misc: mic: Add support for kernel mode SCIF clients

Add support for registration/de-registration of kernel mode SCIF
clients. SCIF clients are probed with new and existing SCIF peer
devices. Similarly the client remove method is called when SCIF
peer devices are removed.

Changes to SCIF peer device framework necessitated by supporting
kernel mode SCIF clients are also included in this patch.

Reviewed-by: Nikhil Rao <nikhil.rao@intel.com>
Reviewed-by: Sudeep Dutt <sudeep.dutt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 58 insertions, 0 deletions

diff --git a/include/linux/scif.h b/include/linux/scif.h
index b1923ad2ddd3..fd62c051b166 100644
--- a/include/linux/scif.h
+++ b/include/linux/scif.h
@@ -55,6 +55,7 @@
 
 #include <linux/types.h>
 #include <linux/poll.h>
+#include <linux/device.h>
 #include <linux/scif_ioctl.h>
 
 #define SCIF_ACCEPT_SYNC	1
@@ -105,6 +106,37 @@ struct scif_pollepd {
 	short revents;
 };
 
+/**
+ * scif_peer_dev - representation of a peer SCIF device
+ *
+ * Peer devices show up as PCIe devices for the mgmt node but not the cards.
+ * The mgmt node discovers all the cards on the PCIe bus and informs the other
+ * cards about their peers. Upon notification of a peer a node adds a peer
+ * device to the peer bus to maintain symmetry in the way devices are
+ * discovered across all nodes in the SCIF network.
+ *
+ * @dev: underlying device
+ * @dnode - The destination node which this device will communicate with.
+ */
+struct scif_peer_dev {
+	struct device dev;
+	u8 dnode;
+};
+
+/**
+ * scif_client - representation of a SCIF client
+ * @name: client name
+ * @probe - client method called when a peer device is registered
+ * @remove - client method called when a peer device is unregistered
+ * @si - subsys_interface used internally for implementing SCIF clients
+ */
+struct scif_client {
+	const char *name;
+	void (*probe)(struct scif_peer_dev *spdev);
+	void (*remove)(struct scif_peer_dev *spdev);
+	struct subsys_interface si;
+};
+
 #define SCIF_OPEN_FAILED ((scif_epd_t)-1)
 #define SCIF_REGISTER_FAILED ((off_t)-1)
 #define SCIF_MMAP_FAILED ((void *)-1)
@@ -1064,4 +1096,30 @@ int scif_get_node_ids(u16 *nodes, int len, u16 *self);
  */
 int scif_poll(struct scif_pollepd *epds, unsigned int nepds, long timeout);
 
+/**
+ * scif_client_register() - Register a SCIF client
+ * @client:	client to be registered
+ *
+ * scif_client_register() registers a SCIF client. The probe() method
+ * of the client is called when SCIF peer devices come online and the
+ * remove() method is called when the peer devices disappear.
+ *
+ * Return:
+ * Upon successful completion, scif_client_register() returns a non-negative
+ * value. Otherwise the return value is the same as subsys_interface_register()
+ * in the kernel.
+ */
+int scif_client_register(struct scif_client *client);
+
+/**
+ * scif_client_unregister() - Unregister a SCIF client
+ * @client:	client to be unregistered
+ *
+ * scif_client_unregister() unregisters a SCIF client.
+ *
+ * Return:
+ * None
+ */
+void scif_client_unregister(struct scif_client *client);
+
 #endif /* __SCIF_H__ */