// SPDX-License-Identifier: GPL-2.0//// Register cache access API - maple tree based cache//// Copyright 2023 Arm, Ltd//// Author: Mark Brown <broonie@kernel.org> #include <linux/debugfs.h>#include <linux/device.h>#include <linux/maple_tree.h>#include <linux/slab.h> #include "internal.h" static int regcache_maple_read(struct regmap *map,			       unsigned int reg, unsigned int *value){	struct maple_tree *mt = map->cache;	MA_STATE(mas, mt, reg, reg);	unsigned long *entry; 	rcu_read_lock(); 	entry = mas_walk(&mas);	if (!entry) {		rcu_read_unlock();		return -ENOENT;	} 	*value = entry[reg - mas.index]; 	rcu_read_unlock(); 	return 0;} static int regcache_maple_write(struct regmap *map, unsigned int reg,				unsigned int val){	struct maple_tree *mt = map->cache;	MA_STATE(mas, mt, reg, reg);	unsigned long *entry, *upper, *lower;	unsigned long index, last;	size_t lower_sz, upper_sz;	int ret; 	rcu_read_lock(); 	entry = mas_walk(&mas);	if (entry) {		entry[reg - mas.index] = val;		rcu_read_unlock();		return 0;	} 	/* Any adjacent entries to extend/merge? */	mas_set_range(&mas, reg - 1, reg + 1);	index = reg;	last = reg; 	lower = mas_find(&mas, reg - 1);	if (lower) {		index = mas.index;		lower_sz = (mas.last - mas.index + 1) * sizeof(unsigned long);	} 	upper = mas_find(&mas, reg + 1);	if (upper) {		last = mas.last;		upper_sz = (mas.last - mas.index + 1) * sizeof(unsigned long);	} 	rcu_read_unlock(); 	entry = kmalloc_array(last - index + 1, sizeof(*entry), map->alloc_flags);	if (!entry)		return -ENOMEM; 	if (lower)		memcpy(entry, lower, lower_sz);	entry[reg - index] = val;	if (upper)		memcpy(&entry[reg - index + 1], upper, upper_sz); 	/*	 * This is safe because the regmap lock means the Maple lock	 * is redundant, but we need to take it due to lockdep asserts	 * in the maple tree code.	 */	mas_lock(&mas); 	mas_set_range(&mas, index, last);	ret = mas_store_gfp(&mas, entry, map->alloc_flags); 	mas_unlock(&mas); 	if (ret) {		kfree(entry);		return ret;	}	kfree(lower);	kfree(upper);	return 0;} static int regcache_maple_drop(struct regmap *map, unsigned int min,			       unsigned int max){	struct maple_tree *mt = map->cache;	MA_STATE(mas, mt, min, max);	unsigned long *entry, *lower, *upper;	/* initialized to work around false-positive -Wuninitialized warning */	unsigned long lower_index = 0, lower_last = 0;	unsigned long upper_index = 0, upper_last = 0;	int ret = 0; 	lower = NULL;	upper = NULL; 	mas_lock(&mas); 	mas_for_each(&mas, entry, max) {		/*		 * This is safe because the regmap lock means the		 * Maple lock is redundant, but we need to take it due		 * to lockdep asserts in the maple tree code.		 */		mas_unlock(&mas); 		/* Do we need to save any of this entry? */		if (mas.index < min) {			lower_index = mas.index;			lower_last = min -1; 			lower = kmemdup_array(entry,					      min - mas.index, sizeof(*lower),					      map->alloc_flags);			if (!lower) {				ret = -ENOMEM;				goto out_unlocked;			}		} 		if (mas.last > max) {			upper_index = max + 1;			upper_last = mas.last; 			upper = kmemdup_array(&entry[max - mas.index + 1],					      mas.last - max, sizeof(*upper),					      map->alloc_flags);			if (!upper) {				ret = -ENOMEM;				goto out_unlocked;			}		} 		kfree(entry);		mas_lock(&mas);		mas_erase(&mas); 		/* Insert new nodes with the saved data */		if (lower) {			mas_set_range(&mas, lower_index, lower_last);			ret = mas_store_gfp(&mas, lower, map->alloc_flags);			if (ret != 0)				goto out;			lower = NULL;		} 		if (upper) {			mas_set_range(&mas, upper_index, upper_last);			ret = mas_store_gfp(&mas, upper, map->alloc_flags);			if (ret != 0)				goto out;			upper = NULL;		}	} out:	mas_unlock(&mas);out_unlocked:	kfree(lower);	kfree(upper); 	return ret;} static int regcache_maple_sync_block(struct regmap *map, unsigned long *entry,				     struct ma_state *mas,				     unsigned int min, unsigned int max){	void *buf;	unsigned long r;	size_t val_bytes = map->format.val_bytes;	int ret = 0; 	mas_pause(mas);	rcu_read_unlock(); 	/*	 * Use a raw write if writing more than one register to a	 * device that supports raw writes to reduce transaction	 * overheads.	 */	if (max - min > 1 && regmap_can_raw_write(map)) {		buf = kmalloc_array(max - min, val_bytes, map->alloc_flags);		if (!buf) {			ret = -ENOMEM;			goto out;		} 		/* Render the data for a raw write */		for (r = min; r < max; r++) {			regcache_set_val(map, buf, r - min,					 entry[r - mas->index]);		} 		ret = _regmap_raw_write(map, min, buf, (max - min) * val_bytes,					false); 		kfree(buf);	} else {		for (r = min; r < max; r++) {			ret = _regmap_write(map, r,					    entry[r - mas->index]);			if (ret != 0)				goto out;		}	} out:	rcu_read_lock(); 	return ret;} static int regcache_maple_sync(struct regmap *map, unsigned int min,			       unsigned int max){	struct maple_tree *mt = map->cache;	unsigned long *entry;	MA_STATE(mas, mt, min, max);	unsigned long lmin = min;	unsigned long lmax = max;	unsigned int r, v, sync_start;	int ret = 0;	bool sync_needed = false; 	map->cache_bypass = true; 	rcu_read_lock(); 	mas_for_each(&mas, entry, max) {		for (r = max(mas.index, lmin); r <= min(mas.last, lmax); r++) {			v = entry[r - mas.index]; 			if (regcache_reg_needs_sync(map, r, v)) {				if (!sync_needed) {					sync_start = r;					sync_needed = true;				}				continue;			} 			if (!sync_needed)				continue; 			ret = regcache_maple_sync_block(map, entry, &mas,							sync_start, r);			if (ret != 0)				goto out;			sync_needed = false;		} 		if (sync_needed) {			ret = regcache_maple_sync_block(map, entry, &mas,							sync_start, r);			if (ret != 0)				goto out;			sync_needed = false;		}	} out:	rcu_read_unlock(); 	map->cache_bypass = false; 	return ret;} static int regcache_maple_init(struct regmap *map){	struct maple_tree *mt; 	mt = kmalloc_obj(*mt, map->alloc_flags);	if (!mt)		return -ENOMEM;	map->cache = mt; 	mt_init(mt); 	if (!mt_external_lock(mt) && map->lock_key)		lockdep_set_class_and_subclass(&mt->ma_lock, map->lock_key, 1); 	return 0;} static void regcache_maple_exit(struct regmap *map){	struct maple_tree *mt = map->cache;	MA_STATE(mas, mt, 0, UINT_MAX);	unsigned int *entry; 	/* if we've already been called then just return */	if (!mt)		return; 	mas_lock(&mas);	mas_for_each(&mas, entry, UINT_MAX)		kfree(entry);	__mt_destroy(mt);	mas_unlock(&mas); 	kfree(mt);	map->cache = NULL;} static int regcache_maple_insert_block(struct regmap *map, int first,					int last){	struct maple_tree *mt = map->cache;	MA_STATE(mas, mt, first, last);	unsigned long *entry;	int i, ret; 	entry = kmalloc_array(last - first + 1, sizeof(*entry), map->alloc_flags);	if (!entry)		return -ENOMEM; 	for (i = 0; i < last - first + 1; i++)		entry[i] = map->reg_defaults[first + i].def; 	mas_lock(&mas); 	mas_set_range(&mas, map->reg_defaults[first].reg,		      map->reg_defaults[last].reg);	ret = mas_store_gfp(&mas, entry, map->alloc_flags); 	mas_unlock(&mas); 	if (ret)		kfree(entry); 	return ret;} static int regcache_maple_populate(struct regmap *map){	int i;	int ret;	int range_start; 	range_start = 0; 	/* Scan for ranges of contiguous registers */	for (i = 1; i < map->num_reg_defaults; i++) {		if (map->reg_defaults[i].reg !=		    map->reg_defaults[i - 1].reg + 1) {			ret = regcache_maple_insert_block(map, range_start,							  i - 1);			if (ret != 0)				return ret; 			range_start = i;		}	} 	/* Add the last block */	return regcache_maple_insert_block(map, range_start, map->num_reg_defaults - 1);} struct regcache_ops regcache_maple_ops = {	.type = REGCACHE_MAPLE,	.name = "maple",	.init = regcache_maple_init,	.exit = regcache_maple_exit,	.populate = regcache_maple_populate,	.read = regcache_maple_read,	.write = regcache_maple_write,	.drop = regcache_maple_drop,	.sync = regcache_maple_sync,};