hw/ssi.c

   1 /*
   2  * QEMU Synchronous Serial Interface support
   3  *
   4  * Copyright (c) 2009 CodeSourcery.
   5  * Written by Paul Brook
   6  *
   7  * This code is licensed under the GNU GPL v2.
   8  *
   9  * Contributions after 2012-01-13 are licensed under the terms of the
  10  * GNU GPL, version 2 or (at your option) any later version.
  11  */
  12
  13 #include "ssi.h"
  14
  15 struct SSIBus {
  16     BusState qbus;
  17 };
  18
  19 static struct BusInfo ssi_bus_info = {
  20     .name = "SSI",
  21     .size = sizeof(SSIBus),
  22 };
  23
  24 static int ssi_slave_init(DeviceState *dev, DeviceInfo *base_info)
  25 {
  26     SSISlaveInfo *info = container_of(base_info, SSISlaveInfo, qdev);
  27     SSISlave *s = SSI_SLAVE_FROM_QDEV(dev);
  28     SSIBus *bus;
  29
  30     bus = FROM_QBUS(SSIBus, qdev_get_parent_bus(dev));
  31     if (QTAILQ_FIRST(&bus->qbus.children) != dev
  32         || QTAILQ_NEXT(dev, sibling) != NULL) {
  33         hw_error("Too many devices on SSI bus");
  34     }
  35
  36     s->info = info;
  37     return info->init(s);
  38 }
  39
  40 void ssi_register_slave(SSISlaveInfo *info)
  41 {
  42     assert(info->qdev.size >= sizeof(SSISlave));
  43     info->qdev.init = ssi_slave_init;
  44     info->qdev.bus_info = &ssi_bus_info;
  45     qdev_register(&info->qdev);
  46 }
  47
  48 DeviceState *ssi_create_slave(SSIBus *bus, const char *name)
  49 {
  50     DeviceState *dev;
  51     dev = qdev_create(&bus->qbus, name);
  52     qdev_init_nofail(dev);
  53     return dev;
  54 }
  55
  56 SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
  57 {
  58     BusState *bus;
  59     bus = qbus_create(&ssi_bus_info, parent, name);
  60     return FROM_QBUS(SSIBus, bus);
  61 }
  62
  63 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
  64 {
  65     DeviceState *dev;
  66     SSISlave *slave;
  67     dev = QTAILQ_FIRST(&bus->qbus.children);
  68     if (!dev) {
  69         return 0;
  70     }
  71     slave = SSI_SLAVE_FROM_QDEV(dev);
  72     return slave->info->transfer(slave, val);
  73 }