drivers/staging/greybus/interface.c

   1 /*
   2  * Greybus interfaces
   3  *
   4  * Copyright 2014 Google Inc.
   5  *
   6  * Released under the GPLv2 only.
   7  */
   8
   9 #include "greybus.h"
  10
  11 /* XXX This could be per-host device or per-module */
  12 static DEFINE_SPINLOCK(gb_interfaces_lock);
  13
  14 /*
  15  * A Greybus interface represents a UniPro device present on a
  16  * module.  For Project Ara, each active Interface Block on a module
  17  * implements a UniPro device, and therefore a Greybus interface.  A
  18  * Greybus module has at least one interface, but can have two (or
  19  * even more).
  20  *
  21  * Create a gb_interface structure to represent a discovered
  22  * interface.  Returns a pointer to the new interface or a null
  23  * pointer if a failure occurs due to memory exhaustion.
  24  */
  25 struct gb_interface *
  26 gb_interface_create(struct gb_module *gmod, u8 interface_id)
  27 {
  28         struct gb_interface *interface;
  29
  30         interface = kzalloc(sizeof(*interface), GFP_KERNEL);
  31         if (!interface)
  32                 return NULL;
  33
  34         interface->gmod = gmod;         /* XXX refcount? */
  35         interface->id = interface_id;
  36         INIT_LIST_HEAD(&interface->connections);
  37
  38         spin_lock_irq(&gb_interfaces_lock);
  39         list_add_tail(&interface->links, &gmod->interfaces);
  40         spin_unlock_irq(&gb_interfaces_lock);
  41
  42         return interface;
  43 }
  44
  45 /*
  46  * Tear down a previously set up interface.
  47  */
  48 void gb_interface_destroy(struct gb_interface *interface)
  49 {
  50         if (WARN_ON(!interface))
  51                 return;
  52
  53         spin_lock_irq(&gb_interfaces_lock);
  54         list_del(&interface->links);
  55         spin_unlock_irq(&gb_interfaces_lock);
  56
  57         gb_interface_connections_exit(interface);
  58
  59         /* kref_put(gmod); */
  60         kfree(interface);
  61 }
  62
  63 struct gb_interface *gb_interface_find(struct gb_module *module,
  64                                       u8 interface_id)
  65 {
  66         struct gb_interface *interface;
  67
  68         list_for_each_entry(interface, &module->interfaces, links)
  69                 if (interface->id == interface_id)
  70                         return interface;
  71
  72         return NULL;
  73 }
  74
  75 int gb_interface_connections_init(struct gb_interface *interface)
  76 {
  77         struct gb_connection *connection;
  78         int ret = 0;
  79
  80         list_for_each_entry(connection, &interface->connections,
  81                         interface_links) {
  82                 ret = gb_connection_init(connection);
  83                 if (ret)
  84                         break;
  85         }
  86
  87         return ret;
  88 }
  89
  90 void gb_interface_connections_exit(struct gb_interface *interface)
  91 {
  92         struct gb_connection *connection;
  93         struct gb_connection *next;
  94
  95         list_for_each_entry_safe(connection, next, &interface->connections,
  96                         interface_links) {
  97                 gb_connection_exit(connection);
  98                 gb_connection_destroy(connection);
  99         }
 100 }