Merge tag 'regmap-async-reg' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap into asoc-dapm

regmap: Provide async single register operations

This helps make it easier for users to take advantage of async I/O by
allowing single register writes to be inserted into sequences.

4 files changed, 192 insertions, 38 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 57f777835d97..6873b4ce03f9 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -44,7 +44,6 @@ struct regmap_format {
 
 struct regmap_async {
         struct list_head list;
-        struct work_struct cleanup;
         struct regmap *map;
         void *work_buf;
 };
@@ -64,9 +63,11 @@ struct regmap {
         void *bus_context;
         const char *name;
 
+        bool async;
         spinlock_t async_lock;
         wait_queue_head_t async_waitq;
         struct list_head async_list;
+        struct list_head async_free;
         int async_ret;
 
 #ifdef CONFIG_DEBUG_FS
@@ -218,7 +219,7 @@ bool regcache_set_val(struct regmap *map, void *base, unsigned int idx,
 int regcache_lookup_reg(struct regmap *map, unsigned int reg);
 
 int _regmap_raw_write(struct regmap *map, unsigned int reg,
-                      const void *val, size_t val_len, bool async);
+                      const void *val, size_t val_len);
 
 void regmap_async_complete_cb(struct regmap_async *async, int ret);
 
diff --git a/drivers/base/regmap/regcache.c b/drivers/base/regmap/regcache.c
index d6c2d691b6e8..a36112af494c 100644
--- a/drivers/base/regmap/regcache.c
+++ b/drivers/base/regmap/regcache.c
@@ -631,8 +631,7 @@ static int regcache_sync_block_raw_flush(struct regmap *map, const void **data,
 
         map->cache_bypass = 1;
 
-        ret = _regmap_raw_write(map, base, *data, count * val_bytes,
-                                false);
+        ret = _regmap_raw_write(map, base, *data, count * val_bytes);
 
         map->cache_bypass = 0;
 
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 7d689a15c500..0503d868ff8c 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -42,15 +42,6 @@ static int _regmap_bus_formatted_write(void *context, unsigned int reg,
 static int _regmap_bus_raw_write(void *context, unsigned int reg,
                                  unsigned int val);
 
-static void async_cleanup(struct work_struct *work)
-{
-        struct regmap_async *async = container_of(work, struct regmap_async,
-                                                  cleanup);
-
-        kfree(async->work_buf);
-        kfree(async);
-}
-
 bool regmap_reg_in_ranges(unsigned int reg,
                           const struct regmap_range *ranges,
                           unsigned int nranges)
@@ -465,6 +456,7 @@ struct regmap *regmap_init(struct device *dev,
 
         spin_lock_init(&map->async_lock);
         INIT_LIST_HEAD(&map->async_list);
+        INIT_LIST_HEAD(&map->async_free);
         init_waitqueue_head(&map->async_waitq);
 
         if (config->read_flag_mask || config->write_flag_mask) {
@@ -942,12 +934,22 @@ EXPORT_SYMBOL_GPL(regmap_reinit_cache);
  */
 void regmap_exit(struct regmap *map)
 {
+        struct regmap_async *async;
+
         regcache_exit(map);
         regmap_debugfs_exit(map);
         regmap_range_exit(map);
         if (map->bus && map->bus->free_context)
                 map->bus->free_context(map->bus_context);
         kfree(map->work_buf);
+        while (!list_empty(&map->async_free)) {
+                async = list_first_entry_or_null(&map->async_free,
+                                                 struct regmap_async,
+                                                 list);
+                list_del(&async->list);
+                kfree(async->work_buf);
+                kfree(async);
+        }
         kfree(map);
 }
 EXPORT_SYMBOL_GPL(regmap_exit);
@@ -1039,7 +1041,7 @@ static int _regmap_select_page(struct regmap *map, unsigned int *reg,
 }
 
 int _regmap_raw_write(struct regmap *map, unsigned int reg,
-                      const void *val, size_t val_len, bool async)
+                      const void *val, size_t val_len)
 {
         struct regmap_range_node *range;
         unsigned long flags;
@@ -1091,7 +1093,7 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
                         dev_dbg(map->dev, "Writing window %d/%zu\n",
                                 win_residue, val_len / map->format.val_bytes);
                         ret = _regmap_raw_write(map, reg, val, win_residue *
-                                                map->format.val_bytes, async);
+                                                map->format.val_bytes);
                         if (ret != 0)
                                 return ret;
 
@@ -1114,21 +1116,42 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
 
         u8[0] |= map->write_flag_mask;
 
-        if (async && map->bus->async_write) {
-                struct regmap_async *async = map->bus->async_alloc();
-                if (!async)
-                        return -ENOMEM;
+        /*
+         * Essentially all I/O mechanisms will be faster with a single
+         * buffer to write.  Since register syncs often generate raw
+         * writes of single registers optimise that case.
+         */
+        if (val != work_val && val_len == map->format.val_bytes) {
+                memcpy(work_val, val, map->format.val_bytes);
+                val = work_val;
+        }
+
+        if (map->async && map->bus->async_write) {
+                struct regmap_async *async;
 
                 trace_regmap_async_write_start(map->dev, reg, val_len);
 
-                async->work_buf = kzalloc(map->format.buf_size,
-                                          GFP_KERNEL | GFP_DMA);
-                if (!async->work_buf) {
-                        kfree(async);
-                        return -ENOMEM;
+                spin_lock_irqsave(&map->async_lock, flags);
+                async = list_first_entry_or_null(&map->async_free,
+                                                 struct regmap_async,
+                                                 list);
+                if (async)
+                        list_del(&async->list);
+                spin_unlock_irqrestore(&map->async_lock, flags);
+
+                if (!async) {
+                        async = map->bus->async_alloc();
+                        if (!async)
+                                return -ENOMEM;
+
+                        async->work_buf = kzalloc(map->format.buf_size,
+                                                  GFP_KERNEL | GFP_DMA);
+                        if (!async->work_buf) {
+                                kfree(async);
+                                return -ENOMEM;
+                        }
                 }
 
-                INIT_WORK(&async->cleanup, async_cleanup);
                 async->map = map;
 
                 /* If the caller supplied the value we can use it safely. */
@@ -1152,11 +1175,8 @@ int _regmap_raw_write(struct regmap *map, unsigned int reg,
                                 ret);
 
                         spin_lock_irqsave(&map->async_lock, flags);
-                        list_del(&async->list);
+                        list_move(&async->list, &map->async_free);
                         spin_unlock_irqrestore(&map->async_lock, flags);
-
-                        kfree(async->work_buf);
-                        kfree(async);
                 }
 
                 return ret;
@@ -1253,7 +1273,7 @@ static int _regmap_bus_raw_write(void *context, unsigned int reg,
                                  map->work_buf +
                                  map->format.reg_bytes +
                                  map->format.pad_bytes,
-                                 map->format.val_bytes, false);
+                                 map->format.val_bytes);
 }
 
 static inline void *_regmap_map_get_context(struct regmap *map)
@@ -1318,6 +1338,37 @@ int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
 EXPORT_SYMBOL_GPL(regmap_write);
 
 /**
+ * regmap_write_async(): Write a value to a single register asynchronously
+ *
+ * @map: Register map to write to
+ * @reg: Register to write to
+ * @val: Value to be written
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_write_async(struct regmap *map, unsigned int reg, unsigned int val)
+{
+        int ret;
+
+        if (reg % map->reg_stride)
+                return -EINVAL;
+
+        map->lock(map->lock_arg);
+
+        map->async = true;
+
+        ret = _regmap_write(map, reg, val);
+
+        map->async = false;
+
+        map->unlock(map->lock_arg);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_write_async);
+
+/**
  * regmap_raw_write(): Write raw values to one or more registers
  *
  * @map: Register map to write to
@@ -1345,7 +1396,7 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
 
         map->lock(map->lock_arg);
 
-        ret = _regmap_raw_write(map, reg, val, val_len, false);
+        ret = _regmap_raw_write(map, reg, val, val_len);
 
         map->unlock(map->lock_arg);
 
@@ -1426,8 +1477,7 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
                                 return ret;
                 }
         } else {
-                ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count,
-                                        false);
+                ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count);
         }
 
         if (val_bytes != 1)
@@ -1473,7 +1523,11 @@ int regmap_raw_write_async(struct regmap *map, unsigned int reg,
 
         map->lock(map->lock_arg);
 
-        ret = _regmap_raw_write(map, reg, val, val_len, true);
+        map->async = true;
+
+        ret = _regmap_raw_write(map, reg, val, val_len);
+
+        map->async = false;
 
         map->unlock(map->lock_arg);
 
@@ -1788,6 +1842,41 @@ int regmap_update_bits(struct regmap *map, unsigned int reg,
 EXPORT_SYMBOL_GPL(regmap_update_bits);
 
 /**
+ * regmap_update_bits_async: Perform a read/modify/write cycle on the register
+ *                           map asynchronously
+ *
+ * @map: Register map to update
+ * @reg: Register to update
+ * @mask: Bitmask to change
+ * @val: New value for bitmask
+ *
+ * With most buses the read must be done synchronously so this is most
+ * useful for devices with a cache which do not need to interact with
+ * the hardware to determine the current register value.
+ *
+ * Returns zero for success, a negative number on error.
+ */
+int regmap_update_bits_async(struct regmap *map, unsigned int reg,
+                             unsigned int mask, unsigned int val)
+{
+        bool change;
+        int ret;
+
+        map->lock(map->lock_arg);
+
+        map->async = true;
+
+        ret = _regmap_update_bits(map, reg, mask, val, &change);
+
+        map->async = false;
+
+        map->unlock(map->lock_arg);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_update_bits_async);
+
+/**
  * regmap_update_bits_check: Perform a read/modify/write cycle on the
  *                           register map and report if updated
  *
@@ -1812,6 +1901,43 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 }
 EXPORT_SYMBOL_GPL(regmap_update_bits_check);
 
+/**
+ * regmap_update_bits_check_async: Perform a read/modify/write cycle on the
+ *                                 register map asynchronously and report if
+ *                                 updated
+ *
+ * @map: Register map to update
+ * @reg: Register to update
+ * @mask: Bitmask to change
+ * @val: New value for bitmask
+ * @change: Boolean indicating if a write was done
+ *
+ * With most buses the read must be done synchronously so this is most
+ * useful for devices with a cache which do not need to interact with
+ * the hardware to determine the current register value.
+ *
+ * Returns zero for success, a negative number on error.
+ */
+int regmap_update_bits_check_async(struct regmap *map, unsigned int reg,
+                                   unsigned int mask, unsigned int val,
+                                   bool *change)
+{
+        int ret;
+
+        map->lock(map->lock_arg);
+
+        map->async = true;
+
+        ret = _regmap_update_bits(map, reg, mask, val, change);
+
+        map->async = false;
+
+        map->unlock(map->lock_arg);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_update_bits_check_async);
+
 void regmap_async_complete_cb(struct regmap_async *async, int ret)
 {
         struct regmap *map = async->map;
@@ -1820,8 +1946,7 @@ void regmap_async_complete_cb(struct regmap_async *async, int ret)
         trace_regmap_async_io_complete(map->dev);
 
         spin_lock(&map->async_lock);
-
-        list_del(&async->list);
+        list_move(&async->list, &map->async_free);
         wake = list_empty(&map->async_list);
 
         if (ret != 0)
@@ -1829,8 +1954,6 @@ void regmap_async_complete_cb(struct regmap_async *async, int ret)
 
         spin_unlock(&map->async_lock);
 
-        schedule_work(&async->cleanup);
-
         if (wake)
                 wake_up(&map->async_waitq);
 }
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index a10380bfbeac..114565befbd2 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -374,6 +374,7 @@ int regmap_reinit_cache(struct regmap *map,
                         const struct regmap_config *config);
 struct regmap *dev_get_regmap(struct device *dev, const char *name);
 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val);
+int regmap_write_async(struct regmap *map, unsigned int reg, unsigned int val);
 int regmap_raw_write(struct regmap *map, unsigned int reg,
                      const void *val, size_t val_len);
 int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
@@ -387,9 +388,14 @@ int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
                      size_t val_count);
 int regmap_update_bits(struct regmap *map, unsigned int reg,
                        unsigned int mask, unsigned int val);
+int regmap_update_bits_async(struct regmap *map, unsigned int reg,
+                             unsigned int mask, unsigned int val);
 int regmap_update_bits_check(struct regmap *map, unsigned int reg,
                              unsigned int mask, unsigned int val,
                              bool *change);
+int regmap_update_bits_check_async(struct regmap *map, unsigned int reg,
+                                   unsigned int mask, unsigned int val,
+                                   bool *change);
 int regmap_get_val_bytes(struct regmap *map);
 int regmap_async_complete(struct regmap *map);
 bool regmap_can_raw_write(struct regmap *map);
@@ -527,6 +533,13 @@ static inline int regmap_write(struct regmap *map, unsigned int reg,
         return -EINVAL;
 }
 
+static inline int regmap_write_async(struct regmap *map, unsigned int reg,
+                                     unsigned int val)
+{
+        WARN_ONCE(1, "regmap API is disabled");
+        return -EINVAL;
+}
+
 static inline int regmap_raw_write(struct regmap *map, unsigned int reg,
                                    const void *val, size_t val_len)
 {
@@ -576,6 +589,14 @@ static inline int regmap_update_bits(struct regmap *map, unsigned int reg,
         return -EINVAL;
 }
 
+static inline int regmap_update_bits_async(struct regmap *map,
+                                           unsigned int reg,
+                                           unsigned int mask, unsigned int val)
+{
+        WARN_ONCE(1, "regmap API is disabled");
+        return -EINVAL;
+}
+
 static inline int regmap_update_bits_check(struct regmap *map,
                                            unsigned int reg,
                                            unsigned int mask, unsigned int val,
@@ -585,6 +606,16 @@ static inline int regmap_update_bits_check(struct regmap *map,
         return -EINVAL;
 }
 
+static inline int regmap_update_bits_check_async(struct regmap *map,
+                                                 unsigned int reg,
+                                                 unsigned int mask,
+                                                 unsigned int val,
+                                                 bool *change)
+{
+        WARN_ONCE(1, "regmap API is disabled");
+        return -EINVAL;
+}
+
 static inline int regmap_get_val_bytes(struct regmap *map)
 {
         WARN_ONCE(1, "regmap API is disabled");