thunderbolt: Add DMA traffic test driver

This driver allows sending DMA traffic over XDomain connection.
Specifically over a loopback connection using either a Thunderbolt/USB4
cable that is connected back to the host router port, or a special
loopback dongle that has RX and TX lines crossed. This can be useful at
manufacturing floor to check whether Thunderbolt/USB4 ports are
functional.

The driver exposes debugfs directory under the XDomain service that can
be used to configure the driver, start the test and check the results.

If a loopback dongle is used the steps to send and receive 1000 packets
can be done like:

  # modprobe thunderbolt_dma_test
  # echo 1000 > /sys/kernel/debug/thunderbolt/<service_id>/dma_test/packets_to_receive
  # echo 1000 > /sys/kernel/debug/thunderbolt/<service_id>/dma_test/packets_to_send
  # echo 1 > /sys/kernel/debug/thunderbolt/<service_id>/dma_test/test
  # cat /sys/kernel/debug/thunderbolt/<service_id>/dma_test/status

When a cable is connected back to host then there are two Thunderbolt
services, one is configured for receiving (does not matter which one):

  # modprobe thunderbolt_dma_test
  # echo 1000 > /sys/kernel/debug/thunderbolt/<service_a>/dma_test/packets_to_receive
  # echo 1 > /sys/kernel/debug/thunderbolt/<service_a>/dma_test/test

The other one for sending:

  # echo 1000 > /sys/kernel/debug/thunderbolt/<service_b>/dma_test/packets_to_send
  # echo 1 > /sys/kernel/debug/thunderbolt/<service_b>/dma_test/test

Results can be read from both services status attributes.

Signed-off-by: Isaac Hazan <isaac.hazan@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 752 insertions, 0 deletions

diff --git a/drivers/thunderbolt/Kconfig b/drivers/thunderbolt/Kconfig
index 7fc058f81d00..4bfec8a28064 100644
--- a/drivers/thunderbolt/Kconfig
+++ b/drivers/thunderbolt/Kconfig
@@ -31,4 +31,17 @@ config USB4_KUNIT_TEST
 	bool "KUnit tests"
 	depends on KUNIT=y
 
+config USB4_DMA_TEST
+	tristate "DMA traffic test driver"
+	depends on DEBUG_FS
+	help
+	  This allows sending and receiving DMA traffic through loopback
+	  connection. Loopback connection can be done by either special
+	  dongle that has TX/RX lines crossed, or by simply connecting a
+	  cable back to the host. Only enable this if you know what you
+	  are doing. Normal users and distro kernels should say N here.
+
+	  To compile this driver a module, choose M here. The module will be
+	  called thunderbolt_dma_test.
+
 endif # USB4
diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index 571537371072..7aa48f6c41d9 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -7,3 +7,6 @@ thunderbolt-objs += nvm.o retimer.o quirks.o
 thunderbolt-${CONFIG_ACPI} += acpi.o
 thunderbolt-$(CONFIG_DEBUG_FS) += debugfs.o
 thunderbolt-${CONFIG_USB4_KUNIT_TEST} += test.o
+
+thunderbolt_dma_test-${CONFIG_USB4_DMA_TEST} += dma_test.o
+obj-$(CONFIG_USB4_DMA_TEST) += thunderbolt_dma_test.o
diff --git a/drivers/thunderbolt/dma_test.c b/drivers/thunderbolt/dma_test.c
new file mode 100644
index 000000000000..f924423fa180
--- /dev/null
+++ b/drivers/thunderbolt/dma_test.c
@@ -0,0 +1,736 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DMA traffic test driver
+ *
+ * Copyright (C) 2020, Intel Corporation
+ * Authors: Isaac Hazan <isaac.hazan@intel.com>
+ *	    Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+
+#include <linux/acpi.h>
+#include <linux/completion.h>
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <linux/thunderbolt.h>
+
+#define DMA_TEST_HOPID			8
+#define DMA_TEST_TX_RING_SIZE		64
+#define DMA_TEST_RX_RING_SIZE		256
+#define DMA_TEST_FRAME_SIZE		SZ_4K
+#define DMA_TEST_DATA_PATTERN		0x0123456789abcdefLL
+#define DMA_TEST_MAX_PACKETS		1000
+
+enum dma_test_frame_pdf {
+	DMA_TEST_PDF_FRAME_START = 1,
+	DMA_TEST_PDF_FRAME_END,
+};
+
+struct dma_test_frame {
+	struct dma_test *dma_test;
+	void *data;
+	struct ring_frame frame;
+};
+
+enum dma_test_test_error {
+	DMA_TEST_NO_ERROR,
+	DMA_TEST_INTERRUPTED,
+	DMA_TEST_BUFFER_ERROR,
+	DMA_TEST_DMA_ERROR,
+	DMA_TEST_CONFIG_ERROR,
+	DMA_TEST_SPEED_ERROR,
+	DMA_TEST_WIDTH_ERROR,
+	DMA_TEST_BONDING_ERROR,
+	DMA_TEST_PACKET_ERROR,
+};
+
+static const char * const dma_test_error_names[] = {
+	[DMA_TEST_NO_ERROR] = "no errors",
+	[DMA_TEST_INTERRUPTED] = "interrupted by signal",
+	[DMA_TEST_BUFFER_ERROR] = "no memory for packet buffers",
+	[DMA_TEST_DMA_ERROR] = "DMA ring setup failed",
+	[DMA_TEST_CONFIG_ERROR] = "configuration is not valid",
+	[DMA_TEST_SPEED_ERROR] = "unexpected link speed",
+	[DMA_TEST_WIDTH_ERROR] = "unexpected link width",
+	[DMA_TEST_BONDING_ERROR] = "lane bonding configuration error",
+	[DMA_TEST_PACKET_ERROR] = "packet check failed",
+};
+
+enum dma_test_result {
+	DMA_TEST_NOT_RUN,
+	DMA_TEST_SUCCESS,
+	DMA_TEST_FAIL,
+};
+
+static const char * const dma_test_result_names[] = {
+	[DMA_TEST_NOT_RUN] = "not run",
+	[DMA_TEST_SUCCESS] = "success",
+	[DMA_TEST_FAIL] = "failed",
+};
+
+/**
+ * struct dma_test - DMA test device driver private data
+ * @svc: XDomain service the driver is bound to
+ * @xd: XDomain the service belongs to
+ * @rx_ring: Software ring holding RX frames
+ * @tx_ring: Software ring holding TX frames
+ * @packets_to_send: Number of packets to send
+ * @packets_to_receive: Number of packets to receive
+ * @packets_sent: Actual number of packets sent
+ * @packets_received: Actual number of packets received
+ * @link_speed: Expected link speed (Gb/s), %0 to use whatever is negotiated
+ * @link_width: Expected link width (Gb/s), %0 to use whatever is negotiated
+ * @crc_errors: Number of CRC errors during the test run
+ * @buffer_overflow_errors: Number of buffer overflow errors during the test
+ *			    run
+ * @result: Result of the last run
+ * @error_code: Error code of the last run
+ * @complete: Used to wait for the Rx to complete
+ * @lock: Lock serializing access to this structure
+ * @debugfs_dir: dentry of this dma_test
+ */
+struct dma_test {
+	const struct tb_service *svc;
+	struct tb_xdomain *xd;
+	struct tb_ring *rx_ring;
+	struct tb_ring *tx_ring;
+	unsigned int packets_to_send;
+	unsigned int packets_to_receive;
+	unsigned int packets_sent;
+	unsigned int packets_received;
+	unsigned int link_speed;
+	unsigned int link_width;
+	unsigned int crc_errors;
+	unsigned int buffer_overflow_errors;
+	enum dma_test_result result;
+	enum dma_test_test_error error_code;
+	struct completion complete;
+	struct mutex lock;
+	struct dentry *debugfs_dir;
+};
+
+/* DMA test property directory UUID: 3188cd10-6523-4a5a-a682-fdca07a248d8 */
+static const uuid_t dma_test_dir_uuid =
+	UUID_INIT(0x3188cd10, 0x6523, 0x4a5a,
+		  0xa6, 0x82, 0xfd, 0xca, 0x07, 0xa2, 0x48, 0xd8);
+
+static struct tb_property_dir *dma_test_dir;
+static void *dma_test_pattern;
+
+static void dma_test_free_rings(struct dma_test *dt)
+{
+	if (dt->rx_ring) {
+		tb_ring_free(dt->rx_ring);
+		dt->rx_ring = NULL;
+	}
+	if (dt->tx_ring) {
+		tb_ring_free(dt->tx_ring);
+		dt->tx_ring = NULL;
+	}
+}
+
+static int dma_test_start_rings(struct dma_test *dt)
+{
+	unsigned int flags = RING_FLAG_FRAME;
+	struct tb_xdomain *xd = dt->xd;
+	int ret, e2e_tx_hop = 0;
+	struct tb_ring *ring;
+
+	/*
+	 * If we are both sender and receiver (traffic goes over a
+	 * special loopback dongle) enable E2E flow control. This avoids
+	 * losing packets.
+	 */
+	if (dt->packets_to_send && dt->packets_to_receive)
+		flags |= RING_FLAG_E2E;
+
+	if (dt->packets_to_send) {
+		ring = tb_ring_alloc_tx(xd->tb->nhi, -1, DMA_TEST_TX_RING_SIZE,
+					flags);
+		if (!ring)
+			return -ENOMEM;
+
+		dt->tx_ring = ring;
+		e2e_tx_hop = ring->hop;
+	}
+
+	if (dt->packets_to_receive) {
+		u16 sof_mask, eof_mask;
+
+		sof_mask = BIT(DMA_TEST_PDF_FRAME_START);
+		eof_mask = BIT(DMA_TEST_PDF_FRAME_END);
+
+		ring = tb_ring_alloc_rx(xd->tb->nhi, -1, DMA_TEST_RX_RING_SIZE,
+					flags, e2e_tx_hop, sof_mask, eof_mask,
+					NULL, NULL);
+		if (!ring) {
+			dma_test_free_rings(dt);
+			return -ENOMEM;
+		}
+
+		dt->rx_ring = ring;
+	}
+
+	ret = tb_xdomain_enable_paths(dt->xd, DMA_TEST_HOPID,
+				      dt->tx_ring ? dt->tx_ring->hop : 0,
+				      DMA_TEST_HOPID,
+				      dt->rx_ring ? dt->rx_ring->hop : 0);
+	if (ret) {
+		dma_test_free_rings(dt);
+		return ret;
+	}
+
+	if (dt->tx_ring)
+		tb_ring_start(dt->tx_ring);
+	if (dt->rx_ring)
+		tb_ring_start(dt->rx_ring);
+
+	return 0;
+}
+
+static void dma_test_stop_rings(struct dma_test *dt)
+{
+	if (dt->rx_ring)
+		tb_ring_stop(dt->rx_ring);
+	if (dt->tx_ring)
+		tb_ring_stop(dt->tx_ring);
+
+	if (tb_xdomain_disable_paths(dt->xd))
+		dev_warn(&dt->svc->dev, "failed to disable DMA paths\n");
+
+	dma_test_free_rings(dt);
+}
+
+static void dma_test_rx_callback(struct tb_ring *ring, struct ring_frame *frame,
+				 bool canceled)
+{
+	struct dma_test_frame *tf = container_of(frame, typeof(*tf), frame);
+	struct dma_test *dt = tf->dma_test;
+	struct device *dma_dev = tb_ring_dma_device(dt->rx_ring);
+
+	dma_unmap_single(dma_dev, tf->frame.buffer_phy, DMA_TEST_FRAME_SIZE,
+			 DMA_FROM_DEVICE);
+	kfree(tf->data);
+
+	if (canceled) {
+		kfree(tf);
+		return;
+	}
+
+	dt->packets_received++;
+	dev_dbg(&dt->svc->dev, "packet %u/%u received\n", dt->packets_received,
+		dt->packets_to_receive);
+
+	if (tf->frame.flags & RING_DESC_CRC_ERROR)
+		dt->crc_errors++;
+	if (tf->frame.flags & RING_DESC_BUFFER_OVERRUN)
+		dt->buffer_overflow_errors++;
+
+	kfree(tf);
+
+	if (dt->packets_received == dt->packets_to_receive)
+		complete(&dt->complete);
+}
+
+static int dma_test_submit_rx(struct dma_test *dt, size_t npackets)
+{
+	struct device *dma_dev = tb_ring_dma_device(dt->rx_ring);
+	int i;
+
+	for (i = 0; i < npackets; i++) {
+		struct dma_test_frame *tf;
+		dma_addr_t dma_addr;
+
+		tf = kzalloc(sizeof(*tf), GFP_KERNEL);
+		if (!tf)
+			return -ENOMEM;
+
+		tf->data = kzalloc(DMA_TEST_FRAME_SIZE, GFP_KERNEL);
+		if (!tf->data) {
+			kfree(tf);
+			return -ENOMEM;
+		}
+
+		dma_addr = dma_map_single(dma_dev, tf->data, DMA_TEST_FRAME_SIZE,
+					  DMA_FROM_DEVICE);
+		if (dma_mapping_error(dma_dev, dma_addr)) {
+			kfree(tf->data);
+			kfree(tf);
+			return -ENOMEM;
+		}
+
+		tf->frame.buffer_phy = dma_addr;
+		tf->frame.callback = dma_test_rx_callback;
+		tf->dma_test = dt;
+		INIT_LIST_HEAD(&tf->frame.list);
+
+		tb_ring_rx(dt->rx_ring, &tf->frame);
+	}
+
+	return 0;
+}
+
+static void dma_test_tx_callback(struct tb_ring *ring, struct ring_frame *frame,
+				 bool canceled)
+{
+	struct dma_test_frame *tf = container_of(frame, typeof(*tf), frame);
+	struct dma_test *dt = tf->dma_test;
+	struct device *dma_dev = tb_ring_dma_device(dt->tx_ring);
+
+	dma_unmap_single(dma_dev, tf->frame.buffer_phy, DMA_TEST_FRAME_SIZE,
+			 DMA_TO_DEVICE);
+	kfree(tf->data);
+	kfree(tf);
+}
+
+static int dma_test_submit_tx(struct dma_test *dt, size_t npackets)
+{
+	struct device *dma_dev = tb_ring_dma_device(dt->tx_ring);
+	int i;
+
+	for (i = 0; i < npackets; i++) {
+		struct dma_test_frame *tf;
+		dma_addr_t dma_addr;
+
+		tf = kzalloc(sizeof(*tf), GFP_KERNEL);
+		if (!tf)
+			return -ENOMEM;
+
+		tf->frame.size = 0; /* means 4096 */
+		tf->dma_test = dt;
+
+		tf->data = kzalloc(DMA_TEST_FRAME_SIZE, GFP_KERNEL);
+		if (!tf->data) {
+			kfree(tf);
+			return -ENOMEM;
+		}
+
+		memcpy(tf->data, dma_test_pattern, DMA_TEST_FRAME_SIZE);
+
+		dma_addr = dma_map_single(dma_dev, tf->data, DMA_TEST_FRAME_SIZE,
+					  DMA_TO_DEVICE);
+		if (dma_mapping_error(dma_dev, dma_addr)) {
+			kfree(tf->data);
+			kfree(tf);
+			return -ENOMEM;
+		}
+
+		tf->frame.buffer_phy = dma_addr;
+		tf->frame.callback = dma_test_tx_callback;
+		tf->frame.sof = DMA_TEST_PDF_FRAME_START;
+		tf->frame.eof = DMA_TEST_PDF_FRAME_END;
+		INIT_LIST_HEAD(&tf->frame.list);
+
+		dt->packets_sent++;
+		dev_dbg(&dt->svc->dev, "packet %u/%u sent\n", dt->packets_sent,
+			dt->packets_to_send);
+
+		tb_ring_tx(dt->tx_ring, &tf->frame);
+	}
+
+	return 0;
+}
+
+#define DMA_TEST_DEBUGFS_ATTR(__fops, __get, __validate, __set)	\
+static int __fops ## _show(void *data, u64 *val)		\
+{								\
+	struct tb_service *svc = data;				\
+	struct dma_test *dt = tb_service_get_drvdata(svc);	\
+	int ret;						\
+								\
+	ret = mutex_lock_interruptible(&dt->lock);		\
+	if (ret)						\
+		return ret;					\
+	__get(dt, val);						\
+	mutex_unlock(&dt->lock);				\
+	return 0;						\
+}								\
+static int __fops ## _store(void *data, u64 val)		\
+{								\
+	struct tb_service *svc = data;				\
+	struct dma_test *dt = tb_service_get_drvdata(svc);	\
+	int ret;						\
+								\
+	ret = __validate(val);					\
+	if (ret)						\
+		return ret;					\
+	ret = mutex_lock_interruptible(&dt->lock);		\
+	if (ret)						\
+		return ret;					\
+	__set(dt, val);						\
+	mutex_unlock(&dt->lock);				\
+	return 0;						\
+}								\
+DEFINE_DEBUGFS_ATTRIBUTE(__fops ## _fops, __fops ## _show,	\
+			 __fops ## _store, "%llu\n")
+
+static void lanes_get(const struct dma_test *dt, u64 *val)
+{
+	*val = dt->link_width;
+}
+
+static int lanes_validate(u64 val)
+{
+	return val > 2 ? -EINVAL : 0;
+}
+
+static void lanes_set(struct dma_test *dt, u64 val)
+{
+	dt->link_width = val;
+}
+DMA_TEST_DEBUGFS_ATTR(lanes, lanes_get, lanes_validate, lanes_set);
+
+static void speed_get(const struct dma_test *dt, u64 *val)
+{
+	*val = dt->link_speed;
+}
+
+static int speed_validate(u64 val)
+{
+	switch (val) {
+	case 20:
+	case 10:
+	case 0:
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+static void speed_set(struct dma_test *dt, u64 val)
+{
+	dt->link_speed = val;
+}
+DMA_TEST_DEBUGFS_ATTR(speed, speed_get, speed_validate, speed_set);
+
+static void packets_to_receive_get(const struct dma_test *dt, u64 *val)
+{
+	*val = dt->packets_to_receive;
+}
+
+static int packets_to_receive_validate(u64 val)
+{
+	return val > DMA_TEST_MAX_PACKETS ? -EINVAL : 0;
+}
+
+static void packets_to_receive_set(struct dma_test *dt, u64 val)
+{
+	dt->packets_to_receive = val;
+}
+DMA_TEST_DEBUGFS_ATTR(packets_to_receive, packets_to_receive_get,
+		      packets_to_receive_validate, packets_to_receive_set);
+
+static void packets_to_send_get(const struct dma_test *dt, u64 *val)
+{
+	*val = dt->packets_to_send;
+}
+
+static int packets_to_send_validate(u64 val)
+{
+	return val > DMA_TEST_MAX_PACKETS ? -EINVAL : 0;
+}
+
+static void packets_to_send_set(struct dma_test *dt, u64 val)
+{
+	dt->packets_to_send = val;
+}
+DMA_TEST_DEBUGFS_ATTR(packets_to_send, packets_to_send_get,
+		      packets_to_send_validate, packets_to_send_set);
+
+static int dma_test_set_bonding(struct dma_test *dt)
+{
+	switch (dt->link_width) {
+	case 2:
+		return tb_xdomain_lane_bonding_enable(dt->xd);
+	case 1:
+		tb_xdomain_lane_bonding_disable(dt->xd);
+		fallthrough;
+	default:
+		return 0;
+	}
+}
+
+static bool dma_test_validate_config(struct dma_test *dt)
+{
+	if (!dt->packets_to_send && !dt->packets_to_receive)
+		return false;
+	if (dt->packets_to_send && dt->packets_to_receive &&
+	    dt->packets_to_send != dt->packets_to_receive)
+		return false;
+	return true;
+}
+
+static void dma_test_check_errors(struct dma_test *dt, int ret)
+{
+	if (!dt->error_code) {
+		if (dt->link_speed && dt->xd->link_speed != dt->link_speed) {
+			dt->error_code = DMA_TEST_SPEED_ERROR;
+		} else if (dt->link_width &&
+			   dt->xd->link_width != dt->link_width) {
+			dt->error_code = DMA_TEST_WIDTH_ERROR;
+		} else if (dt->packets_to_send != dt->packets_sent ||
+			 dt->packets_to_receive != dt->packets_received ||
+			 dt->crc_errors || dt->buffer_overflow_errors) {
+			dt->error_code = DMA_TEST_PACKET_ERROR;
+		} else {
+			return;
+		}
+	}
+
+	dt->result = DMA_TEST_FAIL;
+}
+
+static int test_store(void *data, u64 val)
+{
+	struct tb_service *svc = data;
+	struct dma_test *dt = tb_service_get_drvdata(svc);
+	int ret;
+
+	if (val != 1)
+		return -EINVAL;
+
+	ret = mutex_lock_interruptible(&dt->lock);
+	if (ret)
+		return ret;
+
+	dt->packets_sent = 0;
+	dt->packets_received = 0;
+	dt->crc_errors = 0;
+	dt->buffer_overflow_errors = 0;
+	dt->result = DMA_TEST_SUCCESS;
+	dt->error_code = DMA_TEST_NO_ERROR;
+
+	dev_dbg(&svc->dev, "DMA test starting\n");
+	if (dt->link_speed)
+		dev_dbg(&svc->dev, "link_speed: %u Gb/s\n", dt->link_speed);
+	if (dt->link_width)
+		dev_dbg(&svc->dev, "link_width: %u\n", dt->link_width);
+	dev_dbg(&svc->dev, "packets_to_send: %u\n", dt->packets_to_send);
+	dev_dbg(&svc->dev, "packets_to_receive: %u\n", dt->packets_to_receive);
+
+	if (!dma_test_validate_config(dt)) {
+		dev_err(&svc->dev, "invalid test configuration\n");
+		dt->error_code = DMA_TEST_CONFIG_ERROR;
+		goto out_unlock;
+	}
+
+	ret = dma_test_set_bonding(dt);
+	if (ret) {
+		dev_err(&svc->dev, "failed to set lanes\n");
+		dt->error_code = DMA_TEST_BONDING_ERROR;
+		goto out_unlock;
+	}
+
+	ret = dma_test_start_rings(dt);
+	if (ret) {
+		dev_err(&svc->dev, "failed to enable DMA rings\n");
+		dt->error_code = DMA_TEST_DMA_ERROR;
+		goto out_unlock;
+	}
+
+	if (dt->packets_to_receive) {
+		reinit_completion(&dt->complete);
+		ret = dma_test_submit_rx(dt, dt->packets_to_receive);
+		if (ret) {
+			dev_err(&svc->dev, "failed to submit receive buffers\n");
+			dt->error_code = DMA_TEST_BUFFER_ERROR;
+			goto out_stop;
+		}
+	}
+
+	if (dt->packets_to_send) {
+		ret = dma_test_submit_tx(dt, dt->packets_to_send);
+		if (ret) {
+			dev_err(&svc->dev, "failed to submit transmit buffers\n");
+			dt->error_code = DMA_TEST_BUFFER_ERROR;
+			goto out_stop;
+		}
+	}
+
+	if (dt->packets_to_receive) {
+		ret = wait_for_completion_interruptible(&dt->complete);
+		if (ret) {
+			dt->error_code = DMA_TEST_INTERRUPTED;
+			goto out_stop;
+		}
+	}
+
+out_stop:
+	dma_test_stop_rings(dt);
+out_unlock:
+	dma_test_check_errors(dt, ret);
+	mutex_unlock(&dt->lock);
+
+	dev_dbg(&svc->dev, "DMA test %s\n", dma_test_result_names[dt->result]);
+	return ret;
+}
+DEFINE_DEBUGFS_ATTRIBUTE(test_fops, NULL, test_store, "%llu\n");
+
+static int status_show(struct seq_file *s, void *not_used)
+{
+	struct tb_service *svc = s->private;
+	struct dma_test *dt = tb_service_get_drvdata(svc);
+	int ret;
+
+	ret = mutex_lock_interruptible(&dt->lock);
+	if (ret)
+		return ret;
+
+	seq_printf(s, "result: %s\n", dma_test_result_names[dt->result]);
+	if (dt->result == DMA_TEST_NOT_RUN)
+		goto out_unlock;
+
+	seq_printf(s, "packets received: %u\n", dt->packets_received);
+	seq_printf(s, "packets sent: %u\n", dt->packets_sent);
+	seq_printf(s, "CRC errors: %u\n", dt->crc_errors);
+	seq_printf(s, "buffer overflow errors: %u\n",
+		   dt->buffer_overflow_errors);
+	seq_printf(s, "error: %s\n", dma_test_error_names[dt->error_code]);
+
+out_unlock:
+	mutex_unlock(&dt->lock);
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(status);
+
+static void dma_test_debugfs_init(struct tb_service *svc)
+{
+	struct dma_test *dt = tb_service_get_drvdata(svc);
+
+	dt->debugfs_dir = debugfs_create_dir("dma_test", svc->debugfs_dir);
+
+	debugfs_create_file("lanes", 0600, dt->debugfs_dir, svc, &lanes_fops);
+	debugfs_create_file("speed", 0600, dt->debugfs_dir, svc, &speed_fops);
+	debugfs_create_file("packets_to_receive", 0600, dt->debugfs_dir, svc,
+			    &packets_to_receive_fops);
+	debugfs_create_file("packets_to_send", 0600, dt->debugfs_dir, svc,
+			    &packets_to_send_fops);
+	debugfs_create_file("status", 0400, dt->debugfs_dir, svc, &status_fops);
+	debugfs_create_file("test", 0200, dt->debugfs_dir, svc, &test_fops);
+}
+
+static int dma_test_probe(struct tb_service *svc, const struct tb_service_id *id)
+{
+	struct tb_xdomain *xd = tb_service_parent(svc);
+	struct dma_test *dt;
+
+	dt = devm_kzalloc(&svc->dev, sizeof(*dt), GFP_KERNEL);
+	if (!dt)
+		return -ENOMEM;
+
+	dt->svc = svc;
+	dt->xd = xd;
+	mutex_init(&dt->lock);
+	init_completion(&dt->complete);
+
+	tb_service_set_drvdata(svc, dt);
+	dma_test_debugfs_init(svc);
+
+	return 0;
+}
+
+static void dma_test_remove(struct tb_service *svc)
+{
+	struct dma_test *dt = tb_service_get_drvdata(svc);
+
+	mutex_lock(&dt->lock);
+	debugfs_remove_recursive(dt->debugfs_dir);
+	mutex_unlock(&dt->lock);
+}
+
+static int __maybe_unused dma_test_suspend(struct device *dev)
+{
+	/*
+	 * No need to do anything special here. If userspace is writing
+	 * to the test attribute when suspend started, it comes out from
+	 * wait_for_completion_interruptible() with -ERESTARTSYS and the
+	 * DMA test fails tearing down the rings. Once userspace is
+	 * thawed the kernel restarts the write syscall effectively
+	 * re-running the test.
+	 */
+	return 0;
+}
+
+static int __maybe_unused dma_test_resume(struct device *dev)
+{
+	return 0;
+}
+
+static const struct dev_pm_ops dma_test_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(dma_test_suspend, dma_test_resume)
+};
+
+static const struct tb_service_id dma_test_ids[] = {
+	{ TB_SERVICE("dma_test", 1) },
+	{ },
+};
+MODULE_DEVICE_TABLE(tbsvc, dma_test_ids);
+
+static struct tb_service_driver dma_test_driver = {
+	.driver = {
+		.owner = THIS_MODULE,
+		.name = "thunderbolt_dma_test",
+		.pm = &dma_test_pm_ops,
+	},
+	.probe = dma_test_probe,
+	.remove = dma_test_remove,
+	.id_table = dma_test_ids,
+};
+
+static int __init dma_test_init(void)
+{
+	u64 data_value = DMA_TEST_DATA_PATTERN;
+	int i, ret;
+
+	dma_test_pattern = kmalloc(DMA_TEST_FRAME_SIZE, GFP_KERNEL);
+	if (!dma_test_pattern)
+		return -ENOMEM;
+
+	for (i = 0; i <	DMA_TEST_FRAME_SIZE / sizeof(data_value); i++)
+		((u32 *)dma_test_pattern)[i] = data_value++;
+
+	dma_test_dir = tb_property_create_dir(&dma_test_dir_uuid);
+	if (!dma_test_dir) {
+		ret = -ENOMEM;
+		goto err_free_pattern;
+	}
+
+	tb_property_add_immediate(dma_test_dir, "prtcid", 1);
+	tb_property_add_immediate(dma_test_dir, "prtcvers", 1);
+	tb_property_add_immediate(dma_test_dir, "prtcrevs", 0);
+	tb_property_add_immediate(dma_test_dir, "prtcstns", 0);
+
+	ret = tb_register_property_dir("dma_test", dma_test_dir);
+	if (ret)
+		goto err_free_dir;
+
+	ret = tb_register_service_driver(&dma_test_driver);
+	if (ret)
+		goto err_unregister_dir;
+
+	return 0;
+
+err_unregister_dir:
+	tb_unregister_property_dir("dma_test", dma_test_dir);
+err_free_dir:
+	tb_property_free_dir(dma_test_dir);
+err_free_pattern:
+	kfree(dma_test_pattern);
+
+	return ret;
+}
+module_init(dma_test_init);
+
+static void __exit dma_test_exit(void)
+{
+	tb_unregister_service_driver(&dma_test_driver);
+	tb_unregister_property_dir("dma_test", dma_test_dir);
+	tb_property_free_dir(dma_test_dir);
+	kfree(dma_test_pattern);
+}
+module_exit(dma_test_exit);
+
+MODULE_AUTHOR("Isaac Hazan <isaac.hazan@intel.com>");
+MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
+MODULE_DESCRIPTION("DMA traffic test driver");
+MODULE_LICENSE("GPL v2");