linux/drivers/dma/dmatest.c
Tejun Heo adfa543e73 dmatest: don't use set_freezable_with_signal()
Commit 981ed70d8e (dmatest: make dmatest threads freezable) made
dmatest kthread use set_freezable_with_signal(); however, the
interface is scheduled to be removed in the next merge window.

The problem is that unlike userland tasks there's no default place
which handles signal pending state and it isn't clear who owns and/or
is responsible for clearing TIF_SIGPENDING.  For example, in the
current code, try_to_freeze() clears TIF_SIGPENDING but it isn't sure
whether it actually owns the TIF_SIGPENDING nor is it race-free -
ie. the task may continue to run with TIF_SIGPENDING set after the
freezable section.

Unfortunately, we don't have wait_for_completion_freezable_timeout().
This patch open codes it and uses wait_event_freezable_timeout()
instead and removes timeout reloading - wait_event_freezable_timeout()
won't return across freezing events (currently racy but fix scheduled)
and timer doesn't decrement while the task is in freezer.  Although
this does lose timer-reset-over-freezing, given that timeout is
supposed to be long enough and failure to finish inside is considered
irrecoverable, I don't think this is worth the complexity.

While at it, move completion to outer scope and explain that we're
ignoring dangling pointer problem after timeout.  This should give
slightly better chance at avoiding oops after timeout.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
2011-11-23 09:28:16 -08:00

666 lines
18 KiB
C

/*
* DMA Engine test module
*
* Copyright (C) 2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/freezer.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/wait.h>
static unsigned int test_buf_size = 16384;
module_param(test_buf_size, uint, S_IRUGO);
MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");
static char test_channel[20];
module_param_string(channel, test_channel, sizeof(test_channel), S_IRUGO);
MODULE_PARM_DESC(channel, "Bus ID of the channel to test (default: any)");
static char test_device[20];
module_param_string(device, test_device, sizeof(test_device), S_IRUGO);
MODULE_PARM_DESC(device, "Bus ID of the DMA Engine to test (default: any)");
static unsigned int threads_per_chan = 1;
module_param(threads_per_chan, uint, S_IRUGO);
MODULE_PARM_DESC(threads_per_chan,
"Number of threads to start per channel (default: 1)");
static unsigned int max_channels;
module_param(max_channels, uint, S_IRUGO);
MODULE_PARM_DESC(max_channels,
"Maximum number of channels to use (default: all)");
static unsigned int iterations;
module_param(iterations, uint, S_IRUGO);
MODULE_PARM_DESC(iterations,
"Iterations before stopping test (default: infinite)");
static unsigned int xor_sources = 3;
module_param(xor_sources, uint, S_IRUGO);
MODULE_PARM_DESC(xor_sources,
"Number of xor source buffers (default: 3)");
static unsigned int pq_sources = 3;
module_param(pq_sources, uint, S_IRUGO);
MODULE_PARM_DESC(pq_sources,
"Number of p+q source buffers (default: 3)");
static int timeout = 3000;
module_param(timeout, uint, S_IRUGO);
MODULE_PARM_DESC(timeout, "Transfer Timeout in msec (default: 3000), "
"Pass -1 for infinite timeout");
/*
* Initialization patterns. All bytes in the source buffer has bit 7
* set, all bytes in the destination buffer has bit 7 cleared.
*
* Bit 6 is set for all bytes which are to be copied by the DMA
* engine. Bit 5 is set for all bytes which are to be overwritten by
* the DMA engine.
*
* The remaining bits are the inverse of a counter which increments by
* one for each byte address.
*/
#define PATTERN_SRC 0x80
#define PATTERN_DST 0x00
#define PATTERN_COPY 0x40
#define PATTERN_OVERWRITE 0x20
#define PATTERN_COUNT_MASK 0x1f
struct dmatest_thread {
struct list_head node;
struct task_struct *task;
struct dma_chan *chan;
u8 **srcs;
u8 **dsts;
enum dma_transaction_type type;
};
struct dmatest_chan {
struct list_head node;
struct dma_chan *chan;
struct list_head threads;
};
/*
* These are protected by dma_list_mutex since they're only used by
* the DMA filter function callback
*/
static LIST_HEAD(dmatest_channels);
static unsigned int nr_channels;
static bool dmatest_match_channel(struct dma_chan *chan)
{
if (test_channel[0] == '\0')
return true;
return strcmp(dma_chan_name(chan), test_channel) == 0;
}
static bool dmatest_match_device(struct dma_device *device)
{
if (test_device[0] == '\0')
return true;
return strcmp(dev_name(device->dev), test_device) == 0;
}
static unsigned long dmatest_random(void)
{
unsigned long buf;
get_random_bytes(&buf, sizeof(buf));
return buf;
}
static void dmatest_init_srcs(u8 **bufs, unsigned int start, unsigned int len)
{
unsigned int i;
u8 *buf;
for (; (buf = *bufs); bufs++) {
for (i = 0; i < start; i++)
buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
for ( ; i < start + len; i++)
buf[i] = PATTERN_SRC | PATTERN_COPY
| (~i & PATTERN_COUNT_MASK);
for ( ; i < test_buf_size; i++)
buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
buf++;
}
}
static void dmatest_init_dsts(u8 **bufs, unsigned int start, unsigned int len)
{
unsigned int i;
u8 *buf;
for (; (buf = *bufs); bufs++) {
for (i = 0; i < start; i++)
buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
for ( ; i < start + len; i++)
buf[i] = PATTERN_DST | PATTERN_OVERWRITE
| (~i & PATTERN_COUNT_MASK);
for ( ; i < test_buf_size; i++)
buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
}
}
static void dmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
unsigned int counter, bool is_srcbuf)
{
u8 diff = actual ^ pattern;
u8 expected = pattern | (~counter & PATTERN_COUNT_MASK);
const char *thread_name = current->comm;
if (is_srcbuf)
pr_warning("%s: srcbuf[0x%x] overwritten!"
" Expected %02x, got %02x\n",
thread_name, index, expected, actual);
else if ((pattern & PATTERN_COPY)
&& (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
pr_warning("%s: dstbuf[0x%x] not copied!"
" Expected %02x, got %02x\n",
thread_name, index, expected, actual);
else if (diff & PATTERN_SRC)
pr_warning("%s: dstbuf[0x%x] was copied!"
" Expected %02x, got %02x\n",
thread_name, index, expected, actual);
else
pr_warning("%s: dstbuf[0x%x] mismatch!"
" Expected %02x, got %02x\n",
thread_name, index, expected, actual);
}
static unsigned int dmatest_verify(u8 **bufs, unsigned int start,
unsigned int end, unsigned int counter, u8 pattern,
bool is_srcbuf)
{
unsigned int i;
unsigned int error_count = 0;
u8 actual;
u8 expected;
u8 *buf;
unsigned int counter_orig = counter;
for (; (buf = *bufs); bufs++) {
counter = counter_orig;
for (i = start; i < end; i++) {
actual = buf[i];
expected = pattern | (~counter & PATTERN_COUNT_MASK);
if (actual != expected) {
if (error_count < 32)
dmatest_mismatch(actual, pattern, i,
counter, is_srcbuf);
error_count++;
}
counter++;
}
}
if (error_count > 32)
pr_warning("%s: %u errors suppressed\n",
current->comm, error_count - 32);
return error_count;
}
/* poor man's completion - we want to use wait_event_freezable() on it */
struct dmatest_done {
bool done;
wait_queue_head_t *wait;
};
static void dmatest_callback(void *arg)
{
struct dmatest_done *done = arg;
done->done = true;
wake_up_all(done->wait);
}
/*
* This function repeatedly tests DMA transfers of various lengths and
* offsets for a given operation type until it is told to exit by
* kthread_stop(). There may be multiple threads running this function
* in parallel for a single channel, and there may be multiple channels
* being tested in parallel.
*
* Before each test, the source and destination buffer is initialized
* with a known pattern. This pattern is different depending on
* whether it's in an area which is supposed to be copied or
* overwritten, and different in the source and destination buffers.
* So if the DMA engine doesn't copy exactly what we tell it to copy,
* we'll notice.
*/
static int dmatest_func(void *data)
{
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(done_wait);
struct dmatest_thread *thread = data;
struct dmatest_done done = { .wait = &done_wait };
struct dma_chan *chan;
const char *thread_name;
unsigned int src_off, dst_off, len;
unsigned int error_count;
unsigned int failed_tests = 0;
unsigned int total_tests = 0;
dma_cookie_t cookie;
enum dma_status status;
enum dma_ctrl_flags flags;
u8 pq_coefs[pq_sources + 1];
int ret;
int src_cnt;
int dst_cnt;
int i;
thread_name = current->comm;
set_freezable();
ret = -ENOMEM;
smp_rmb();
chan = thread->chan;
if (thread->type == DMA_MEMCPY)
src_cnt = dst_cnt = 1;
else if (thread->type == DMA_XOR) {
src_cnt = xor_sources | 1; /* force odd to ensure dst = src */
dst_cnt = 1;
} else if (thread->type == DMA_PQ) {
src_cnt = pq_sources | 1; /* force odd to ensure dst = src */
dst_cnt = 2;
for (i = 0; i < src_cnt; i++)
pq_coefs[i] = 1;
} else
goto err_srcs;
thread->srcs = kcalloc(src_cnt+1, sizeof(u8 *), GFP_KERNEL);
if (!thread->srcs)
goto err_srcs;
for (i = 0; i < src_cnt; i++) {
thread->srcs[i] = kmalloc(test_buf_size, GFP_KERNEL);
if (!thread->srcs[i])
goto err_srcbuf;
}
thread->srcs[i] = NULL;
thread->dsts = kcalloc(dst_cnt+1, sizeof(u8 *), GFP_KERNEL);
if (!thread->dsts)
goto err_dsts;
for (i = 0; i < dst_cnt; i++) {
thread->dsts[i] = kmalloc(test_buf_size, GFP_KERNEL);
if (!thread->dsts[i])
goto err_dstbuf;
}
thread->dsts[i] = NULL;
set_user_nice(current, 10);
/*
* src buffers are freed by the DMAEngine code with dma_unmap_single()
* dst buffers are freed by ourselves below
*/
flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT
| DMA_COMPL_SKIP_DEST_UNMAP | DMA_COMPL_SRC_UNMAP_SINGLE;
while (!kthread_should_stop()
&& !(iterations && total_tests >= iterations)) {
struct dma_device *dev = chan->device;
struct dma_async_tx_descriptor *tx = NULL;
dma_addr_t dma_srcs[src_cnt];
dma_addr_t dma_dsts[dst_cnt];
u8 align = 0;
total_tests++;
/* honor alignment restrictions */
if (thread->type == DMA_MEMCPY)
align = dev->copy_align;
else if (thread->type == DMA_XOR)
align = dev->xor_align;
else if (thread->type == DMA_PQ)
align = dev->pq_align;
if (1 << align > test_buf_size) {
pr_err("%u-byte buffer too small for %d-byte alignment\n",
test_buf_size, 1 << align);
break;
}
len = dmatest_random() % test_buf_size + 1;
len = (len >> align) << align;
if (!len)
len = 1 << align;
src_off = dmatest_random() % (test_buf_size - len + 1);
dst_off = dmatest_random() % (test_buf_size - len + 1);
src_off = (src_off >> align) << align;
dst_off = (dst_off >> align) << align;
dmatest_init_srcs(thread->srcs, src_off, len);
dmatest_init_dsts(thread->dsts, dst_off, len);
for (i = 0; i < src_cnt; i++) {
u8 *buf = thread->srcs[i] + src_off;
dma_srcs[i] = dma_map_single(dev->dev, buf, len,
DMA_TO_DEVICE);
}
/* map with DMA_BIDIRECTIONAL to force writeback/invalidate */
for (i = 0; i < dst_cnt; i++) {
dma_dsts[i] = dma_map_single(dev->dev, thread->dsts[i],
test_buf_size,
DMA_BIDIRECTIONAL);
}
if (thread->type == DMA_MEMCPY)
tx = dev->device_prep_dma_memcpy(chan,
dma_dsts[0] + dst_off,
dma_srcs[0], len,
flags);
else if (thread->type == DMA_XOR)
tx = dev->device_prep_dma_xor(chan,
dma_dsts[0] + dst_off,
dma_srcs, src_cnt,
len, flags);
else if (thread->type == DMA_PQ) {
dma_addr_t dma_pq[dst_cnt];
for (i = 0; i < dst_cnt; i++)
dma_pq[i] = dma_dsts[i] + dst_off;
tx = dev->device_prep_dma_pq(chan, dma_pq, dma_srcs,
src_cnt, pq_coefs,
len, flags);
}
if (!tx) {
for (i = 0; i < src_cnt; i++)
dma_unmap_single(dev->dev, dma_srcs[i], len,
DMA_TO_DEVICE);
for (i = 0; i < dst_cnt; i++)
dma_unmap_single(dev->dev, dma_dsts[i],
test_buf_size,
DMA_BIDIRECTIONAL);
pr_warning("%s: #%u: prep error with src_off=0x%x "
"dst_off=0x%x len=0x%x\n",
thread_name, total_tests - 1,
src_off, dst_off, len);
msleep(100);
failed_tests++;
continue;
}
done.done = false;
tx->callback = dmatest_callback;
tx->callback_param = &done;
cookie = tx->tx_submit(tx);
if (dma_submit_error(cookie)) {
pr_warning("%s: #%u: submit error %d with src_off=0x%x "
"dst_off=0x%x len=0x%x\n",
thread_name, total_tests - 1, cookie,
src_off, dst_off, len);
msleep(100);
failed_tests++;
continue;
}
dma_async_issue_pending(chan);
wait_event_freezable_timeout(done_wait, done.done,
msecs_to_jiffies(timeout));
status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
if (!done.done) {
/*
* We're leaving the timed out dma operation with
* dangling pointer to done_wait. To make this
* correct, we'll need to allocate wait_done for
* each test iteration and perform "who's gonna
* free it this time?" dancing. For now, just
* leave it dangling.
*/
pr_warning("%s: #%u: test timed out\n",
thread_name, total_tests - 1);
failed_tests++;
continue;
} else if (status != DMA_SUCCESS) {
pr_warning("%s: #%u: got completion callback,"
" but status is \'%s\'\n",
thread_name, total_tests - 1,
status == DMA_ERROR ? "error" : "in progress");
failed_tests++;
continue;
}
/* Unmap by myself (see DMA_COMPL_SKIP_DEST_UNMAP above) */
for (i = 0; i < dst_cnt; i++)
dma_unmap_single(dev->dev, dma_dsts[i], test_buf_size,
DMA_BIDIRECTIONAL);
error_count = 0;
pr_debug("%s: verifying source buffer...\n", thread_name);
error_count += dmatest_verify(thread->srcs, 0, src_off,
0, PATTERN_SRC, true);
error_count += dmatest_verify(thread->srcs, src_off,
src_off + len, src_off,
PATTERN_SRC | PATTERN_COPY, true);
error_count += dmatest_verify(thread->srcs, src_off + len,
test_buf_size, src_off + len,
PATTERN_SRC, true);
pr_debug("%s: verifying dest buffer...\n",
thread->task->comm);
error_count += dmatest_verify(thread->dsts, 0, dst_off,
0, PATTERN_DST, false);
error_count += dmatest_verify(thread->dsts, dst_off,
dst_off + len, src_off,
PATTERN_SRC | PATTERN_COPY, false);
error_count += dmatest_verify(thread->dsts, dst_off + len,
test_buf_size, dst_off + len,
PATTERN_DST, false);
if (error_count) {
pr_warning("%s: #%u: %u errors with "
"src_off=0x%x dst_off=0x%x len=0x%x\n",
thread_name, total_tests - 1, error_count,
src_off, dst_off, len);
failed_tests++;
} else {
pr_debug("%s: #%u: No errors with "
"src_off=0x%x dst_off=0x%x len=0x%x\n",
thread_name, total_tests - 1,
src_off, dst_off, len);
}
}
ret = 0;
for (i = 0; thread->dsts[i]; i++)
kfree(thread->dsts[i]);
err_dstbuf:
kfree(thread->dsts);
err_dsts:
for (i = 0; thread->srcs[i]; i++)
kfree(thread->srcs[i]);
err_srcbuf:
kfree(thread->srcs);
err_srcs:
pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
thread_name, total_tests, failed_tests, ret);
/* terminate all transfers on specified channels */
chan->device->device_control(chan, DMA_TERMINATE_ALL, 0);
if (iterations > 0)
while (!kthread_should_stop()) {
DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wait_dmatest_exit);
interruptible_sleep_on(&wait_dmatest_exit);
}
return ret;
}
static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
{
struct dmatest_thread *thread;
struct dmatest_thread *_thread;
int ret;
list_for_each_entry_safe(thread, _thread, &dtc->threads, node) {
ret = kthread_stop(thread->task);
pr_debug("dmatest: thread %s exited with status %d\n",
thread->task->comm, ret);
list_del(&thread->node);
kfree(thread);
}
/* terminate all transfers on specified channels */
dtc->chan->device->device_control(dtc->chan, DMA_TERMINATE_ALL, 0);
kfree(dtc);
}
static int dmatest_add_threads(struct dmatest_chan *dtc, enum dma_transaction_type type)
{
struct dmatest_thread *thread;
struct dma_chan *chan = dtc->chan;
char *op;
unsigned int i;
if (type == DMA_MEMCPY)
op = "copy";
else if (type == DMA_XOR)
op = "xor";
else if (type == DMA_PQ)
op = "pq";
else
return -EINVAL;
for (i = 0; i < threads_per_chan; i++) {
thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
if (!thread) {
pr_warning("dmatest: No memory for %s-%s%u\n",
dma_chan_name(chan), op, i);
break;
}
thread->chan = dtc->chan;
thread->type = type;
smp_wmb();
thread->task = kthread_run(dmatest_func, thread, "%s-%s%u",
dma_chan_name(chan), op, i);
if (IS_ERR(thread->task)) {
pr_warning("dmatest: Failed to run thread %s-%s%u\n",
dma_chan_name(chan), op, i);
kfree(thread);
break;
}
/* srcbuf and dstbuf are allocated by the thread itself */
list_add_tail(&thread->node, &dtc->threads);
}
return i;
}
static int dmatest_add_channel(struct dma_chan *chan)
{
struct dmatest_chan *dtc;
struct dma_device *dma_dev = chan->device;
unsigned int thread_count = 0;
int cnt;
dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
if (!dtc) {
pr_warning("dmatest: No memory for %s\n", dma_chan_name(chan));
return -ENOMEM;
}
dtc->chan = chan;
INIT_LIST_HEAD(&dtc->threads);
if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
cnt = dmatest_add_threads(dtc, DMA_MEMCPY);
thread_count += cnt > 0 ? cnt : 0;
}
if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
cnt = dmatest_add_threads(dtc, DMA_XOR);
thread_count += cnt > 0 ? cnt : 0;
}
if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
cnt = dmatest_add_threads(dtc, DMA_PQ);
thread_count += cnt > 0 ?: 0;
}
pr_info("dmatest: Started %u threads using %s\n",
thread_count, dma_chan_name(chan));
list_add_tail(&dtc->node, &dmatest_channels);
nr_channels++;
return 0;
}
static bool filter(struct dma_chan *chan, void *param)
{
if (!dmatest_match_channel(chan) || !dmatest_match_device(chan->device))
return false;
else
return true;
}
static int __init dmatest_init(void)
{
dma_cap_mask_t mask;
struct dma_chan *chan;
int err = 0;
dma_cap_zero(mask);
dma_cap_set(DMA_MEMCPY, mask);
for (;;) {
chan = dma_request_channel(mask, filter, NULL);
if (chan) {
err = dmatest_add_channel(chan);
if (err) {
dma_release_channel(chan);
break; /* add_channel failed, punt */
}
} else
break; /* no more channels available */
if (max_channels && nr_channels >= max_channels)
break; /* we have all we need */
}
return err;
}
/* when compiled-in wait for drivers to load first */
late_initcall(dmatest_init);
static void __exit dmatest_exit(void)
{
struct dmatest_chan *dtc, *_dtc;
struct dma_chan *chan;
list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
list_del(&dtc->node);
chan = dtc->chan;
dmatest_cleanup_channel(dtc);
pr_debug("dmatest: dropped channel %s\n",
dma_chan_name(chan));
dma_release_channel(chan);
}
}
module_exit(dmatest_exit);
MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
MODULE_LICENSE("GPL v2");