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 {
  60         struct ida *id_map = &hd->cport_id_map;
  61         int ida_start, ida_end;
  62
  63         if (cport_id < 0) {
  64                 ida_start = 0;
  65                 ida_end = hd->num_cports;
  66         } else if (cport_id < hd->num_cports) {
  67                 ida_start = cport_id;
  68                 ida_end = cport_id + 1;
  69         } else {
  70                 dev_err(&hd->dev, "cport %d not available\n", cport_id);
  71                 return -EINVAL;
  72         }
  73
  74         return ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
  75 }
  76
  77 /* Locking: Caller guarantees serialisation */
  78 void gb_hd_cport_release(struct gb_host_device *hd, u16 cport_id)
  79 {
  80         ida_simple_remove(&hd->cport_id_map, cport_id);
  81 }
  82
  83 static void gb_hd_release(struct device *dev)
  84 {
  85         struct gb_host_device *hd = to_gb_host_device(dev);
  86
  87         if (hd->svc)
  88                 gb_svc_put(hd->svc);
  89         ida_simple_remove(&gb_hd_bus_id_map, hd->bus_id);
  90         ida_destroy(&hd->cport_id_map);
  91         kfree(hd);
  92 }
  93
  94 struct device_type greybus_hd_type = {
  95         .name           = "greybus_host_device",
  96         .release        = gb_hd_release,
  97 };
  98
  99 struct gb_host_device *gb_hd_create(struct gb_hd_driver *driver,
 100                                         struct device *parent,
 101                                         size_t buffer_size_max,
 102                                         size_t num_cports)
 103 {
 104         struct gb_host_device *hd;
 105         int ret;
 106
 107         /*
 108          * Validate that the driver implements all of the callbacks
 109          * so that we don't have to every time we make them.
 110          */
 111         if ((!driver->message_send) || (!driver->message_cancel)) {
 112                 dev_err(parent, "mandatory hd-callbacks missing\n");
 113                 return ERR_PTR(-EINVAL);
 114         }
 115
 116         if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
 117                 dev_err(parent, "greybus host-device buffers too small\n");
 118                 return ERR_PTR(-EINVAL);
 119         }
 120
 121         if (num_cports == 0 || num_cports > CPORT_ID_MAX + 1) {
 122                 dev_err(parent, "Invalid number of CPorts: %zu\n", num_cports);
 123                 return ERR_PTR(-EINVAL);
 124         }
 125
 126         /*
 127          * Make sure to never allocate messages larger than what the Greybus
 128          * protocol supports.
 129          */
 130         if (buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) {
 131                 dev_warn(parent, "limiting buffer size to %u\n",
 132                          GB_OPERATION_MESSAGE_SIZE_MAX);
 133                 buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX;
 134         }
 135
 136         hd = kzalloc(sizeof(*hd) + driver->hd_priv_size, GFP_KERNEL);
 137         if (!hd)
 138                 return ERR_PTR(-ENOMEM);
 139
 140         ret = ida_simple_get(&gb_hd_bus_id_map, 1, 0, GFP_KERNEL);
 141         if (ret < 0) {
 142                 kfree(hd);
 143                 return ERR_PTR(ret);
 144         }
 145         hd->bus_id = ret;
 146
 147         hd->driver = driver;
 148         INIT_LIST_HEAD(&hd->modules);
 149         INIT_LIST_HEAD(&hd->connections);
 150         ida_init(&hd->cport_id_map);
 151         hd->buffer_size_max = buffer_size_max;
 152         hd->num_cports = num_cports;
 153
 154         hd->dev.parent = parent;
 155         hd->dev.bus = &greybus_bus_type;
 156         hd->dev.type = &greybus_hd_type;
 157         hd->dev.groups = bus_groups;
 158         hd->dev.dma_mask = hd->dev.parent->dma_mask;
 159         device_initialize(&hd->dev);
 160         dev_set_name(&hd->dev, "greybus%d", hd->bus_id);
 161
 162         hd->svc = gb_svc_create(hd);
 163         if (!hd->svc) {
 164                 dev_err(&hd->dev, "failed to create svc\n");
 165                 put_device(&hd->dev);
 166                 return ERR_PTR(-ENOMEM);
 167         }
 168
 169         return hd;
 170 }
 171 EXPORT_SYMBOL_GPL(gb_hd_create);
 172
 173 int gb_hd_add(struct gb_host_device *hd)
 174 {
 175         int ret;
 176
 177         ret = device_add(&hd->dev);
 178         if (ret)
 179                 return ret;
 180
 181         ret = gb_svc_add(hd->svc);
 182         if (ret) {
 183                 device_del(&hd->dev);
 184                 return ret;
 185         }
 186
 187         return 0;
 188 }
 189 EXPORT_SYMBOL_GPL(gb_hd_add);
 190
 191 void gb_hd_del(struct gb_host_device *hd)
 192 {
 193         /*
 194          * Tear down the svc and flush any on-going hotplug processing before
 195          * removing the remaining interfaces.
 196          */
 197         gb_svc_del(hd->svc);
 198
 199         device_del(&hd->dev);
 200 }
 201 EXPORT_SYMBOL_GPL(gb_hd_del);
 202
 203 void gb_hd_put(struct gb_host_device *hd)
 204 {
 205         put_device(&hd->dev);
 206 }
 207 EXPORT_SYMBOL_GPL(gb_hd_put);
 208
 209 int __init gb_hd_init(void)
 210 {
 211         ida_init(&gb_hd_bus_id_map);
 212
 213         return 0;
 214 }
 215
 216 void gb_hd_exit(void)
 217 {
 218         ida_destroy(&gb_hd_bus_id_map);
 219 }