[PATCH v17 4/6] fpga: add fpga bridge framework

[Alan Tull]

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 
---
v2:  Minor cleanup
v12: Bump version to line up with simple fpga bus
 Remove sysfs
 Improve get/put functions, get the low level driver too.
 Clean up class implementation
 Add kernel doc documentation
 Rename (un)register_fpga_bridge -> fpga_bridge_(un)register
v13: Add inlined empty functions for if not CONFIG_FPGA_BRIDGE
 Clean up debugging
 Remove unneeded #include in .h
 Remove unnecessary prints
 Remove 'label' DT binding.
 Document the mutex
v14: Allow bridges with no ops
 *const* struct fpga_bridge_ops
 Add functions to git/put/enable/disable list of bridges
 Add list node to struct fpga_bridge
 Do of_node_get/put in of_fpga_bridge_get()
 Add r/o attributes: name and state
v15: No change in this patch for v15 of this patch set
v16: Remove of_get_fpga_bus function
v17: No change to this patch in v17 of patch set
---
 drivers/fpga/Kconfig |7 +
 drivers/fpga/Makefile|3 +
 drivers/fpga/fpga-bridge.c   |  388 ++
 include/linux/fpga/fpga-bridge.h |   55 ++
 4 files changed, 453 insertions(+)
 create mode 100644 drivers/fpga/fpga-bridge.c
 create mode 100644 include/linux/fpga/fpga-bridge.h

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index c9b9fdf..b6cfd89 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -24,6 +24,13 @@ config FPGA_MGR_ZYNQ_FPGA
help
  FPGA manager driver support for Xilinx Zynq FPGAs.
 
+config FPGA_BRIDGE
+   bool "FPGA Bridge Framework"
+   depends on OF
+   help
+ Say Y here if you want to support bridges connected between host
+processors and FPGAs or between FPGAs.
+
 endif # FPGA
 
 endmenu
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index 8d83fc6..4baef00 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -8,3 +8,6 @@ obj-$(CONFIG_FPGA)  += fpga-mgr.o
 # FPGA Manager Drivers
 obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o
 obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)   += zynq-fpga.o
+
+# FPGA Bridge Drivers
+obj-$(CONFIG_FPGA_BRIDGE)  += fpga-bridge.o
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
new file mode 100644
index 000..5119d8e
--- /dev/null
+++ b/drivers/fpga/fpga-bridge.c
@@ -0,0 +1,388 @@
+/*
+ * FPGA Bridge Framework Driver
+ *
+ *  Copyright (C) 2013-2015 Altera Corporation, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see .
+ */
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+static DEFINE_IDA(fpga_bridge_ida);
+static struct class *fpga_bridge_class;
+
+/* Lock for adding/removing bridges to linked lists*/
+spinlock_t bridge_list_lock;
+
+static int fpga_bridge_of_node_match(struct device *dev, const void *data)
+{
+   return dev->of_node == data;
+}
+
+/**
+ * fpga_bridge_enable - Enable transactions on the bridge
+ *
+ * @bridge: FPGA bridge
+ *
+ * Return: 0 for success, error code otherwise.
+ */
+int fpga_bridge_enable(struct fpga_bridge *bridge)
+{
+   dev_dbg(>dev, "enable\n");
+
+   if (bridge->br_ops && bridge->br_ops->enable_set)
+   return bridge->br_ops->enable_set(bridge, 1);
+
+   return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_enable);
+
+/**
+ * fpga_bridge_disable - Disable transactions on the bridge
+ *
+ * @bridge: FPGA bridge
+ *
+ * Return: 0 for success, error code otherwise.
+ */

[PATCH v17 4/6] fpga: add fpga bridge framework

[Alan Tull]

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 
---
v2:  Minor cleanup
v12: Bump version to line up with simple fpga bus
 Remove sysfs
 Improve get/put functions, get the low level driver too.
 Clean up class implementation
 Add kernel doc documentation
 Rename (un)register_fpga_bridge -> fpga_bridge_(un)register
v13: Add inlined empty functions for if not CONFIG_FPGA_BRIDGE
 Clean up debugging
 Remove unneeded #include in .h
 Remove unnecessary prints
 Remove 'label' DT binding.
 Document the mutex
v14: Allow bridges with no ops
 *const* struct fpga_bridge_ops
 Add functions to git/put/enable/disable list of bridges
 Add list node to struct fpga_bridge
 Do of_node_get/put in of_fpga_bridge_get()
 Add r/o attributes: name and state
v15: No change in this patch for v15 of this patch set
v16: Remove of_get_fpga_bus function
v17: No change to this patch in v17 of patch set
---
 drivers/fpga/Kconfig |7 +
 drivers/fpga/Makefile|3 +
 drivers/fpga/fpga-bridge.c   |  388 ++
 include/linux/fpga/fpga-bridge.h |   55 ++
 4 files changed, 453 insertions(+)
 create mode 100644 drivers/fpga/fpga-bridge.c
 create mode 100644 include/linux/fpga/fpga-bridge.h

diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index c9b9fdf..b6cfd89 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -24,6 +24,13 @@ config FPGA_MGR_ZYNQ_FPGA
help
  FPGA manager driver support for Xilinx Zynq FPGAs.
 
+config FPGA_BRIDGE
+   bool "FPGA Bridge Framework"
+   depends on OF
+   help
+ Say Y here if you want to support bridges connected between host
+processors and FPGAs or between FPGAs.
+
 endif # FPGA
 
 endmenu
diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
index 8d83fc6..4baef00 100644
--- a/drivers/fpga/Makefile
+++ b/drivers/fpga/Makefile
@@ -8,3 +8,6 @@ obj-$(CONFIG_FPGA)  += fpga-mgr.o
 # FPGA Manager Drivers
 obj-$(CONFIG_FPGA_MGR_SOCFPGA) += socfpga.o
 obj-$(CONFIG_FPGA_MGR_ZYNQ_FPGA)   += zynq-fpga.o
+
+# FPGA Bridge Drivers
+obj-$(CONFIG_FPGA_BRIDGE)  += fpga-bridge.o
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
new file mode 100644
index 000..5119d8e
--- /dev/null
+++ b/drivers/fpga/fpga-bridge.c
@@ -0,0 +1,388 @@
+/*
+ * FPGA Bridge Framework Driver
+ *
+ *  Copyright (C) 2013-2015 Altera Corporation, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see .
+ */
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
+
+static DEFINE_IDA(fpga_bridge_ida);
+static struct class *fpga_bridge_class;
+
+/* Lock for adding/removing bridges to linked lists*/
+spinlock_t bridge_list_lock;
+
+static int fpga_bridge_of_node_match(struct device *dev, const void *data)
+{
+   return dev->of_node == data;
+}
+
+/**
+ * fpga_bridge_enable - Enable transactions on the bridge
+ *
+ * @bridge: FPGA bridge
+ *
+ * Return: 0 for success, error code otherwise.
+ */
+int fpga_bridge_enable(struct fpga_bridge *bridge)
+{
+   dev_dbg(>dev, "enable\n");
+
+   if (bridge->br_ops && bridge->br_ops->enable_set)
+   return bridge->br_ops->enable_set(bridge, 1);
+
+   return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_enable);
+
+/**
+ * fpga_bridge_disable - Disable transactions on the bridge
+ *
+ * @bridge: FPGA bridge
+ *
+ * Return: 0 for success, error code otherwise.
+ */
+int fpga_bridge_disable(struct