diff options
| -rw-r--r-- | Documentation/filesystems/debugfs.txt | 32 | ||||
| -rw-r--r-- | fs/debugfs/file.c | 90 | ||||
| -rw-r--r-- | include/linux/debugfs.h | 26 |
3 files changed, 147 insertions, 1 deletions
diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt index 742cc06e138f..f04066a37f4c 100644 --- 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, diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index 90f76575c056..f31a27c60fc6 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -15,6 +15,7 @@ #include <linux/module.h> #include <linux/fs.h> +#include <linux/seq_file.h> #include <linux/pagemap.h> #include <linux/namei.h> #include <linux/debugfs.h> @@ -525,3 +526,92 @@ struct dentry *debugfs_create_blob(const char *name, mode_t mode, return debugfs_create_file(name, mode, parent, blob, &fops_blob); } EXPORT_SYMBOL_GPL(debugfs_create_blob); + +/* + * The regset32 stuff is used to print 32-bit registers using the + * seq_file utilities. We offer printing a register set in an already-opened + * sequential file or create a debugfs file that only prints a regset32. + */ + +/** + * debugfs_print_regs32 - use seq_print to describe a set of registers + * @s: the seq_file structure being used to generate output + * @regs: an array if struct debugfs_reg32 structures + * @mregs: the length of the above array + * @base: the base address to be used in reading the registers + * @prefix: a string to be prefixed to every output line + * + * This function outputs a text block describing the current values of + * some 32-bit hardware registers. It is meant to be used within debugfs + * files based on seq_file that need to show registers, intermixed with other + * information. The prefix argument may be used to specify a leading string, + * because some peripherals have several blocks of identical registers, + * for example configuration of dma channels + */ +int debugfs_print_regs32(struct seq_file *s, struct debugfs_reg32 *regs, + int nregs, void __iomem *base, char *prefix) +{ + int i, ret = 0; + + for (i = 0; i < nregs; i++, regs++) { + if (prefix) + ret += seq_printf(s, "%s", prefix); + ret += seq_printf(s, "%s = 0x%08x\n", regs->name, + readl((void *)(base + regs->offset))); + } + return ret; +} +EXPORT_SYMBOL_GPL(debugfs_print_regs32); + +static int debugfs_show_regset32(struct seq_file *s, void *data) +{ + struct debugfs_regset32 *regset = s->private; + + debugfs_print_regs32(s, regset->regs, regset->nregs, regset->base, ""); + return 0; +} + +static int debugfs_open_regset32(struct inode *inode, struct file *file) +{ + return single_open(file, debugfs_show_regset32, inode->i_private); +} + +static const struct file_operations fops_regset32 = { + .open = debugfs_open_regset32, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/** + * debugfs_create_regset32 - create a debugfs file that returns register values + * @name: a pointer to a string containing the name of the file to create. + * @mode: the permission that the file should have + * @parent: a pointer to the parent dentry for this file. This should be a + * directory dentry if set. If this parameter is %NULL, then the + * file will be created in the root of the debugfs filesystem. + * @regset: a pointer to a struct debugfs_regset32, which contains a pointer + * to an array of register definitions, the array size and the base + * address where the register bank is to be found. + * + * This function creates a file in debugfs with the given name that reports + * the names and values of a set of 32-bit registers. If the @mode variable + * is so set it can be read from. Writing is not supported. + * + * This function will return a pointer to a dentry if it succeeds. This + * pointer must be passed to the debugfs_remove() function when the file is + * to be removed (no automatic cleanup happens if your module is unloaded, + * you are responsible here.) If an error occurs, %NULL will be returned. + * + * If debugfs is not enabled in the kernel, the value -%ENODEV will be + * returned. It is not wise to check for this value, but rather, check for + * %NULL or !%NULL instead as to eliminate the need for #ifdef in the calling + * code. + */ +struct dentry *debugfs_create_regset32(const char *name, mode_t mode, + struct dentry *parent, + struct debugfs_regset32 *regset) +{ + return debugfs_create_file(name, mode, parent, regset, &fops_regset32); +} +EXPORT_SYMBOL_GPL(debugfs_create_regset32); diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h index e7d9b20ddc5b..5e6b01f6db4c 100644 --- a/include/linux/debugfs.h +++ b/include/linux/debugfs.h @@ -16,6 +16,7 @@ #define _DEBUGFS_H_ #include <linux/fs.h> +#include <linux/seq_file.h> #include <linux/types.h> @@ -26,6 +27,17 @@ struct debugfs_blob_wrapper { unsigned long size; }; +struct debugfs_reg32 { + char *name; + unsigned long offset; +}; + +struct debugfs_regset32 { + struct debugfs_reg32 *regs; + int nregs; + void __iomem *base; +}; + extern struct dentry *arch_debugfs_dir; #if defined(CONFIG_DEBUG_FS) @@ -74,6 +86,13 @@ struct dentry *debugfs_create_blob(const char *name, mode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob); +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); + bool debugfs_initialized(void); #else @@ -188,6 +207,13 @@ static inline struct dentry *debugfs_create_blob(const char *name, mode_t mode, return ERR_PTR(-ENODEV); } +static inline struct dentry *debugfs_create_regset32(const char *name, + mode_t mode, struct dentry *parent, + struct debugfs_regset32 *regset) +{ + return ERR_PTR(-ENODEV); +} + static inline bool debugfs_initialized(void) { return false; |