[alsa-devel] [PATCH v2 03/12] ASoC: SOF: Add driver debug support.

[Liam Girdwood]

Add debugFS files that can be used to expose DSP memories and
and peripherals to userspace to assist with firmware debugging.

Signed-off-by: Liam Girdwood <liam.r.girdwood at linux.intel.com>
---
 sound/soc/sof/debug.c | 157 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 157 insertions(+)
 create mode 100644 sound/soc/sof/debug.c

diff --git a/sound/soc/sof/debug.c b/sound/soc/sof/debug.c
new file mode 100644
index 000000000000..67c195573d79
--- /dev/null
+++ b/sound/soc/sof/debug.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation. All rights reserved.
+//
+// Author: Liam Girdwood <liam.r.girdwood at linux.intel.com>
+//         Yan Wang <yan.wan at linux.intel.com>
+//
+// Generic debug routines used to export DSP MMIO and memories to userspace
+// for firmware debugging.
+//
+
+#include <linux/delay.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <uapi/sound/sof-ipc.h>
+#include "sof-priv.h"
+#include "ops.h"
+
+static int sof_dfsentry_open(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+
+	return 0;
+}
+
+static ssize_t sof_dfsentry_read(struct file *file, char __user *buffer,
+				 size_t count, loff_t *ppos)
+{
+	struct snd_sof_dfsentry_io *dfse = file->private_data;
+	struct snd_sof_dev *sdev = dfse->sdev;
+	int size, err;
+	u32 *buf;
+	loff_t pos = *ppos;
+	size_t ret;
+
+	size = dfse->size;
+
+	/* validate position & count */
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= size || !count)
+		return 0;
+	if (count > size - pos)
+		count = size - pos;
+
+	/* intermediate buffer size must be u32 multiple */
+	size = (count + 3) & ~3;
+	buf = kzalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* copy from DSP MMIO */
+	err = pm_runtime_get_sync(sdev->dev);
+	if (err < 0) {
+		dev_err(sdev->dev, "error: debugFS failed to resume %d\n",
+			err);
+		return err;
+	}
+
+	memcpy_fromio(buf,  dfse->buf + pos, size);
+
+	ret = pm_runtime_put(sdev->dev);
+	if (ret < 0)
+		dev_err(sdev->dev, "error: debugFS failed to idle %zd\n",
+			ret);
+
+	/* copy to userspace */
+	ret = copy_to_user(buffer, buf, count);
+	kfree(buf);
+
+	/* update count & position if copy succeeded */
+	if (ret == count)
+		return -EFAULT;
+	count -= ret;
+	*ppos = pos + count;
+
+	return count;
+}
+
+static const struct file_operations sof_dfs_fops = {
+	.open = sof_dfsentry_open,
+	.read = sof_dfsentry_read,
+	.llseek = default_llseek,
+};
+
+int snd_sof_debugfs_create_item(struct snd_sof_dev *sdev,
+				void __iomem *base, size_t size,
+				const char *name)
+{
+	struct snd_sof_dfsentry_io *dfse;
+
+	if (!sdev)
+		return -EINVAL;
+
+	dfse = kzalloc(sizeof(*dfse), GFP_KERNEL);
+	if (!dfse)
+		return -ENOMEM;
+
+	dfse->buf = base;
+	dfse->size = size;
+	dfse->sdev = sdev;
+
+	dfse->dfsentry = debugfs_create_file(name, 0444, sdev->debugfs_root,
+					     dfse, &sof_dfs_fops);
+	if (!dfse->dfsentry) {
+		dev_err(sdev->dev, "cannot create debugfs entry.\n");
+		kfree(dfse);
+		return -ENODEV;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(snd_sof_debugfs_create_item);
+
+int snd_sof_dbg_init(struct snd_sof_dev *sdev)
+{
+	const struct snd_sof_dsp_ops *ops = sdev->ops;
+	const struct snd_sof_debugfs_map *map;
+	int err = 0, i;
+
+	/* use "sof" as top level debugFS dir */
+	sdev->debugfs_root = debugfs_create_dir("sof", NULL);
+	if (IS_ERR_OR_NULL(sdev->debugfs_root)) {
+		dev_err(sdev->dev, "error: failed to create debugfs directory\n");
+		return -EINVAL;
+	}
+
+	/* create debugFS files for platform specific MMIO/DSP memories */
+	for (i = 0; i < ops->debug_map_count; i++) {
+		map = &ops->debug_map[i];
+
+		err = snd_sof_debugfs_create_item(sdev, sdev->bar[map->bar] +
+						  map->offset, map->size,
+						  map->name);
+		if (err < 0)
+			dev_err(sdev->dev, "cannot create debugfs for %s\n",
+				map->name);
+	}
+
+	return err;
+}
+EXPORT_SYMBOL(snd_sof_dbg_init);
+
+void snd_sof_free_debug(struct snd_sof_dev *sdev)
+{
+	debugfs_remove_recursive(sdev->debugfs_root);
+}
+EXPORT_SYMBOL(snd_sof_free_debug);
-- 
2.17.1