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 OBJECT_DECLARE_SIMPLE_TYPE(SSIBus, SSI_BUS)
  28
  29 static const TypeInfo ssi_bus_info = {
  30     .name = TYPE_SSI_BUS,
  31     .parent = TYPE_BUS,
  32     .instance_size = sizeof(SSIBus),
  33 };
  34
  35 static void ssi_cs_default(void *opaque, int n, int level)
  36 {
  37     SSIPeripheral *s = SSI_PERIPHERAL(opaque);
  38     bool cs = !!level;
  39     assert(n == 0);
  40     if (s->cs != cs) {
  41         if (s->spc->set_cs) {
  42             s->spc->set_cs(s, cs);
  43         }
  44     }
  45     s->cs = cs;
  46 }
  47
  48 static uint32_t ssi_transfer_raw_default(SSIPeripheral *dev, uint32_t val)
  49 {
  50     SSIPeripheralClass *ssc = dev->spc;
  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_peripheral_realize(DeviceState *dev, Error **errp)
  61 {
  62     SSIPeripheral *s = SSI_PERIPHERAL(dev);
  63     SSIPeripheralClass *ssc = SSI_PERIPHERAL_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     s->spc = ssc;
  70
  71     ssc->realize(s, errp);
  72 }
  73
  74 static void ssi_peripheral_class_init(ObjectClass *klass, void *data)
  75 {
  76     SSIPeripheralClass *ssc = SSI_PERIPHERAL_CLASS(klass);
  77     DeviceClass *dc = DEVICE_CLASS(klass);
  78
  79     dc->realize = ssi_peripheral_realize;
  80     dc->bus_type = TYPE_SSI_BUS;
  81     if (!ssc->transfer_raw) {
  82         ssc->transfer_raw = ssi_transfer_raw_default;
  83     }
  84 }
  85
  86 static const TypeInfo ssi_peripheral_info = {
  87     .name = TYPE_SSI_PERIPHERAL,
  88     .parent = TYPE_DEVICE,
  89     .class_init = ssi_peripheral_class_init,
  90     .class_size = sizeof(SSIPeripheralClass),
  91     .abstract = true,
  92 };
  93
  94 bool ssi_realize_and_unref(DeviceState *dev, SSIBus *bus, Error **errp)
  95 {
  96     return qdev_realize_and_unref(dev, &bus->parent_obj, errp);
  97 }
  98
  99 DeviceState *ssi_create_peripheral(SSIBus *bus, const char *name)
 100 {
 101     DeviceState *dev = qdev_new(name);
 102
 103     ssi_realize_and_unref(dev, bus, &error_fatal);
 104     return dev;
 105 }
 106
 107 SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
 108 {
 109     BusState *bus;
 110     bus = qbus_new(TYPE_SSI_BUS, parent, name);
 111     return SSI_BUS(bus);
 112 }
 113
 114 uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
 115 {
 116     BusState *b = BUS(bus);
 117     BusChild *kid;
 118     uint32_t r = 0;
 119
 120     QTAILQ_FOREACH(kid, &b->children, sibling) {
 121         SSIPeripheral *p = SSI_PERIPHERAL(kid->child);
 122         r |= p->spc->transfer_raw(p, val);
 123     }
 124
 125     return r;
 126 }
 127
 128 const VMStateDescription vmstate_ssi_peripheral = {
 129     .name = "SSISlave",
 130     .version_id = 1,
 131     .minimum_version_id = 1,
 132     .fields = (VMStateField[]) {
 133         VMSTATE_BOOL(cs, SSIPeripheral),
 134         VMSTATE_END_OF_LIST()
 135     }
 136 };
 137
 138 static void ssi_peripheral_register_types(void)
 139 {
 140     type_register_static(&ssi_bus_info);
 141     type_register_static(&ssi_peripheral_info);
 142 }
 143
 144 type_init(ssi_peripheral_register_types)