i2c: implement broadcast write
This does a write to every slaves when the I2C bus get a write to address 0. Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com> Reviewed-by: Alistair Francis <alistair.francis@xilinx.com> Reviewed-by: Peter Crosthwaite <crosthwaite.peter@gmail.com> Tested-By: Hyun Kwon <hyun.kwon@xilinx.com> Message-id: 1465833014-21982-3-git-send-email-fred.konrad@greensocs.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
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132
hw/i2c/core.c
132
hw/i2c/core.c
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@ -10,11 +10,19 @@
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#include "qemu/osdep.h"
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#include "hw/i2c/i2c.h"
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typedef struct I2CNode I2CNode;
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struct I2CNode {
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I2CSlave *elt;
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QLIST_ENTRY(I2CNode) next;
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};
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struct I2CBus
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{
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BusState qbus;
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I2CSlave *current_dev;
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QLIST_HEAD(, I2CNode) current_devs;
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uint8_t saved_address;
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bool broadcast;
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};
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static Property i2c_props[] = {
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@ -35,17 +43,12 @@ static void i2c_bus_pre_save(void *opaque)
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{
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I2CBus *bus = opaque;
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bus->saved_address = bus->current_dev ? bus->current_dev->address : -1;
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}
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static int i2c_bus_post_load(void *opaque, int version_id)
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{
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I2CBus *bus = opaque;
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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->current_dev = NULL;
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return 0;
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bus->saved_address = -1;
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if (!QLIST_EMPTY(&bus->current_devs)) {
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if (!bus->broadcast) {
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bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;
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}
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}
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}
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static const VMStateDescription vmstate_i2c_bus = {
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@ -53,9 +56,9 @@ static const VMStateDescription vmstate_i2c_bus = {
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.version_id = 1,
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.minimum_version_id = 1,
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.pre_save = i2c_bus_pre_save,
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.post_load = i2c_bus_post_load,
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.fields = (VMStateField[]) {
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VMSTATE_UINT8(saved_address, I2CBus),
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VMSTATE_BOOL(broadcast, I2CBus),
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VMSTATE_END_OF_LIST()
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}
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};
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@ -66,6 +69,7 @@ I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
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I2CBus *bus;
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bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
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QLIST_INIT(&bus->current_devs);
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vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);
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return bus;
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}
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@ -78,7 +82,7 @@ void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
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/* Return nonzero if bus is busy. */
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int i2c_bus_busy(I2CBus *bus)
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{
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return bus->current_dev != NULL;
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return !QLIST_EMPTY(&bus->current_devs);
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}
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/* Returns non-zero if the address is not valid. */
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@ -86,95 +90,111 @@ int i2c_bus_busy(I2CBus *bus)
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int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
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{
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BusChild *kid;
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I2CSlave *slave = NULL;
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I2CSlaveClass *sc;
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I2CNode *node;
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if (address == 0x00) {
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/*
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* This is a broadcast, the current_devs will be all the devices of the
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* bus.
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*/
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bus->broadcast = true;
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}
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QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
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DeviceState *qdev = kid->child;
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I2CSlave *candidate = I2C_SLAVE(qdev);
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if (candidate->address == address) {
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slave = candidate;
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break;
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if ((candidate->address == address) || (bus->broadcast)) {
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node = g_malloc(sizeof(struct I2CNode));
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node->elt = candidate;
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QLIST_INSERT_HEAD(&bus->current_devs, node, next);
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if (!bus->broadcast) {
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break;
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}
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}
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}
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if (!slave) {
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if (QLIST_EMPTY(&bus->current_devs)) {
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return 1;
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}
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sc = I2C_SLAVE_GET_CLASS(slave);
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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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if (sc->event) {
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sc->event(slave, recv ? I2C_START_RECV : I2C_START_SEND);
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QLIST_FOREACH(node, &bus->current_devs, next) {
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sc = I2C_SLAVE_GET_CLASS(node->elt);
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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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if (sc->event) {
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sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
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}
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}
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return 0;
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}
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void i2c_end_transfer(I2CBus *bus)
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{
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I2CSlave *dev = bus->current_dev;
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I2CSlaveClass *sc;
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I2CNode *node, *next;
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if (!dev) {
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if (QLIST_EMPTY(&bus->current_devs)) {
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return;
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}
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sc = I2C_SLAVE_GET_CLASS(dev);
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if (sc->event) {
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sc->event(dev, I2C_FINISH);
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QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
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sc = I2C_SLAVE_GET_CLASS(node->elt);
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if (sc->event) {
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sc->event(node->elt, I2C_FINISH);
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}
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QLIST_REMOVE(node, next);
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g_free(node);
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}
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bus->current_dev = NULL;
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bus->broadcast = false;
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}
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int i2c_send(I2CBus *bus, uint8_t data)
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{
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I2CSlave *dev = bus->current_dev;
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I2CSlaveClass *sc;
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I2CNode *node;
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int ret = 0;
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if (!dev) {
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return -1;
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QLIST_FOREACH(node, &bus->current_devs, next) {
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sc = I2C_SLAVE_GET_CLASS(node->elt);
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if (sc->send) {
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ret = ret || sc->send(node->elt, data);
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} else {
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ret = -1;
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}
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}
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sc = I2C_SLAVE_GET_CLASS(dev);
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if (sc->send) {
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return sc->send(dev, data);
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}
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return -1;
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return ret ? -1 : 0;
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}
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int i2c_recv(I2CBus *bus)
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{
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I2CSlave *dev = bus->current_dev;
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I2CSlaveClass *sc;
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if (!dev) {
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if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {
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return -1;
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}
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sc = I2C_SLAVE_GET_CLASS(dev);
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sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
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if (sc->recv) {
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return sc->recv(dev);
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return sc->recv(QLIST_FIRST(&bus->current_devs)->elt);
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}
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return -1;
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}
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void i2c_nack(I2CBus *bus)
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{
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I2CSlave *dev = bus->current_dev;
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I2CSlaveClass *sc;
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I2CNode *node;
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if (!dev) {
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if (QLIST_EMPTY(&bus->current_devs)) {
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return;
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}
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sc = I2C_SLAVE_GET_CLASS(dev);
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if (sc->event) {
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sc->event(dev, I2C_NACK);
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QLIST_FOREACH(node, &bus->current_devs, next) {
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sc = I2C_SLAVE_GET_CLASS(node->elt);
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if (sc->event) {
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sc->event(node->elt, I2C_NACK);
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}
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}
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}
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@ -182,9 +202,13 @@ static int i2c_slave_post_load(void *opaque, int version_id)
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{
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I2CSlave *dev = opaque;
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I2CBus *bus;
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I2CNode *node;
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bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
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if (bus->saved_address == dev->address) {
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bus->current_dev = dev;
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if ((bus->saved_address == dev->address) || (bus->broadcast)) {
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node = g_malloc(sizeof(struct I2CNode));
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node->elt = dev;
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QLIST_INSERT_HEAD(&bus->current_devs, node, next);
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}
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return 0;
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}
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