hw/ssi/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 "qemu/osdep.h"
  16 #include "hw/ssi/ssi.h"
  17 #include "migration/vmstate.h"
  18 #include "qemu/module.h"
  19 #include "qapi/error.h"
  20
  21 struct SSIBus {
  22     BusState parent_obj;
  23 };
  24
  25 #define TYPE_SSI_BUS "SSI"
  26 #define SSI_BUS(obj) OBJECT_CHECK(SSIBus, (obj), TYPE_SSI_BUS)
  27
  28 static const TypeInfo ssi_bus_info = {
  29     .name = TYPE_SSI_BUS,
  30     .parent = TYPE_BUS,
  31     .instance_size = sizeof(SSIBus),
  32 };
  33
  34 static void ssi_cs_default(void *opaque, int n, int level)
  35 {
  36     SSISlave *s = SSI_SLAVE(opaque);
  37     bool cs = !!level;
  38     assert(n == 0);
  39     if (s->cs != cs) {
  40         SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
  41         if (ssc->set_cs) {
  42             ssc->set_cs(s, cs);
  43         }
  44     }
  45     s->cs = cs;
  46 }
  47
  48 static uint32_t ssi_transfer_raw_default(SSISlave *dev, uint32_t val)
  49 {
  50     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(dev);
  51
  52     if ((dev->cs && ssc->cs_polarity == SSI_CS_HIGH) ||
  53             (!dev->cs && ssc->cs_polarity == SSI_CS_LOW) ||
  54             ssc->cs_polarity == SSI_CS_NONE) {
  55         return ssc->transfer(dev, val);
  56     }
  57     return 0;
  58 }
  59
  60 static void ssi_slave_realize(DeviceState *dev, Error **errp)
  61 {
  62     SSISlave *s = SSI_SLAVE(dev);
  63     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
  64
  65     if (ssc->transfer_raw == ssi_transfer_raw_default &&
  66             ssc->cs_polarity != SSI_CS_NONE) {
  67         qdev_init_gpio_in_named(dev, ssi_cs_default, SSI_GPIO_CS, 1);
  68     }
  69
  70     ssc->realize(s, errp);
  71 }
  72
  73 static void ssi_slave_class_init(ObjectClass *klass, void *data)
  74 {
  75     SSISlaveClass *ssc = SSI_SLAVE_CLASS(klass);
  76     DeviceClass *dc = DEVICE_CLASS(klass);
  77
  78     dc->realize = ssi_slave_realize;
  79     dc->bus_type = TYPE_SSI_BUS;
  80     if (!ssc->transfer_raw) {
  81         ssc->transfer_raw = ssi_transfer_raw_default;
  82     }
  83 }
  84
  85 static const TypeInfo ssi_slave_info = {
  86     .name = TYPE_SSI_SLAVE,
  87     .parent = TYPE_DEVICE,
  88     .class_init = ssi_slave_class_init,
  89     .class_size = sizeof(SSISlaveClass),
  90     .abstract = true,
  91 };
  92
  93 DeviceState *ssi_create_slave(SSIBus *bus, const char *name)
  94 {
  95     DeviceState *dev = qdev_new(name);
  96
  97     qdev_realize_and_unref(dev, &bus->parent_obj, &error_fatal);
  98     return dev;
  99 }
 100
 101 SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
 102 {
 103     BusState *bus;
 104     bus = qbus_create(TYPE_SSI_BUS, parent, name);
 105     return SSI_BUS(bus);
 106 }
 107
 108 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
 109 {
 110     BusState *b = BUS(bus);
 111     BusChild *kid;
 112     SSISlaveClass *ssc;
 113     uint32_t r = 0;
 114
 115     QTAILQ_FOREACH(kid, &b->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     .fields = (VMStateField[]) {
 129         VMSTATE_BOOL(cs, SSISlave),
 130         VMSTATE_END_OF_LIST()
 131     }
 132 };
 133
 134 static void ssi_slave_register_types(void)
 135 {
 136     type_register_static(&ssi_bus_info);
 137     type_register_static(&ssi_slave_info);
 138 }
 139
 140 type_init(ssi_slave_register_types)