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|
// SPDX-License-Identifier: GPL-2.0
//
// Register map access API - debugfs
//
// Copyright 2011 Wolfson Microelectronics plc
//
// Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
#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 unsigned int dummy_index;
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;
const char *name = "nodev";
int ret;
char *buf;
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (map->dev && map->dev->driver)
name = map->dev->driver->name;
ret = snprintf(buf, PAGE_SIZE, "%s\n", 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 int regmap_next_readable_reg(struct regmap *map, int reg)
{
struct regmap_debugfs_off_cache *c;
int ret = -EINVAL;
if (regmap_printable(map, reg + map->reg_stride)) {
ret = reg + map->reg_stride;
} else {
mutex_lock(&map->cache_lock);
list_for_each_entry(c, &map->debugfs_off_cache, list) {
if (reg > c->max_reg)
continue;
if (reg < c->base_reg) {
ret = c->base_reg;
break;
}
}
mutex_unlock(&map->cache_lock);
}
return ret;
}
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;
if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
count = PAGE_SIZE << (MAX_ORDER - 1);
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 >= 0 && i <= to;
i = regmap_next_readable_reg(map, i)) {
/* 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;
if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
count = PAGE_SIZE << (MAX_ORDER - 1);
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;
}
DEFINE_SHOW_ATTRIBUTE(regmap_access);
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);
bool new_val, require_sync = false;
int err;
err = kstrtobool_from_user(user_buf, count, &new_val);
/* Ignore malforned data like debugfs_write_file_bool() */
if (err)
return count;
err = debugfs_file_get(file->f_path.dentry);
if (err)
return err;
map->lock(map->lock_arg);
if (new_val && !map->cache_only) {
dev_warn(map->dev, "debugfs cache_only=Y forced\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
} else if (!new_val && map->cache_only) {
dev_warn(map->dev, "debugfs cache_only=N forced: syncing cache\n");
require_sync = true;
}
map->cache_only = new_val;
map->unlock(map->lock_arg);
debugfs_file_put(file->f_path.dentry);
if (require_sync) {
err = regcache_sync(map);
if (err)
dev_err(map->dev, "Failed to sync cache %d\n", err);
}
return count;
}
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);
bool new_val;
int err;
err = kstrtobool_from_user(user_buf, count, &new_val);
/* Ignore malforned data like debugfs_write_file_bool() */
if (err)
return count;
err = debugfs_file_get(file->f_path.dentry);
if (err)
return err;
map->lock(map->lock_arg);
if (new_val && !map->cache_bypass) {
dev_warn(map->dev, "debugfs cache_bypass=Y forced\n");
add_taint(TAINT_USER, LOCKDEP_STILL_OK);
} else if (!new_val && map->cache_bypass) {
dev_warn(map->dev, "debugfs cache_bypass=N forced\n");
}
map->cache_bypass = new_val;
map->unlock(map->lock_arg);
debugfs_file_put(file->f_path.dentry);
return count;
}
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";
/*
* Userspace can initiate reads from the hardware over debugfs.
* Normally internal regmap structures and buffers are protected with
* a mutex or a spinlock, but if the regmap owner decided to disable
* all locking mechanisms, this is no longer the case. For safety:
* don't create the debugfs entries if locking is disabled.
*/
if (map->debugfs_disable) {
dev_dbg(map->dev, "regmap locking disabled - not creating debugfs entries\n");
return;
}
/* 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(®map_debugfs_early_lock);
list_add(&node->link, ®map_debugfs_early_list);
mutex_unlock(®map_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;
}
if (!strcmp(name, "dummy")) {
kfree(map->debugfs_name);
map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d",
dummy_index);
name = map->debugfs_name;
dummy_index++;
}
map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
debugfs_create_file("name", 0400, map->debugfs,
map, ®map_name_fops);
debugfs_create_file("range", 0400, map->debugfs,
map, ®map_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, ®map_map_fops);
debugfs_create_file("access", 0400, map->debugfs,
map, ®map_access_fops);
}
if (map->cache_type) {
debugfs_create_file("cache_only", 0600, map->debugfs,
&map->cache_only, ®map_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,
®map_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,
®map_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(®map_debugfs_early_lock);
list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list,
link) {
if (node->map == map) {
list_del(&node->link);
kfree(node);
}
}
mutex_unlock(®map_debugfs_early_lock);
}
}
void regmap_debugfs_initcall(void)
{
struct regmap_debugfs_node *node, *tmp;
regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
mutex_lock(®map_debugfs_early_lock);
list_for_each_entry_safe(node, tmp, ®map_debugfs_early_list, link) {
regmap_debugfs_init(node->map, node->name);
list_del(&node->link);
kfree(node);
}
mutex_unlock(®map_debugfs_early_lock);
}
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