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 (file)
--- a/drivers/staging/greybus/Makefile
+++ b/drivers/staging/greybus/Makefile
@@ -4,6 +4,7 @@ greybus-y :=    core.o          \
                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 (file)
--- 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 (file)
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 (file)
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 (file)
--- a/drivers/staging/greybus/module.c
+++ b/drivers/staging/greybus/module.c
@@ -67,6 +67,7 @@ struct gb_module *gb_module_create(struct greybus_host_device *hd, u8 module_id)
 
        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 (file)
--- 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 */