// 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; 	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; 	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);	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,

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