <linux/module.h>
   5#include <linux/io.h>
   6#include <linux/mmiotrace.h>
   7
   8#define MODULE_NAME "testmmiotrace"
   9
  10static unsigned long mmio_address;
  11module_param(mmio_address, ulong, 0);
  12MODULE_PARM_DESC(mmio_address, "Start address of the mapping of 16 kB.");
  13
  14static void do_write_test(void __iomem *p)
  15{
  16        unsigned int i;
  17        mmiotrace_printk("Write test.\n");
  18        for (i = 0; i < 256; i++)
  19                iowrite8(i, p + i);
  20        for (i = 1024; i < (5 * 1024); i += 2)
  21                iowrite16(i * 12 + 7, p + i);
  22        for (i = (5 * 1024); i < (16 * 1024); i += 4)
  23                iowrite32(i * 212371 + 13, p + i);
  24}
  25
  26static void do_read_test(void __iomem *p)
  27{
  28        unsigned int i;
  29        mmiotrace_printk("Read test.\n");
  30        for (i = 0; i < 256; i++)
  31                ioread8(p + i);
  32        for (i = 1024; i < (5 * 1024); i += 2)
  33                ioread16(p + i);
  34        for (i = (5 * 1024); i < (16 * 1024); i += 4)
  35                ioread32(p + i);
  36}
  37
  38static void do_test(void)
  39{
  40        void __iomem *p = ioremap_nocache(mmio_address, 0x4000);
  41        if (!p) {
  42                pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
  43                return;
  44        }
  45        mmiotrace_printk("ioremap returned %p.\n", p);
  46        do_write_test(p);
  47        do_read_test(p);
  48        iounmap(p);
  49}
  50
  51static int __init init(void)
  52{
  53        if (mmio_address == 0) {
  54                pr_err(MODULE_NAME ": you have to use the module argument "
  55                                                        "mmio_address.\n");
  56                pr_err(MODULE_NAME ": DO NOT LOAD THIS MODULE UNLESS"
  57                                " YOU REALLY KNOW WHAT YOU ARE DOING!\n");
  58                return -ENXIO;
  59        }
  60
  61        pr_warning(MODULE_NAME ": WARNING: mapping 16 kB @ 0x%08lx "
  62                                        "in PCI address space, and writing "
  63                                        "rubbish in there.\n", mmio_address);
  64        do_test();
  65        return 0;
  66}
  67
  68static void __exit cleanup(void)
  69{
  70        pr_debug(MODULE_NAME ": unloaded.\n");
  71}
  72
  73module_init(init);
  74module_exit(cleanup);
  75MODULE_LICENSE("GPL");
  76