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 #include "qom/object.h"
  21
  22 struct SSIBus {
  23     BusState parent_obj;
  24 };
  25
  26 #define TYPE_SSI_BUS "SSI"
  27 DECLARE_INSTANCE_CHECKER(SSIBus, SSI_BUS,
  28                          TYPE_SSI_BUS)
  29
  30 static const TypeInfo ssi_bus_info = {
  31     .name = TYPE_SSI_BUS,
  32     .parent = TYPE_BUS,
  33     .instance_size = sizeof(SSIBus),
  34 };
  35
  36 static void ssi_cs_default(void *opaque, int n, int level)
  37 {
  38     SSISlave *s = SSI_SLAVE(opaque);
  39     bool cs = !!level;
  40     assert(n == 0);
  41     if (s->cs != cs) {
  42         SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
  43         if (ssc->set_cs) {
  44             ssc->set_cs(s, cs);
  45         }
  46     }
  47     s->cs = cs;
  48 }
  49
  50 static uint32_t ssi_transfer_raw_default(SSISlave *dev, uint32_t val)
  51 {
  52     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(dev);
  53
  54     if ((dev->cs && ssc->cs_polarity == SSI_CS_HIGH) ||
  55             (!dev->cs && ssc->cs_polarity == SSI_CS_LOW) ||
  56             ssc->cs_polarity == SSI_CS_NONE) {
  57         return ssc->transfer(dev, val);
  58     }
  59     return 0;
  60 }
  61
  62 static void ssi_slave_realize(DeviceState *dev, Error **errp)
  63 {
  64     SSISlave *s = SSI_SLAVE(dev);
  65     SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
  66
  67     if (ssc->transfer_raw == ssi_transfer_raw_default &&
  68             ssc->cs_polarity != SSI_CS_NONE) {
  69         qdev_init_gpio_in_named(dev, ssi_cs_default, SSI_GPIO_CS, 1);
  70     }
  71
  72     ssc->realize(s, errp);
  73 }
  74
  75 static void ssi_slave_class_init(ObjectClass *klass, void *data)
  76 {
  77     SSISlaveClass *ssc = SSI_SLAVE_CLASS(klass);
  78     DeviceClass *dc = DEVICE_CLASS(klass);
  79
  80     dc->realize = ssi_slave_realize;
  81     dc->bus_type = TYPE_SSI_BUS;
  82     if (!ssc->transfer_raw) {
  83         ssc->transfer_raw = ssi_transfer_raw_default;
  84     }
  85 }
  86
  87 static const TypeInfo ssi_slave_info = {
  88     .name = TYPE_SSI_SLAVE,
  89     .parent = TYPE_DEVICE,
  90     .class_init = ssi_slave_class_init,
  91     .class_size = sizeof(SSISlaveClass),
  92     .abstract = true,
  93 };
  94
  95 bool ssi_realize_and_unref(DeviceState *dev, SSIBus *bus, Error **errp)
  96 {
  97     return qdev_realize_and_unref(dev, &bus->parent_obj, errp);
  98 }
  99
 100 DeviceState *ssi_create_slave(SSIBus *bus, const char *name)
 101 {
 102     DeviceState *dev = qdev_new(name);
 103
 104     ssi_realize_and_unref(dev, bus, &error_fatal);
 105     return dev;
 106 }
 107
 108 SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
 109 {
 110     BusState *bus;
 111     bus = qbus_create(TYPE_SSI_BUS, parent, name);
 112     return SSI_BUS(bus);
 113 }
 114
 115 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
 116 {
 117     BusState *b = BUS(bus);
 118     BusChild *kid;
 119     SSISlaveClass *ssc;
 120     uint32_t r = 0;
 121
 122     QTAILQ_FOREACH(kid, &b->children, sibling) {
 123         SSISlave *slave = SSI_SLAVE(kid->child);
 124         ssc = SSI_SLAVE_GET_CLASS(slave);
 125         r |= ssc->transfer_raw(slave, val);
 126     }
 127
 128     return r;
 129 }
 130
 131 const VMStateDescription vmstate_ssi_slave = {
 132     .name = "SSISlave",
 133     .version_id = 1,
 134     .minimum_version_id = 1,
 135     .fields = (VMStateField[]) {
 136         VMSTATE_BOOL(cs, SSISlave),
 137         VMSTATE_END_OF_LIST()
 138     }
 139 };
 140
 141 static void ssi_slave_register_types(void)
 142 {
 143     type_register_static(&ssi_bus_info);
 144     type_register_static(&ssi_slave_info);
 145 }
 146
 147 type_init(ssi_slave_register_types)