From a42678c4c8b5f6d489829ffc3071fa1f08ee99d1 Mon Sep 17 00:00:00 2001 From: Stephen Warren Date: Wed, 4 Apr 2012 15:48:28 -0600 Subject: [PATCH] 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 Signed-off-by: Mark Brown --- drivers/base/regmap/internal.h | 8 +++- drivers/base/regmap/regcache-rbtree.c | 4 +- drivers/base/regmap/regcache.c | 20 ++++----- drivers/base/regmap/regmap.c | 62 +++++++++++++++++++-------- include/linux/regmap.h | 3 ++ 5 files changed, 67 insertions(+), 30 deletions(-) diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h index 4f87633d56e9..44e3b1c438f4 100644 --- a/drivers/base/regmap/internal.h +++ b/drivers/base/regmap/internal.h @@ -31,8 +31,14 @@ struct regmap_format { unsigned int (*parse_val)(void *buf); }; +typedef void (*regmap_lock)(struct regmap *map); +typedef void (*regmap_unlock)(struct regmap *map); + struct regmap { - struct mutex lock; + struct mutex mutex; + spinlock_t spinlock; + regmap_lock lock; + regmap_unlock unlock; struct device *dev; /* Device we do I/O on */ void *work_buf; /* Scratch buffer used to format I/O */ diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c index 92b779ee002b..e49e71fab184 100644 --- a/drivers/base/regmap/regcache-rbtree.c +++ b/drivers/base/regmap/regcache-rbtree.c @@ -140,7 +140,7 @@ static int rbtree_show(struct seq_file *s, void *ignored) int registers = 0; int average; - mutex_lock(&map->lock); + map->lock(map); for (node = rb_first(&rbtree_ctx->root); node != NULL; node = rb_next(node)) { @@ -161,7 +161,7 @@ static int rbtree_show(struct seq_file *s, void *ignored) seq_printf(s, "%d nodes, %d registers, average %d registers\n", nodes, registers, average); - mutex_unlock(&map->lock); + map->unlock(map); return 0; } diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c index 74b69095def6..d4368e8b6f9d 100644 --- a/drivers/base/regmap/regcache.c +++ b/drivers/base/regmap/regcache.c @@ -264,7 +264,7 @@ int regcache_sync(struct regmap *map) BUG_ON(!map->cache_ops || !map->cache_ops->sync); - mutex_lock(&map->lock); + map->lock(map); /* Remember the initial bypass state */ bypass = map->cache_bypass; dev_dbg(map->dev, "Syncing %s cache\n", @@ -296,7 +296,7 @@ out: trace_regcache_sync(map->dev, name, "stop"); /* Restore the bypass state */ map->cache_bypass = bypass; - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -323,7 +323,7 @@ int regcache_sync_region(struct regmap *map, unsigned int min, BUG_ON(!map->cache_ops || !map->cache_ops->sync); - mutex_lock(&map->lock); + map->lock(map); /* Remember the initial bypass state */ bypass = map->cache_bypass; @@ -342,7 +342,7 @@ out: trace_regcache_sync(map->dev, name, "stop region"); /* Restore the bypass state */ map->cache_bypass = bypass; - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -362,11 +362,11 @@ EXPORT_SYMBOL_GPL(regcache_sync_region); */ void regcache_cache_only(struct regmap *map, bool enable) { - mutex_lock(&map->lock); + map->lock(map); WARN_ON(map->cache_bypass && enable); map->cache_only = enable; trace_regmap_cache_only(map->dev, enable); - mutex_unlock(&map->lock); + map->unlock(map); } EXPORT_SYMBOL_GPL(regcache_cache_only); @@ -381,9 +381,9 @@ EXPORT_SYMBOL_GPL(regcache_cache_only); */ void regcache_mark_dirty(struct regmap *map) { - mutex_lock(&map->lock); + map->lock(map); map->cache_dirty = true; - mutex_unlock(&map->lock); + map->unlock(map); } EXPORT_SYMBOL_GPL(regcache_mark_dirty); @@ -400,11 +400,11 @@ EXPORT_SYMBOL_GPL(regcache_mark_dirty); */ void regcache_cache_bypass(struct regmap *map, bool enable) { - mutex_lock(&map->lock); + map->lock(map); WARN_ON(map->cache_only && enable); map->cache_bypass = enable; trace_regmap_cache_bypass(map->dev, enable); - mutex_unlock(&map->lock); + map->unlock(map); } EXPORT_SYMBOL_GPL(regcache_cache_bypass); diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c index 8cfe79c6323f..004a08d54f07 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -179,6 +179,26 @@ static unsigned int regmap_parse_32(void *buf) return b[0]; } +static void regmap_lock_mutex(struct regmap *map) +{ + mutex_lock(&map->mutex); +} + +static void regmap_unlock_mutex(struct regmap *map) +{ + mutex_unlock(&map->mutex); +} + +static void regmap_lock_spinlock(struct regmap *map) +{ + spin_lock(&map->spinlock); +} + +static void regmap_unlock_spinlock(struct regmap *map) +{ + spin_unlock(&map->spinlock); +} + /** * regmap_init(): Initialise register map * @@ -208,7 +228,15 @@ struct regmap *regmap_init(struct device *dev, goto err; } - mutex_init(&map->lock); + if (bus->fast_io) { + spin_lock_init(&map->spinlock); + map->lock = regmap_lock_spinlock; + map->unlock = regmap_unlock_spinlock; + } else { + mutex_init(&map->mutex); + map->lock = regmap_lock_mutex; + map->unlock = regmap_unlock_mutex; + } map->format.buf_size = (config->reg_bits + config->val_bits) / 8; map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8); map->format.pad_bytes = config->pad_bits / 8; @@ -391,7 +419,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config) { int ret; - mutex_lock(&map->lock); + map->lock(map); regcache_exit(map); regmap_debugfs_exit(map); @@ -410,7 +438,7 @@ int regmap_reinit_cache(struct regmap *map, const struct regmap_config *config) ret = regcache_init(map, config); - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -562,11 +590,11 @@ int regmap_write(struct regmap *map, unsigned int reg, unsigned int val) { int ret; - mutex_lock(&map->lock); + map->lock(map); ret = _regmap_write(map, reg, val); - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -593,11 +621,11 @@ int regmap_raw_write(struct regmap *map, unsigned int reg, { int ret; - mutex_lock(&map->lock); + map->lock(map); ret = _regmap_raw_write(map, reg, val, val_len); - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -627,7 +655,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val, if (!map->format.parse_val) return -EINVAL; - mutex_lock(&map->lock); + map->lock(map); /* No formatting is require if val_byte is 1 */ if (val_bytes == 1) { @@ -648,7 +676,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val, kfree(wval); out: - mutex_unlock(&map->lock); + map->unlock(map); return ret; } EXPORT_SYMBOL_GPL(regmap_bulk_write); @@ -722,11 +750,11 @@ int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val) { int ret; - mutex_lock(&map->lock); + map->lock(map); ret = _regmap_read(map, reg, val); - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -751,7 +779,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, unsigned int v; int ret, i; - mutex_lock(&map->lock); + map->lock(map); if (regmap_volatile_range(map, reg, val_count) || map->cache_bypass || map->cache_type == REGCACHE_NONE) { @@ -772,7 +800,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, } out: - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -825,7 +853,7 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg, int ret; unsigned int tmp, orig; - mutex_lock(&map->lock); + map->lock(map); ret = _regmap_read(map, reg, &orig); if (ret != 0) @@ -842,7 +870,7 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg, } out: - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -909,7 +937,7 @@ int regmap_register_patch(struct regmap *map, const struct reg_default *regs, if (map->patch) return -EBUSY; - mutex_lock(&map->lock); + map->lock(map); bypass = map->cache_bypass; @@ -937,7 +965,7 @@ int regmap_register_patch(struct regmap *map, const struct reg_default *regs, out: map->cache_bypass = bypass; - mutex_unlock(&map->lock); + map->unlock(map); return ret; } diff --git a/include/linux/regmap.h b/include/linux/regmap.h index 8fd341e613d6..f14588a96eaf 100644 --- a/include/linux/regmap.h +++ b/include/linux/regmap.h @@ -110,6 +110,8 @@ typedef void (*regmap_hw_free_context)(void *context); /** * Description of a hardware bus for the register map infrastructure. * + * @fast_io: Register IO is fast. Use a spinlock instead of a mutex + * to perform locking. * @write: Write operation. * @gather_write: Write operation with split register/value, return -ENOTSUPP * if not implemented on a given device. @@ -119,6 +121,7 @@ typedef void (*regmap_hw_free_context)(void *context); * a read. */ struct regmap_bus { + bool fast_io; regmap_hw_write write; regmap_hw_gather_write gather_write; regmap_hw_read read; -- 2.20.1