rpmsg_port_spi: add spi transport layer

Add Rpmsg-Port-SPI transport layer.
Rpmsg Port SPI is a new rpmsg transport layer based on the Rpmsg Port,
it provides the capability for two SPI-connected (and two extra GPIO)
chips to communicate with each other using Rpmsg.

All already implemented Rpmsg Services can be used with this new transport
layer without any modifications.

Signed-off-by: liaoao <liaoao@xiaomi.com>

drivers/rpmsg/CMakeLists.txt

@@ -33,6 +33,10 @@ if(CONFIG_RPMSG)
                                PRIVATE ${NUTTX_DIR}/openamp/open-amp/lib)
   endif()
 
+  if(CONFIG_RPMSG_PORT_SPI)
+    list(APPEND SRCS rpmsg_port_spi.c)
+  endif()
+
   if(CONFIG_RPMSG_VIRTIO)
     list(APPEND SRCS rpmsg_virtio.c)
   endif()

drivers/rpmsg/Kconfig

@@ -27,6 +27,34 @@ config RPMSG_PORT
 	---help---
 		Rpmsg port transport layer used for cross chip communication.
 
+config RPMSG_PORT_SPI
+	bool "Rpmsg SPI Port Driver Support"
+	default n
+	select RPMSG_PORT
+	---help---
+		Rpmsg SPI Port driver used for cross chip communication.
+
+if RPMSG_PORT_SPI
+
+config RPMSG_PORT_SPI_THREAD_PRIORITY
+	int "Rpmsg SPI Port Thread Priority"
+	default 224
+
+config RPMSG_PORT_SPI_THREAD_STACKSIZE
+	int "Rpmsg SPI Port Stack Size"
+	default DEFAULT_TASK_STACKSIZE
+
+config RPMSG_PORT_SPI_CRC
+	bool "Rpmsg SPI Port Use CRC Check"
+	default n
+
+config RPMSG_PORT_SPI_RX_THRESHOLD
+	int "Rpmsg SPI Port Rx Buffer Threshold"
+	default 50
+	range 0 100
+
+endif # RPMSG_PORT_SPI
+
 endif # RPMSG
 
 config RPMSG_VIRTIO

drivers/rpmsg/Make.defs

@@ -33,6 +33,10 @@ CSRCS += rpmsg_port.c
 CFLAGS += ${INCDIR_PREFIX}$(TOPDIR)$(DELIM)openamp$(DELIM)open-amp$(DELIM)lib
 endif
 
+ifeq ($(CONFIG_RPMSG_PORT_SPI),y)
+CSRCS += rpmsg_port_spi.c
+endif
+
 ifeq ($(CONFIG_RPMSG_VIRTIO),y)
 CSRCS += rpmsg_virtio.c
 CFLAGS += ${INCDIR_PREFIX}$(TOPDIR)$(DELIM)openamp$(DELIM)open-amp$(DELIM)lib

include/nuttx/rpmsg/rpmsg_port.h

@@ -28,6 +28,9 @@
 #include <nuttx/config.h>
 #include <stdint.h>
 
+#include <nuttx/ioexpander/ioexpander.h>
+#include <nuttx/spi/spi.h>
+
 #ifdef CONFIG_RPMSG_PORT
 
 /****************************************************************************
@@ -50,5 +53,79 @@ struct rpmsg_port_config_s
   FAR void       *rxbuf;
 };
 
+#ifdef CONFIG_RPMSG_PORT_SPI
+
+/* There are two gpios used for communication between two chips. At the SPI
+ * master side, mreq is an output gpio pin which is used to notify the
+ * slave side there is a data packet to be sent. it actually transfers the
+ * data only when it receives an interrupt from sreq pin. and at the SPI
+ * slave side, it prepares the data to be sent, and activates the sreq to
+ * the master side, master will initiate a transfer immediately when it
+ * receives an interrupt from sreq pin to receive the data.
+ *
+ * If IOEXPANDER_OPTION_INVERT option of pin is set to be 0, then it will
+ * be triggered an interrupt at the rising edge. or it will be triggered
+ * at the falling edge.
+ */
+
+struct rpmsg_port_spi_config_s
+{
+  /* GPIO configurations of pins used for communication between two chips. */
+
+  uint8_t         mreq_pin;
+  uint8_t         sreq_pin;
+  int             mreq_invert;
+  int             sreq_invert; /* Pin options described in ioexpander.h */
+
+  enum spi_mode_e mode;
+  uint32_t        devid;       /* Device ID of enum spi_devtype_e */
+  uint32_t        freq;        /* SPI frequency (Hz) */
+};
+
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+#ifdef CONFIG_RPMSG_PORT_SPI
+
+/****************************************************************************
+ * Name: rpmsg_port_spi_initialize
+ *
+ * Description:
+ *   Initialize a rpmsg_port_spi device to communicate between two chips.
+ *
+ * Input Parameters:
+ *   cfg     - Configuration of buffers needed for communication.
+ *   spicfg  - SPI device's configuration.
+ *   spi     - SPI device used for transfer data between two chips.
+ *   ioe     - ioexpander used to config gpios.
+ *
+ * Returned Value:
+ *   Zero on success or an negative value on failure.
+ *
+ ****************************************************************************/
+
+int
+rpmsg_port_spi_initialize(FAR const struct rpmsg_port_config_s *cfg,
+                          FAR const struct rpmsg_port_spi_config_s *spicfg,
+                          FAR struct spi_dev_s *spi,
+                          FAR struct ioexpander_dev_s *ioe);
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* CONFIG_RPMSG_PORT */
 #endif /* __INCLUDE_NUTTX_RPMSG_RPMSG_PORT_H */