linux/drivers/base/regmap/regmap-debugfs.c
Cristian Birsan 359a2f1760 regmap: debugfs: Add support for dumping write only device registers
Add support for dumping write only device registers in debugfs. This is
useful for audio codecs that have write only registers (like WM8731).
The logic that decides if a value can be printed is moved to
regmap_printable() function to allow for easier future updates.

Signed-off-by: Cristian Birsan <cristian.birsan@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2016-08-09 13:43:33 +01:00

654 lines
16 KiB
C

/*
* Register map access API - debugfs
*
* Copyright 2011 Wolfson Microelectronics plc
*
* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/device.h>
#include <linux/list.h>
#include "internal.h"
struct regmap_debugfs_node {
struct regmap *map;
const char *name;
struct list_head link;
};
static struct dentry *regmap_debugfs_root;
static LIST_HEAD(regmap_debugfs_early_list);
static DEFINE_MUTEX(regmap_debugfs_early_lock);
/* Calculate the length of a fixed format */
static size_t regmap_calc_reg_len(int max_val)
{
return snprintf(NULL, 0, "%x", max_val);
}
static ssize_t regmap_name_read_file(struct file *file,
char __user *user_buf, size_t count,
loff_t *ppos)
{
struct regmap *map = file->private_data;
int ret;
char *buf;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
return -ENOMEM;
ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
if (ret < 0) {
kfree(buf);
return ret;
}
ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
kfree(buf);
return ret;
}
static const struct file_operations regmap_name_fops = {
.open = simple_open,
.read = regmap_name_read_file,
.llseek = default_llseek,
};
static void regmap_debugfs_free_dump_cache(struct regmap *map)
{
struct regmap_debugfs_off_cache *c;
while (!list_empty(&map->debugfs_off_cache)) {
c = list_first_entry(&map->debugfs_off_cache,
struct regmap_debugfs_off_cache,
list);
list_del(&c->list);
kfree(c);
}
}
static bool regmap_printable(struct regmap *map, unsigned int reg)
{
if (regmap_precious(map, reg))
return false;
if (!regmap_readable(map, reg) && !regmap_cached(map, reg))
return false;
return true;
}
/*
* Work out where the start offset maps into register numbers, bearing
* in mind that we suppress hidden registers.
*/
static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
unsigned int base,
loff_t from,
loff_t *pos)
{
struct regmap_debugfs_off_cache *c = NULL;
loff_t p = 0;
unsigned int i, ret;
unsigned int fpos_offset;
unsigned int reg_offset;
/* Suppress the cache if we're using a subrange */
if (base)
return base;
/*
* If we don't have a cache build one so we don't have to do a
* linear scan each time.
*/
mutex_lock(&map->cache_lock);
i = base;
if (list_empty(&map->debugfs_off_cache)) {
for (; i <= map->max_register; i += map->reg_stride) {
/* Skip unprinted registers, closing off cache entry */
if (!regmap_printable(map, i)) {
if (c) {
c->max = p - 1;
c->max_reg = i - map->reg_stride;
list_add_tail(&c->list,
&map->debugfs_off_cache);
c = NULL;
}
continue;
}
/* No cache entry? Start a new one */
if (!c) {
c = kzalloc(sizeof(*c), GFP_KERNEL);
if (!c) {
regmap_debugfs_free_dump_cache(map);
mutex_unlock(&map->cache_lock);
return base;
}
c->min = p;
c->base_reg = i;
}
p += map->debugfs_tot_len;
}
}
/* Close the last entry off if we didn't scan beyond it */
if (c) {
c->max = p - 1;
c->max_reg = i - map->reg_stride;
list_add_tail(&c->list,
&map->debugfs_off_cache);
}
/*
* This should never happen; we return above if we fail to
* allocate and we should never be in this code if there are
* no registers at all.
*/
WARN_ON(list_empty(&map->debugfs_off_cache));
ret = base;
/* Find the relevant block:offset */
list_for_each_entry(c, &map->debugfs_off_cache, list) {
if (from >= c->min && from <= c->max) {
fpos_offset = from - c->min;
reg_offset = fpos_offset / map->debugfs_tot_len;
*pos = c->min + (reg_offset * map->debugfs_tot_len);
mutex_unlock(&map->cache_lock);
return c->base_reg + (reg_offset * map->reg_stride);
}
*pos = c->max;
ret = c->max_reg;
}
mutex_unlock(&map->cache_lock);
return ret;
}
static inline void regmap_calc_tot_len(struct regmap *map,
void *buf, size_t count)
{
/* Calculate the length of a fixed format */
if (!map->debugfs_tot_len) {
map->debugfs_reg_len = regmap_calc_reg_len(map->max_register),
map->debugfs_val_len = 2 * map->format.val_bytes;
map->debugfs_tot_len = map->debugfs_reg_len +
map->debugfs_val_len + 3; /* : \n */
}
}
static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
unsigned int to, char __user *user_buf,
size_t count, loff_t *ppos)
{
size_t buf_pos = 0;
loff_t p = *ppos;
ssize_t ret;
int i;
char *buf;
unsigned int val, start_reg;
if (*ppos < 0 || !count)
return -EINVAL;
buf = kmalloc(count, GFP_KERNEL);
if (!buf)
return -ENOMEM;
regmap_calc_tot_len(map, buf, count);
/* Work out which register we're starting at */
start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);
for (i = start_reg; i <= to; i += map->reg_stride) {
if (!regmap_readable(map, i) && !regmap_cached(map, i))
continue;
if (regmap_precious(map, i))
continue;
/* If we're in the region the user is trying to read */
if (p >= *ppos) {
/* ...but not beyond it */
if (buf_pos + map->debugfs_tot_len > count)
break;
/* Format the register */
snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
map->debugfs_reg_len, i - from);
buf_pos += map->debugfs_reg_len + 2;
/* Format the value, write all X if we can't read */
ret = regmap_read(map, i, &val);
if (ret == 0)
snprintf(buf + buf_pos, count - buf_pos,
"%.*x", map->debugfs_val_len, val);
else
memset(buf + buf_pos, 'X',
map->debugfs_val_len);
buf_pos += 2 * map->format.val_bytes;
buf[buf_pos++] = '\n';
}
p += map->debugfs_tot_len;
}
ret = buf_pos;
if (copy_to_user(user_buf, buf, buf_pos)) {
ret = -EFAULT;
goto out;
}
*ppos += buf_pos;
out:
kfree(buf);
return ret;
}
static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct regmap *map = file->private_data;
return regmap_read_debugfs(map, 0, map->max_register, user_buf,
count, ppos);
}
#undef REGMAP_ALLOW_WRITE_DEBUGFS
#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
/*
* This can be dangerous especially when we have clients such as
* PMICs, therefore don't provide any real compile time configuration option
* for this feature, people who want to use this will need to modify
* the source code directly.
*/
static ssize_t regmap_map_write_file(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[32];
size_t buf_size;
char *start = buf;
unsigned long reg, value;
struct regmap *map = file->private_data;
int ret;
buf_size = min(count, (sizeof(buf)-1));
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
buf[buf_size] = 0;
while (*start == ' ')
start++;
reg = simple_strtoul(start, &start, 16);
while (*start == ' ')
start++;
if (kstrtoul(start, 16, &value))
return -EINVAL;
/* Userspace has been fiddling around behind the kernel's back */
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
ret = regmap_write(map, reg, value);
if (ret < 0)
return ret;
return buf_size;
}
#else
#define regmap_map_write_file NULL
#endif
static const struct file_operations regmap_map_fops = {
.open = simple_open,
.read = regmap_map_read_file,
.write = regmap_map_write_file,
.llseek = default_llseek,
};
static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
struct regmap_range_node *range = file->private_data;
struct regmap *map = range->map;
return regmap_read_debugfs(map, range->range_min, range->range_max,
user_buf, count, ppos);
}
static const struct file_operations regmap_range_fops = {
.open = simple_open,
.read = regmap_range_read_file,
.llseek = default_llseek,
};
static ssize_t regmap_reg_ranges_read_file(struct file *file,
char __user *user_buf, size_t count,
loff_t *ppos)
{
struct regmap *map = file->private_data;
struct regmap_debugfs_off_cache *c;
loff_t p = 0;
size_t buf_pos = 0;
char *buf;
char *entry;
int ret;
unsigned entry_len;
if (*ppos < 0 || !count)
return -EINVAL;
buf = kmalloc(count, GFP_KERNEL);
if (!buf)
return -ENOMEM;
entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!entry) {
kfree(buf);
return -ENOMEM;
}
/* While we are at it, build the register dump cache
* now so the read() operation on the `registers' file
* can benefit from using the cache. We do not care
* about the file position information that is contained
* in the cache, just about the actual register blocks */
regmap_calc_tot_len(map, buf, count);
regmap_debugfs_get_dump_start(map, 0, *ppos, &p);
/* Reset file pointer as the fixed-format of the `registers'
* file is not compatible with the `range' file */
p = 0;
mutex_lock(&map->cache_lock);
list_for_each_entry(c, &map->debugfs_off_cache, list) {
entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
c->base_reg, c->max_reg);
if (p >= *ppos) {
if (buf_pos + entry_len > count)
break;
memcpy(buf + buf_pos, entry, entry_len);
buf_pos += entry_len;
}
p += entry_len;
}
mutex_unlock(&map->cache_lock);
kfree(entry);
ret = buf_pos;
if (copy_to_user(user_buf, buf, buf_pos)) {
ret = -EFAULT;
goto out_buf;
}
*ppos += buf_pos;
out_buf:
kfree(buf);
return ret;
}
static const struct file_operations regmap_reg_ranges_fops = {
.open = simple_open,
.read = regmap_reg_ranges_read_file,
.llseek = default_llseek,
};
static int regmap_access_show(struct seq_file *s, void *ignored)
{
struct regmap *map = s->private;
int i, reg_len;
reg_len = regmap_calc_reg_len(map->max_register);
for (i = 0; i <= map->max_register; i += map->reg_stride) {
/* Ignore registers which are neither readable nor writable */
if (!regmap_readable(map, i) && !regmap_writeable(map, i))
continue;
/* Format the register */
seq_printf(s, "%.*x: %c %c %c %c\n", reg_len, i,
regmap_readable(map, i) ? 'y' : 'n',
regmap_writeable(map, i) ? 'y' : 'n',
regmap_volatile(map, i) ? 'y' : 'n',
regmap_precious(map, i) ? 'y' : 'n');
}
return 0;
}
static int access_open(struct inode *inode, struct file *file)
{
return single_open(file, regmap_access_show, inode->i_private);
}
static const struct file_operations regmap_access_fops = {
.open = access_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static ssize_t regmap_cache_only_write_file(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct regmap *map = container_of(file->private_data,
struct regmap, cache_only);
ssize_t result;
bool was_enabled, require_sync = false;
int err;
map->lock(map->lock_arg);
was_enabled = map->cache_only;
result = debugfs_write_file_bool(file, user_buf, count, ppos);
if (result < 0) {
map->unlock(map->lock_arg);
return result;
}
if (map->cache_only && !was_enabled) {
dev_warn(map->dev, "debugfs cache_only=Y forced\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
} else if (!map->cache_only && was_enabled) {
dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
require_sync = true;
}
map->unlock(map->lock_arg);
if (require_sync) {
err = regcache_sync(map);
if (err)
dev_err(map->dev, "Failed to sync cache %d\n", err);
}
return result;
}
static const struct file_operations regmap_cache_only_fops = {
.open = simple_open,
.read = debugfs_read_file_bool,
.write = regmap_cache_only_write_file,
};
static ssize_t regmap_cache_bypass_write_file(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct regmap *map = container_of(file->private_data,
struct regmap, cache_bypass);
ssize_t result;
bool was_enabled;
map->lock(map->lock_arg);
was_enabled = map->cache_bypass;
result = debugfs_write_file_bool(file, user_buf, count, ppos);
if (result < 0)
goto out;
if (map->cache_bypass && !was_enabled) {
dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
} else if (!map->cache_bypass && was_enabled) {
dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
}
out:
map->unlock(map->lock_arg);
return result;
}
static const struct file_operations regmap_cache_bypass_fops = {
.open = simple_open,
.read = debugfs_read_file_bool,
.write = regmap_cache_bypass_write_file,
};
void regmap_debugfs_init(struct regmap *map, const char *name)
{
struct rb_node *next;
struct regmap_range_node *range_node;
const char *devname = "dummy";
/* If we don't have the debugfs root yet, postpone init */
if (!regmap_debugfs_root) {
struct regmap_debugfs_node *node;
node = kzalloc(sizeof(*node), GFP_KERNEL);
if (!node)
return;
node->map = map;
node->name = name;
mutex_lock(&regmap_debugfs_early_lock);
list_add(&node->link, &regmap_debugfs_early_list);
mutex_unlock(&regmap_debugfs_early_lock);
return;
}
INIT_LIST_HEAD(&map->debugfs_off_cache);
mutex_init(&map->cache_lock);
if (map->dev)
devname = dev_name(map->dev);
if (name) {
map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
devname, name);
name = map->debugfs_name;
} else {
name = devname;
}
map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
if (!map->debugfs) {
dev_warn(map->dev, "Failed to create debugfs directory\n");
return;
}
debugfs_create_file("name", 0400, map->debugfs,
map, &regmap_name_fops);
debugfs_create_file("range", 0400, map->debugfs,
map, &regmap_reg_ranges_fops);
if (map->max_register || regmap_readable(map, 0)) {
umode_t registers_mode;
#if defined(REGMAP_ALLOW_WRITE_DEBUGFS)
registers_mode = 0600;
#else
registers_mode = 0400;
#endif
debugfs_create_file("registers", registers_mode, map->debugfs,
map, &regmap_map_fops);
debugfs_create_file("access", 0400, map->debugfs,
map, &regmap_access_fops);
}
if (map->cache_type) {
debugfs_create_file("cache_only", 0600, map->debugfs,
&map->cache_only, &regmap_cache_only_fops);
debugfs_create_bool("cache_dirty", 0400, map->debugfs,
&map->cache_dirty);
debugfs_create_file("cache_bypass", 0600, map->debugfs,
&map->cache_bypass,
&regmap_cache_bypass_fops);
}
next = rb_first(&map->range_tree);
while (next) {
range_node = rb_entry(next, struct regmap_range_node, node);
if (range_node->name)
debugfs_create_file(range_node->name, 0400,
map->debugfs, range_node,
&regmap_range_fops);
next = rb_next(&range_node->node);
}
if (map->cache_ops && map->cache_ops->debugfs_init)
map->cache_ops->debugfs_init(map);
}
void regmap_debugfs_exit(struct regmap *map)
{
if (map->debugfs) {
debugfs_remove_recursive(map->debugfs);
mutex_lock(&map->cache_lock);
regmap_debugfs_free_dump_cache(map);
mutex_unlock(&map->cache_lock);
kfree(map->debugfs_name);
} else {
struct regmap_debugfs_node *node, *tmp;
mutex_lock(&regmap_debugfs_early_lock);
list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list,
link) {
if (node->map == map) {
list_del(&node->link);
kfree(node);
}
}
mutex_unlock(&regmap_debugfs_early_lock);
}
}
void regmap_debugfs_initcall(void)
{
struct regmap_debugfs_node *node, *tmp;
regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
if (!regmap_debugfs_root) {
pr_warn("regmap: Failed to create debugfs root\n");
return;
}
mutex_lock(&regmap_debugfs_early_lock);
list_for_each_entry_safe(node, tmp, &regmap_debugfs_early_list, link) {
regmap_debugfs_init(node->map, node->name);
list_del(&node->link);
kfree(node);
}
mutex_unlock(&regmap_debugfs_early_lock);
}