drivers/staging/greybus/hd.c

   1 /*
   2  * Greybus Host Device
   3  *
   4  * Copyright 2014-2015 Google Inc.
   5  * Copyright 2014-2015 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14
  15 #include "greybus.h"
  16
  17 static DEFINE_MUTEX(hd_mutex);
  18
  19
  20 static void free_hd(struct kref *kref)
  21 {
  22         struct gb_host_device *hd;
  23
  24         hd = container_of(kref, struct gb_host_device, kref);
  25
  26         ida_destroy(&hd->cport_id_map);
  27         kfree(hd);
  28         mutex_unlock(&hd_mutex);
  29 }
  30
  31 struct gb_host_device *greybus_create_hd(struct greybus_host_driver *driver,
  32                                               struct device *parent,
  33                                               size_t buffer_size_max,
  34                                               size_t num_cports)
  35 {
  36         struct gb_host_device *hd;
  37
  38         /*
  39          * Validate that the driver implements all of the callbacks
  40          * so that we don't have to every time we make them.
  41          */
  42         if ((!driver->message_send) || (!driver->message_cancel)) {
  43                 pr_err("Must implement all greybus_host_driver callbacks!\n");
  44                 return ERR_PTR(-EINVAL);
  45         }
  46
  47         if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
  48                 dev_err(parent, "greybus host-device buffers too small\n");
  49                 return ERR_PTR(-EINVAL);
  50         }
  51
  52         if (num_cports == 0 || num_cports > CPORT_ID_MAX) {
  53                 dev_err(parent, "Invalid number of CPorts: %zu\n", num_cports);
  54                 return ERR_PTR(-EINVAL);
  55         }
  56
  57         /*
  58          * Make sure to never allocate messages larger than what the Greybus
  59          * protocol supports.
  60          */
  61         if (buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) {
  62                 dev_warn(parent, "limiting buffer size to %u\n",
  63                          GB_OPERATION_MESSAGE_SIZE_MAX);
  64                 buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX;
  65         }
  66
  67         hd = kzalloc(sizeof(*hd) + driver->hd_priv_size, GFP_KERNEL);
  68         if (!hd)
  69                 return ERR_PTR(-ENOMEM);
  70
  71         kref_init(&hd->kref);
  72         hd->parent = parent;
  73         hd->driver = driver;
  74         INIT_LIST_HEAD(&hd->interfaces);
  75         INIT_LIST_HEAD(&hd->connections);
  76         ida_init(&hd->cport_id_map);
  77         hd->buffer_size_max = buffer_size_max;
  78         hd->num_cports = num_cports;
  79
  80         /*
  81          * Initialize AP's SVC protocol connection:
  82          *
  83          * This is required as part of early initialization of the host device
  84          * as we need this connection in order to start any kind of message
  85          * exchange between the AP and the SVC. SVC will start with a
  86          * 'get-version' request followed by a 'svc-hello' message and at that
  87          * time we will create a fully initialized svc-connection, as we need
  88          * endo-id and AP's interface id for that.
  89          */
  90         if (!gb_ap_svc_connection_create(hd)) {
  91                 kref_put_mutex(&hd->kref, free_hd, &hd_mutex);
  92                 return ERR_PTR(-ENOMEM);
  93         }
  94
  95         return hd;
  96 }
  97 EXPORT_SYMBOL_GPL(greybus_create_hd);
  98
  99 void greybus_remove_hd(struct gb_host_device *hd)
 100 {
 101         /*
 102          * Tear down all interfaces, modules, and the endo that is associated
 103          * with this host controller before freeing the memory associated with
 104          * the host controller.
 105          */
 106         gb_interfaces_remove(hd);
 107         gb_endo_remove(hd->endo);
 108
 109         /* Is the SVC still using the partially uninitialized connection ? */
 110         if (hd->initial_svc_connection)
 111                 gb_connection_destroy(hd->initial_svc_connection);
 112
 113         kref_put_mutex(&hd->kref, free_hd, &hd_mutex);
 114 }
 115 EXPORT_SYMBOL_GPL(greybus_remove_hd);