arch/x86/mm/testmmiotrace.c

   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
  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 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
  26 static 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
  38 static 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
  51 static 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
  68 static void __exit cleanup(void)
  69 {
  70         pr_debug(MODULE_NAME ": unloaded.\n");
  71 }
  72
  73 module_init(init);
  74 module_exit(cleanup);
  75 MODULE_LICENSE("GPL");