diff options
Diffstat (limited to 'kernel/Documentation/filesystems/debugfs.txt')
| -rw-r--r-- | kernel/Documentation/filesystems/debugfs.txt | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/kernel/Documentation/filesystems/debugfs.txt b/kernel/Documentation/filesystems/debugfs.txt index 88ab81c79..4f45f7114 100644 --- a/kernel/Documentation/filesystems/debugfs.txt +++ b/kernel/Documentation/filesystems/debugfs.txt @@ -51,6 +51,17 @@ 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 @@ -94,12 +105,20 @@ a variable of type size_t. Boolean values can be placed in debugfs with: struct dentry *debugfs_create_bool(const char *name, umode_t mode, - struct dentry *parent, u32 *value); + struct dentry *parent, bool *value); 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 +166,27 @@ 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: |