qemu-patch-raspberry4/hw/ssi.c
Peter A. G. Crosthwaite b4a76e84f4 ssi: Support for multiple attached devices
Removed assertion that only one device is attached to the SSI bus.

When multiple devices are attached, all slaves have their transfer function
called for transfers. Each device is responsible for knowing whether or not its
CS is active, and if not returning 0. The returned data is the logical or of
all responses from the (mulitple) devices.

Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
Acked-by: Peter Maydell <peter.maydell@linaro.org>
2012-10-10 11:13:31 +10:00

90 lines
2 KiB
C

/*
* QEMU Synchronous Serial Interface support
*
* Copyright (c) 2009 CodeSourcery.
* Copyright (c) 2012 Peter A.G. Crosthwaite (peter.crosthwaite@petalogix.com)
* Copyright (c) 2012 PetaLogix Pty Ltd.
* Written by Paul Brook
*
* This code is licensed under the GNU GPL v2.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "ssi.h"
struct SSIBus {
BusState qbus;
};
#define TYPE_SSI_BUS "SSI"
#define SSI_BUS(obj) OBJECT_CHECK(SSIBus, (obj), TYPE_SSI_BUS)
static const TypeInfo ssi_bus_info = {
.name = TYPE_SSI_BUS,
.parent = TYPE_BUS,
.instance_size = sizeof(SSIBus),
};
static int ssi_slave_init(DeviceState *dev)
{
SSISlave *s = SSI_SLAVE(dev);
SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
return ssc->init(s);
}
static void ssi_slave_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->init = ssi_slave_init;
dc->bus_type = TYPE_SSI_BUS;
}
static TypeInfo ssi_slave_info = {
.name = TYPE_SSI_SLAVE,
.parent = TYPE_DEVICE,
.class_init = ssi_slave_class_init,
.class_size = sizeof(SSISlaveClass),
.abstract = true,
};
DeviceState *ssi_create_slave(SSIBus *bus, const char *name)
{
DeviceState *dev;
dev = qdev_create(&bus->qbus, name);
qdev_init_nofail(dev);
return dev;
}
SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
{
BusState *bus;
bus = qbus_create(TYPE_SSI_BUS, parent, name);
return FROM_QBUS(SSIBus, bus);
}
uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
{
BusChild *kid;
SSISlaveClass *ssc;
uint32_t r = 0;
QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
SSISlave *slave = SSI_SLAVE(kid->child);
ssc = SSI_SLAVE_GET_CLASS(slave);
r |= ssc->transfer(slave, val);
}
return r;
}
static void ssi_slave_register_types(void)
{
type_register_static(&ssi_bus_info);
type_register_static(&ssi_slave_info);
}
type_init(ssi_slave_register_types)