1 files changed, 265 insertions, 108 deletions

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 53495753fbdb..c9b4c04b1cf6 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -1,30 +1,34 @@
-/*
- * 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.
- */
+// 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;
+	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, char *buf, size_t buf_size)
+static size_t regmap_calc_reg_len(int max_val)
 {
-	snprintf(buf, buf_size, "%x", max_val);
-	return strlen(buf);
+	return snprintf(NULL, 0, "%x", max_val);
 }
 
 static ssize_t regmap_name_read_file(struct file *file,
@@ -32,6 +36,7 @@ static ssize_t regmap_name_read_file(struct file *file,
 				     loff_t *ppos)
 {
 	struct regmap *map = file->private_data;
+	const char *name = "nodev";
 	int ret;
 	char *buf;
 
@@ -39,8 +44,11 @@ static ssize_t regmap_name_read_file(struct file *file,
 	if (!buf)
 		return -ENOMEM;
 
-	ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
-	if (ret < 0) {
+	if (map->dev && map->dev->driver)
+		name = map->dev->driver->name;
+
+	ret = snprintf(buf, PAGE_SIZE, "%s\n", name);
+	if (ret >= PAGE_SIZE) {
 		kfree(buf);
 		return ret;
 	}
@@ -69,6 +77,17 @@ static void regmap_debugfs_free_dump_cache(struct regmap *map)
 	}
 }
 
+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.
@@ -85,8 +104,8 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
 	unsigned int reg_offset;
 
 	/* Suppress the cache if we're using a subrange */
-	if (from)
-		return from;
+	if (base)
+		return base;
 
 	/*
 	 * If we don't have a cache build one so we don't have to do a
@@ -97,8 +116,7 @@ static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
 	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_readable(map, i) ||
-			    regmap_precious(map, i)) {
+			if (!regmap_printable(map, i)) {
 				if (c) {
 					c->max = p - 1;
 					c->max_reg = i - map->reg_stride;
@@ -165,14 +183,35 @@ static inline void regmap_calc_tot_len(struct regmap *map,
 {
 	/* Calculate the length of a fixed format  */
 	if (!map->debugfs_tot_len) {
-		map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
-							   buf, count);
+		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)
@@ -187,6 +226,9 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 	if (*ppos < 0 || !count)
 		return -EINVAL;
 
+	if (count > (PAGE_SIZE << MAX_PAGE_ORDER))
+		count = PAGE_SIZE << MAX_PAGE_ORDER;
+
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -196,12 +238,8 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 	/* 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))
-			continue;
-
-		if (regmap_precious(map, i))
-			continue;
+	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) {
@@ -281,7 +319,7 @@ static ssize_t regmap_map_write_file(struct file *file,
 	reg = simple_strtoul(start, &start, 16);
 	while (*start == ' ')
 		start++;
-	if (strict_strtoul(start, 16, &value))
+	if (kstrtoul(start, 16, &value))
 		return -EINVAL;
 
 	/* Userspace has been fiddling around behind the kernel's back */
@@ -330,10 +368,14 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file,
 	char *buf;
 	char *entry;
 	int ret;
+	unsigned int entry_len;
 
 	if (*ppos < 0 || !count)
 		return -EINVAL;
 
+	if (count > (PAGE_SIZE << MAX_PAGE_ORDER))
+		count = PAGE_SIZE << MAX_PAGE_ORDER;
+
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;
@@ -357,18 +399,15 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file,
 	p = 0;
 	mutex_lock(&map->cache_lock);
 	list_for_each_entry(c, &map->debugfs_off_cache, list) {
-		snprintf(entry, PAGE_SIZE, "%x-%x",
-			 c->base_reg, c->max_reg);
+		entry_len = snprintf(entry, PAGE_SIZE, "%x-%x\n",
+				     c->base_reg, c->max_reg);
 		if (p >= *ppos) {
-			if (buf_pos + 1 + strlen(entry) > count)
+			if (buf_pos + entry_len > count)
 				break;
-			snprintf(buf + buf_pos, count - buf_pos,
-				 "%s", entry);
-			buf_pos += strlen(entry);
-			buf[buf_pos] = '\n';
-			buf_pos++;
+			memcpy(buf + buf_pos, entry, entry_len);
+			buf_pos += entry_len;
 		}
-		p += strlen(entry) + 1;
+		p += entry_len;
 	}
 	mutex_unlock(&map->cache_lock);
 
@@ -392,118 +431,212 @@ static const struct file_operations regmap_reg_ranges_fops = {
 	.llseek = default_llseek,
 };
 
-static ssize_t regmap_access_read_file(struct file *file,
-				       char __user *user_buf, size_t count,
-				       loff_t *ppos)
+static int regmap_access_show(struct seq_file *s, void *ignored)
 {
-	int reg_len, tot_len;
-	size_t buf_pos = 0;
-	loff_t p = 0;
-	ssize_t ret;
-	int i;
-	struct regmap *map = file->private_data;
-	char *buf;
-
-	if (*ppos < 0 || !count)
-		return -EINVAL;
-
-	buf = kmalloc(count, GFP_KERNEL);
-	if (!buf)
-		return -ENOMEM;
+	struct regmap *map = s->private;
+	int i, reg_len;
 
-	/* Calculate the length of a fixed format  */
-	reg_len = regmap_calc_reg_len(map->max_register, buf, count);
-	tot_len = reg_len + 10; /* ': R W V P\n' */
+	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;
 
-		/* If we're in the region the user is trying to read */
-		if (p >= *ppos) {
-			/* ...but not beyond it */
-			if (buf_pos >= count - 1 - tot_len)
-				break;
+		/* 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');
+	}
 
-			/* Format the register */
-			snprintf(buf + buf_pos, count - buf_pos,
-				 "%.*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');
-
-			buf_pos += tot_len;
-		}
-		p += tot_len;
+	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;
+
+	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;
 
-	ret = buf_pos;
+	map->unlock(map->lock_arg);
 
-	if (copy_to_user(user_buf, buf, buf_pos)) {
-		ret = -EFAULT;
-		goto out;
+	if (require_sync) {
+		err = regcache_sync(map);
+		if (err)
+			dev_err(map->dev, "Failed to sync cache %d\n", err);
 	}
 
-	*ppos += buf_pos;
+	return count;
+}
 
-out:
-	kfree(buf);
-	return ret;
+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;
+
+	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);
+
+	return count;
 }
 
-static const struct file_operations regmap_access_fops = {
+static const struct file_operations regmap_cache_bypass_fops = {
 	.open = simple_open,
-	.read = regmap_access_read_file,
-	.llseek = default_llseek,
+	.read = debugfs_read_file_bool,
+	.write = regmap_cache_bypass_write_file,
 };
 
-void regmap_debugfs_init(struct regmap *map, const char *name)
+void regmap_debugfs_init(struct regmap *map)
 {
 	struct rb_node *next;
 	struct regmap_range_node *range_node;
+	const char *devname = "dummy";
+	const char *name = map->name;
+
+	/*
+	 * 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;
+		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",
-					      dev_name(map->dev), name);
+		if (!map->debugfs_name) {
+			map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
+					      devname, name);
+			if (!map->debugfs_name)
+				return;
+		}
 		name = map->debugfs_name;
 	} else {
-		name = dev_name(map->dev);
+		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;
+	if (!strcmp(name, "dummy")) {
+		kfree(map->debugfs_name);
+		map->debugfs_name = kasprintf(GFP_KERNEL, "dummy%d",
+						dummy_index);
+		if (!map->debugfs_name)
+			return;
+		name = map->debugfs_name;
+		dummy_index++;
 	}
 
+	map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
+
 	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) {
-		debugfs_create_file("registers", 0400, map->debugfs,
+	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_bool("cache_only", 0400, map->debugfs,
-				    &map->cache_only);
+		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_bool("cache_bypass", 0400, map->debugfs,
-				    &map->cache_bypass);
+		debugfs_create_file("cache_bypass", 0600, map->debugfs,
+				    &map->cache_bypass,
+				    &regmap_cache_bypass_fops);
 	}
 
+	/*
+	 * This could interfere with driver operation. Therefore, don't provide
+	 * any real compile time configuration option for this feature. One will
+	 * have to modify the source code directly in order to use it.
+	 */
+#undef REGMAP_ALLOW_FORCE_WRITE_FIELD_DEBUGFS
+#ifdef REGMAP_ALLOW_FORCE_WRITE_FIELD_DEBUGFS
+	debugfs_create_bool("force_write_field", 0600, map->debugfs,
+			    &map->force_write_field);
+#endif
+
 	next = rb_first(&map->range_tree);
 	while (next) {
 		range_node = rb_entry(next, struct regmap_range_node, node);
@@ -515,22 +648,46 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
 
 		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)
 {
-	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);
+	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);
+		map->debugfs_name = NULL;
+	} 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);
+		list_del(&node->link);
+		kfree(node);
 	}
+	mutex_unlock(&regmap_debugfs_early_lock);
 }