2 files changed, 66 insertions, 2 deletions

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 7344f5dbd501..dc003a3a787d 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -169,7 +169,12 @@ static void dma_client_chan_alloc(struct dma_client *client)
         enum dma_state_client ack;
 
         /* Find a channel */
-        list_for_each_entry(device, &dma_device_list, global_node)
+        list_for_each_entry(device, &dma_device_list, global_node) {
+                /* Does the client require a specific DMA controller? */
+                if (client->slave && client->slave->dma_dev
+                                && client->slave->dma_dev != device->dev)
+                        continue;
+
                 list_for_each_entry(chan, &device->channels, device_node) {
                         if (!dma_chan_satisfies_mask(chan, client->cap_mask))
                                 continue;
@@ -191,6 +196,7 @@ static void dma_client_chan_alloc(struct dma_client *client)
                                         return;
                         }
                 }
+        }
 }
 
 enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie)
@@ -289,6 +295,10 @@ static void dma_clients_notify_removed(struct dma_chan *chan)
  */
 void dma_async_client_register(struct dma_client *client)
 {
+        /* validate client data */
+        BUG_ON(dma_has_cap(DMA_SLAVE, client->cap_mask) &&
+                !client->slave);
+
         mutex_lock(&dma_list_mutex);
         list_add_tail(&client->global_node, &dma_client_list);
         mutex_unlock(&dma_list_mutex);
@@ -365,6 +375,10 @@ int dma_async_device_register(struct dma_device *device)
                 !device->device_prep_dma_memset);
         BUG_ON(dma_has_cap(DMA_INTERRUPT, device->cap_mask) &&
                 !device->device_prep_dma_interrupt);
+        BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
+                !device->device_prep_slave_sg);
+        BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) &&
+                !device->device_terminate_all);
 
         BUG_ON(!device->device_alloc_chan_resources);
         BUG_ON(!device->device_free_chan_resources);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index b058d6360383..9b91d341e1fa 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -89,10 +89,23 @@ enum dma_transaction_type {
         DMA_MEMSET,
         DMA_MEMCPY_CRC32C,
         DMA_INTERRUPT,
+        DMA_SLAVE,
 };
 
 /* last transaction type for creation of the capabilities mask */
-#define DMA_TX_TYPE_END (DMA_INTERRUPT + 1)
+#define DMA_TX_TYPE_END (DMA_SLAVE + 1)
+
+/**
+ * enum dma_slave_width - DMA slave register access width.
+ * @DMA_SLAVE_WIDTH_8BIT: Do 8-bit slave register accesses
+ * @DMA_SLAVE_WIDTH_16BIT: Do 16-bit slave register accesses
+ * @DMA_SLAVE_WIDTH_32BIT: Do 32-bit slave register accesses
+ */
+enum dma_slave_width {
+        DMA_SLAVE_WIDTH_8BIT,
+        DMA_SLAVE_WIDTH_16BIT,
+        DMA_SLAVE_WIDTH_32BIT,
+};
 
 /**
  * enum dma_ctrl_flags - DMA flags to augment operation preparation,
@@ -119,6 +132,32 @@ enum dma_ctrl_flags {
 typedef struct { DECLARE_BITMAP(bits, DMA_TX_TYPE_END); } dma_cap_mask_t;
 
 /**
+ * struct dma_slave - Information about a DMA slave
+ * @dev: device acting as DMA slave
+ * @dma_dev: required DMA master device. If non-NULL, the client can not be
+ *      bound to other masters than this.
+ * @tx_reg: physical address of data register used for
+ *      memory-to-peripheral transfers
+ * @rx_reg: physical address of data register used for
+ *      peripheral-to-memory transfers
+ * @reg_width: peripheral register width
+ *
+ * If dma_dev is non-NULL, the client can not be bound to other DMA
+ * masters than the one corresponding to this device. The DMA master
+ * driver may use this to determine if there is controller-specific
+ * data wrapped around this struct. Drivers of platform code that sets
+ * the dma_dev field must therefore make sure to use an appropriate
+ * controller-specific dma slave structure wrapping this struct.
+ */
+struct dma_slave {
+        struct device           *dev;
+        struct device           *dma_dev;
+        dma_addr_t              tx_reg;
+        dma_addr_t              rx_reg;
+        enum dma_slave_width    reg_width;
+};
+
+/**
  * struct dma_chan_percpu - the per-CPU part of struct dma_chan
  * @refcount: local_t used for open-coded "bigref" counting
  * @memcpy_count: transaction counter
@@ -208,11 +247,14 @@ typedef enum dma_state_client (*dma_event_callback) (struct dma_client *client,
  * @event_callback: func ptr to call when something happens
  * @cap_mask: only return channels that satisfy the requested capabilities
  *  a value of zero corresponds to any capability
+ * @slave: data for preparing slave transfer. Must be non-NULL iff the
+ *  DMA_SLAVE capability is requested.
  * @global_node: list_head for global dma_client_list
  */
 struct dma_client {
         dma_event_callback      event_callback;
         dma_cap_mask_t          cap_mask;
+        struct dma_slave        *slave;
         struct list_head        global_node;
 };
 
@@ -269,6 +311,8 @@ struct dma_async_tx_descriptor {
  * @device_prep_dma_zero_sum: prepares a zero_sum operation
  * @device_prep_dma_memset: prepares a memset operation
  * @device_prep_dma_interrupt: prepares an end of chain interrupt operation
+ * @device_prep_slave_sg: prepares a slave dma operation
+ * @device_terminate_all: terminate all pending operations
  * @device_issue_pending: push pending transactions to hardware
  */
 struct dma_device {
@@ -304,6 +348,12 @@ struct dma_device {
         struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
                 struct dma_chan *chan, unsigned long flags);
 
+        struct dma_async_tx_descriptor *(*device_prep_slave_sg)(
+                struct dma_chan *chan, struct scatterlist *sgl,
+                unsigned int sg_len, enum dma_data_direction direction,
+                unsigned long flags);
+        void (*device_terminate_all)(struct dma_chan *chan);
+
         enum dma_status (*device_is_tx_complete)(struct dma_chan *chan,
                         dma_cookie_t cookie, dma_cookie_t *last,
                         dma_cookie_t *used);