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                                 "(or 8 MB if read_far is non-zero).");
  14
  15 static unsigned long read_far = 0x400100;
  16 module_param(read_far, ulong, 0);
  17 MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
  18                                 "(default: 0x400100).");
  19
  20 static unsigned v16(unsigned i)
  21 {
  22         return i * 12 + 7;
  23 }
  24
  25 static unsigned v32(unsigned i)
  26 {
  27         return i * 212371 + 13;
  28 }
  29
  30 static void do_write_test(void __iomem *p)
  31 {
  32         unsigned int i;
  33         pr_info(MODULE_NAME ": write test.\n");
  34         mmiotrace_printk("Write test.\n");
  35
  36         for (i = 0; i < 256; i++)
  37                 iowrite8(i, p + i);
  38
  39         for (i = 1024; i < (5 * 1024); i += 2)
  40                 iowrite16(v16(i), p + i);
  41
  42         for (i = (5 * 1024); i < (16 * 1024); i += 4)
  43                 iowrite32(v32(i), p + i);
  44 }
  45
  46 static void do_read_test(void __iomem *p)
  47 {
  48         unsigned int i;
  49         unsigned errs[3] = { 0 };
  50         pr_info(MODULE_NAME ": read test.\n");
  51         mmiotrace_printk("Read test.\n");
  52
  53         for (i = 0; i < 256; i++)
  54                 if (ioread8(p + i) != i)
  55                         ++errs[0];
  56
  57         for (i = 1024; i < (5 * 1024); i += 2)
  58                 if (ioread16(p + i) != v16(i))
  59                         ++errs[1];
  60
  61         for (i = (5 * 1024); i < (16 * 1024); i += 4)
  62                 if (ioread32(p + i) != v32(i))
  63                         ++errs[2];
  64
  65         mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
  66                                                 errs[0], errs[1], errs[2]);
  67 }
  68
  69 static void do_read_far_test(void __iomem *p)
  70 {
  71         pr_info(MODULE_NAME ": read far test.\n");
  72         mmiotrace_printk("Read far test.\n");
  73
  74         ioread32(p + read_far);
  75 }
  76
  77 static void do_test(unsigned long size)
  78 {
  79         void __iomem *p = ioremap_nocache(mmio_address, size);
  80         if (!p) {
  81                 pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
  82                 return;
  83         }
  84         mmiotrace_printk("ioremap returned %p.\n", p);
  85         do_write_test(p);
  86         do_read_test(p);
  87         if (read_far && read_far < size - 4)
  88                 do_read_far_test(p);
  89         iounmap(p);
  90 }
  91
  92 static int __init init(void)
  93 {
  94         unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
  95
  96         if (mmio_address == 0) {
  97                 pr_err(MODULE_NAME ": you have to use the module argument "
  98                                                         "mmio_address.\n");
  99                 pr_err(MODULE_NAME ": DO NOT LOAD THIS MODULE UNLESS"
 100                                 " YOU REALLY KNOW WHAT YOU ARE DOING!\n");
 101                 return -ENXIO;
 102         }
 103
 104         pr_warning(MODULE_NAME ": WARNING: mapping %lu kB @ 0x%08lx in PCI "
 105                 "address space, and writing 16 kB of rubbish in there.\n",
 106                  size >> 10, mmio_address);
 107         do_test(size);
 108         pr_info(MODULE_NAME ": All done.\n");
 109         return 0;
 110 }
 111
 112 static void __exit cleanup(void)
 113 {
 114         pr_debug(MODULE_NAME ": unloaded.\n");
 115 }
 116
 117 module_init(init);
 118 module_exit(cleanup);
 119 MODULE_LICENSE("GPL");