Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

[pandora-kernel.git] / Documentation / filesystems / debugfs.txt

diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt
index 9281a95..6872c91 100644 (file)
--- a/Documentation/filesystems/debugfs.txt
+++ b/Documentation/filesystems/debugfs.txt
@@ -97,7 +97,8 @@ 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;
@@ -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,