Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 915 insertions, 0 deletions

diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
new file mode 100644
index 000000000..0d58d900a
--- /dev/null
+++ b/drivers/base/regmap/regcache.c
@@ -0,0 +1,915 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Register cache access API
+//
+// Copyright 2011 Wolfson Microelectronics plc
+//
+// Author: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
+
+#include <linux/bsearch.h>
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/sort.h>
+
+#include "trace.h"
+#include "internal.h"
+
+static const struct regcache_ops *cache_types[] = {
+	&regcache_flat_sparse_ops,
+	&regcache_rbtree_ops,
+	&regcache_maple_ops,
+	&regcache_flat_ops,
+};
+
+static int regcache_defaults_cmp(const void *a, const void *b)
+{
+	const struct reg_default *x = a;
+	const struct reg_default *y = b;
+
+	if (x->reg > y->reg)
+		return 1;
+	else if (x->reg < y->reg)
+		return -1;
+	else
+		return 0;
+}
+
+void regcache_sort_defaults(struct reg_default *defaults, unsigned int ndefaults)
+{
+	sort(defaults, ndefaults, sizeof(*defaults),
+	     regcache_defaults_cmp, NULL);
+}
+EXPORT_SYMBOL_GPL(regcache_sort_defaults);
+
+static int regcache_count_cacheable_registers(struct regmap *map)
+{
+	unsigned int count;
+
+	/* calculate the size of reg_defaults */
+	count = 0;
+	for (unsigned int i = 0; i < map->num_reg_defaults_raw; i++)
+		if (regmap_readable(map, i * map->reg_stride) &&
+		    !regmap_volatile(map, i * map->reg_stride))
+			count++;
+
+	return count;
+}
+
+static int regcache_hw_init(struct regmap *map)
+{
+	int ret;
+	unsigned int reg, val;
+	void *tmp_buf;
+
+	if (!map->reg_defaults_raw) {
+		bool cache_bypass = map->cache_bypass;
+		dev_dbg(map->dev, "No cache defaults, reading back from HW\n");
+
+		/* Bypass the cache access till data read from HW */
+		map->cache_bypass = true;
+		tmp_buf = kmalloc(map->cache_size_raw, GFP_KERNEL);
+		if (!tmp_buf)
+			return -ENOMEM;
+		ret = regmap_raw_read(map, 0, tmp_buf,
+				      map->cache_size_raw);
+		map->cache_bypass = cache_bypass;
+		if (ret == 0) {
+			map->reg_defaults_raw = tmp_buf;
+			map->cache_free = true;
+		} else {
+			kfree(tmp_buf);
+		}
+	}
+
+	/* fill the reg_defaults */
+	for (unsigned int i = 0, j = 0; i < map->num_reg_defaults_raw; i++) {
+		reg = i * map->reg_stride;
+
+		if (!regmap_readable(map, reg))
+			continue;
+
+		if (regmap_volatile(map, reg))
+			continue;
+
+		if (map->reg_defaults_raw) {
+			val = regcache_get_val(map, map->reg_defaults_raw, i);
+		} else {
+			bool cache_bypass = map->cache_bypass;
+
+			map->cache_bypass = true;
+			ret = regmap_read(map, reg, &val);
+			map->cache_bypass = cache_bypass;
+			if (ret != 0) {
+				dev_err(map->dev, "Failed to read %x: %d\n",
+					reg, ret);
+				return ret;
+			}
+		}
+
+		map->reg_defaults[j].reg = reg;
+		map->reg_defaults[j].def = val;
+		j++;
+	}
+
+	return 0;
+}
+
+static void regcache_hw_exit(struct regmap *map)
+{
+	if (map->cache_free)
+		kfree(map->reg_defaults_raw);
+}
+
+int regcache_init(struct regmap *map, const struct regmap_config *config)
+{
+	bool sort_defaults = false;
+	unsigned int reg_prev = 0;
+	int count = 0;
+	int ret;
+	int i;
+	void *tmp_buf;
+
+	if (map->cache_type == REGCACHE_NONE) {
+		if (config->reg_defaults || config->num_reg_defaults_raw)
+			dev_warn(map->dev,
+				 "No cache used with register defaults set!\n");
+
+		map->cache_bypass = true;
+		return 0;
+	}
+
+	if (config->reg_defaults && !config->num_reg_defaults) {
+		dev_err(map->dev,
+			 "Register defaults are set without the number!\n");
+		return -EINVAL;
+	}
+
+	if (config->num_reg_defaults && !config->reg_defaults) {
+		dev_err(map->dev,
+			"Register defaults number are set without the reg!\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < config->num_reg_defaults; i++) {
+		if (config->reg_defaults[i].reg % map->reg_stride)
+			return -EINVAL;
+
+		if (reg_prev > config->reg_defaults[i].reg)
+			sort_defaults = true;
+
+		reg_prev = config->reg_defaults[i].reg;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(cache_types); i++)
+		if (cache_types[i]->type == map->cache_type)
+			break;
+
+	if (i == ARRAY_SIZE(cache_types)) {
+		dev_err(map->dev, "Could not match cache type: %d\n",
+			map->cache_type);
+		return -EINVAL;
+	}
+
+	map->num_reg_defaults = config->num_reg_defaults;
+	map->num_reg_defaults_raw = config->num_reg_defaults_raw;
+	map->reg_defaults_raw = config->reg_defaults_raw;
+	map->cache_word_size = BITS_TO_BYTES(config->val_bits);
+	map->cache_size_raw = map->cache_word_size * config->num_reg_defaults_raw;
+
+	map->cache = NULL;
+	map->cache_ops = cache_types[i];
+
+	if (!map->cache_ops->read ||
+	    !map->cache_ops->write ||
+	    !map->cache_ops->name)
+		return -EINVAL;
+
+	/* We still need to ensure that the reg_defaults
+	 * won't vanish from under us.  We'll need to make
+	 * a copy of it.
+	 */
+	if (config->reg_defaults) {
+		tmp_buf = kmemdup_array(config->reg_defaults, map->num_reg_defaults,
+					sizeof(*map->reg_defaults), GFP_KERNEL);
+		if (!tmp_buf)
+			return -ENOMEM;
+
+		/* regcache_lookup_reg() bsearch()es this array */
+		if (sort_defaults) {
+			dev_warn(map->dev,
+				 "Driver needs fixing: Unsorted reg_defaults, sorting the copy\n");
+			regcache_sort_defaults(tmp_buf, map->num_reg_defaults);
+		}
+		map->reg_defaults = tmp_buf;
+	} else if (map->num_reg_defaults_raw) {
+		count = regcache_count_cacheable_registers(map);
+		if (!count)
+			map->cache_bypass = true;
+
+		/* All registers are unreadable or volatile, so just bypass */
+		if (map->cache_bypass)
+			return 0;
+
+		map->num_reg_defaults = count;
+		map->reg_defaults = kmalloc_objs(struct reg_default, count);
+		if (!map->reg_defaults)
+			return -ENOMEM;
+	}
+
+	if (!map->max_register_is_set && map->num_reg_defaults_raw) {
+		map->max_register = (map->num_reg_defaults_raw  - 1) * map->reg_stride;
+		map->max_register_is_set = true;
+	}
+
+	if (map->cache_ops->init) {
+		dev_dbg(map->dev, "Initializing %s cache\n",
+			map->cache_ops->name);
+		map->lock(map->lock_arg);
+		ret = map->cache_ops->init(map);
+		map->unlock(map->lock_arg);
+		if (ret)
+			goto err_free_reg_defaults;
+	}
+
+	/*
+	 * Some devices such as PMICs don't have cache defaults,
+	 * we cope with this by reading back the HW registers and
+	 * crafting the cache defaults by hand.
+	 */
+	if (count) {
+		ret = regcache_hw_init(map);
+		if (ret)
+			goto err_exit;
+	}
+
+	if (map->cache_ops->populate &&
+	    (map->num_reg_defaults || map->reg_default_cb)) {
+		dev_dbg(map->dev, "Populating %s cache\n", map->cache_ops->name);
+		map->lock(map->lock_arg);
+		ret = map->cache_ops->populate(map);
+		map->unlock(map->lock_arg);
+		if (ret)
+			goto err_free;
+	}
+	return 0;
+
+err_free:
+	regcache_hw_exit(map);
+err_exit:
+	if (map->cache_ops->exit) {
+		dev_dbg(map->dev, "Destroying %s cache\n", map->cache_ops->name);
+		map->lock(map->lock_arg);
+		map->cache_ops->exit(map);
+		map->unlock(map->lock_arg);
+	}
+err_free_reg_defaults:
+	kfree(map->reg_defaults);
+
+	return ret;
+}
+
+void regcache_exit(struct regmap *map)
+{
+	if (map->cache_type == REGCACHE_NONE)
+		return;
+
+	BUG_ON(!map->cache_ops);
+
+	regcache_hw_exit(map);
+
+	if (map->cache_ops->exit) {
+		dev_dbg(map->dev, "Destroying %s cache\n",
+			map->cache_ops->name);
+		map->lock(map->lock_arg);
+		map->cache_ops->exit(map);
+		map->unlock(map->lock_arg);
+	}
+
+	kfree(map->reg_defaults);
+}
+
+/**
+ * regcache_read - Fetch the value of a given register from the cache.
+ *
+ * @map: map to configure.
+ * @reg: The register index.
+ * @value: The value to be returned.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_read(struct regmap *map,
+		  unsigned int reg, unsigned int *value)
+{
+	int ret;
+
+	if (map->cache_type == REGCACHE_NONE)
+		return -EINVAL;
+
+	BUG_ON(!map->cache_ops);
+
+	if (!regmap_volatile(map, reg)) {
+		ret = map->cache_ops->read(map, reg, value);
+
+		if (ret == 0)
+			trace_regmap_reg_read_cache(map, reg, *value);
+
+		return ret;
+	}
+
+	return -EINVAL;
+}
+
+/**
+ * regcache_write - Set the value of a given register in the cache.
+ *
+ * @map: map to configure.
+ * @reg: The register index.
+ * @value: The new register value.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_write(struct regmap *map,
+		   unsigned int reg, unsigned int value)
+{
+	if (map->cache_type == REGCACHE_NONE)
+		return 0;
+
+	BUG_ON(!map->cache_ops);
+
+	if (!regmap_volatile(map, reg))
+		return map->cache_ops->write(map, reg, value);
+
+	return 0;
+}
+
+bool regcache_reg_needs_sync(struct regmap *map, unsigned int reg,
+			     unsigned int val)
+{
+	int ret;
+
+	if (!regmap_writeable(map, reg))
+		return false;
+
+	/* If we don't know the chip just got reset, then sync everything. */
+	if (!map->no_sync_defaults)
+		return true;
+
+	/* Is this the hardware default?  If so skip. */
+	ret = regcache_lookup_reg(map, reg);
+	if (ret >= 0 && val == map->reg_defaults[ret].def)
+		return false;
+	return true;
+}
+
+static int regcache_default_sync(struct regmap *map, unsigned int min,
+				 unsigned int max)
+{
+	unsigned int reg;
+
+	for (reg = min; reg <= max; reg += map->reg_stride) {
+		unsigned int val;
+		int ret;
+
+		if (regmap_volatile(map, reg) ||
+		    !regmap_writeable(map, reg))
+			continue;
+
+		ret = regcache_read(map, reg, &val);
+		if (ret == -ENOENT)
+			continue;
+		if (ret)
+			return ret;
+
+		if (!regcache_reg_needs_sync(map, reg, val))
+			continue;
+
+		map->cache_bypass = true;
+		ret = _regmap_write(map, reg, val);
+		map->cache_bypass = false;
+		if (ret) {
+			dev_err(map->dev, "Unable to sync register %#x. %d\n",
+				reg, ret);
+			return ret;
+		}
+		dev_dbg(map->dev, "Synced register %#x, value %#x\n", reg, val);
+	}
+
+	return 0;
+}
+
+static int rbtree_all(const void *key, const struct rb_node *node)
+{
+	return 0;
+}
+
+/**
+ * regcache_sync - Sync the register cache with the hardware.
+ *
+ * @map: map to configure.
+ *
+ * Any registers that should not be synced should be marked as
+ * volatile.  In general drivers can choose not to use the provided
+ * syncing functionality if they so require.
+ *
+ * This pushes cached changes made while cache_only (e.g. suspend) down
+ * to hardware. The caller must disable cache_only before calling this
+ * function.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_sync(struct regmap *map)
+{
+	int sync_ret = 0;
+	int selector_ret = 0;
+	unsigned int i;
+	const char *name;
+	bool bypass;
+	struct rb_node *node;
+
+	if (WARN_ON(map->cache_type == REGCACHE_NONE))
+		return -EINVAL;
+
+	BUG_ON(!map->cache_ops);
+
+	map->lock(map->lock_arg);
+
+	if (WARN_ON(map->cache_only)) {
+		map->unlock(map->lock_arg);
+		return -EINVAL;
+	}
+
+	/* Remember the initial bypass state */
+	bypass = map->cache_bypass;
+	dev_dbg(map->dev, "Syncing %s cache\n",
+		map->cache_ops->name);
+	name = map->cache_ops->name;
+	trace_regcache_sync(map, name, "start");
+
+	if (!map->cache_dirty)
+		goto out;
+
+	/* Apply any patch first */
+	map->cache_bypass = true;
+	for (i = 0; i < map->patch_regs; i++) {
+		sync_ret = _regmap_write(map, map->patch[i].reg, map->patch[i].def);
+		if (sync_ret != 0) {
+			dev_err(map->dev, "Failed to write %x = %x: %d\n",
+				map->patch[i].reg, map->patch[i].def, sync_ret);
+			goto out;
+		}
+	}
+	map->cache_bypass = false;
+
+	if (map->cache_ops->sync)
+		sync_ret = map->cache_ops->sync(map, 0, map->max_register);
+	else
+		sync_ret = regcache_default_sync(map, 0, map->max_register);
+
+	if (sync_ret == 0)
+		map->cache_dirty = false;
+
+out:
+	/* Restore the bypass state */
+	map->cache_bypass = bypass;
+	map->no_sync_defaults = false;
+
+	/*
+	 * If we did any paging with cache bypassed and a cached
+	 * paging register then the register and cache state might
+	 * have gone out of sync, force writes of all the paging
+	 * registers.
+	 */
+	rb_for_each(node, NULL, &map->range_tree, rbtree_all) {
+		struct regmap_range_node *this =
+			rb_entry(node, struct regmap_range_node, node);
+
+		/* If there's nothing in the cache there's nothing to sync */
+		if (regcache_read(map, this->selector_reg, &i) != 0)
+			continue;
+
+		selector_ret = _regmap_write(map, this->selector_reg, i);
+		if (selector_ret != 0) {
+			map->cache_dirty = true;
+			dev_err(map->dev, "Failed to write %x = %x: %d\n",
+				this->selector_reg, i, selector_ret);
+			break;
+		}
+	}
+
+	map->unlock(map->lock_arg);
+
+	regmap_async_complete(map);
+
+	trace_regcache_sync(map, name, "stop");
+
+	return sync_ret ? sync_ret : selector_ret;
+}
+EXPORT_SYMBOL_GPL(regcache_sync);
+
+/**
+ * regcache_sync_region - Sync part  of the register cache with the hardware.
+ *
+ * @map: map to sync.
+ * @min: first register to sync
+ * @max: last register to sync
+ *
+ * Write all non-default register values in the specified region to
+ * the hardware.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_sync_region(struct regmap *map, unsigned int min,
+			 unsigned int max)
+{
+	int ret = 0;
+	const char *name;
+	bool bypass;
+
+	if (WARN_ON(map->cache_type == REGCACHE_NONE))
+		return -EINVAL;
+
+	BUG_ON(!map->cache_ops);
+
+	map->lock(map->lock_arg);
+
+	if (WARN_ON(map->cache_only)) {
+		map->unlock(map->lock_arg);
+		return -EINVAL;
+	}
+	/* Remember the initial bypass state */
+	bypass = map->cache_bypass;
+
+	name = map->cache_ops->name;
+	dev_dbg(map->dev, "Syncing %s cache from %#x-%#x\n", name, min, max);
+
+	trace_regcache_sync(map, name, "start region");
+
+	if (!map->cache_dirty)
+		goto out;
+
+	map->async = true;
+
+	if (map->cache_ops->sync)
+		ret = map->cache_ops->sync(map, min, max);
+	else
+		ret = regcache_default_sync(map, min, max);
+
+out:
+	/* Restore the bypass state */
+	map->cache_bypass = bypass;
+	map->async = false;
+	map->no_sync_defaults = false;
+	map->unlock(map->lock_arg);
+
+	regmap_async_complete(map);
+
+	trace_regcache_sync(map, name, "stop region");
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regcache_sync_region);
+
+/**
+ * regcache_drop_region - Discard part of the register cache
+ *
+ * @map: map to operate on
+ * @min: first register to discard
+ * @max: last register to discard
+ *
+ * Discard part of the register cache.
+ *
+ * Return a negative value on failure, 0 on success.
+ */
+int regcache_drop_region(struct regmap *map, unsigned int min,
+			 unsigned int max)
+{
+	int ret = 0;
+
+	if (!map->cache_ops || !map->cache_ops->drop)
+		return -EINVAL;
+
+	map->lock(map->lock_arg);
+
+	trace_regcache_drop_region(map, min, max);
+
+	ret = map->cache_ops->drop(map, min, max);
+
+	map->unlock(map->lock_arg);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regcache_drop_region);
+
+/**
+ * regcache_cache_only - Put a register map into cache only mode
+ *
+ * @map: map to configure
+ * @enable: flag if changes should be written to the hardware
+ *
+ * When a register map is marked as cache only writes to the register
+ * map API will only update the register cache, they will not cause
+ * any hardware changes.  This is useful for allowing portions of
+ * drivers to act as though the device were functioning as normal when
+ * it is disabled for power saving reasons.
+ */
+void regcache_cache_only(struct regmap *map, bool enable)
+{
+	map->lock(map->lock_arg);
+	WARN_ON(map->cache_type != REGCACHE_NONE &&
+		map->cache_bypass && enable);
+	map->cache_only = enable;
+	trace_regmap_cache_only(map, enable);
+	map->unlock(map->lock_arg);
+}
+EXPORT_SYMBOL_GPL(regcache_cache_only);
+
+/**
+ * regcache_mark_dirty - Indicate that HW registers were reset to default values
+ *
+ * @map: map to mark
+ *
+ * Inform regcache that the device has been powered down or reset, so that
+ * on resume, regcache_sync() knows to write out all non-default values
+ * stored in the cache.
+ *
+ * If this function is not called, regcache_sync() will assume that
+ * the hardware state still matches the cache state, modulo any writes that
+ * happened when cache_only was true.
+ */
+void regcache_mark_dirty(struct regmap *map)
+{
+	map->lock(map->lock_arg);
+	map->cache_dirty = true;
+	map->no_sync_defaults = true;
+	map->unlock(map->lock_arg);
+}
+EXPORT_SYMBOL_GPL(regcache_mark_dirty);
+
+/**
+ * regcache_cache_bypass - Put a register map into cache bypass mode
+ *
+ * @map: map to configure
+ * @enable: flag if changes should not be written to the cache
+ *
+ * When a register map is marked with the cache bypass option, writes
+ * to the register map API will only update the hardware and not
+ * the cache directly.  This is useful when syncing the cache back to
+ * the hardware.
+ */
+void regcache_cache_bypass(struct regmap *map, bool enable)
+{
+	map->lock(map->lock_arg);
+	WARN_ON(map->cache_only && enable);
+	map->cache_bypass = enable;
+	trace_regmap_cache_bypass(map, enable);
+	map->unlock(map->lock_arg);
+}
+EXPORT_SYMBOL_GPL(regcache_cache_bypass);
+
+/**
+ * regcache_reg_cached - Check if a register is cached
+ *
+ * @map: map to check
+ * @reg: register to check
+ *
+ * Reports if a register is cached.
+ */
+bool regcache_reg_cached(struct regmap *map, unsigned int reg)
+{
+	unsigned int val;
+	int ret;
+
+	map->lock(map->lock_arg);
+
+	ret = regcache_read(map, reg, &val);
+
+	map->unlock(map->lock_arg);
+
+	return ret == 0;
+}
+EXPORT_SYMBOL_GPL(regcache_reg_cached);
+
+void regcache_set_val(struct regmap *map, void *base, unsigned int idx,
+		      unsigned int val)
+{
+	/* Use device native format if possible */
+	if (map->format.format_val) {
+		map->format.format_val(base + (map->cache_word_size * idx),
+				       val, 0);
+		return;
+	}
+
+	switch (map->cache_word_size) {
+	case 1: {
+		u8 *cache = base;
+
+		cache[idx] = val;
+		break;
+	}
+	case 2: {
+		u16 *cache = base;
+
+		cache[idx] = val;
+		break;
+	}
+	case 4: {
+		u32 *cache = base;
+
+		cache[idx] = val;
+		break;
+	}
+	default:
+		BUG();
+	}
+}
+
+unsigned int regcache_get_val(struct regmap *map, const void *base,
+			      unsigned int idx)
+{
+	if (!base)
+		return -EINVAL;
+
+	/* Use device native format if possible */
+	if (map->format.parse_val)
+		return map->format.parse_val(regcache_get_val_addr(map, base,
+								   idx));
+
+	switch (map->cache_word_size) {
+	case 1: {
+		const u8 *cache = base;
+
+		return cache[idx];
+	}
+	case 2: {
+		const u16 *cache = base;
+
+		return cache[idx];
+	}
+	case 4: {
+		const u32 *cache = base;
+
+		return cache[idx];
+	}
+	default:
+		BUG();
+	}
+	/* unreachable */
+	return -1;
+}
+
+int regcache_lookup_reg(struct regmap *map, unsigned int reg)
+{
+	struct reg_default key;
+	struct reg_default *r;
+
+	key.reg = reg;
+	key.def = 0;
+
+	r = bsearch(&key, map->reg_defaults, map->num_reg_defaults,
+		    sizeof(struct reg_default), regcache_defaults_cmp);
+
+	if (r)
+		return r - map->reg_defaults;
+	else
+		return -ENOENT;
+}
+
+static bool regcache_reg_present(unsigned long *cache_present, unsigned int idx)
+{
+	if (!cache_present)
+		return true;
+
+	return test_bit(idx, cache_present);
+}
+
+int regcache_sync_val(struct regmap *map, unsigned int reg, unsigned int val)
+{
+	int ret;
+
+	if (!regcache_reg_needs_sync(map, reg, val))
+		return 0;
+
+	map->cache_bypass = true;
+
+	ret = _regmap_write(map, reg, val);
+
+	map->cache_bypass = false;
+
+	if (ret != 0) {
+		dev_err(map->dev, "Unable to sync register %#x. %d\n",
+			reg, ret);
+		return ret;
+	}
+	dev_dbg(map->dev, "Synced register %#x, value %#x\n",
+		reg, val);
+
+	return 0;
+}
+
+static int regcache_sync_block_single(struct regmap *map, void *block,
+				      unsigned long *cache_present,
+				      unsigned int block_base,
+				      unsigned int start, unsigned int end)
+{
+	unsigned int i, regtmp, val;
+	int ret;
+
+	for (i = start; i < end; i++) {
+		regtmp = block_base + (i * map->reg_stride);
+
+		if (!regcache_reg_present(cache_present, i) ||
+		    !regmap_writeable(map, regtmp))
+			continue;
+
+		val = regcache_get_val(map, block, i);
+		ret = regcache_sync_val(map, regtmp, val);
+		if (ret != 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
+					 unsigned int base, unsigned int cur)
+{
+	size_t val_bytes = map->format.val_bytes;
+	int ret, count;
+
+	if (*data == NULL)
+		return 0;
+
+	count = (cur - base) / map->reg_stride;
+
+	dev_dbg(map->dev, "Writing %zu bytes for %d registers from 0x%x-0x%x\n",
+		count * val_bytes, count, base, cur - map->reg_stride);
+
+	map->cache_bypass = true;
+
+	ret = _regmap_raw_write(map, base, *data, count * val_bytes, false);
+	if (ret)
+		dev_err(map->dev, "Unable to sync registers %#x-%#x. %d\n",
+			base, cur - map->reg_stride, ret);
+
+	map->cache_bypass = false;
+
+	*data = NULL;
+
+	return ret;
+}
+
+static int regcache_sync_block_raw(struct regmap *map, void *block,
+			    unsigned long *cache_present,
+			    unsigned int block_base, unsigned int start,
+			    unsigned int end)
+{
+	unsigned int regtmp = 0;
+	unsigned int base = 0;
+	const void *data = NULL;
+	unsigned int val;
+	int ret;
+
+	for (unsigned int i = start; i < end; i++) {
+		regtmp = block_base + (i * map->reg_stride);
+
+		if (!regcache_reg_present(cache_present, i) ||
+		    !regmap_writeable(map, regtmp)) {
+			ret = regcache_sync_block_raw_flush(map, &data,
+							    base, regtmp);
+			if (ret != 0)
+				return ret;
+			continue;
+		}
+
+		val = regcache_get_val(map, block, i);
+		if (!regcache_reg_needs_sync(map, regtmp, val)) {
+			ret = regcache_sync_block_raw_flush(map, &data,
+							    base, regtmp);
+			if (ret != 0)
+				return ret;
+			continue;
+		}
+
+		if (!data) {
+			data = regcache_get_val_addr(map, block, i);
+			base = regtmp;
+		}
+	}
+
+	return regcache_sync_block_raw_flush(map, &data, base, regtmp +
+			map->reg_stride);
+}
+
+int regcache_sync_block(struct regmap *map, void *block,
+			unsigned long *cache_present,
+			unsigned int block_base, unsigned int start,
+			unsigned int end)
+{
+	if (regmap_can_raw_write(map) && !map->use_single_write)
+		return regcache_sync_block_raw(map, block, cache_present,
+					       block_base, start, end);
+	else
+		return regcache_sync_block_single(map, block, cache_present,
+						  block_base, start, end);
+}