From: Stephen Warren Date: Wed, 4 Apr 2012 21:48:28 +0000 (-0600) Subject: regmap: introduce fast_io busses, and use a spinlock for them X-Git-Tag: upstream/snapshot3+hdmi~7411^2~7^3~5 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=bacdbe077342ecc9e7b3e374cc5a41995116706a;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git 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 --- diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h index b95fd1f..e46c279 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 5157fa0..cca4600 100644 --- a/drivers/base/regmap/regcache-rbtree.c +++ b/drivers/base/regmap/regcache-rbtree.c @@ -139,7 +139,7 @@ static int rbtree_show(struct seq_file *s, void *ignored) int nodes = 0; int registers = 0; - mutex_lock(&map->lock); + map->lock(map); for (node = rb_first(&rbtree_ctx->root); node != NULL; node = rb_next(node)) { @@ -155,7 +155,7 @@ static int rbtree_show(struct seq_file *s, void *ignored) seq_printf(s, "%d nodes, %d registers, average %d registers\n", nodes, registers, registers / nodes); - mutex_unlock(&map->lock); + map->unlock(map); return 0; } diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c index 87f54db..4ad1850 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; } @@ -361,11 +361,11 @@ out: */ 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); @@ -380,9 +380,9 @@ 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); @@ -399,11 +399,11 @@ 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 bde30c5..6b4a775 100644 --- a/drivers/base/regmap/regmap.c +++ b/drivers/base/regmap/regmap.c @@ -158,6 +158,26 @@ 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 * @@ -187,7 +207,15 @@ 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; @@ -365,7 +393,7 @@ 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); @@ -384,7 +412,7 @@ 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; } @@ -536,11 +564,11 @@ 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; } @@ -567,11 +595,11 @@ 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; } @@ -601,7 +629,7 @@ 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) { @@ -622,7 +650,7 @@ 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); @@ -696,11 +724,11 @@ 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; } @@ -725,7 +753,7 @@ 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) { @@ -746,7 +774,7 @@ int regmap_raw_read(struct regmap *map, unsigned int reg, void *val, } out: - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -799,7 +827,7 @@ 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) @@ -816,7 +844,7 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg, } out: - mutex_unlock(&map->lock); + map->unlock(map); return ret; } @@ -883,7 +911,7 @@ 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; @@ -911,7 +939,7 @@ 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 8fd341e..f14588a 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;