1 files changed, 30 insertions, 0 deletions
diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h
index 5ca3b708c0..9b9581d230 100644
--- a/include/hw/i2c/i2c.h
+++ b/include/hw/i2c/i2c.h
@@ -12,6 +12,7 @@
 enum i2c_event {
     I2C_START_RECV,
     I2C_START_SEND,
+    I2C_START_SEND_ASYNC,
     I2C_FINISH,
     I2C_NACK /* Masker NACKed a receive byte.  */
 };
@@ -28,6 +29,9 @@ struct I2CSlaveClass {
     /* Master to slave. Returns non-zero for a NAK, 0 for success. */
     int (*send)(I2CSlave *s, uint8_t data);
 
+    /* Master to slave (asynchronous). Receiving slave must call i2c_ack(). */
+    void (*send_async)(I2CSlave *s, uint8_t data);
+
     /*
      * Slave to master.  This cannot fail, the device should always
      * return something here.
@@ -69,13 +73,25 @@ struct I2CNode {
     QLIST_ENTRY(I2CNode) next;
 };
 
+typedef struct I2CPendingMaster I2CPendingMaster;
+
+struct I2CPendingMaster {
+    QEMUBH *bh;
+    QSIMPLEQ_ENTRY(I2CPendingMaster) entry;
+};
+
 typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList;
+typedef QSIMPLEQ_HEAD(I2CPendingMasters, I2CPendingMaster) I2CPendingMasters;
 
 struct I2CBus {
     BusState qbus;
     I2CNodeList current_devs;
+    I2CPendingMasters pending_masters;
     uint8_t saved_address;
     bool broadcast;
+
+    /* Set from slave currently mastering the bus. */
+    QEMUBH *bh;
 };
 
 I2CBus *i2c_init_bus(DeviceState *parent, const char *name);
@@ -115,9 +131,23 @@ int i2c_start_recv(I2CBus *bus, uint8_t address);
  */
 int i2c_start_send(I2CBus *bus, uint8_t address);
 
+/**
+ * i2c_start_send_async: start an asynchronous 'send' transfer on an I2C bus.
+ *
+ * @bus: #I2CBus to be used
+ * @address: address of the slave
+ *
+ * Return: 0 on success, -1 on error
+ */
+int i2c_start_send_async(I2CBus *bus, uint8_t address);
+
 void i2c_end_transfer(I2CBus *bus);
 void i2c_nack(I2CBus *bus);
+void i2c_ack(I2CBus *bus);
+void i2c_bus_master(I2CBus *bus, QEMUBH *bh);
+void i2c_bus_release(I2CBus *bus);
 int i2c_send(I2CBus *bus, uint8_t data);
+int i2c_send_async(I2CBus *bus, uint8_t data);
 uint8_t i2c_recv(I2CBus *bus);
 bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
                   I2CNodeList *current_devs);