drivers/staging/greybus/module.c

   1 /*
   2  * Greybus Module code
   3  *
   4  * Copyright 2016 Google Inc.
   5  * Copyright 2016 Linaro Ltd.
   6  *
   7  * Released under the GPLv2 only.
   8  */
   9
  10 #include "greybus.h"
  11 #include "greybus_trace.h"
  12
  13
  14 static ssize_t eject_store(struct device *dev,
  15                                 struct device_attribute *attr,
  16                                 const char *buf, size_t len)
  17 {
  18         struct gb_module *module = to_gb_module(dev);
  19         struct gb_interface *intf;
  20         size_t i;
  21         long val;
  22         int ret;
  23
  24         ret = kstrtol(buf, 0, &val);
  25         if (ret)
  26                 return ret;
  27
  28         if (!val)
  29                 return len;
  30
  31         for (i = 0; i < module->num_interfaces; ++i) {
  32                 intf = module->interfaces[i];
  33
  34                 mutex_lock(&intf->mutex);
  35                 /* Set flag to prevent concurrent activation. */
  36                 intf->ejected = true;
  37                 gb_interface_disable(intf);
  38                 gb_interface_deactivate(intf);
  39                 mutex_unlock(&intf->mutex);
  40         }
  41
  42         /* Tell the SVC to eject the primary interface. */
  43         ret = gb_svc_intf_eject(module->hd->svc, module->module_id);
  44         if (ret)
  45                 return ret;
  46
  47         return len;
  48 }
  49 static DEVICE_ATTR_WO(eject);
  50
  51 static ssize_t module_id_show(struct device *dev,
  52                                 struct device_attribute *attr, char *buf)
  53 {
  54         struct gb_module *module = to_gb_module(dev);
  55
  56         return sprintf(buf, "%u\n", module->module_id);
  57 }
  58 static DEVICE_ATTR_RO(module_id);
  59
  60 static ssize_t num_interfaces_show(struct device *dev,
  61                                 struct device_attribute *attr, char *buf)
  62 {
  63         struct gb_module *module = to_gb_module(dev);
  64
  65         return sprintf(buf, "%zu\n", module->num_interfaces);
  66 }
  67 static DEVICE_ATTR_RO(num_interfaces);
  68
  69 static struct attribute *module_attrs[] = {
  70         &dev_attr_eject.attr,
  71         &dev_attr_module_id.attr,
  72         &dev_attr_num_interfaces.attr,
  73         NULL,
  74 };
  75 ATTRIBUTE_GROUPS(module);
  76
  77 static void gb_module_release(struct device *dev)
  78 {
  79         struct gb_module *module = to_gb_module(dev);
  80
  81         trace_gb_module_release(module);
  82
  83         kfree(module);
  84 }
  85
  86 struct device_type greybus_module_type = {
  87         .name           = "greybus_module",
  88         .release        = gb_module_release,
  89 };
  90
  91 struct gb_module *gb_module_create(struct gb_host_device *hd, u8 module_id,
  92                                         size_t num_interfaces)
  93 {
  94         struct gb_interface *intf;
  95         struct gb_module *module;
  96         int i;
  97
  98         module = kzalloc(sizeof(*module) + num_interfaces * sizeof(intf),
  99                                 GFP_KERNEL);
 100         if (!module)
 101                 return NULL;
 102
 103         module->hd = hd;
 104         module->module_id = module_id;
 105         module->num_interfaces = num_interfaces;
 106
 107         module->dev.parent = &hd->dev;
 108         module->dev.bus = &greybus_bus_type;
 109         module->dev.type = &greybus_module_type;
 110         module->dev.groups = module_groups;
 111         module->dev.dma_mask = hd->dev.dma_mask;
 112         device_initialize(&module->dev);
 113         dev_set_name(&module->dev, "%d-%u", hd->bus_id, module_id);
 114
 115         trace_gb_module_create(module);
 116
 117         for (i = 0; i < num_interfaces; ++i) {
 118                 intf = gb_interface_create(module, module_id + i);
 119                 if (!intf) {
 120                         dev_err(&module->dev, "failed to create interface %u\n",
 121                                         module_id + i);
 122                         goto err_put_interfaces;
 123                 }
 124                 module->interfaces[i] = intf;
 125         }
 126
 127         return module;
 128
 129 err_put_interfaces:
 130         for (--i; i >= 0; --i)
 131                 gb_interface_put(module->interfaces[i]);
 132
 133         put_device(&module->dev);
 134
 135         return NULL;
 136 }
 137
 138 /*
 139  * Register and enable an interface after first attempting to activate it.
 140  */
 141 static void gb_module_register_interface(struct gb_interface *intf)
 142 {
 143         struct gb_module *module = intf->module;
 144         u8 intf_id = intf->interface_id;
 145         int ret;
 146
 147         mutex_lock(&intf->mutex);
 148
 149         ret = gb_interface_activate(intf);
 150         if (ret) {
 151                 if (intf->type != GB_INTERFACE_TYPE_DUMMY) {
 152                         dev_err(&module->dev,
 153                                         "failed to activate interface %u: %d\n",
 154                                         intf_id, ret);
 155                 }
 156
 157                 gb_interface_add(intf);
 158                 goto err_unlock;
 159         }
 160
 161         ret = gb_interface_add(intf);
 162         if (ret)
 163                 goto err_interface_deactivate;
 164
 165         ret = gb_interface_enable(intf);
 166         if (ret) {
 167                 dev_err(&module->dev, "failed to enable interface %u: %d\n",
 168                                 intf_id, ret);
 169                 goto err_interface_deactivate;
 170         }
 171
 172         mutex_unlock(&intf->mutex);
 173
 174         return;
 175
 176 err_interface_deactivate:
 177         gb_interface_deactivate(intf);
 178 err_unlock:
 179         mutex_unlock(&intf->mutex);
 180 }
 181
 182 static void gb_module_deregister_interface(struct gb_interface *intf)
 183 {
 184         /* Mark as disconnected to prevent I/O during disable. */
 185         if (intf->module->disconnected)
 186                 intf->disconnected = true;
 187
 188         mutex_lock(&intf->mutex);
 189         intf->removed = true;
 190         gb_interface_disable(intf);
 191         gb_interface_deactivate(intf);
 192         mutex_unlock(&intf->mutex);
 193
 194         gb_interface_del(intf);
 195 }
 196
 197 /* Register a module and its interfaces. */
 198 int gb_module_add(struct gb_module *module)
 199 {
 200         size_t i;
 201         int ret;
 202
 203         ret = device_add(&module->dev);
 204         if (ret) {
 205                 dev_err(&module->dev, "failed to register module: %d\n", ret);
 206                 return ret;
 207         }
 208
 209         trace_gb_module_add(module);
 210
 211         for (i = 0; i < module->num_interfaces; ++i)
 212                 gb_module_register_interface(module->interfaces[i]);
 213
 214         return 0;
 215 }
 216
 217 /* Deregister a module and its interfaces. */
 218 void gb_module_del(struct gb_module *module)
 219 {
 220         size_t i;
 221
 222         for (i = 0; i < module->num_interfaces; ++i)
 223                 gb_module_deregister_interface(module->interfaces[i]);
 224
 225         trace_gb_module_del(module);
 226
 227         device_del(&module->dev);
 228 }
 229
 230 void gb_module_put(struct gb_module *module)
 231 {
 232         size_t i;
 233
 234         for (i = 0; i < module->num_interfaces; ++i)
 235                 gb_interface_put(module->interfaces[i]);
 236
 237         put_device(&module->dev);
 238 }