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

regmap: Add async I/O support

Allow drivers to take advantage of any support the underlying transports
may have for pipelining data.

4 files changed, 351 insertions, 47 deletions

diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 401d1919635a..202518641779 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -16,6 +16,7 @@
 #include <linux/regmap.h>
 #include <linux/fs.h>
 #include <linux/list.h>
+#include <linux/wait.h>
 
 struct regmap;
 struct regcache_ops;
@@ -39,6 +40,13 @@ struct regmap_format {
         unsigned int (*parse_val)(void *buf);
 };
 
+struct regmap_async {
+        struct list_head list;
+        struct work_struct cleanup;
+        struct regmap *map;
+        void *work_buf;
+};
+
 struct regmap {
         struct mutex mutex;
         spinlock_t spinlock;
@@ -53,6 +61,11 @@ struct regmap {
         void *bus_context;
         const char *name;
 
+        spinlock_t async_lock;
+        wait_queue_head_t async_waitq;
+        struct list_head async_list;
+        int async_ret;
+
 #ifdef CONFIG_DEBUG_FS
         struct dentry *debugfs;
         const char *debugfs_name;
@@ -74,6 +87,9 @@ struct regmap {
         const struct regmap_access_table *volatile_table;
         const struct regmap_access_table *precious_table;
 
+        int (*reg_read)(void *context, unsigned int reg, unsigned int *val);
+        int (*reg_write)(void *context, unsigned int reg, unsigned int val);
+
         u8 read_flag_mask;
         u8 write_flag_mask;
 
@@ -175,6 +191,8 @@ bool regcache_set_val(void *base, unsigned int idx,
                       unsigned int val, unsigned int word_size);
 int regcache_lookup_reg(struct regmap *map, unsigned int reg);
 
+void regmap_async_complete_cb(struct regmap_async *async, int ret);
+
 extern struct regcache_ops regcache_rbtree_ops;
 extern struct regcache_ops regcache_lzo_ops;
 
diff --git a/drivers/base/regmap/regmap-spi.c b/drivers/base/regmap/regmap-spi.c
index ffa46a92ad33..913274b5f00a 100644
--- a/drivers/base/regmap/regmap-spi.c
+++ b/drivers/base/regmap/regmap-spi.c
@@ -15,6 +15,21 @@
 #include <linux/init.h>
 #include <linux/module.h>
 
+#include "internal.h"
+
+struct regmap_async_spi {
+        struct regmap_async core;
+        struct spi_message m;
+        struct spi_transfer t[2];
+};
+
+static void regmap_spi_complete(void *data)
+{
+        struct regmap_async_spi *async = data;
+
+        regmap_async_complete_cb(&async->core, async->m.status);
+}
+
 static int regmap_spi_write(void *context, const void *data, size_t count)
 {
         struct device *dev = context;
@@ -40,6 +55,41 @@ static int regmap_spi_gather_write(void *context,
         return spi_sync(spi, &m);
 }
 
+static int regmap_spi_async_write(void *context,
+                                  const void *reg, size_t reg_len,
+                                  const void *val, size_t val_len,
+                                  struct regmap_async *a)
+{
+        struct regmap_async_spi *async = container_of(a,
+                                                      struct regmap_async_spi,
+                                                      core);
+        struct device *dev = context;
+        struct spi_device *spi = to_spi_device(dev);
+
+        async->t[0].tx_buf = reg;
+        async->t[0].len = reg_len;
+        async->t[1].tx_buf = val;
+        async->t[1].len = val_len;
+
+        spi_message_init(&async->m);
+        spi_message_add_tail(&async->t[0], &async->m);
+        spi_message_add_tail(&async->t[1], &async->m);
+
+        async->m.complete = regmap_spi_complete;
+        async->m.context = async;
+
+        return spi_async(spi, &async->m);
+}
+
+static struct regmap_async *regmap_spi_async_alloc(void)
+{
+        struct regmap_async_spi *async_spi;
+
+        async_spi = kzalloc(sizeof(*async_spi), GFP_KERNEL);
+
+        return &async_spi->core;
+}
+
 static int regmap_spi_read(void *context,
                            const void *reg, size_t reg_size,
                            void *val, size_t val_size)
@@ -53,6 +103,8 @@ static int regmap_spi_read(void *context,
 static struct regmap_bus regmap_spi = {
         .write = regmap_spi_write,
         .gather_write = regmap_spi_gather_write,
+        .async_write = regmap_spi_async_write,
+        .async_alloc = regmap_spi_async_alloc,
         .read = regmap_spi_read,
         .read_flag_mask = 0x80,
 };
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 42d5cb0f503f..6d1e756e90ad 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -16,6 +16,7 @@
 #include <linux/mutex.h>
 #include <linux/err.h>
 #include <linux/rbtree.h>
+#include <linux/sched.h>
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/regmap.h>
@@ -34,6 +35,22 @@ static int _regmap_update_bits(struct regmap *map, unsigned int reg,
                                unsigned int mask, unsigned int val,
                                bool *change);
 
+static int _regmap_bus_read(void *context, unsigned int reg,
+                            unsigned int *val);
+static int _regmap_bus_formatted_write(void *context, unsigned int reg,
+                                       unsigned int val);
+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)
@@ -423,6 +440,10 @@ struct regmap *regmap_init(struct device *dev,
         map->cache_type = config->cache_type;
         map->name = config->name;
 
+        spin_lock_init(&map->async_lock);
+        INIT_LIST_HEAD(&map->async_list);
+        init_waitqueue_head(&map->async_waitq);
+
         if (config->read_flag_mask || config->write_flag_mask) {
                 map->read_flag_mask = config->read_flag_mask;
                 map->write_flag_mask = config->write_flag_mask;
@@ -430,6 +451,8 @@ struct regmap *regmap_init(struct device *dev,
                 map->read_flag_mask = bus->read_flag_mask;
         }
 
+        map->reg_read = _regmap_bus_read;
+
         reg_endian = config->reg_format_endian;
         if (reg_endian == REGMAP_ENDIAN_DEFAULT)
                 reg_endian = bus->reg_format_endian_default;
@@ -575,6 +598,11 @@ struct regmap *regmap_init(struct device *dev,
                 goto err_map;
         }
 
+        if (map->format.format_write)
+                map->reg_write = _regmap_bus_formatted_write;
+        else if (map->format.format_val)
+                map->reg_write = _regmap_bus_raw_write;
+
         map->range_tree = RB_ROOT;
         for (i = 0; i < config->num_ranges; i++) {
                 const struct regmap_range_cfg *range_cfg = &config->ranges[i];
@@ -870,10 +898,13 @@ static int _regmap_select_page(struct regmap *map, unsigned int *reg,
 }
 
 static int _regmap_raw_write(struct regmap *map, unsigned int reg,
-                             const void *val, size_t val_len)
+                             const void *val, size_t val_len, bool async)
 {
         struct regmap_range_node *range;
+        unsigned long flags;
         u8 *u8 = map->work_buf;
+        void *work_val = map->work_buf + map->format.reg_bytes +
+                map->format.pad_bytes;
         void *buf;
         int ret = -ENOTSUPP;
         size_t len;
@@ -918,7 +949,7 @@ static 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);
+                                                map->format.val_bytes, async);
                         if (ret != 0)
                                 return ret;
 
@@ -941,6 +972,50 @@ static 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;
+
+                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. */
+                memcpy(async->work_buf, map->work_buf, map->format.pad_bytes +
+                       map->format.reg_bytes + map->format.val_bytes);
+                if (val == work_val)
+                        val = async->work_buf + map->format.pad_bytes +
+                                map->format.reg_bytes;
+
+                spin_lock_irqsave(&map->async_lock, flags);
+                list_add_tail(&async->list, &map->async_list);
+                spin_unlock_irqrestore(&map->async_lock, flags);
+
+                ret = map->bus->async_write(map->bus_context, async->work_buf,
+                                            map->format.reg_bytes +
+                                            map->format.pad_bytes,
+                                            val, val_len, async);
+
+                if (ret != 0) {
+                        dev_err(map->dev, "Failed to schedule write: %d\n",
+                                ret);
+
+                        spin_lock_irqsave(&map->async_lock, flags);
+                        list_del(&async->list);
+                        spin_unlock_irqrestore(&map->async_lock, flags);
+
+                        kfree(async->work_buf);
+                        kfree(async);
+                }
+        }
+
         trace_regmap_hw_write_start(map->dev, reg,
                                     val_len / map->format.val_bytes);
 
@@ -948,8 +1023,7 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
          * send the work_buf directly, otherwise try to do a gather
          * write.
          */
-        if (val == (map->work_buf + map->format.pad_bytes +
-                    map->format.reg_bytes))
+        if (val == work_val)
                 ret = map->bus->write(map->bus_context, map->work_buf,
                                       map->format.reg_bytes +
                                       map->format.pad_bytes +
@@ -981,12 +1055,54 @@ static int _regmap_raw_write(struct regmap *map, unsigned int reg,
         return ret;
 }
 
+static int _regmap_bus_formatted_write(void *context, unsigned int reg,
+                                       unsigned int val)
+{
+        int ret;
+        struct regmap_range_node *range;
+        struct regmap *map = context;
+
+        BUG_ON(!map->format.format_write);
+
+        range = _regmap_range_lookup(map, reg);
+        if (range) {
+                ret = _regmap_select_page(map, &reg, range, 1);
+                if (ret != 0)
+                        return ret;
+        }
+
+        map->format.format_write(map, reg, val);
+
+        trace_regmap_hw_write_start(map->dev, reg, 1);
+
+        ret = map->bus->write(map->bus_context, map->work_buf,
+                              map->format.buf_size);
+
+        trace_regmap_hw_write_done(map->dev, reg, 1);
+
+        return ret;
+}
+
+static int _regmap_bus_raw_write(void *context, unsigned int reg,
+                                 unsigned int val)
+{
+        struct regmap *map = context;
+
+        BUG_ON(!map->format.format_val);
+
+        map->format.format_val(map->work_buf + map->format.reg_bytes
+                               + map->format.pad_bytes, val, 0);
+        return _regmap_raw_write(map, reg,
+                                 map->work_buf +
+                                 map->format.reg_bytes +
+                                 map->format.pad_bytes,
+                                 map->format.val_bytes, false);
+}
+
 int _regmap_write(struct regmap *map, unsigned int reg,
                   unsigned int val)
 {
-        struct regmap_range_node *range;
         int ret;
-        BUG_ON(!map->format.format_write && !map->format.format_val);
 
         if (!map->cache_bypass && map->format.format_write) {
                 ret = regcache_write(map, reg, val);
@@ -1005,33 +1121,7 @@ int _regmap_write(struct regmap *map, unsigned int reg,
 
         trace_regmap_reg_write(map->dev, reg, val);
 
-        if (map->format.format_write) {
-                range = _regmap_range_lookup(map, reg);
-                if (range) {
-                        ret = _regmap_select_page(map, &reg, range, 1);
-                        if (ret != 0)
-                                return ret;
-                }
-
-                map->format.format_write(map, reg, val);
-
-                trace_regmap_hw_write_start(map->dev, reg, 1);
-
-                ret = map->bus->write(map->bus_context, map->work_buf,
-                                      map->format.buf_size);
-
-                trace_regmap_hw_write_done(map->dev, reg, 1);
-
-                return ret;
-        } else {
-                map->format.format_val(map->work_buf + map->format.reg_bytes
-                                       + map->format.pad_bytes, val, 0);
-                return _regmap_raw_write(map, reg,
-                                         map->work_buf +
-                                         map->format.reg_bytes +
-                                         map->format.pad_bytes,
-                                         map->format.val_bytes);
-        }
+        return map->reg_write(map, reg, val);
 }
 
 /**
@@ -1089,7 +1179,7 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
 
         map->lock(map->lock_arg);
 
-        ret = _regmap_raw_write(map, reg, val, val_len);
+        ret = _regmap_raw_write(map, reg, val, val_len, false);
 
         map->unlock(map->lock_arg);
 
@@ -1145,14 +1235,15 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
         if (map->use_single_rw) {
                 for (i = 0; i < val_count; i++) {
                         ret = regmap_raw_write(map,
-                                                reg + (i * map->reg_stride),
-                                                val + (i * val_bytes),
-                                                val_bytes);
+                                               reg + (i * map->reg_stride),
+                                               val + (i * val_bytes),
+                                               val_bytes);
                         if (ret != 0)
                                 return ret;
                 }
         } else {
-                ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count);
+                ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count,
+                                        false);
         }
 
         if (val_bytes != 1)
@@ -1164,6 +1255,48 @@ out:
 }
 EXPORT_SYMBOL_GPL(regmap_bulk_write);
 
+/**
+ * regmap_raw_write_async(): Write raw values to one or more registers
+ *                           asynchronously
+ *
+ * @map: Register map to write to
+ * @reg: Initial register to write to
+ * @val: Block of data to be written, laid out for direct transmission to the
+ *       device.  Must be valid until regmap_async_complete() is called.
+ * @val_len: Length of data pointed to by val.
+ *
+ * This function is intended to be used for things like firmware
+ * download where a large block of data needs to be transferred to the
+ * device.  No formatting will be done on the data provided.
+ *
+ * If supported by the underlying bus the write will be scheduled
+ * asynchronously, helping maximise I/O speed on higher speed buses
+ * like SPI.  regmap_async_complete() can be called to ensure that all
+ * asynchrnous writes have been completed.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_raw_write_async(struct regmap *map, unsigned int reg,
+                           const void *val, size_t val_len)
+{
+        int ret;
+
+        if (val_len % map->format.val_bytes)
+                return -EINVAL;
+        if (reg % map->reg_stride)
+                return -EINVAL;
+
+        map->lock(map->lock_arg);
+
+        ret = _regmap_raw_write(map, reg, val, val_len, true);
+
+        map->unlock(map->lock_arg);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_raw_write_async);
+
 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
                             unsigned int val_len)
 {
@@ -1202,10 +1335,27 @@ static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
         return ret;
 }
 
+static int _regmap_bus_read(void *context, unsigned int reg,
+                            unsigned int *val)
+{
+        int ret;
+        struct regmap *map = context;
+
+        if (!map->format.parse_val)
+                return -EINVAL;
+
+        ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
+        if (ret == 0)
+                *val = map->format.parse_val(map->work_buf);
+
+        return ret;
+}
+
 static int _regmap_read(struct regmap *map, unsigned int reg,
                         unsigned int *val)
 {
         int ret;
+        BUG_ON(!map->reg_read);
 
         if (!map->cache_bypass) {
                 ret = regcache_read(map, reg, val);
@@ -1213,26 +1363,21 @@ static int _regmap_read(struct regmap *map, unsigned int reg,
                         return 0;
         }
 
-        if (!map->format.parse_val)
-                return -EINVAL;
-
         if (map->cache_only)
                 return -EBUSY;
 
-        ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
+        ret = map->reg_read(map, reg, val);
         if (ret == 0) {
-                *val = map->format.parse_val(map->work_buf);
-
 #ifdef LOG_DEVICE
                 if (strcmp(dev_name(map->dev), LOG_DEVICE) == 0)
                         dev_info(map->dev, "%x => %x\n", reg, *val);
 #endif
 
                 trace_regmap_reg_read(map->dev, reg, *val);
-        }
 
-        if (ret == 0 && !map->cache_bypass)
-                regcache_write(map, reg, *val);
+                if (!map->cache_bypass)
+                        regcache_write(map, reg, *val);
+        }
 
         return ret;
 }
@@ -1450,6 +1595,67 @@ int regmap_update_bits_check(struct regmap *map, unsigned int reg,
 }
 EXPORT_SYMBOL_GPL(regmap_update_bits_check);
 
+void regmap_async_complete_cb(struct regmap_async *async, int ret)
+{
+        struct regmap *map = async->map;
+        bool wake;
+
+        spin_lock(&map->async_lock);
+
+        list_del(&async->list);
+        wake = list_empty(&map->async_list);
+
+        if (ret != 0)
+                map->async_ret = ret;
+
+        spin_unlock(&map->async_lock);
+
+        schedule_work(&async->cleanup);
+
+        if (wake)
+                wake_up(&map->async_waitq);
+}
+EXPORT_SYMBOL_GPL(regmap_async_complete_cb);
+
+static int regmap_async_is_done(struct regmap *map)
+{
+        unsigned long flags;
+        int ret;
+
+        spin_lock_irqsave(&map->async_lock, flags);
+        ret = list_empty(&map->async_list);
+        spin_unlock_irqrestore(&map->async_lock, flags);
+
+        return ret;
+}
+
+/**
+ * regmap_async_complete: Ensure all asynchronous I/O has completed.
+ *
+ * @map: Map to operate on.
+ *
+ * Blocks until any pending asynchronous I/O has completed.  Returns
+ * an error code for any failed I/O operations.
+ */
+int regmap_async_complete(struct regmap *map)
+{
+        unsigned long flags;
+        int ret;
+
+        /* Nothing to do with no async support */
+        if (!map->bus->async_write)
+                return 0;
+
+        wait_event(map->async_waitq, regmap_async_is_done(map));
+
+        spin_lock_irqsave(&map->async_lock, flags);
+        ret = map->async_ret;
+        map->async_ret = 0;
+        spin_unlock_irqrestore(&map->async_lock, flags);
+
+        return ret;
+}
+
 /**
  * regmap_register_patch: Register and apply register updates to be applied
  *                        on device initialistion
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index b7e95bf942c9..f9b7fbe35ab1 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -235,14 +235,21 @@ struct regmap_range_cfg {
         unsigned int window_len;
 };
 
+struct regmap_async;
+
 typedef int (*regmap_hw_write)(void *context, const void *data,
                                size_t count);
 typedef int (*regmap_hw_gather_write)(void *context,
                                       const void *reg, size_t reg_len,
                                       const void *val, size_t val_len);
+typedef int (*regmap_hw_async_write)(void *context,
+                                     const void *reg, size_t reg_len,
+                                     const void *val, size_t val_len,
+                                     struct regmap_async *async);
 typedef int (*regmap_hw_read)(void *context,
                               const void *reg_buf, size_t reg_size,
                               void *val_buf, size_t val_size);
+typedef struct regmap_async *(*regmap_hw_async_alloc)(void);
 typedef void (*regmap_hw_free_context)(void *context);
 
 /**
@@ -255,8 +262,11 @@ typedef void (*regmap_hw_free_context)(void *context);
  * @write: Write operation.
  * @gather_write: Write operation with split register/value, return -ENOTSUPP
  *                if not implemented  on a given device.
+ * @async_write: Write operation which completes asynchronously, optional and
+ *               must serialise with respect to non-async I/O.
  * @read: Read operation.  Data is returned in the buffer used to transmit
  *         data.
+ * @async_alloc: Allocate a regmap_async() structure.
  * @read_flag_mask: Mask to be set in the top byte of the register when doing
  *                  a read.
  * @reg_format_endian_default: Default endianness for formatted register
@@ -265,13 +275,16 @@ typedef void (*regmap_hw_free_context)(void *context);
  * @val_format_endian_default: Default endianness for formatted register
  *     values. Used when the regmap_config specifies DEFAULT. If this is
  *     DEFAULT, BIG is assumed.
+ * @async_size: Size of struct used for async work.
  */
 struct regmap_bus {
         bool fast_io;
         regmap_hw_write write;
         regmap_hw_gather_write gather_write;
+        regmap_hw_async_write async_write;
         regmap_hw_read read;
         regmap_hw_free_context free_context;
+        regmap_hw_async_alloc async_alloc;
         u8 read_flag_mask;
         enum regmap_endian reg_format_endian_default;
         enum regmap_endian val_format_endian_default;
@@ -310,6 +323,8 @@ 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,
                         size_t val_count);
+int regmap_raw_write_async(struct regmap *map, unsigned int reg,
+                           const void *val, size_t val_len);
 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
 int regmap_raw_read(struct regmap *map, unsigned int reg,
                     void *val, size_t val_len);
@@ -321,6 +336,7 @@ int regmap_update_bits_check(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);
 
 int regcache_sync(struct regmap *map);
 int regcache_sync_region(struct regmap *map, unsigned int min,
@@ -422,6 +438,13 @@ static inline int regmap_raw_write(struct regmap *map, unsigned int reg,
         return -EINVAL;
 }
 
+static inline int regmap_raw_write_async(struct regmap *map, unsigned int reg,
+                                         const void *val, size_t val_len)
+{
+        WARN_ONCE(1, "regmap API is disabled");
+        return -EINVAL;
+}
+
 static inline int regmap_bulk_write(struct regmap *map, unsigned int reg,
                                     const void *val, size_t val_count)
 {
@@ -500,6 +523,11 @@ static inline void regcache_mark_dirty(struct regmap *map)
         WARN_ONCE(1, "regmap API is disabled");
 }
 
+static inline void regmap_async_complete(struct regmap *map)
+{
+        WARN_ONCE(1, "regmap API is disabled");
+}
+
 static inline int regmap_register_patch(struct regmap *map,
                                         const struct reg_default *regs,
                                         int num_regs)