regmap: introduce fast_io busses, and use a spinlock for them
Some bus types have very fast IO. For these, acquiring a mutex for every IO operation is a significant overhead. Allow busses to indicate their IO is fast, and enhance regmap to use a spinlock for those busses. [Currently limited to native endian registers -- broonie] Signed-off-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
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0135bbcc7a
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bacdbe0773
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@ -31,8 +31,14 @@ struct regmap_format {
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unsigned int (*parse_val)(void *buf);
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};
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typedef void (*regmap_lock)(struct regmap *map);
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typedef void (*regmap_unlock)(struct regmap *map);
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struct regmap {
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struct mutex lock;
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struct mutex mutex;
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spinlock_t spinlock;
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regmap_lock lock;
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regmap_unlock unlock;
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struct device *dev; /* Device we do I/O on */
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void *work_buf; /* Scratch buffer used to format I/O */
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@ -139,7 +139,7 @@ static int rbtree_show(struct seq_file *s, void *ignored)
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int nodes = 0;
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int registers = 0;
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mutex_lock(&map->lock);
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map->lock(map);
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for (node = rb_first(&rbtree_ctx->root); node != NULL;
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node = rb_next(node)) {
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@ -155,7 +155,7 @@ static int rbtree_show(struct seq_file *s, void *ignored)
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seq_printf(s, "%d nodes, %d registers, average %d registers\n",
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nodes, registers, registers / nodes);
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mutex_unlock(&map->lock);
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map->unlock(map);
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return 0;
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}
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@ -264,7 +264,7 @@ int regcache_sync(struct regmap *map)
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BUG_ON(!map->cache_ops || !map->cache_ops->sync);
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mutex_lock(&map->lock);
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map->lock(map);
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/* Remember the initial bypass state */
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bypass = map->cache_bypass;
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dev_dbg(map->dev, "Syncing %s cache\n",
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@ -296,7 +296,7 @@ out:
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trace_regcache_sync(map->dev, name, "stop");
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/* Restore the bypass state */
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map->cache_bypass = bypass;
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -323,7 +323,7 @@ int regcache_sync_region(struct regmap *map, unsigned int min,
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BUG_ON(!map->cache_ops || !map->cache_ops->sync);
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mutex_lock(&map->lock);
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map->lock(map);
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/* Remember the initial bypass state */
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bypass = map->cache_bypass;
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@ -342,7 +342,7 @@ out:
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trace_regcache_sync(map->dev, name, "stop region");
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/* Restore the bypass state */
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map->cache_bypass = bypass;
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -361,11 +361,11 @@ out:
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*/
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void regcache_cache_only(struct regmap *map, bool enable)
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{
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mutex_lock(&map->lock);
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map->lock(map);
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WARN_ON(map->cache_bypass && enable);
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map->cache_only = enable;
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trace_regmap_cache_only(map->dev, enable);
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mutex_unlock(&map->lock);
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map->unlock(map);
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}
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EXPORT_SYMBOL_GPL(regcache_cache_only);
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@ -380,9 +380,9 @@ EXPORT_SYMBOL_GPL(regcache_cache_only);
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*/
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void regcache_mark_dirty(struct regmap *map)
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{
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mutex_lock(&map->lock);
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map->lock(map);
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map->cache_dirty = true;
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mutex_unlock(&map->lock);
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map->unlock(map);
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}
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EXPORT_SYMBOL_GPL(regcache_mark_dirty);
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@ -399,11 +399,11 @@ EXPORT_SYMBOL_GPL(regcache_mark_dirty);
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*/
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void regcache_cache_bypass(struct regmap *map, bool enable)
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{
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mutex_lock(&map->lock);
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map->lock(map);
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WARN_ON(map->cache_only && enable);
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map->cache_bypass = enable;
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trace_regmap_cache_bypass(map->dev, enable);
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mutex_unlock(&map->lock);
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map->unlock(map);
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}
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EXPORT_SYMBOL_GPL(regcache_cache_bypass);
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@ -158,6 +158,26 @@ static unsigned int regmap_parse_32(void *buf)
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return b[0];
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}
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static void regmap_lock_mutex(struct regmap *map)
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{
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mutex_lock(&map->mutex);
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}
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static void regmap_unlock_mutex(struct regmap *map)
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{
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mutex_unlock(&map->mutex);
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}
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static void regmap_lock_spinlock(struct regmap *map)
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{
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spin_lock(&map->spinlock);
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}
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static void regmap_unlock_spinlock(struct regmap *map)
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{
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spin_unlock(&map->spinlock);
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}
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/**
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* regmap_init(): Initialise register map
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*
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@ -187,7 +207,15 @@ struct regmap *regmap_init(struct device *dev,
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goto err;
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}
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mutex_init(&map->lock);
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if (bus->fast_io) {
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spin_lock_init(&map->spinlock);
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map->lock = regmap_lock_spinlock;
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map->unlock = regmap_unlock_spinlock;
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} else {
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mutex_init(&map->mutex);
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map->lock = regmap_lock_mutex;
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map->unlock = regmap_unlock_mutex;
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}
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map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
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map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
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map->format.pad_bytes = config->pad_bits / 8;
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@ -365,7 +393,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
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{
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int ret;
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mutex_lock(&map->lock);
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map->lock(map);
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regcache_exit(map);
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regmap_debugfs_exit(map);
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@ -384,7 +412,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config)
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ret = regcache_init(map, config);
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -536,11 +564,11 @@ int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
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{
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int ret;
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mutex_lock(&map->lock);
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map->lock(map);
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ret = _regmap_write(map, reg, val);
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -567,11 +595,11 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
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{
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int ret;
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mutex_lock(&map->lock);
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map->lock(map);
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ret = _regmap_raw_write(map, reg, val, val_len);
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -601,7 +629,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
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if (!map->format.parse_val)
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return -EINVAL;
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mutex_lock(&map->lock);
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map->lock(map);
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/* No formatting is require if val_byte is 1 */
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if (val_bytes == 1) {
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@ -622,7 +650,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
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kfree(wval);
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out:
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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EXPORT_SYMBOL_GPL(regmap_bulk_write);
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@ -696,11 +724,11 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
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{
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int ret;
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mutex_lock(&map->lock);
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map->lock(map);
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ret = _regmap_read(map, reg, val);
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -725,7 +753,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
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unsigned int v;
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int ret, i;
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mutex_lock(&map->lock);
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map->lock(map);
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if (regmap_volatile_range(map, reg, val_count) || map->cache_bypass ||
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map->cache_type == REGCACHE_NONE) {
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}
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out:
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -799,7 +827,7 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
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int ret;
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unsigned int tmp, orig;
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mutex_lock(&map->lock);
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map->lock(map);
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ret = _regmap_read(map, reg, &orig);
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if (ret != 0)
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}
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out:
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -883,7 +911,7 @@ int regmap_register_patch(struct regmap *map, const struct reg_default *regs,
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if (map->patch)
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return -EBUSY;
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mutex_lock(&map->lock);
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map->lock(map);
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bypass = map->cache_bypass;
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out:
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map->cache_bypass = bypass;
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mutex_unlock(&map->lock);
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map->unlock(map);
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return ret;
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}
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@ -110,6 +110,8 @@ typedef void (*regmap_hw_free_context)(void *context);
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/**
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* Description of a hardware bus for the register map infrastructure.
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*
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* @fast_io: Register IO is fast. Use a spinlock instead of a mutex
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* to perform locking.
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* @write: Write operation.
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* @gather_write: Write operation with split register/value, return -ENOTSUPP
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* if not implemented on a given device.
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* a read.
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*/
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struct regmap_bus {
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bool fast_io;
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regmap_hw_write write;
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regmap_hw_gather_write gather_write;
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regmap_hw_read read;
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