hw/ssi.c

   1 /*
   2  * QEMU Synchronous Serial Interface support
   3  *
   4  * Copyright (c) 2009 CodeSourcery.
   5  * Copyright (c) 2012 Peter A.G. Crosthwaite (peter.crosthwaite@petalogix.com)
   6  * Copyright (c) 2012 PetaLogix Pty Ltd.
   7  * Written by Paul Brook
   8  *
   9  * This code is licensed under the GNU GPL v2.
  10  *
  11  * Contributions after 2012-01-13 are licensed under the terms of the
  12  * GNU GPL, version 2 or (at your option) any later version.
  13  */
  14
  15 #include "ssi.h"
  16
  17 struct SSIBus {
  18     BusState qbus;
  19 };
  20
  21 #define TYPE_SSI_BUS "SSI"
  22 #define SSI_BUS(obj) OBJECT_CHECK(SSIBus, (obj), TYPE_SSI_BUS)
  23
  24 static const TypeInfo ssi_bus_info = {
  25     .name = TYPE_SSI_BUS,
  26     .parent = TYPE_BUS,
  27     .instance_size = sizeof(SSIBus),
  28 };
  29
  30 static void ssi_cs_default(void *opaque, int n, int level)
  31 {
  32     SSISlave *s = SSI_SLAVE(opaque);
  33     bool cs = !!level;
  34     assert(n == 0);
  35     if (s->cs != cs) {
  36         SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
  37         if (ssc->set_cs) {
  38             ssc->set_cs(s, cs);
  39         }
  40     }
  41     s->cs = cs;
  42 }
  43
  44 static uint32_t ssi_transfer_raw_default(SSISlave *dev, uint32_t val)
  45 {
  46     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(dev);
  47
  48     if ((dev->cs && ssc->cs_polarity == SSI_CS_HIGH) ||
  49             (!dev->cs && ssc->cs_polarity == SSI_CS_LOW) ||
  50             ssc->cs_polarity == SSI_CS_NONE) {
  51         return ssc->transfer(dev, val);
  52     }
  53     return 0;
  54 }
  55
  56 static int ssi_slave_init(DeviceState *dev)
  57 {
  58     SSISlave *s = SSI_SLAVE(dev);
  59     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
  60
  61     if (ssc->transfer_raw == ssi_transfer_raw_default &&
  62             ssc->cs_polarity != SSI_CS_NONE) {
  63         qdev_init_gpio_in(&s->qdev, ssi_cs_default, 1);
  64     }
  65
  66     return ssc->init(s);
  67 }
  68
  69 static void ssi_slave_class_init(ObjectClass *klass, void *data)
  70 {
  71     SSISlaveClass *ssc = SSI_SLAVE_CLASS(klass);
  72     DeviceClass *dc = DEVICE_CLASS(klass);
  73
  74     dc->init = ssi_slave_init;
  75     dc->bus_type = TYPE_SSI_BUS;
  76     if (!ssc->transfer_raw) {
  77         ssc->transfer_raw = ssi_transfer_raw_default;
  78     }
  79 }
  80
  81 static TypeInfo ssi_slave_info = {
  82     .name = TYPE_SSI_SLAVE,
  83     .parent = TYPE_DEVICE,
  84     .class_init = ssi_slave_class_init,
  85     .class_size = sizeof(SSISlaveClass),
  86     .abstract = true,
  87 };
  88
  89 DeviceState *ssi_create_slave_no_init(SSIBus *bus, const char *name)
  90 {
  91     return qdev_create(&bus->qbus, name);
  92 }
  93
  94 DeviceState *ssi_create_slave(SSIBus *bus, const char *name)
  95 {
  96     DeviceState *dev = ssi_create_slave_no_init(bus, name);
  97
  98     qdev_init_nofail(dev);
  99     return dev;
 100 }
 101
 102 SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
 103 {
 104     BusState *bus;
 105     bus = qbus_create(TYPE_SSI_BUS, parent, name);
 106     return FROM_QBUS(SSIBus, bus);
 107 }
 108
 109 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
 110 {
 111     BusChild *kid;
 112     SSISlaveClass *ssc;
 113     uint32_t r = 0;
 114
 115     QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
 116         SSISlave *slave = SSI_SLAVE(kid->child);
 117         ssc = SSI_SLAVE_GET_CLASS(slave);
 118         r |= ssc->transfer_raw(slave, val);
 119     }
 120
 121     return r;
 122 }
 123
 124 const VMStateDescription vmstate_ssi_slave = {
 125     .name = "SSISlave",
 126     .version_id = 1,
 127     .minimum_version_id = 1,
 128     .minimum_version_id_old = 1,
 129     .fields      = (VMStateField[]) {
 130         VMSTATE_BOOL(cs, SSISlave),
 131         VMSTATE_END_OF_LIST()
 132     }
 133 };
 134
 135 static void ssi_slave_register_types(void)
 136 {
 137     type_register_static(&ssi_bus_info);
 138     type_register_static(&ssi_slave_info);
 139 }
 140
 141 type_init(ssi_slave_register_types)
 142
 143 typedef struct SSIAutoConnectArg {
 144     qemu_irq **cs_linep;
 145     SSIBus *bus;
 146 } SSIAutoConnectArg;
 147
 148 static int ssi_auto_connect_slave(Object *child, void *opaque)
 149 {
 150     SSIAutoConnectArg *arg = opaque;
 151     SSISlave *dev = (SSISlave *)object_dynamic_cast(child, TYPE_SSI_SLAVE);
 152     qemu_irq cs_line;
 153
 154     if (!dev) {
 155         return 0;
 156     }
 157
 158     cs_line = qdev_get_gpio_in(DEVICE(dev), 0);
 159     qdev_set_parent_bus(DEVICE(dev), &arg->bus->qbus);
 160     **arg->cs_linep = cs_line;
 161     (*arg->cs_linep)++;
 162     return 0;
 163 }
 164
 165 void ssi_auto_connect_slaves(DeviceState *parent, qemu_irq *cs_line,
 166                              SSIBus *bus)
 167 {
 168     SSIAutoConnectArg arg = {
 169         .cs_linep = &cs_line,
 170         .bus = bus
 171     };
 172
 173     object_child_foreach(OBJECT(parent), ssi_auto_connect_slave, &arg);
 174 }