>-----Original Message-----
>From: Haavard Skinnemoen [mailto:[email protected]]
>
>This client tests DMA memcpy using various lengths and various offsets
>into the source and destination buffers. It will initialize both
>buffers with a know pattern and verify that the DMA engine copies the
>requested region and nothing more.
>
>Signed-off-by: Haavard Skinnemoen <[email protected]>
>---
[...]
>diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
>new file mode 100644
>index 0000000..d9e9866
>--- /dev/null
>+++ b/drivers/dma/dmatest.c
>@@ -0,0 +1,272 @@
>+/*
>+ * 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/dmaengine.h>
>+#include <linux/init.h>
>+#include <linux/kthread.h>
>+#include <linux/module.h>
>+#include <linux/random.h>
>+#include <linux/wait.h>
>+
>+#define TEST_BUF_SIZE (16384)
You might make this a module parameter so we can test with various
sizes.
>+
>+#define SRC_PATTERN 0x7c
>+#define SRC_PATTERN_OUTSIDE 0X8d
>+#define POISON_UNINIT 0x49
>+#define POISON_OUTSIDE 0x37
>+
>+struct dmatest {
>+ spinlock_t lock;
>+ struct dma_client client;
>+ struct task_struct *thread;
>+ struct dma_chan *chan;
>+ wait_queue_head_t wq;
>+ u8 *srcbuf;
>+ u8 *dstbuf;
>+};
>+
>+static inline struct dmatest *to_dmatest(struct dma_client *client)
>+{
>+ return container_of(client, struct dmatest, client);
>+}
>+
>+static enum dma_state_client
>+dmatest_event(struct dma_client *client, struct dma_chan *chan,
>+ enum dma_state state)
>+{
>+ struct dmatest *test = to_dmatest(client);
>+ enum dma_state_client ack = DMA_DUP;
DMA_NAK is better default for DMA_RESOURCE_AVAILABLE once you've got the
channel you want, as that will stop DMAEngine from handing you more, and
doesn't bother the DMA_RESOURCE_REMOVED process.
>+
>+ spin_lock(&test->lock);
>+ switch (state) {
>+ case DMA_RESOURCE_AVAILABLE:
>+ if (!test->chan) {
>+ printk(KERN_INFO "dmatest: Got channel %s\n",
>+ chan->dev.bus_id);
>+ test->chan = chan;
>+ wake_up_interruptible(&test->wq);
>+ ack = DMA_ACK;
>+ }
>+ break;
Do you ever want to test a specific channel? Is there a way to identify
specific channels, perhaps by checking the PCI bus/chan/func? This
could be useful in debugging specific hardware issues - a frilly extra
feature and very HW specific, but potentially useful. I suppose this
might also depend upon your hardware - is there more than one channel in
your gizmo?
>+
>+ case DMA_RESOURCE_REMOVED:
>+ if (test->chan == chan) {
Should you use your test->lock here?
>+ printk(KERN_INFO "dmatest: Lost channel %s\n",
>+ chan->dev.bus_id);
>+ test->chan = NULL;
>+ ack = DMA_ACK;
>+ }
>+ break;
>+
>+ default:
Since this is a test program, perhaps a printk() here might be useful...
>+ break;
>+ }
>+ spin_unlock(&test->lock);
>+
>+ return ack;
>+}
>+
>+static unsigned long dmatest_random(void)
>+{
>+ unsigned long buf;
>+
>+ get_random_bytes(&buf, sizeof(buf));
>+ return buf;
>+}
>+
>+static unsigned int dmatest_verify(u8 *buf, unsigned int start,
>+ unsigned int end, u8 expected)
>+{
>+ unsigned int i;
>+ unsigned int error_count = 0;
>+
>+ for (i = start; i < end; i++) {
>+ if (buf[i] != expected) {
>+ if (error_count < 32)
>+ printk(KERN_ERR "dmatest:
>buf[0x%x] = %02x "
>+ "(expected %02x)\n",
>+ i, buf[i], expected);
>+ error_count++;
>+ }
>+ }
>+
>+ if (error_count > 32)
>+ printk(KERN_ERR "dmatest: %u errors suppressed\n",
>+ error_count - 32);
>+
>+ return error_count;
>+}
>+
>+static int dmatest_func(void *data)
>+{
>+ struct dmatest *test = data;
>+ struct dma_chan *chan;
>+ bool should_stop = false;
>+ unsigned int src_off, dst_off, len;
>+ unsigned int error_count;
>+ dma_cookie_t cookie;
>+ enum dma_status status;
>+
>+ dma_cap_set(DMA_MEMCPY, test->client.cap_mask);
>+ dma_async_client_register(&test->client);
>+ dma_async_client_chan_request(&test->client);
>+
>+ for (;;) {
>+ DEFINE_WAIT(chan_wait);
>+
>+ pr_debug("dmatest: Waiting for a channel...\n");
>+ for (;;) {
>+ spin_lock(&test->lock);
>+ prepare_to_wait(&test->wq, &chan_wait,
>+ TASK_UNINTERRUPTIBLE);
Hmmm - so the only way to trigger the loop is to remove then add a
channel, basically rmmod and insmod your dma driver? It would be nice
to have a method to trigger more than one test, maybe even a stream of
copy requests. Or am I asking for too many features? :-)
>+ if (kthread_should_stop()) {
>+ should_stop = true;
>+ break;
>+ }
>+
>+ if (test->chan) {
>+ chan = test->chan;
>+ dma_chan_get(chan);
I suppose you are doing this extra get and put to be absolutely sure the
channel doesn't disappear out from under you, even though your
dmatest_event() already ACK'd the removal, right?
[...]
Thanks for posting this.
sln
--
======================================================================
Mr. Shannon Nelson LAN Access Division, Intel Corp.
[email protected] I don't speak for Intel
(503) 712-7659 Parents can't afford to be squeamish.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
