fpga: add fpga bridge framework

This framework adds API functions for enabling/
disabling FPGA bridges under kernel control.

This allows the Linux kernel to disable FPGA bridges
during FPGA reprogramming and to enable FPGA bridges
when FPGA reprogramming is done.  This framework is
be manufacturer-agnostic, allowing it to be used in
interfaces that use the FPGA Manager Framework to
reprogram FPGA's.

The functions are:
* of_fpga_bridge_get
* fpga_bridge_put
   Get/put an exclusive reference to a FPGA bridge.

* fpga_bridge_enable
* fpga_bridge_disable
   Enable/Disable traffic through a bridge.

* fpga_bridge_register
* fpga_bridge_unregister
   Register/unregister a device-specific low level FPGA
   Bridge driver.

Get an exclusive reference to a bridge and add it to a list:
* fpga_bridge_get_to_list

To enable/disable/put a set of bridges that are on a list:
* fpga_bridges_enable
* fpga_bridges_disable
* fpga_bridges_put

Signed-off-by: Alan Tull <atull@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 60 insertions, 0 deletions

diff --git a/include/linux/fpga/fpga-bridge.h b/include/linux/fpga/fpga-bridge.h
new file mode 100644
index 000000000000..dba6e3c697c7
--- /dev/null
+++ b/include/linux/fpga/fpga-bridge.h
@@ -0,0 +1,60 @@
+#include <linux/device.h>
+#include <linux/fpga/fpga-mgr.h>
+
+#ifndef _LINUX_FPGA_BRIDGE_H
+#define _LINUX_FPGA_BRIDGE_H
+
+struct fpga_bridge;
+
+/**
+ * struct fpga_bridge_ops - ops for low level FPGA bridge drivers
+ * @enable_show: returns the FPGA bridge's status
+ * @enable_set: set a FPGA bridge as enabled or disabled
+ * @fpga_bridge_remove: set FPGA into a specific state during driver remove
+ */
+struct fpga_bridge_ops {
+        int (*enable_show)(struct fpga_bridge *bridge);
+        int (*enable_set)(struct fpga_bridge *bridge, bool enable);
+        void (*fpga_bridge_remove)(struct fpga_bridge *bridge);
+};
+
+/**
+ * struct fpga_bridge - FPGA bridge structure
+ * @name: name of low level FPGA bridge
+ * @dev: FPGA bridge device
+ * @mutex: enforces exclusive reference to bridge
+ * @br_ops: pointer to struct of FPGA bridge ops
+ * @info: fpga image specific information
+ * @node: FPGA bridge list node
+ * @priv: low level driver private date
+ */
+struct fpga_bridge {
+        const char *name;
+        struct device dev;
+        struct mutex mutex; /* for exclusive reference to bridge */
+        const struct fpga_bridge_ops *br_ops;
+        struct fpga_image_info *info;
+        struct list_head node;
+        void *priv;
+};
+
+#define to_fpga_bridge(d) container_of(d, struct fpga_bridge, dev)
+
+struct fpga_bridge *of_fpga_bridge_get(struct device_node *node,
+                                       struct fpga_image_info *info);
+void fpga_bridge_put(struct fpga_bridge *bridge);
+int fpga_bridge_enable(struct fpga_bridge *bridge);
+int fpga_bridge_disable(struct fpga_bridge *bridge);
+
+int fpga_bridges_enable(struct list_head *bridge_list);
+int fpga_bridges_disable(struct list_head *bridge_list);
+void fpga_bridges_put(struct list_head *bridge_list);
+int fpga_bridge_get_to_list(struct device_node *np,
+                            struct fpga_image_info *info,
+                            struct list_head *bridge_list);
+
+int fpga_bridge_register(struct device *dev, const char *name,
+                         const struct fpga_bridge_ops *br_ops, void *priv);
+void fpga_bridge_unregister(struct device *dev);
+
+#endif /* _LINUX_FPGA_BRIDGE_H */