176 lines
3.6 KiB
C
176 lines
3.6 KiB
C
/*
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* QEMU I2C bus interface.
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*
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* Copyright (c) 2007 CodeSourcery.
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* Written by Paul Brook
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*
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* This code is licenced under the LGPL.
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*/
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#include "i2c.h"
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struct i2c_bus
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{
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BusState qbus;
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i2c_slave *current_dev;
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i2c_slave *dev;
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int saved_address;
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};
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static struct BusInfo i2c_bus_info = {
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.name = "I2C",
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.size = sizeof(i2c_bus),
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};
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static void i2c_bus_save(QEMUFile *f, void *opaque)
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{
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i2c_bus *bus = (i2c_bus *)opaque;
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qemu_put_byte(f, bus->current_dev ? bus->current_dev->address : -1);
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}
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static int i2c_bus_load(QEMUFile *f, void *opaque, int version_id)
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{
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i2c_bus *bus = (i2c_bus *)opaque;
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if (version_id != 1)
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return -EINVAL;
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/* The bus is loaded before attached devices, so load and save the
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current device id. Devices will check themselves as loaded. */
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bus->saved_address = (int8_t) qemu_get_byte(f);
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bus->current_dev = NULL;
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return 0;
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}
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/* Create a new I2C bus. */
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i2c_bus *i2c_init_bus(DeviceState *parent, const char *name)
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{
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i2c_bus *bus;
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bus = FROM_QBUS(i2c_bus, qbus_create(&i2c_bus_info, parent, name));
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register_savevm("i2c_bus", -1, 1, i2c_bus_save, i2c_bus_load, bus);
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return bus;
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}
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void i2c_set_slave_address(i2c_slave *dev, int address)
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{
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dev->address = address;
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}
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/* Return nonzero if bus is busy. */
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int i2c_bus_busy(i2c_bus *bus)
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{
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return bus->current_dev != NULL;
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}
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/* Returns non-zero if the address is not valid. */
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/* TODO: Make this handle multiple masters. */
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int i2c_start_transfer(i2c_bus *bus, int address, int recv)
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{
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DeviceState *qdev;
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i2c_slave *slave = NULL;
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LIST_FOREACH(qdev, &bus->qbus.children, sibling) {
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slave = I2C_SLAVE_FROM_QDEV(qdev);
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if (slave->address == address)
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break;
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}
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if (!slave)
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return 1;
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/* If the bus is already busy, assume this is a repeated
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start condition. */
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bus->current_dev = slave;
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slave->info->event(slave, recv ? I2C_START_RECV : I2C_START_SEND);
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return 0;
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}
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void i2c_end_transfer(i2c_bus *bus)
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{
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i2c_slave *dev = bus->current_dev;
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if (!dev)
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return;
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dev->info->event(dev, I2C_FINISH);
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bus->current_dev = NULL;
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}
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int i2c_send(i2c_bus *bus, uint8_t data)
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{
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i2c_slave *dev = bus->current_dev;
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if (!dev)
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return -1;
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return dev->info->send(dev, data);
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}
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int i2c_recv(i2c_bus *bus)
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{
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i2c_slave *dev = bus->current_dev;
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if (!dev)
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return -1;
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return dev->info->recv(dev);
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}
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void i2c_nack(i2c_bus *bus)
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{
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i2c_slave *dev = bus->current_dev;
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if (!dev)
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return;
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dev->info->event(dev, I2C_NACK);
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}
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void i2c_slave_save(QEMUFile *f, i2c_slave *dev)
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{
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qemu_put_byte(f, dev->address);
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}
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void i2c_slave_load(QEMUFile *f, i2c_slave *dev)
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{
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i2c_bus *bus;
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bus = FROM_QBUS(i2c_bus, qdev_get_parent_bus(&dev->qdev));
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dev->address = qemu_get_byte(f);
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if (bus->saved_address == dev->address) {
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bus->current_dev = dev;
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}
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}
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static void i2c_slave_qdev_init(DeviceState *dev, DeviceInfo *base)
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{
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I2CSlaveInfo *info = container_of(base, I2CSlaveInfo, qdev);
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i2c_slave *s = I2C_SLAVE_FROM_QDEV(dev);
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s->info = info;
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s->address = qdev_get_prop_int(dev, "address", 0);
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info->init(s);
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}
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void i2c_register_slave(I2CSlaveInfo *info)
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{
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assert(info->qdev.size >= sizeof(i2c_slave));
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info->qdev.init = i2c_slave_qdev_init;
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info->qdev.bus_info = &i2c_bus_info;
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qdev_register(&info->qdev);
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}
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DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, int addr)
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{
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DeviceState *dev;
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dev = qdev_create(&bus->qbus, name);
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qdev_set_prop_int(dev, "address", addr);
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qdev_init(dev);
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return dev;
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}
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