ASoC: SOF: Convert the generic IPC flood test into SOF client

Move the IPC flood test code out from the debug file as separate SOF client
driver.

Based on the kernel configuration, the device registration for the new IPC
flood test is going to happen in the core.
With the separate client driver it is going to be possible to run multiple
flood tests in parallel to increase the stress, the new Kconfig option can
be used to select this (defaults to 1).
In order to preserve backward compatibility with existing SW/scripts, the
first IPC flood test's debugfs files have been linked to the old files.
Signed-off-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Co-developed-by: Fred Oh <fred.oh@linux.intel.com>
Signed-off-by: Fred Oh <fred.oh@linux.intel.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
Link: https://lore.kernel.org/r/20220210150525.30756-8-peter.ujfalusi@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/Kconfig

@@ -194,13 +194,23 @@ config SND_SOC_SOF_DEBUG_ENABLE_FIRMWARE_TRACE
 	  If unsure, select "N".
 
 config SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST
-	bool "SOF enable IPC flood test"
+	tristate "SOF enable IPC flood test"
+	select SND_SOC_SOF_CLIENT
 	help
-	  This option enables the IPC flood test which can be used to flood
-	  the DSP with test IPCs and gather stats about response times.
+	  This option enables a separate client device for IPC flood test
+	  which can be used to flood the DSP with test IPCs and gather stats
+	  about response times.
 	  Say Y if you want to enable IPC flood test.
 	  If unsure, select "N".
 
+config SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST_NUM
+	int "Number of IPC flood test clients"
+	range 1 32
+	default 2
+	depends on SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST
+	help
+	  Select the number of IPC flood test clients to be created.
+
 config SND_SOC_SOF_DEBUG_IPC_MSG_INJECTOR
 	bool "SOF enable IPC message injector"
 	help

sound/soc/sof/Makefile

@@ -11,6 +11,8 @@ snd-sof-pci-objs := sof-pci-dev.o
 snd-sof-acpi-objs := sof-acpi-dev.o
 snd-sof-of-objs := sof-of-dev.o
 
+snd-sof-ipc-flood-test-objs := sof-client-ipc-flood-test.o
+
 snd-sof-nocodec-objs := nocodec.o
 
 snd-sof-utils-objs := sof-utils.o
@@ -24,6 +26,8 @@ obj-$(CONFIG_SND_SOC_SOF_ACPI_DEV) += snd-sof-acpi.o
 obj-$(CONFIG_SND_SOC_SOF_OF_DEV) += snd-sof-of.o
 obj-$(CONFIG_SND_SOC_SOF_PCI_DEV) += snd-sof-pci.o
 
+obj-$(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST) += snd-sof-ipc-flood-test.o
+
 obj-$(CONFIG_SND_SOC_SOF_INTEL_TOPLEVEL) += intel/
 obj-$(CONFIG_SND_SOC_SOF_IMX_TOPLEVEL) += imx/
 obj-$(CONFIG_SND_SOC_SOF_AMD_TOPLEVEL) += amd/

sound/soc/sof/core.c

@@ -484,3 +484,4 @@ MODULE_AUTHOR("Liam Girdwood");
 MODULE_DESCRIPTION("Sound Open Firmware (SOF) Core");
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_ALIAS("platform:sof-audio");
+MODULE_IMPORT_NS(SND_SOC_SOF_CLIENT);

sound/soc/sof/debug.c

@@ -234,107 +234,6 @@ static int snd_sof_debugfs_probe_item(struct snd_sof_dev *sdev,
 }
 #endif
 
-#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
-#define MAX_IPC_FLOOD_DURATION_MS 1000
-#define MAX_IPC_FLOOD_COUNT 10000
-#define IPC_FLOOD_TEST_RESULT_LEN 512
-
-static int sof_debug_ipc_flood_test(struct snd_sof_dev *sdev,
-				    struct snd_sof_dfsentry *dfse,
-				    bool flood_duration_test,
-				    unsigned long ipc_duration_ms,
-				    unsigned long ipc_count)
-{
-	struct sof_ipc_cmd_hdr hdr;
-	struct sof_ipc_reply reply;
-	u64 min_response_time = U64_MAX;
-	ktime_t start, end, test_end;
-	u64 avg_response_time = 0;
-	u64 max_response_time = 0;
-	u64 ipc_response_time;
-	int i = 0;
-	int ret;
-
-	/* configure test IPC */
-	hdr.cmd = SOF_IPC_GLB_TEST_MSG | SOF_IPC_TEST_IPC_FLOOD;
-	hdr.size = sizeof(hdr);
-
-	/* set test end time for duration flood test */
-	if (flood_duration_test)
-		test_end = ktime_get_ns() + ipc_duration_ms * NSEC_PER_MSEC;
-
-	/* send test IPC's */
-	while (1) {
-		start = ktime_get();
-		ret = sof_ipc_tx_message(sdev->ipc, hdr.cmd, &hdr, hdr.size,
-					 &reply, sizeof(reply));
-		end = ktime_get();
-
-		if (ret < 0)
-			break;
-
-		/* compute min and max response times */
-		ipc_response_time = ktime_to_ns(ktime_sub(end, start));
-		min_response_time = min(min_response_time, ipc_response_time);
-		max_response_time = max(max_response_time, ipc_response_time);
-
-		/* sum up response times */
-		avg_response_time += ipc_response_time;
-		i++;
-
-		/* test complete? */
-		if (flood_duration_test) {
-			if (ktime_to_ns(end) >= test_end)
-				break;
-		} else {
-			if (i == ipc_count)
-				break;
-		}
-	}
-
-	if (ret < 0)
-		dev_err(sdev->dev,
-			"error: ipc flood test failed at %d iterations\n", i);
-
-	/* return if the first IPC fails */
-	if (!i)
-		return ret;
-
-	/* compute average response time */
-	do_div(avg_response_time, i);
-
-	/* clear previous test output */
-	memset(dfse->cache_buf, 0, IPC_FLOOD_TEST_RESULT_LEN);
-
-	if (flood_duration_test) {
-		dev_dbg(sdev->dev, "IPC Flood test duration: %lums\n",
-			ipc_duration_ms);
-		snprintf(dfse->cache_buf, IPC_FLOOD_TEST_RESULT_LEN,
-			 "IPC Flood test duration: %lums\n", ipc_duration_ms);
-	}
-
-	dev_dbg(sdev->dev,
-		"IPC Flood count: %d, Avg response time: %lluns\n",
-		i, avg_response_time);
-	dev_dbg(sdev->dev, "Max response time: %lluns\n",
-		max_response_time);
-	dev_dbg(sdev->dev, "Min response time: %lluns\n",
-		min_response_time);
-
-	/* format output string */
-	snprintf(dfse->cache_buf + strlen(dfse->cache_buf),
-		 IPC_FLOOD_TEST_RESULT_LEN - strlen(dfse->cache_buf),
-		 "IPC Flood count: %d\nAvg response time: %lluns\n",
-		 i, avg_response_time);
-
-	snprintf(dfse->cache_buf + strlen(dfse->cache_buf),
-		 IPC_FLOOD_TEST_RESULT_LEN - strlen(dfse->cache_buf),
-		 "Max response time: %lluns\nMin response time: %lluns\n",
-		 max_response_time, min_response_time);
-
-	return ret;
-}
-#endif
 
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_MSG_INJECTOR)
 static ssize_t msg_inject_read(struct file *file, char __user *buffer,
@@ -437,15 +336,6 @@ static int snd_sof_debugfs_msg_inject_item(struct snd_sof_dev *sdev,
 static ssize_t sof_dfsentry_write(struct file *file, const char __user *buffer,
 				  size_t count, loff_t *ppos)
 {
-#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
-	struct snd_sof_dfsentry *dfse = file->private_data;
-	struct snd_sof_dev *sdev = dfse->sdev;
-	unsigned long ipc_duration_ms = 0;
-	bool flood_duration_test = false;
-	unsigned long ipc_count = 0;
-	struct dentry *dentry;
-	int err;
-#endif
 	size_t size;
 	char *string;
 	int ret;
@@ -457,78 +347,6 @@ static ssize_t sof_dfsentry_write(struct file *file, const char __user *buffer,
 	size = simple_write_to_buffer(string, count, ppos, buffer, count);
 	ret = size;
 
-#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
-	/*
-	 * write op is only supported for ipc_flood_count or
-	 * ipc_flood_duration_ms debugfs entries atm.
-	 * ipc_flood_count floods the DSP with the number of IPC's specified.
-	 * ipc_duration_ms test floods the DSP for the time specified
-	 * in the debugfs entry.
-	 */
-	dentry = file->f_path.dentry;
-	if (strcmp(dentry->d_name.name, "ipc_flood_count") &&
-	    strcmp(dentry->d_name.name, "ipc_flood_duration_ms")) {
-		ret = -EINVAL;
-		goto out;
-	}
-
-	if (!strcmp(dentry->d_name.name, "ipc_flood_duration_ms"))
-		flood_duration_test = true;
-
-	/* test completion criterion */
-	if (flood_duration_test)
-		ret = kstrtoul(string, 0, &ipc_duration_ms);
-	else
-		ret = kstrtoul(string, 0, &ipc_count);
-	if (ret < 0)
-		goto out;
-
-	/* limit max duration/ipc count for flood test */
-	if (flood_duration_test) {
-		if (!ipc_duration_ms) {
-			ret = size;
-			goto out;
-		}
-
-		/* find the minimum. min() is not used to avoid warnings */
-		if (ipc_duration_ms > MAX_IPC_FLOOD_DURATION_MS)
-			ipc_duration_ms = MAX_IPC_FLOOD_DURATION_MS;
-	} else {
-		if (!ipc_count) {
-			ret = size;
-			goto out;
-		}
-
-		/* find the minimum. min() is not used to avoid warnings */
-		if (ipc_count > MAX_IPC_FLOOD_COUNT)
-			ipc_count = MAX_IPC_FLOOD_COUNT;
-	}
-
-	ret = pm_runtime_get_sync(sdev->dev);
-	if (ret < 0 && ret != -EACCES) {
-		dev_err_ratelimited(sdev->dev,
-				    "error: debugfs write failed to resume %d\n",
-				    ret);
-		pm_runtime_put_noidle(sdev->dev);
-		goto out;
-	}
-
-	/* flood test */
-	ret = sof_debug_ipc_flood_test(sdev, dfse, flood_duration_test,
-				       ipc_duration_ms, ipc_count);
-
-	pm_runtime_mark_last_busy(sdev->dev);
-	err = pm_runtime_put_autosuspend(sdev->dev);
-	if (err < 0)
-		dev_err_ratelimited(sdev->dev,
-				    "error: debugfs write failed to idle %d\n",
-				    err);
-
-	/* return size if test is successful */
-	if (ret >= 0)
-		ret = size;
-out:
-#endif
 	kfree(string);
 	return ret;
 }
@@ -544,24 +362,6 @@ static ssize_t sof_dfsentry_read(struct file *file, char __user *buffer,
 	int size;
 	u8 *buf;
 
-#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
-	struct dentry *dentry;
-
-	dentry = file->f_path.dentry;
-	if ((!strcmp(dentry->d_name.name, "ipc_flood_count") ||
-	     !strcmp(dentry->d_name.name, "ipc_flood_duration_ms"))) {
-		if (*ppos)
-			return 0;
-
-		count = strlen(dfse->cache_buf);
-		size_ret = copy_to_user(buffer, dfse->cache_buf, count);
-		if (size_ret)
-			return -EFAULT;
-
-		*ppos += count;
-		return count;
-	}
-#endif
 	size = dfse->size;
 
 	/* validate position & count */
@@ -719,19 +519,6 @@ int snd_sof_debugfs_buf_item(struct snd_sof_dev *sdev,
 	dfse->size = size;
 	dfse->sdev = sdev;
 
-#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
-	if (!strncmp(name, "ipc_flood", strlen("ipc_flood"))) {
-		/*
-		 * cache_buf is unused for SOF_DFSENTRY_TYPE_BUF debugfs entries.
-		 * So, use it to save the results of the last IPC flood test.
-		 */
-		dfse->cache_buf = devm_kzalloc(sdev->dev, IPC_FLOOD_TEST_RESULT_LEN,
-					       GFP_KERNEL);
-		if (!dfse->cache_buf)
-			return -ENOMEM;
-	}
-#endif
-
 	debugfs_create_file(name, mode, sdev->debugfs_root, dfse,
 			    &sof_dfs_fops);
 	/* add to dfsentry list */
@@ -892,24 +679,6 @@ int snd_sof_dbg_init(struct snd_sof_dev *sdev)
 		return err;
 #endif
 
-#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
-	/* create read-write ipc_flood_count debugfs entry */
-	err = snd_sof_debugfs_buf_item(sdev, NULL, 0,
-				       "ipc_flood_count", 0666);
-
-	/* errors are only due to memory allocation, not debugfs */
-	if (err < 0)
-		return err;
-
-	/* create read-write ipc_flood_duration_ms debugfs entry */
-	err = snd_sof_debugfs_buf_item(sdev, NULL, 0,
-				       "ipc_flood_duration_ms", 0666);
-
-	/* errors are only due to memory allocation, not debugfs */
-	if (err < 0)
-		return err;
-#endif
-
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_MSG_INJECTOR)
 	err = snd_sof_debugfs_msg_inject_item(sdev, "ipc_msg_inject", 0644,
 					      &msg_inject_fops);

sound/soc/sof/sof-client-ipc-flood-test.c

+// SPDX-License-Identifier: GPL-2.0-only
+//
+// Copyright(c) 2022 Intel Corporation. All rights reserved.
+//
+// Authors: Ranjani Sridharan <ranjani.sridharan@linux.intel.com>
+//	    Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
+//
+
+#include <linux/auxiliary_bus.h>
+#include <linux/completion.h>
+#include <linux/debugfs.h>
+#include <linux/ktime.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <sound/sof/header.h>
+
+#include "sof-client.h"
+
+#define MAX_IPC_FLOOD_DURATION_MS	1000
+#define MAX_IPC_FLOOD_COUNT		10000
+#define IPC_FLOOD_TEST_RESULT_LEN	512
+#define SOF_IPC_CLIENT_SUSPEND_DELAY_MS	3000
+
+#define DEBUGFS_IPC_FLOOD_COUNT		"ipc_flood_count"
+#define DEBUGFS_IPC_FLOOD_DURATION	"ipc_flood_duration_ms"
+
+struct sof_ipc_flood_priv {
+	struct dentry *dfs_root;
+	struct dentry *dfs_link[2];
+	char *buf;
+};
+
+static int sof_ipc_flood_dfs_open(struct inode *inode, struct file *file)
+{
+	struct sof_client_dev *cdev = inode->i_private;
+	int ret;
+
+	if (sof_client_get_fw_state(cdev) == SOF_FW_CRASHED)
+		return -ENODEV;
+
+	ret = debugfs_file_get(file->f_path.dentry);
+	if (unlikely(ret))
+		return ret;
+
+	ret = simple_open(inode, file);
+	if (ret)
+		debugfs_file_put(file->f_path.dentry);
+
+	return ret;
+}
+
+/*
+ * helper function to perform the flood test. Only one of the two params, ipc_duration_ms
+ * or ipc_count, will be non-zero and will determine the type of test
+ */
+static int sof_debug_ipc_flood_test(struct sof_client_dev *cdev,
+				    bool flood_duration_test,
+				    unsigned long ipc_duration_ms,
+				    unsigned long ipc_count)
+{
+	struct sof_ipc_flood_priv *priv = cdev->data;
+	struct device *dev = &cdev->auxdev.dev;
+	struct sof_ipc_cmd_hdr hdr;
+	struct sof_ipc_reply reply;
+	u64 min_response_time = U64_MAX;
+	ktime_t start, end, test_end;
+	u64 avg_response_time = 0;
+	u64 max_response_time = 0;
+	u64 ipc_response_time;
+	int i = 0;
+	int ret;
+
+	/* configure test IPC */
+	hdr.cmd = SOF_IPC_GLB_TEST_MSG | SOF_IPC_TEST_IPC_FLOOD;
+	hdr.size = sizeof(hdr);
+
+	/* set test end time for duration flood test */
+	if (flood_duration_test)
+		test_end = ktime_get_ns() + ipc_duration_ms * NSEC_PER_MSEC;
+
+	/* send test IPC's */
+	while (1) {
+		start = ktime_get();
+		ret = sof_client_ipc_tx_message(cdev, &hdr, &reply, sizeof(reply));
+		end = ktime_get();
+
+		if (ret < 0)
+			break;
+
+		/* compute min and max response times */
+		ipc_response_time = ktime_to_ns(ktime_sub(end, start));
+		min_response_time = min(min_response_time, ipc_response_time);
+		max_response_time = max(max_response_time, ipc_response_time);
+
+		/* sum up response times */
+		avg_response_time += ipc_response_time;
+		i++;
+
+		/* test complete? */
+		if (flood_duration_test) {
+			if (ktime_to_ns(end) >= test_end)
+				break;
+		} else {
+			if (i == ipc_count)
+				break;
+		}
+	}
+
+	if (ret < 0)
+		dev_err(dev, "ipc flood test failed at %d iterations\n", i);
+
+	/* return if the first IPC fails */
+	if (!i)
+		return ret;
+
+	/* compute average response time */
+	do_div(avg_response_time, i);
+
+	/* clear previous test output */
+	memset(priv->buf, 0, IPC_FLOOD_TEST_RESULT_LEN);
+
+	if (!ipc_count) {
+		dev_dbg(dev, "IPC Flood test duration: %lums\n", ipc_duration_ms);
+		snprintf(priv->buf, IPC_FLOOD_TEST_RESULT_LEN,
+			 "IPC Flood test duration: %lums\n", ipc_duration_ms);
+	}
+
+	dev_dbg(dev, "IPC Flood count: %d, Avg response time: %lluns\n",
+		i, avg_response_time);
+	dev_dbg(dev, "Max response time: %lluns\n", max_response_time);
+	dev_dbg(dev, "Min response time: %lluns\n", min_response_time);
+
+	/* format output string and save test results */
+	snprintf(priv->buf + strlen(priv->buf),
+		 IPC_FLOOD_TEST_RESULT_LEN - strlen(priv->buf),
+		 "IPC Flood count: %d\nAvg response time: %lluns\n",
+		 i, avg_response_time);
+
+	snprintf(priv->buf + strlen(priv->buf),
+		 IPC_FLOOD_TEST_RESULT_LEN - strlen(priv->buf),
+		 "Max response time: %lluns\nMin response time: %lluns\n",
+		 max_response_time, min_response_time);
+
+	return ret;
+}
+
+/*
+ * Writing to the debugfs entry initiates the IPC flood test based on
+ * the IPC count or the duration specified by the user.
+ */
+static ssize_t sof_ipc_flood_dfs_write(struct file *file, const char __user *buffer,
+				       size_t count, loff_t *ppos)
+{
+	struct sof_client_dev *cdev = file->private_data;
+	struct device *dev = &cdev->auxdev.dev;
+	unsigned long ipc_duration_ms = 0;
+	bool flood_duration_test = false;
+	unsigned long ipc_count = 0;
+	struct dentry *dentry;
+	int err;
+	size_t size;
+	char *string;
+	int ret;
+
+	string = kzalloc(count + 1, GFP_KERNEL);
+	if (!string)
+		return -ENOMEM;
+
+	size = simple_write_to_buffer(string, count, ppos, buffer, count);
+
+	/*
+	 * write op is only supported for ipc_flood_count or
+	 * ipc_flood_duration_ms debugfs entries atm.
+	 * ipc_flood_count floods the DSP with the number of IPC's specified.
+	 * ipc_duration_ms test floods the DSP for the time specified
+	 * in the debugfs entry.
+	 */
+	dentry = file->f_path.dentry;
+	if (strcmp(dentry->d_name.name, DEBUGFS_IPC_FLOOD_COUNT) &&
+	    strcmp(dentry->d_name.name, DEBUGFS_IPC_FLOOD_DURATION)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (!strcmp(dentry->d_name.name, DEBUGFS_IPC_FLOOD_DURATION))
+		flood_duration_test = true;
+
+	/* test completion criterion */
+	if (flood_duration_test)
+		ret = kstrtoul(string, 0, &ipc_duration_ms);
+	else
+		ret = kstrtoul(string, 0, &ipc_count);
+	if (ret < 0)
+		goto out;
+
+	/* limit max duration/ipc count for flood test */
+	if (flood_duration_test) {
+		if (!ipc_duration_ms) {
+			ret = size;
+			goto out;
+		}
+
+		/* find the minimum. min() is not used to avoid warnings */
+		if (ipc_duration_ms > MAX_IPC_FLOOD_DURATION_MS)
+			ipc_duration_ms = MAX_IPC_FLOOD_DURATION_MS;
+	} else {
+		if (!ipc_count) {
+			ret = size;
+			goto out;
+		}
+
+		/* find the minimum. min() is not used to avoid warnings */
+		if (ipc_count > MAX_IPC_FLOOD_COUNT)
+			ipc_count = MAX_IPC_FLOOD_COUNT;
+	}
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0 && ret != -EACCES) {
+		dev_err_ratelimited(dev, "debugfs write failed to resume %d\n", ret);
+		pm_runtime_put_noidle(dev);
+		goto out;
+	}
+
+	/* flood test */
+	ret = sof_debug_ipc_flood_test(cdev, flood_duration_test,
+				       ipc_duration_ms, ipc_count);
+
+	pm_runtime_mark_last_busy(dev);
+	err = pm_runtime_put_autosuspend(dev);
+	if (err < 0)
+		dev_err_ratelimited(dev, "debugfs write failed to idle %d\n", err);
+
+	/* return size if test is successful */
+	if (ret >= 0)
+		ret = size;
+out:
+	kfree(string);
+	return ret;
+}
+
+/* return the result of the last IPC flood test */
+static ssize_t sof_ipc_flood_dfs_read(struct file *file, char __user *buffer,
+				      size_t count, loff_t *ppos)
+{
+	struct sof_client_dev *cdev = file->private_data;
+	struct sof_ipc_flood_priv *priv = cdev->data;
+	size_t size_ret;
+
+	struct dentry *dentry;
+
+	dentry = file->f_path.dentry;
+	if (!strcmp(dentry->d_name.name, DEBUGFS_IPC_FLOOD_COUNT) ||
+	    !strcmp(dentry->d_name.name, DEBUGFS_IPC_FLOOD_DURATION)) {
+		if (*ppos)
+			return 0;
+
+		count = min_t(size_t, count, strlen(priv->buf));
+		size_ret = copy_to_user(buffer, priv->buf, count);
+		if (size_ret)
+			return -EFAULT;
+
+		*ppos += count;
+		return count;
+	}
+	return count;
+}
+
+static int sof_ipc_flood_dfs_release(struct inode *inode, struct file *file)
+{
+	debugfs_file_put(file->f_path.dentry);
+
+	return 0;
+}
+
+static const struct file_operations sof_ipc_flood_fops = {
+	.open = sof_ipc_flood_dfs_open,
+	.read = sof_ipc_flood_dfs_read,
+	.llseek = default_llseek,
+	.write = sof_ipc_flood_dfs_write,
+	.release = sof_ipc_flood_dfs_release,
+
+	.owner = THIS_MODULE,
+};
+
+/*
+ * The IPC test client creates a couple of debugfs entries that will be used
+ * flood tests. Users can write to these entries to execute the IPC flood test
+ * by specifying either the number of IPCs to flood the DSP with or the duration
+ * (in ms) for which the DSP should be flooded with test IPCs. At the
+ * end of each test, the average, min and max response times are reported back.
+ * The results of the last flood test can be accessed by reading the debugfs
+ * entries.
+ */
+static int sof_ipc_flood_probe(struct auxiliary_device *auxdev,
+			       const struct auxiliary_device_id *id)
+{
+	struct sof_client_dev *cdev = auxiliary_dev_to_sof_client_dev(auxdev);
+	struct dentry *debugfs_root = sof_client_get_debugfs_root(cdev);
+	struct device *dev = &auxdev->dev;
+	struct sof_ipc_flood_priv *priv;
+
+	/* allocate memory for client data */
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->buf = devm_kmalloc(dev, IPC_FLOOD_TEST_RESULT_LEN, GFP_KERNEL);
+	if (!priv->buf)
+		return -ENOMEM;
+
+	cdev->data = priv;
+
+	/* create debugfs root folder with device name under parent SOF dir */
+	priv->dfs_root = debugfs_create_dir(dev_name(dev), debugfs_root);
+	if (!IS_ERR_OR_NULL(priv->dfs_root)) {
+		/* create read-write ipc_flood_count debugfs entry */
+		debugfs_create_file(DEBUGFS_IPC_FLOOD_COUNT, 0644, priv->dfs_root,
+				    cdev, &sof_ipc_flood_fops);
+
+		/* create read-write ipc_flood_duration_ms debugfs entry */
+		debugfs_create_file(DEBUGFS_IPC_FLOOD_DURATION, 0644,
+				    priv->dfs_root, cdev, &sof_ipc_flood_fops);
+
+		if (auxdev->id == 0) {
+			/*
+			 * Create symlinks for backwards compatibility to the
+			 * first IPC flood test instance
+			 */
+			char target[100];
+
+			snprintf(target, 100, "%s/" DEBUGFS_IPC_FLOOD_COUNT,
+				 dev_name(dev));
+			priv->dfs_link[0] =
+				debugfs_create_symlink(DEBUGFS_IPC_FLOOD_COUNT,
+						       debugfs_root, target);
+
+			snprintf(target, 100, "%s/" DEBUGFS_IPC_FLOOD_DURATION,
+				 dev_name(dev));
+			priv->dfs_link[1] =
+				debugfs_create_symlink(DEBUGFS_IPC_FLOOD_DURATION,
+						       debugfs_root, target);
+		}
+	}
+
+	/* enable runtime PM */
+	pm_runtime_set_autosuspend_delay(dev, SOF_IPC_CLIENT_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_idle(dev);
+
+	return 0;
+}
+
+static void sof_ipc_flood_remove(struct auxiliary_device *auxdev)
+{
+	struct sof_client_dev *cdev = auxiliary_dev_to_sof_client_dev(auxdev);
+	struct sof_ipc_flood_priv *priv = cdev->data;
+
+	pm_runtime_disable(&auxdev->dev);
+
+	if (auxdev->id == 0) {
+		debugfs_remove(priv->dfs_link[0]);
+		debugfs_remove(priv->dfs_link[1]);
+	}
+
+	debugfs_remove_recursive(priv->dfs_root);
+}
+
+static const struct auxiliary_device_id sof_ipc_flood_client_id_table[] = {
+	{ .name = "snd_sof.ipc_flood" },
+	{},
+};
+MODULE_DEVICE_TABLE(auxiliary, sof_ipc_flood_client_id_table);
+
+/*
+ * No need for driver pm_ops as the generic pm callbacks in the auxiliary bus
+ * type are enough to ensure that the parent SOF device resumes to bring the DSP
+ * back to D0.
+ * Driver name will be set based on KBUILD_MODNAME.
+ */
+static struct auxiliary_driver sof_ipc_flood_client_drv = {
+	.probe = sof_ipc_flood_probe,
+	.remove = sof_ipc_flood_remove,
+
+	.id_table = sof_ipc_flood_client_id_table,
+};
+
+module_auxiliary_driver(sof_ipc_flood_client_drv);
+
+MODULE_DESCRIPTION("SOF IPC Flood Test Client Driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(SND_SOC_SOF_CLIENT);

sound/soc/sof/sof-client.c

@@ -66,18 +66,70 @@ static int sof_client_dev_add_data(struct sof_client_dev *cdev, const void *data
 	return 0;
 }
 
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST)
+static int sof_register_ipc_flood_test(struct snd_sof_dev *sdev)
+{
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST_NUM; i++) {
+		ret = sof_client_dev_register(sdev, "ipc_flood", i, NULL, 0);
+		if (ret < 0)
+			break;
+	}
+
+	if (ret) {
+		for (; i >= 0; --i)
+			sof_client_dev_unregister(sdev, "ipc_flood", i);
+	}
+
+	return ret;
+}
+
+static void sof_unregister_ipc_flood_test(struct snd_sof_dev *sdev)
+{
+	int i;
+
+	for (i = 0; i < CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST_NUM; i++)
+		sof_client_dev_unregister(sdev, "ipc_flood", i);
+}
+#else
+static inline int sof_register_ipc_flood_test(struct snd_sof_dev *sdev)
+{
+	return 0;
+}
+
+static inline void sof_unregister_ipc_flood_test(struct snd_sof_dev *sdev) {}
+#endif /* CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST */
+
 int sof_register_clients(struct snd_sof_dev *sdev)
 {
+	int ret;
+
+	/* Register platform independent client devices */
+	ret = sof_register_ipc_flood_test(sdev);
+	if (ret) {
+		dev_err(sdev->dev, "IPC flood test client registration failed\n");
+		return ret;
+	}
+
+	/* Platform depndent client device registration */
+
 	if (sof_ops(sdev) && sof_ops(sdev)->register_ipc_clients)
-		return sof_ops(sdev)->register_ipc_clients(sdev);
+		ret = sof_ops(sdev)->register_ipc_clients(sdev);
 
-	return 0;
+	if (ret)
+		sof_unregister_ipc_flood_test(sdev);
+
+	return ret;
 }
 
 void sof_unregister_clients(struct snd_sof_dev *sdev)
 {
 	if (sof_ops(sdev) && sof_ops(sdev)->unregister_ipc_clients)
 		sof_ops(sdev)->unregister_ipc_clients(sdev);
+
+	sof_unregister_ipc_flood_test(sdev);
 }
 
 int sof_client_dev_register(struct snd_sof_dev *sdev, const char *name, u32 id,

sound/soc/sof/sof-priv.h

@@ -69,10 +69,6 @@ bool sof_debug_check_flag(int mask);
 #define SOF_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S24_LE | \
 	SNDRV_PCM_FMTBIT_S32_LE | SNDRV_PCM_FMTBIT_FLOAT)
 
-#define ENABLE_DEBUGFS_CACHEBUF \
-	(IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE) || \
-	 IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST))
-
 /* So far the primary core on all DSPs has ID 0 */
 #define SOF_DSP_PRIMARY_CORE 0
 
@@ -326,7 +322,7 @@ struct snd_sof_dfsentry {
 	 * or if it is accessible only when the DSP is in D0.
 	 */
 	enum sof_debugfs_access_type access_type;
-#if ENABLE_DEBUGFS_CACHEBUF
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE)
 	char *cache_buf; /* buffer to cache the contents of debugfs memory */
 #endif
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG_IPC_MSG_INJECTOR)