1 files changed, 36 insertions, 2 deletions

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index a1d4ca290862..36c86ef51ff3 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -24,6 +24,9 @@
 #include <linux/slab.h>
 #include <linux/kthread.h>
 #include <linux/completion.h>
+#include <linux/scatterlist.h>
+
+struct dma_chan;
 
 /*
  * INTERFACES between SPI master-side drivers and SPI infrastructure.
@@ -266,6 +269,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  * @auto_runtime_pm: the core should ensure a runtime PM reference is held
  *                   while the hardware is prepared, using the parent
  *                   device for the spidev
+ * @max_dma_len: Maximum length of a DMA transfer for the device.
  * @prepare_transfer_hardware: a message will soon arrive from the queue
  *      so the subsystem requests the driver to prepare the transfer hardware
  *      by issuing this call
@@ -273,7 +277,7 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  *      message while queuing transfers that arrive in the meantime. When the
  *      driver is finished with this message, it must call
  *      spi_finalize_current_message() so the subsystem can issue the next
- *      transfer
+ *      message
  * @unprepare_transfer_hardware: there are currently no more messages on the
  *      queue so the subsystem notifies the driver that it may relax the
  *      hardware by issuing this call
@@ -287,7 +291,10 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
  *                  - return 1 if the transfer is still in progress. When
  *                    the driver is finished with this transfer it must
  *                    call spi_finalize_current_transfer() so the subsystem
- *                    can issue the next transfer
+ *                    can issue the next transfer. Note: transfer_one and
+ *                    transfer_one_message are mutually exclusive; when both
+ *                    are set, the generic subsystem does not call your
+ *                    transfer_one callback.
  * @unprepare_message: undo any work done by prepare_message().
  * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS
  *      number. Any individual value may be -ENOENT for CS lines that
@@ -345,6 +352,8 @@ struct spi_master {
 #define SPI_MASTER_HALF_DUPLEX  BIT(0)          /* can't do full duplex */
 #define SPI_MASTER_NO_RX        BIT(1)          /* can't do buffer read */
 #define SPI_MASTER_NO_TX        BIT(2)          /* can't do buffer write */
+#define SPI_MASTER_MUST_RX      BIT(3)          /* requires rx */
+#define SPI_MASTER_MUST_TX      BIT(4)          /* requires tx */
 
         /* lock and mutex for SPI bus locking */
         spinlock_t              bus_lock_spinlock;
@@ -387,6 +396,17 @@ struct spi_master {
         void                    (*cleanup)(struct spi_device *spi);
 
         /*
+         * Used to enable core support for DMA handling, if can_dma()
+         * exists and returns true then the transfer will be mapped
+         * prior to transfer_one() being called.  The driver should
+         * not modify or store xfer and dma_tx and dma_rx must be set
+         * while the device is prepared.
+         */
+        bool                    (*can_dma)(struct spi_master *master,
+                                           struct spi_device *spi,
+                                           struct spi_transfer *xfer);
+
+        /*
          * These hooks are for drivers that want to use the generic
          * master transfer queueing mechanism. If these are used, the
          * transfer() function above must NOT be specified by the driver.
@@ -404,7 +424,9 @@ struct spi_master {
         bool                            rt;
         bool                            auto_runtime_pm;
         bool                            cur_msg_prepared;
+        bool                            cur_msg_mapped;
         struct completion               xfer_completion;
+        size_t                          max_dma_len;
 
         int (*prepare_transfer_hardware)(struct spi_master *master);
         int (*transfer_one_message)(struct spi_master *master,
@@ -425,6 +447,14 @@ struct spi_master {
 
         /* gpio chip select */
         int                     *cs_gpios;
+
+        /* DMA channels for use with core dmaengine helpers */
+        struct dma_chan         *dma_tx;
+        struct dma_chan         *dma_rx;
+
+        /* dummy data for full duplex devices */
+        void                    *dummy_rx;
+        void                    *dummy_tx;
 };
 
 static inline void *spi_master_get_devdata(struct spi_master *master)
@@ -509,6 +539,8 @@ extern struct spi_master *spi_busnum_to_master(u16 busnum);
  *      (optionally) changing the chipselect status, then starting
  *      the next transfer or completing this @spi_message.
  * @transfer_list: transfers are sequenced through @spi_message.transfers
+ * @tx_sg: Scatterlist for transmit, currently not for client use
+ * @rx_sg: Scatterlist for receive, currently not for client use
  *
  * SPI transfers always write the same number of bytes as they read.
  * Protocol drivers should always provide @rx_buf and/or @tx_buf.
@@ -576,6 +608,8 @@ struct spi_transfer {
 
         dma_addr_t      tx_dma;
         dma_addr_t      rx_dma;
+        struct sg_table tx_sg;
+        struct sg_table rx_sg;
 
         unsigned        cs_change:1;
         unsigned        tx_nbits:3;