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]>
---
Changes since v1:
* Remove extra dashes around "help" in Kconfig
* Remove "default n" from Kconfig
* Turn TEST_BUF_SIZE into a module parameter
* Return DMA_NAK instead of DMA_DUP
* Print unhandled events
* Support testing specific channels and devices
* Move to the end of the Makefile
Big thanks to Sam Ravnborg and Shannon Nelson for feedback.
I haven't added support for testing multiple channels at once, or
for testing a single channel using multiple threads. It will be a
rather big change, but I think it might be worth it since it will make
the module much better at catching nasty race conditions in the DMA
Engine driver.
drivers/dma/Kconfig | 7 +
drivers/dma/Makefile | 1 +
drivers/dma/dmatest.c | 304 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 312 insertions(+), 0 deletions(-)
create mode 100644 drivers/dma/dmatest.c
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index 6a7d25f..3bb9f2c 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -49,4 +49,11 @@ config NET_DMA
Since this is the main user of the DMA engine, it should be enabled;
say Y here.
+config DMATEST
+ tristate "DMA Test client"
+ depends on DMA_ENGINE
+ help
+ Simple DMA test client. Say N unless you're debugging a
+ DMA Device driver.
+
endif
diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
index b152cd8..cecfb60 100644
--- a/drivers/dma/Makefile
+++ b/drivers/dma/Makefile
@@ -3,3 +3,4 @@ obj-$(CONFIG_NET_DMA) += iovlock.o
obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o
ioatdma-objs := ioat.o ioat_dma.o ioat_dca.o
obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
+obj-$(CONFIG_DMATEST) += dmatest.o
diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
new file mode 100644
index 0000000..523ee93
--- /dev/null
+++ b/drivers/dma/dmatest.c
@@ -0,0 +1,304 @@
+/*
+ * 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/moduleparam.h>
+#include <linux/random.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[BUS_ID_SIZE];
+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[BUS_ID_SIZE];
+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)");
+
+#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 bool dmatest_match_channel(struct dma_chan *chan)
+{
+ if (test_channel[0] == '\0')
+ return true;
+ return strcmp(chan->dev.bus_id, test_channel) == 0;
+}
+
+static bool dmatest_match_device(struct dma_device *device)
+{
+ if (test_device[0] == '\0')
+ return true;
+ return strcmp(device->dev->bus_id, test_device) == 0;
+}
+
+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_NAK;
+
+ spin_lock(&test->lock);
+ switch (state) {
+ case DMA_RESOURCE_AVAILABLE:
+ if (test->chan) {
+ ack = DMA_NAK;
+ } else if (dmatest_match_channel(chan)
+ && dmatest_match_device(chan->device)) {
+ printk(KERN_INFO "dmatest: Got channel %s\n",
+ chan->dev.bus_id);
+ test->chan = chan;
+ wake_up_interruptible(&test->wq);
+ ack = DMA_ACK;
+ } else {
+ ack = DMA_DUP;
+ }
+ break;
+
+ case DMA_RESOURCE_REMOVED:
+ if (test->chan == chan) {
+ printk(KERN_INFO "dmatest: Lost channel %s\n",
+ chan->dev.bus_id);
+ test->chan = NULL;
+ ack = DMA_ACK;
+ }
+ break;
+
+ default:
+ printk(KERN_INFO "dmatest: Unhandled event %u (%s)\n",
+ state, chan->dev.bus_id);
+ 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);
+ if (kthread_should_stop()) {
+ should_stop = true;
+ break;
+ }
+
+ if (test->chan) {
+ chan = test->chan;
+ dma_chan_get(chan);
+ break;
+ }
+ spin_unlock(&test->lock);
+
+ schedule();
+ }
+ finish_wait(&test->wq, &chan_wait);
+ spin_unlock(&test->lock);
+
+ if (should_stop)
+ break;
+
+ pr_debug("dmatest: Got it!\n");
+
+ len = dmatest_random() % test_buf_size;
+ src_off = dmatest_random() % (test_buf_size - len);
+ dst_off = dmatest_random() % (test_buf_size - len);
+
+ memset(test->srcbuf, SRC_PATTERN_OUTSIDE, src_off);
+ memset(test->srcbuf + src_off, SRC_PATTERN, len);
+ memset(test->srcbuf + src_off + len, SRC_PATTERN_OUTSIDE,
+ test_buf_size - (src_off + len));
+ memset(test->dstbuf, POISON_OUTSIDE, dst_off);
+ memset(test->dstbuf + dst_off, POISON_UNINIT, len);
+ memset(test->dstbuf + dst_off + len, POISON_OUTSIDE,
+ test_buf_size - (dst_off + len));
+
+ cookie = dma_async_memcpy_buf_to_buf(chan,
+ test->dstbuf + dst_off,
+ test->srcbuf + src_off,
+ len);
+ if (dma_submit_error(cookie)) {
+ printk("dmatest: submit error: %d\n", cookie);
+ dma_chan_put(chan);
+ msleep(100);
+ continue;
+ }
+ dma_async_memcpy_issue_pending(chan);
+
+ do {
+ msleep(1);
+ status = dma_async_memcpy_complete(
+ chan, cookie, NULL, NULL);
+ } while (status == DMA_IN_PROGRESS);
+
+ dma_chan_put(chan);
+
+ if (status == DMA_ERROR) {
+ printk("dmatest: error during copy\n");
+ continue;
+ }
+
+ error_count = 0;
+
+ printk(KERN_INFO "dmatest: verifying source buffer...\n");
+ error_count += dmatest_verify(test->srcbuf, 0, src_off,
+ SRC_PATTERN_OUTSIDE);
+ error_count += dmatest_verify(test->srcbuf, src_off,
+ src_off + len, SRC_PATTERN);
+ error_count += dmatest_verify(test->srcbuf, src_off + len,
+ test_buf_size, SRC_PATTERN_OUTSIDE);
+
+ printk(KERN_INFO "dmatest: verifying dest buffer...\n");
+ error_count += dmatest_verify(test->dstbuf, 0, dst_off,
+ POISON_OUTSIDE);
+ error_count += dmatest_verify(test->dstbuf, dst_off,
+ dst_off + len, SRC_PATTERN);
+ error_count += dmatest_verify(test->dstbuf, dst_off + len,
+ test_buf_size, POISON_OUTSIDE);
+
+ if (error_count)
+ printk(KERN_ERR "dmatest: %u errors with "
+ "src_off=0x%x dst_off=0x%x len=0x%x\n",
+ error_count, src_off, dst_off, len);
+ else
+ printk(KERN_INFO "dmatest: No errors with "
+ "src_off=0x%x dst_off=0x%x len=0x%x\n",
+ src_off, dst_off, len);
+ }
+
+ dma_async_client_unregister(&test->client);
+
+ return 0;
+}
+
+static struct dmatest dmatest_data = {
+ .client = {
+ .event_callback = dmatest_event,
+ },
+ .wq = __WAIT_QUEUE_HEAD_INITIALIZER(dmatest_data.wq),
+};
+
+static int __init dmatest_init(void)
+{
+ struct dmatest *test = &dmatest_data;
+ int ret = -ENOMEM;
+
+ spin_lock_init(&test->lock);
+
+ test->srcbuf = kmalloc(test_buf_size, GFP_KERNEL);
+ if (!test->srcbuf)
+ goto err_srcbuf;
+ test->dstbuf = kmalloc(test_buf_size, GFP_KERNEL);
+ if (!test->dstbuf)
+ goto err_dstbuf;
+
+ test->thread = kthread_run(dmatest_func, test, "kdmatestd");
+ if (IS_ERR(test->thread)) {
+ ret = PTR_ERR(test->thread);
+ goto err_kthread;
+ }
+
+ return 0;
+
+err_kthread:
+ kfree(test->dstbuf);
+err_dstbuf:
+ kfree(test->srcbuf);
+err_srcbuf:
+ return ret;
+}
+module_init(dmatest_init);
+
+static void __exit dmatest_exit(void)
+{
+ int ret;
+
+ ret = kthread_stop(dmatest_data.thread);
+ printk("dmatest: Thread exited with status %d\n", ret);
+ kfree(dmatest_data.srcbuf);
+ kfree(dmatest_data.dstbuf);
+}
+module_exit(dmatest_exit);
+
+MODULE_AUTHOR("Haavard Skinnemoen <[email protected]>");
+MODULE_LICENSE("GPL v2");
--
1.5.3.4
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