arch/x86/mm/testmmiotrace.c

   1 /*
   2  * Written by Pekka Paalanen, 2008-2009 <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
  10 static unsigned long mmio_address;
  11 module_param(mmio_address, ulong, 0);
  12 MODULE_PARM_DESC(mmio_address, "Start address of the mapping of 16 kB.");
  13
  14 static unsigned v16(unsigned i)
  15 {
  16         return i * 12 + 7;
  17 }
  18
  19 static unsigned v32(unsigned i)
  20 {
  21         return i * 212371 + 13;
  22 }
  23
  24 static void do_write_test(void __iomem *p)
  25 {
  26         unsigned int i;
  27         mmiotrace_printk("Write test.\n");
  28
  29         for (i = 0; i < 256; i++)
  30                 iowrite8(i, p + i);
  31
  32         for (i = 1024; i < (5 * 1024); i += 2)
  33                 iowrite16(v16(i), p + i);
  34
  35         for (i = (5 * 1024); i < (16 * 1024); i += 4)
  36                 iowrite32(v32(i), p + i);
  37 }
  38
  39 static void do_read_test(void __iomem *p)
  40 {
  41         unsigned int i;
  42         unsigned errs[3] = { 0 };
  43         mmiotrace_printk("Read test.\n");
  44
  45         for (i = 0; i < 256; i++)
  46                 if (ioread8(p + i) != i)
  47                         ++errs[0];
  48
  49         for (i = 1024; i < (5 * 1024); i += 2)
  50                 if (ioread16(p + i) != v16(i))
  51                         ++errs[1];
  52
  53         for (i = (5 * 1024); i < (16 * 1024); i += 4)
  54                 if (ioread32(p + i) != v32(i))
  55                         ++errs[2];
  56
  57         mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
  58                                                 errs[0], errs[1], errs[2]);
  59 }
  60
  61 static void do_test(void)
  62 {
  63         void __iomem *p = ioremap_nocache(mmio_address, 0x4000);
  64         if (!p) {
  65                 pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
  66                 return;
  67         }
  68         mmiotrace_printk("ioremap returned %p.\n", p);
  69         do_write_test(p);
  70         do_read_test(p);
  71         iounmap(p);
  72 }
  73
  74 static int __init init(void)
  75 {
  76         if (mmio_address == 0) {
  77                 pr_err(MODULE_NAME ": you have to use the module argument "
  78                                                         "mmio_address.\n");
  79                 pr_err(MODULE_NAME ": DO NOT LOAD THIS MODULE UNLESS"
  80                                 " YOU REALLY KNOW WHAT YOU ARE DOING!\n");
  81                 return -ENXIO;
  82         }
  83
  84         pr_warning(MODULE_NAME ": WARNING: mapping 16 kB @ 0x%08lx "
  85                                         "in PCI address space, and writing "
  86                                         "rubbish in there.\n", mmio_address);
  87         do_test();
  88         return 0;
  89 }
  90
  91 static void __exit cleanup(void)
  92 {
  93         pr_debug(MODULE_NAME ": unloaded.\n");
  94 }
  95
  96 module_init(init);
  97 module_exit(cleanup);
  98 MODULE_LICENSE("GPL");