1 files changed, 43 insertions, 13 deletions

diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 742cc06e138f..6872c91bce35 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,