87ecb68bdf
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3674 c046a42c-6fe2-441c-8c8c-71466251a162
149 lines
2.7 KiB
C
149 lines
2.7 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 "hw.h"
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#include "i2c.h"
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struct i2c_bus
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{
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i2c_slave *current_dev;
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i2c_slave *dev;
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};
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/* Create a new I2C bus. */
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i2c_bus *i2c_init_bus(void)
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{
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i2c_bus *bus;
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bus = (i2c_bus *)qemu_mallocz(sizeof(i2c_bus));
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return bus;
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}
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/* Create a new slave device. */
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i2c_slave *i2c_slave_init(i2c_bus *bus, int address, int size)
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{
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i2c_slave *dev;
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if (size < sizeof(i2c_slave))
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hw_error("I2C struct too small");
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dev = (i2c_slave *)qemu_mallocz(size);
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dev->address = address;
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dev->next = bus->dev;
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bus->dev = dev;
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return dev;
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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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i2c_slave *dev;
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for (dev = bus->dev; dev; dev = dev->next) {
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if (dev->address == address)
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break;
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}
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if (!dev)
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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 = dev;
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dev->event(dev, 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->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->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->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->event(dev, I2C_NACK);
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}
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void i2c_bus_save(QEMUFile *f, i2c_bus *bus)
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{
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qemu_put_byte(f, bus->current_dev ? bus->current_dev->address : 0x00);
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}
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void i2c_bus_load(QEMUFile *f, i2c_bus *bus)
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{
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i2c_slave *dev;
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uint8_t address = qemu_get_byte(f);
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if (address) {
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for (dev = bus->dev; dev; dev = dev->next)
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if (dev->address == address) {
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bus->current_dev = dev;
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return;
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}
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fprintf(stderr, "%s: I2C slave with address %02x disappeared\n",
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__FUNCTION__, address);
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}
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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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dev->address = qemu_get_byte(f);
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}
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