greybus: define greybus interface abstraction
Define new source files "interface.h" and "interface.c" to contain
the definitions of the Greybus interface abstraction. A Greybus
interface represents a UniPro device present in a UniPro module.
For Project Ara, each interface block on a module implements a
UniPro interface.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
diff --git a/drivers/staging/greybus/Makefile b/drivers/staging/greybus/Makefile
index 9b5d8e9..21f6358 100644
--- a/drivers/staging/greybus/Makefile
+++ b/drivers/staging/greybus/Makefile
@@ -4,6 +4,7 @@
debugfs.o \
ap.o \
module.o \
+ interface.o \
i2c-gb.o \
gpio-gb.o \
sdio-gb.o \
diff --git a/drivers/staging/greybus/greybus.h b/drivers/staging/greybus/greybus.h
index a4fad87..c82c630 100644
--- a/drivers/staging/greybus/greybus.h
+++ b/drivers/staging/greybus/greybus.h
@@ -21,6 +21,7 @@
#include "greybus_id.h"
#include "greybus_manifest.h"
#include "module.h"
+#include "interface.h"
/* Matches up with the Greybus Protocol specification document */
diff --git a/drivers/staging/greybus/interface.c b/drivers/staging/greybus/interface.c
new file mode 100644
index 0000000..a6e6e0e
--- /dev/null
+++ b/drivers/staging/greybus/interface.c
@@ -0,0 +1,58 @@
+/*
+ * Greybus interfaces
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+
+/* XXX This could be per-host device or per-module */
+static DEFINE_SPINLOCK(gb_interfaces_lock);
+
+/*
+ * A Greybus interface represents a UniPro device present on a
+ * module. For Project Ara, each active Interface Block on a module
+ * implements a UniPro device, and therefore a Greybus interface. A
+ * Greybus module has at least one interface, but can have two (or
+ * even more).
+ *
+ * Create a gb_interface structure to represent a discovered
+ * interface. Returns a pointer to the new interface or a null
+ * pointer if a failure occurs due to memory exhaustion.
+ */
+struct gb_interface *
+gb_interface_create(struct gb_module *gmod, u8 interface_id)
+{
+ struct gb_interface *interface;
+
+ interface = kzalloc(sizeof(*interface), GFP_KERNEL);
+ if (!interface)
+ return NULL;
+
+ interface->gmod = gmod; /* XXX refcount? */
+ interface->interface_id = interface_id;
+
+ spin_lock_irq(&gb_interfaces_lock);
+ list_add_tail(&interface->links, &gmod->interfaces);
+ spin_unlock_irq(&gb_interfaces_lock);
+
+ return interface;
+}
+
+/*
+ * Tear down a previously set up interface.
+ */
+void gb_interface_destroy(struct gb_interface *interface)
+{
+ if (WARN_ON(!interface))
+ return;
+
+ spin_lock_irq(&gb_interfaces_lock);
+ list_del(&interface->links);
+ spin_unlock_irq(&gb_interfaces_lock);
+
+ /* kref_put(gmod); */
+ kfree(interface);
+}
diff --git a/drivers/staging/greybus/interface.h b/drivers/staging/greybus/interface.h
new file mode 100644
index 0000000..63ae762
--- /dev/null
+++ b/drivers/staging/greybus/interface.h
@@ -0,0 +1,24 @@
+/*
+ * Greybus interfaces
+ *
+ * Copyright 2014 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#ifndef __INTERFACE_H
+#define __INTERFACE_H
+
+#include <linux/list.h>
+
+struct gb_interface {
+ struct gb_module *gmod;
+ u8 interface_id;
+
+ struct list_head links; /* module->interfaces */
+};
+
+struct gb_interface *gb_interface_create(struct gb_module *gmod, u8 module_id);
+void gb_interface_destroy(struct gb_interface *interface);
+
+#endif /* __INTERFACE_H */
diff --git a/drivers/staging/greybus/module.c b/drivers/staging/greybus/module.c
index 31017c2..e777912 100644
--- a/drivers/staging/greybus/module.c
+++ b/drivers/staging/greybus/module.c
@@ -67,6 +67,7 @@
module->hd = hd; /* XXX refcount? */
module->module_id = module_id;
+ INIT_LIST_HEAD(&module->interfaces);
spin_lock_irq(&gb_modules_lock);
list_add_tail(&module->links, &hd->modules);
diff --git a/drivers/staging/greybus/module.h b/drivers/staging/greybus/module.h
index 0d0f19f..921c001 100644
--- a/drivers/staging/greybus/module.h
+++ b/drivers/staging/greybus/module.h
@@ -16,6 +16,7 @@
struct gb_module {
struct device dev;
+ struct list_head interfaces;
struct list_head links; /* greybus_host_device->modules */
u8 module_id; /* Physical location within the Endo */
