This patch update the Documentation/filesystems/debugfs.txt
file. The main work is to add the description of the following
functions:
debugfs_create_atomic_t
debugfs_create_u32_array
debugfs_create_devm_seqfile
debugfs_create_file_size
Signed-off-by: Wang Long <long.wanglong@xxxxxxxxxx>
---
Documentation/filesystems/debugfs.txt | 41 +++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 88ab81c..b1ba8df 100644
--- a/Documentation/filesystems/debugfs.txt
+++ b/Documentation/filesystems/debugfs.txt
@@ -1,4 +1,5 @@
Copyright 2009 Jonathan Corbet <corbet@xxxxxxx>
+Updated by Wang Long <long.wanglong@xxxxxxxxxx> on 2015/07/16
Debugfs exists as a simple way for kernel developers to make information
available to user space. Unlike /proc, which is only meant for information
@@ -51,6 +52,17 @@ operations should be provided; others can be included as needed. Again,
the return value will be a dentry pointer to the created file, NULL for
error, or ERR_PTR(-ENODEV) if debugfs support is missing.
+Create a file with an initial size, the following function can be used
+instead:
+
+ struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
+ struct dentry *parent, void *data,
+ const struct file_operations *fops,
+ loff_t file_size);
+
+file_size is the initial file size. The other parameters are the same
+as the function debugfs_create_file.
+
In a number of cases, the creation of a set of file operations is not
actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
@@ -100,6 +112,14 @@ A read on the resulting file will yield either Y (for non-zero values) or
N, followed by a newline. If written to, it will accept either upper- or
lower-case values, or 1 or 0. Any other input will be silently ignored.
+Also, atomic_t values can be placed in debugfs with:
+
+ struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode,
+ struct dentry *parent, atomic_t *value)
+
+A read of this file will get atomic_t values, and a write of this file
+will set atomic_t values.
+
Another option is exporting a block of arbitrary binary data, with
this structure and function:
@@ -147,6 +167,27 @@ The "base" argument may be 0, but you may want to build the reg32 array
using __stringify, and a number of register names (macros) are actually
byte offsets over a base for the register block.
+If you want to dump an u32 array in debugfs, you can create file with:
+
+ struct dentry *debugfs_create_u32_array(const char *name, umode_t mode,
+ struct dentry *parent,
+ u32 *array, u32 elements);
+
+The "array" argument provides data, and the "elements" argument is
+the number of elements in the array. Note: Once array is created its
+size can not be changed.
+
+There is a helper function to create device related seq_file:
+
+ struct dentry *debugfs_create_devm_seqfile(struct device *dev,
+ const char *name,
+ struct dentry *parent,
+ int (*read_fn)(struct seq_file *s,
+ void *data));
+
+The "dev" argument is the device related to this debugfs file, and
+the "read_fn" is a function pointer which to be called to print the
+seq_file content.
There are a couple of other directory-oriented helper functions:
--
1.8.3.4
--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
