| /* |
| * QEMU I2C bus interface. |
| * |
| * Copyright (c) 2007 CodeSourcery. |
| * Written by Paul Brook |
| * |
| * This code is licensed under the LGPL. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "hw/i2c/i2c.h" |
| #include "hw/qdev-properties.h" |
| #include "migration/vmstate.h" |
| #include "qapi/error.h" |
| #include "qemu/module.h" |
| #include "qemu/main-loop.h" |
| #include "trace.h" |
| |
| #define I2C_BROADCAST 0x00 |
| |
| static Property i2c_props[] = { |
| DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0), |
| DEFINE_PROP_END_OF_LIST(), |
| }; |
| |
| static const TypeInfo i2c_bus_info = { |
| .name = TYPE_I2C_BUS, |
| .parent = TYPE_BUS, |
| .instance_size = sizeof(I2CBus), |
| }; |
| |
| static int i2c_bus_pre_save(void *opaque) |
| { |
| I2CBus *bus = opaque; |
| |
| bus->saved_address = -1; |
| if (!QLIST_EMPTY(&bus->current_devs)) { |
| if (!bus->broadcast) { |
| bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address; |
| } else { |
| bus->saved_address = I2C_BROADCAST; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static const VMStateDescription vmstate_i2c_bus = { |
| .name = "i2c_bus", |
| .version_id = 1, |
| .minimum_version_id = 1, |
| .pre_save = i2c_bus_pre_save, |
| .fields = (VMStateField[]) { |
| VMSTATE_UINT8(saved_address, I2CBus), |
| VMSTATE_END_OF_LIST() |
| } |
| }; |
| |
| /* Create a new I2C bus. */ |
| I2CBus *i2c_init_bus(DeviceState *parent, const char *name) |
| { |
| I2CBus *bus; |
| |
| bus = I2C_BUS(qbus_new(TYPE_I2C_BUS, parent, name)); |
| QLIST_INIT(&bus->current_devs); |
| QSIMPLEQ_INIT(&bus->pending_masters); |
| vmstate_register_any(NULL, &vmstate_i2c_bus, bus); |
| return bus; |
| } |
| |
| void i2c_slave_set_address(I2CSlave *dev, uint8_t address) |
| { |
| dev->address = address; |
| } |
| |
| /* Return nonzero if bus is busy. */ |
| int i2c_bus_busy(I2CBus *bus) |
| { |
| return !QLIST_EMPTY(&bus->current_devs) || bus->bh; |
| } |
| |
| bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast, |
| I2CNodeList *current_devs) |
| { |
| BusChild *kid; |
| |
| QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) { |
| DeviceState *qdev = kid->child; |
| I2CSlave *candidate = I2C_SLAVE(qdev); |
| I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(candidate); |
| |
| if (sc->match_and_add(candidate, address, broadcast, current_devs)) { |
| if (!broadcast) { |
| return true; |
| } |
| } |
| } |
| |
| /* |
| * If broadcast was true, and the list was full or empty, return true. If |
| * broadcast was false, return false. |
| */ |
| return broadcast; |
| } |
| |
| /* TODO: Make this handle multiple masters. */ |
| /* |
| * Start or continue an i2c transaction. When this is called for the |
| * first time or after an i2c_end_transfer(), if it returns an error |
| * the bus transaction is terminated (or really never started). If |
| * this is called after another i2c_start_transfer() without an |
| * intervening i2c_end_transfer(), and it returns an error, the |
| * transaction will not be terminated. The caller must do it. |
| * |
| * This corresponds with the way real hardware works. The SMBus |
| * protocol uses a start transfer to switch from write to read mode |
| * without releasing the bus. If that fails, the bus is still |
| * in a transaction. |
| * |
| * @event must be I2C_START_RECV or I2C_START_SEND. |
| */ |
| static int i2c_do_start_transfer(I2CBus *bus, uint8_t address, |
| enum i2c_event event) |
| { |
| I2CSlaveClass *sc; |
| I2CNode *node; |
| bool bus_scanned = false; |
| |
| if (address == I2C_BROADCAST) { |
| /* |
| * This is a broadcast, the current_devs will be all the devices of the |
| * bus. |
| */ |
| bus->broadcast = true; |
| } |
| |
| /* |
| * If there are already devices in the list, that means we are in |
| * the middle of a transaction and we shouldn't rescan the bus. |
| * |
| * This happens with any SMBus transaction, even on a pure I2C |
| * device. The interface does a transaction start without |
| * terminating the previous transaction. |
| */ |
| if (QLIST_EMPTY(&bus->current_devs)) { |
| /* Disregard whether devices were found. */ |
| (void)i2c_scan_bus(bus, address, bus->broadcast, &bus->current_devs); |
| bus_scanned = true; |
| } |
| |
| if (QLIST_EMPTY(&bus->current_devs)) { |
| return 1; |
| } |
| |
| QLIST_FOREACH(node, &bus->current_devs, next) { |
| I2CSlave *s = node->elt; |
| int rv; |
| |
| sc = I2C_SLAVE_GET_CLASS(s); |
| /* If the bus is already busy, assume this is a repeated |
| start condition. */ |
| |
| if (sc->event) { |
| trace_i2c_event(event == I2C_START_SEND ? "start" : "start_async", |
| s->address); |
| rv = sc->event(s, event); |
| if (rv && !bus->broadcast) { |
| if (bus_scanned) { |
| /* First call, terminate the transfer. */ |
| i2c_end_transfer(bus); |
| } |
| return rv; |
| } |
| } |
| } |
| return 0; |
| } |
| |
| int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv) |
| { |
| return i2c_do_start_transfer(bus, address, is_recv |
| ? I2C_START_RECV |
| : I2C_START_SEND); |
| } |
| |
| void i2c_bus_master(I2CBus *bus, QEMUBH *bh) |
| { |
| I2CPendingMaster *node = g_new(struct I2CPendingMaster, 1); |
| node->bh = bh; |
| |
| QSIMPLEQ_INSERT_TAIL(&bus->pending_masters, node, entry); |
| } |
| |
| void i2c_schedule_pending_master(I2CBus *bus) |
| { |
| I2CPendingMaster *node; |
| |
| if (i2c_bus_busy(bus)) { |
| /* someone is already controlling the bus; wait for it to release it */ |
| return; |
| } |
| |
| if (QSIMPLEQ_EMPTY(&bus->pending_masters)) { |
| return; |
| } |
| |
| node = QSIMPLEQ_FIRST(&bus->pending_masters); |
| bus->bh = node->bh; |
| |
| QSIMPLEQ_REMOVE_HEAD(&bus->pending_masters, entry); |
| g_free(node); |
| |
| qemu_bh_schedule(bus->bh); |
| } |
| |
| void i2c_bus_release(I2CBus *bus) |
| { |
| bus->bh = NULL; |
| |
| i2c_schedule_pending_master(bus); |
| } |
| |
| int i2c_start_recv(I2CBus *bus, uint8_t address) |
| { |
| return i2c_do_start_transfer(bus, address, I2C_START_RECV); |
| } |
| |
| int i2c_start_send(I2CBus *bus, uint8_t address) |
| { |
| return i2c_do_start_transfer(bus, address, I2C_START_SEND); |
| } |
| |
| int i2c_start_send_async(I2CBus *bus, uint8_t address) |
| { |
| return i2c_do_start_transfer(bus, address, I2C_START_SEND_ASYNC); |
| } |
| |
| void i2c_end_transfer(I2CBus *bus) |
| { |
| I2CSlaveClass *sc; |
| I2CNode *node, *next; |
| |
| QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) { |
| I2CSlave *s = node->elt; |
| sc = I2C_SLAVE_GET_CLASS(s); |
| if (sc->event) { |
| trace_i2c_event("finish", s->address); |
| sc->event(s, I2C_FINISH); |
| } |
| QLIST_REMOVE(node, next); |
| g_free(node); |
| } |
| bus->broadcast = false; |
| } |
| |
| int i2c_send(I2CBus *bus, uint8_t data) |
| { |
| I2CSlaveClass *sc; |
| I2CSlave *s; |
| I2CNode *node; |
| int ret = 0; |
| |
| QLIST_FOREACH(node, &bus->current_devs, next) { |
| s = node->elt; |
| sc = I2C_SLAVE_GET_CLASS(s); |
| if (sc->send) { |
| trace_i2c_send(s->address, data); |
| ret = ret || sc->send(s, data); |
| } else { |
| ret = -1; |
| } |
| } |
| |
| return ret ? -1 : 0; |
| } |
| |
| int i2c_send_async(I2CBus *bus, uint8_t data) |
| { |
| I2CNode *node = QLIST_FIRST(&bus->current_devs); |
| I2CSlave *slave = node->elt; |
| I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(slave); |
| |
| if (!sc->send_async) { |
| return -1; |
| } |
| |
| trace_i2c_send_async(slave->address, data); |
| |
| sc->send_async(slave, data); |
| |
| return 0; |
| } |
| |
| uint8_t i2c_recv(I2CBus *bus) |
| { |
| uint8_t data = 0xff; |
| I2CSlaveClass *sc; |
| I2CSlave *s; |
| |
| if (!QLIST_EMPTY(&bus->current_devs) && !bus->broadcast) { |
| sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt); |
| if (sc->recv) { |
| s = QLIST_FIRST(&bus->current_devs)->elt; |
| data = sc->recv(s); |
| trace_i2c_recv(s->address, data); |
| } |
| } |
| |
| return data; |
| } |
| |
| void i2c_nack(I2CBus *bus) |
| { |
| I2CSlaveClass *sc; |
| I2CNode *node; |
| |
| if (QLIST_EMPTY(&bus->current_devs)) { |
| return; |
| } |
| |
| QLIST_FOREACH(node, &bus->current_devs, next) { |
| sc = I2C_SLAVE_GET_CLASS(node->elt); |
| if (sc->event) { |
| trace_i2c_event("nack", node->elt->address); |
| sc->event(node->elt, I2C_NACK); |
| } |
| } |
| } |
| |
| void i2c_ack(I2CBus *bus) |
| { |
| if (!bus->bh) { |
| return; |
| } |
| |
| trace_i2c_ack(); |
| |
| qemu_bh_schedule(bus->bh); |
| } |
| |
| static int i2c_slave_post_load(void *opaque, int version_id) |
| { |
| I2CSlave *dev = opaque; |
| I2CBus *bus; |
| I2CNode *node; |
| |
| bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev))); |
| if ((bus->saved_address == dev->address) || |
| (bus->saved_address == I2C_BROADCAST)) { |
| node = g_new(struct I2CNode, 1); |
| node->elt = dev; |
| QLIST_INSERT_HEAD(&bus->current_devs, node, next); |
| } |
| return 0; |
| } |
| |
| const VMStateDescription vmstate_i2c_slave = { |
| .name = "I2CSlave", |
| .version_id = 1, |
| .minimum_version_id = 1, |
| .post_load = i2c_slave_post_load, |
| .fields = (VMStateField[]) { |
| VMSTATE_UINT8(address, I2CSlave), |
| VMSTATE_END_OF_LIST() |
| } |
| }; |
| |
| I2CSlave *i2c_slave_new(const char *name, uint8_t addr) |
| { |
| DeviceState *dev; |
| |
| dev = qdev_new(name); |
| qdev_prop_set_uint8(dev, "address", addr); |
| return I2C_SLAVE(dev); |
| } |
| |
| bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp) |
| { |
| return qdev_realize_and_unref(&dev->qdev, &bus->qbus, errp); |
| } |
| |
| I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr) |
| { |
| I2CSlave *dev = i2c_slave_new(name, addr); |
| |
| i2c_slave_realize_and_unref(dev, bus, &error_abort); |
| |
| return dev; |
| } |
| |
| static bool i2c_slave_match(I2CSlave *candidate, uint8_t address, |
| bool broadcast, I2CNodeList *current_devs) |
| { |
| if ((candidate->address == address) || (broadcast)) { |
| I2CNode *node = g_new(struct I2CNode, 1); |
| node->elt = candidate; |
| QLIST_INSERT_HEAD(current_devs, node, next); |
| return true; |
| } |
| |
| /* Not found and not broadcast. */ |
| return false; |
| } |
| |
| static void i2c_slave_class_init(ObjectClass *klass, void *data) |
| { |
| DeviceClass *k = DEVICE_CLASS(klass); |
| I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass); |
| set_bit(DEVICE_CATEGORY_MISC, k->categories); |
| k->bus_type = TYPE_I2C_BUS; |
| device_class_set_props(k, i2c_props); |
| sc->match_and_add = i2c_slave_match; |
| } |
| |
| static const TypeInfo i2c_slave_type_info = { |
| .name = TYPE_I2C_SLAVE, |
| .parent = TYPE_DEVICE, |
| .instance_size = sizeof(I2CSlave), |
| .abstract = true, |
| .class_size = sizeof(I2CSlaveClass), |
| .class_init = i2c_slave_class_init, |
| }; |
| |
| static void i2c_slave_register_types(void) |
| { |
| type_register_static(&i2c_bus_info); |
| type_register_static(&i2c_slave_type_info); |
| } |
| |
| type_init(i2c_slave_register_types) |