aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/filesystems/debugfs.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/filesystems/debugfs.txt')
-rw-r--r--Documentation/filesystems/debugfs.txt56
1 files changed, 43 insertions, 13 deletions
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 742cc06e138..6872c91bce3 100644
--- a/Documentation/filesystems/debugfs.txt
+++ b/Documentation/filesystems/debugfs.txt
@@ -35,7 +35,7 @@ described below will work.
The most general way to create a file within a debugfs directory is with:
- struct dentry *debugfs_create_file(const char *name, mode_t mode,
+ struct dentry *debugfs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);
@@ -53,13 +53,13 @@ actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
created with any of:
- struct dentry *debugfs_create_u8(const char *name, mode_t mode,
+ struct dentry *debugfs_create_u8(const char *name, umode_t mode,
struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_u16(const char *name, mode_t mode,
+ struct dentry *debugfs_create_u16(const char *name, umode_t mode,
struct dentry *parent, u16 *value);
- struct dentry *debugfs_create_u32(const char *name, mode_t mode,
+ struct dentry *debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_u64(const char *name, mode_t mode,
+ struct dentry *debugfs_create_u64(const char *name, umode_t mode,
struct dentry *parent, u64 *value);
These files support both reading and writing the given value; if a specific
@@ -67,13 +67,13 @@ file should not be written to, simply set the mode bits accordingly. The
values in these files are in decimal; if hexadecimal is more appropriate,
the following functions can be used instead:
- struct dentry *debugfs_create_x8(const char *name, mode_t mode,
+ struct dentry *debugfs_create_x8(const char *name, umode_t mode,
struct dentry *parent, u8 *value);
- struct dentry *debugfs_create_x16(const char *name, mode_t mode,
+ struct dentry *debugfs_create_x16(const char *name, umode_t mode,
struct dentry *parent, u16 *value);
- struct dentry *debugfs_create_x32(const char *name, mode_t mode,
+ struct dentry *debugfs_create_x32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
- struct dentry *debugfs_create_x64(const char *name, mode_t mode,
+ struct dentry *debugfs_create_x64(const char *name, umode_t mode,
struct dentry *parent, u64 *value);
These functions are useful as long as the developer knows the size of the
@@ -81,7 +81,7 @@ value to be exported. Some types can have different widths on different
architectures, though, complicating the situation somewhat. There is a
function meant to help out in one special case:
- struct dentry *debugfs_create_size_t(const char *name, mode_t mode,
+ struct dentry *debugfs_create_size_t(const char *name, umode_t mode,
struct dentry *parent,
size_t *value);
@@ -90,21 +90,22 @@ a variable of type size_t.
Boolean values can be placed in debugfs with:
- struct dentry *debugfs_create_bool(const char *name, mode_t mode,
+ struct dentry *debugfs_create_bool(const char *name, umode_t mode,
struct dentry *parent, u32 *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.
-Finally, a block of arbitrary binary data can be exported with:
+Another option is exporting a block of arbitrary binary data, with
+this structure and function:
struct debugfs_blob_wrapper {
void *data;
unsigned long size;
};
- struct dentry *debugfs_create_blob(const char *name, mode_t mode,
+ struct dentry *debugfs_create_blob(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_blob_wrapper *blob);
@@ -115,6 +116,35 @@ can be used to export binary information, but there does not appear to be
any code which does so in the mainline. Note that all files created with
debugfs_create_blob() are read-only.
+If you want to dump a block of registers (something that happens quite
+often during development, even if little such code reaches mainline.
+Debugfs offers two functions: one to make a registers-only file, and
+another to insert a register block in the middle of another sequential
+file.
+
+ struct debugfs_reg32 {
+ char *name;
+ unsigned long offset;
+ };
+
+ struct debugfs_regset32 {
+ struct debugfs_reg32 *regs;
+ int nregs;
+ void __iomem *base;
+ };
+
+ struct dentry *debugfs_create_regset32(const char *name, mode_t mode,
+ struct dentry *parent,
+ struct debugfs_regset32 *regset);
+
+ int debugfs_print_regs32(struct seq_file *s, struct debugfs_reg32 *regs,
+ int nregs, void __iomem *base, char *prefix);
+
+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.
+
+
There are a couple of other directory-oriented helper functions:
struct dentry *debugfs_rename(struct dentry *old_dir,