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// SPDX-License-Identifier: GPL-2.0-only
/*
* Written by Pekka Paalanen, 2008-2009 <pq@iki.fi>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/io.h>
#include <linux/mmiotrace.h>
#include <linux/security.h>
static unsigned long mmio_address;
module_param_hw(mmio_address, ulong, iomem, 0);
MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
"(or 8 MB if read_far is non-zero).");
static unsigned long read_far = 0x400100;
module_param(read_far, ulong, 0);
MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
"(default: 0x400100).");
static unsigned v16(unsigned i)
{
return i * 12 + 7;
}
static unsigned v32(unsigned i)
{
return i * 212371 + 13;
}
static void do_write_test(void __iomem *p)
{
unsigned int i;
pr_info("write test.\n");
mmiotrace_printk("Write test.\n");
for (i = 0; i < 256; i++)
iowrite8(i, p + i);
for (i = 1024; i < (5 * 1024); i += 2)
iowrite16(v16(i), p + i);
for (i = (5 * 1024); i < (16 * 1024); i += 4)
iowrite32(v32(i), p + i);
}
static void do_read_test(void __iomem *p)
{
unsigned int i;
unsigned errs[3] = { 0 };
pr_info("read test.\n");
mmiotrace_printk("Read test.\n");
for (i = 0; i < 256; i++)
if (ioread8(p + i) != i)
++errs[0];
for (i = 1024; i < (5 * 1024); i += 2)
if (ioread16(p + i) != v16(i))
++errs[1];
for (i = (5 * 1024); i < (16 * 1024); i += 4)
if (ioread32(p + i) != v32(i))
++errs[2];
mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
errs[0], errs[1], errs[2]);
}
static void do_read_far_test(void __iomem *p)
{
pr_info("read far test.\n");
mmiotrace_printk("Read far test.\n");
ioread32(p + read_far);
}
static void do_test(unsigned long size)
{
void __iomem *p = ioremap_nocache(mmio_address, size);
if (!p) {
pr_err("could not ioremap, aborting.\n");
return;
}
mmiotrace_printk("ioremap returned %p.\n", p);
do_write_test(p);
do_read_test(p);
if (read_far && read_far < size - 4)
do_read_far_test(p);
iounmap(p);
}
/*
* Tests how mmiotrace behaves in face of multiple ioremap / iounmaps in
* a short time. We had a bug in deferred freeing procedure which tried
* to free this region multiple times (ioremap can reuse the same address
* for many mappings).
*/
static void do_test_bulk_ioremapping(void)
{
void __iomem *p;
int i;
for (i = 0; i < 10; ++i) {
p = ioremap_nocache(mmio_address, PAGE_SIZE);
if (p)
iounmap(p);
}
/* Force freeing. If it will crash we will know why. */
synchronize_rcu();
}
static int __init init(void)
{
unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
int ret = security_locked_down(LOCKDOWN_MMIOTRACE);
if (ret)
return ret;
if (mmio_address == 0) {
pr_err("you have to use the module argument mmio_address.\n");
pr_err("DO NOT LOAD THIS MODULE UNLESS YOU REALLY KNOW WHAT YOU ARE DOING!\n");
return -ENXIO;
}
pr_warning("WARNING: mapping %lu kB @ 0x%08lx in PCI address space, "
"and writing 16 kB of rubbish in there.\n",
size >> 10, mmio_address);
do_test(size);
do_test_bulk_ioremapping();
pr_info("All done.\n");
return 0;
}
static void __exit cleanup(void)
{
pr_debug("unloaded.\n");
}
module_init(init);
module_exit(cleanup);
MODULE_LICENSE("GPL");
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