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 #include <linux/kernel.h>
  11 #include <linux/slab.h>
  12
  13 #include "greybus.h"
  14
  15
  16 static struct ida gb_hd_bus_id_map;
  17
  18 int gb_hd_output(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
  19                  bool async)
  20 {
  21         if (!hd || !hd->driver || !hd->driver->output)
  22                 return -EINVAL;
  23         return hd->driver->output(hd, req, size, cmd, async);
  24 }
  25 EXPORT_SYMBOL_GPL(gb_hd_output);
  26
  27 static ssize_t bus_id_show(struct device *dev,
  28                                 struct device_attribute *attr, char *buf)
  29 {
  30         struct gb_host_device *hd = to_gb_host_device(dev);
  31
  32         return sprintf(buf, "%d\n", hd->bus_id);
  33 }
  34 static DEVICE_ATTR_RO(bus_id);
  35
  36 static struct attribute *bus_attrs[] = {
  37         &dev_attr_bus_id.attr,
  38         NULL
  39 };
  40 ATTRIBUTE_GROUPS(bus);
  41
  42 int gb_hd_cport_reserve(struct gb_host_device *hd, u16 cport_id)
  43 {
  44         struct ida *id_map = &hd->cport_id_map;
  45         int ret;
  46
  47         ret = ida_simple_get(id_map, cport_id, cport_id + 1, GFP_KERNEL);
  48         if (ret < 0) {
  49                 dev_err(&hd->dev, "failed to reserve cport %u\n", cport_id);
  50                 return ret;
  51         }
  52
  53         return 0;
  54 }
  55 EXPORT_SYMBOL_GPL(gb_hd_cport_reserve);
  56
  57 /* Locking: Caller guarantees serialisation */
  58 int gb_hd_cport_allocate(struct gb_host_device *hd, int cport_id,
  59                                 unsigned long flags)
  60 {
  61         struct ida *id_map = &hd->cport_id_map;
  62         int ida_start, ida_end;
  63
  64         if (hd->driver->cport_allocate)
  65                 return hd->driver->cport_allocate(hd, cport_id, flags);
  66
  67         if (cport_id < 0) {
  68                 ida_start = 0;
  69                 ida_end = hd->num_cports;
  70         } else if (cport_id < hd->num_cports) {
  71                 ida_start = cport_id;
  72                 ida_end = cport_id + 1;
  73         } else {
  74                 dev_err(&hd->dev, "cport %d not available\n", cport_id);
  75                 return -EINVAL;
  76         }
  77
  78         return ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
  79 }
  80
  81 /* Locking: Caller guarantees serialisation */
  82 void gb_hd_cport_release(struct gb_host_device *hd, u16 cport_id)
  83 {
  84         if (hd->driver->cport_release) {
  85                 hd->driver->cport_release(hd, cport_id);
  86                 return;
  87         }
  88
  89         ida_simple_remove(&hd->cport_id_map, cport_id);
  90 }
  91
  92 static void gb_hd_release(struct device *dev)
  93 {
  94         struct gb_host_device *hd = to_gb_host_device(dev);
  95
  96         if (hd->svc)
  97                 gb_svc_put(hd->svc);
  98         ida_simple_remove(&gb_hd_bus_id_map, hd->bus_id);
  99         ida_destroy(&hd->cport_id_map);
 100         kfree(hd);
 101 }
 102
 103 struct device_type greybus_hd_type = {
 104         .name           = "greybus_host_device",
 105         .release        = gb_hd_release,
 106 };
 107
 108 struct gb_host_device *gb_hd_create(struct gb_hd_driver *driver,
 109                                         struct device *parent,
 110                                         size_t buffer_size_max,
 111                                         size_t num_cports)
 112 {
 113         struct gb_host_device *hd;
 114         int ret;
 115
 116         /*
 117          * Validate that the driver implements all of the callbacks
 118          * so that we don't have to every time we make them.
 119          */
 120         if ((!driver->message_send) || (!driver->message_cancel)) {
 121                 dev_err(parent, "mandatory hd-callbacks missing\n");
 122                 return ERR_PTR(-EINVAL);
 123         }
 124
 125         if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
 126                 dev_err(parent, "greybus host-device buffers too small\n");
 127                 return ERR_PTR(-EINVAL);
 128         }
 129
 130         if (num_cports == 0 || num_cports > CPORT_ID_MAX + 1) {
 131                 dev_err(parent, "Invalid number of CPorts: %zu\n", num_cports);
 132                 return ERR_PTR(-EINVAL);
 133         }
 134
 135         /*
 136          * Make sure to never allocate messages larger than what the Greybus
 137          * protocol supports.
 138          */
 139         if (buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) {
 140                 dev_warn(parent, "limiting buffer size to %u\n",
 141                          GB_OPERATION_MESSAGE_SIZE_MAX);
 142                 buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX;
 143         }
 144
 145         hd = kzalloc(sizeof(*hd) + driver->hd_priv_size, GFP_KERNEL);
 146         if (!hd)
 147                 return ERR_PTR(-ENOMEM);
 148
 149         ret = ida_simple_get(&gb_hd_bus_id_map, 1, 0, GFP_KERNEL);
 150         if (ret < 0) {
 151                 kfree(hd);
 152                 return ERR_PTR(ret);
 153         }
 154         hd->bus_id = ret;
 155
 156         hd->driver = driver;
 157         INIT_LIST_HEAD(&hd->modules);
 158         INIT_LIST_HEAD(&hd->connections);
 159         ida_init(&hd->cport_id_map);
 160         hd->buffer_size_max = buffer_size_max;
 161         hd->num_cports = num_cports;
 162
 163         hd->dev.parent = parent;
 164         hd->dev.bus = &greybus_bus_type;
 165         hd->dev.type = &greybus_hd_type;
 166         hd->dev.groups = bus_groups;
 167         hd->dev.dma_mask = hd->dev.parent->dma_mask;
 168         device_initialize(&hd->dev);
 169         dev_set_name(&hd->dev, "greybus%d", hd->bus_id);
 170
 171         hd->svc = gb_svc_create(hd);
 172         if (!hd->svc) {
 173                 dev_err(&hd->dev, "failed to create svc\n");
 174                 put_device(&hd->dev);
 175                 return ERR_PTR(-ENOMEM);
 176         }
 177
 178         return hd;
 179 }
 180 EXPORT_SYMBOL_GPL(gb_hd_create);
 181
 182 int gb_hd_add(struct gb_host_device *hd)
 183 {
 184         int ret;
 185
 186         ret = device_add(&hd->dev);
 187         if (ret)
 188                 return ret;
 189
 190         ret = gb_svc_add(hd->svc);
 191         if (ret) {
 192                 device_del(&hd->dev);
 193                 return ret;
 194         }
 195
 196         return 0;
 197 }
 198 EXPORT_SYMBOL_GPL(gb_hd_add);
 199
 200 void gb_hd_del(struct gb_host_device *hd)
 201 {
 202         /*
 203          * Tear down the svc and flush any on-going hotplug processing before
 204          * removing the remaining interfaces.
 205          */
 206         gb_svc_del(hd->svc);
 207
 208         device_del(&hd->dev);
 209 }
 210 EXPORT_SYMBOL_GPL(gb_hd_del);
 211
 212 void gb_hd_put(struct gb_host_device *hd)
 213 {
 214         put_device(&hd->dev);
 215 }
 216 EXPORT_SYMBOL_GPL(gb_hd_put);
 217
 218 int __init gb_hd_init(void)
 219 {
 220         ida_init(&gb_hd_bus_id_map);
 221
 222         return 0;
 223 }
 224
 225 void gb_hd_exit(void)
 226 {
 227         ida_destroy(&gb_hd_bus_id_map);
 228 }