Commit 2293c27f authored by KONRAD Frederic's avatar KONRAD Frederic Committed by Peter Maydell
Browse files

i2c: implement broadcast write 



This does a write to every slaves when the I2C bus get a write to address 0.

Signed-off-by: default avatarKONRAD Frederic <fred.konrad@greensocs.com>
Reviewed-by: default avatarAlistair Francis <alistair.francis@xilinx.com>
Reviewed-by: default avatarPeter Crosthwaite <crosthwaite.peter@gmail.com>
Tested-By: default avatarHyun Kwon <hyun.kwon@xilinx.com>
Message-id: 1465833014-21982-3-git-send-email-fred.konrad@greensocs.com
Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parent a9d2f1d4

hw/i2c/core.c

+79 −55
Original line number Diff line number Diff line
@@ -10,11 +10,19 @@ 
#include "qemu/osdep.h"

#include "hw/i2c/i2c.h"



typedef struct I2CNode I2CNode;



struct I2CNode {

    I2CSlave *elt;

    QLIST_ENTRY(I2CNode) next;

};



struct I2CBus

{

    BusState qbus;

    I2CSlave *current_dev;

    QLIST_HEAD(, I2CNode) current_devs;

    uint8_t saved_address;

    bool broadcast;

};



static Property i2c_props[] = {
@@ -35,17 +43,12 @@ static void i2c_bus_pre_save(void *opaque) 
{

    I2CBus *bus = opaque;



    bus->saved_address = bus->current_dev ? bus->current_dev->address : -1;

    bus->saved_address = -1;

    if (!QLIST_EMPTY(&bus->current_devs)) {

        if (!bus->broadcast) {

            bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;

        }

    }



static int i2c_bus_post_load(void *opaque, int version_id)

{

    I2CBus *bus = opaque;



    /* The bus is loaded before attached devices, so load and save the

       current device id.  Devices will check themselves as loaded.  */

    bus->current_dev = NULL;

    return 0;

}



static const VMStateDescription vmstate_i2c_bus = {
@@ -53,9 +56,9 @@ static const VMStateDescription vmstate_i2c_bus = { 
    .version_id = 1,

    .minimum_version_id = 1,

    .pre_save = i2c_bus_pre_save,

    .post_load = i2c_bus_post_load,

    .fields = (VMStateField[]) {

        VMSTATE_UINT8(saved_address, I2CBus),

        VMSTATE_BOOL(broadcast, I2CBus),

        VMSTATE_END_OF_LIST()

    }

};
@@ -66,6 +69,7 @@ I2CBus *i2c_init_bus(DeviceState *parent, const char *name) 
    I2CBus *bus;



    bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));

    QLIST_INIT(&bus->current_devs);

    vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);

    return bus;

}
@@ -78,7 +82,7 @@ void i2c_set_slave_address(I2CSlave *dev, uint8_t address) 
/* Return nonzero if bus is busy.  */

int i2c_bus_busy(I2CBus *bus)

{

    return bus->current_dev != NULL;

    return !QLIST_EMPTY(&bus->current_devs);

}



/* Returns non-zero if the address is not valid.  */
@@ -86,95 +90,111 @@ int i2c_bus_busy(I2CBus *bus) 
int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)

{

    BusChild *kid;

    I2CSlave *slave = NULL;

    I2CSlaveClass *sc;

    I2CNode *node;



    if (address == 0x00) {

        /*

         * This is a broadcast, the current_devs will be all the devices of the

         * bus.

         */

        bus->broadcast = true;

    }



    QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {

        DeviceState *qdev = kid->child;

        I2CSlave *candidate = I2C_SLAVE(qdev);

        if (candidate->address == address) {

            slave = candidate;

        if ((candidate->address == address) || (bus->broadcast)) {

            node = g_malloc(sizeof(struct I2CNode));

            node->elt = candidate;

            QLIST_INSERT_HEAD(&bus->current_devs, node, next);

            if (!bus->broadcast) {

                break;

            }

        }

    }



    if (!slave) {

    if (QLIST_EMPTY(&bus->current_devs)) {

        return 1;

    }



    sc = I2C_SLAVE_GET_CLASS(slave);

    QLIST_FOREACH(node, &bus->current_devs, next) {

        sc = I2C_SLAVE_GET_CLASS(node->elt);

        /* If the bus is already busy, assume this is a repeated

           start condition.  */

    bus->current_dev = slave;

        if (sc->event) {

        sc->event(slave, recv ? I2C_START_RECV : I2C_START_SEND);

            sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);

        }

    }

    return 0;

}



void i2c_end_transfer(I2CBus *bus)

{

    I2CSlave *dev = bus->current_dev;

    I2CSlaveClass *sc;

    I2CNode *node, *next;



    if (!dev) {

    if (QLIST_EMPTY(&bus->current_devs)) {

        return;

    }



    sc = I2C_SLAVE_GET_CLASS(dev);

    QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {

        sc = I2C_SLAVE_GET_CLASS(node->elt);

        if (sc->event) {

        sc->event(dev, I2C_FINISH);

            sc->event(node->elt, I2C_FINISH);

        }



    bus->current_dev = NULL;

        QLIST_REMOVE(node, next);

        g_free(node);

    }

    bus->broadcast = false;

}



int i2c_send(I2CBus *bus, uint8_t data)

{

    I2CSlave *dev = bus->current_dev;

    I2CSlaveClass *sc;

    I2CNode *node;

    int ret = 0;



    if (!dev) {

        return -1;

    }



    sc = I2C_SLAVE_GET_CLASS(dev);

    QLIST_FOREACH(node, &bus->current_devs, next) {

        sc = I2C_SLAVE_GET_CLASS(node->elt);

        if (sc->send) {

        return sc->send(dev, data);

            ret = ret || sc->send(node->elt, data);

        } else {

            ret = -1;

        }



    return -1;

    }

    return ret ? -1 : 0;

}



int i2c_recv(I2CBus *bus)

{

    I2CSlave *dev = bus->current_dev;

    I2CSlaveClass *sc;



    if (!dev) {

    if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {

        return -1;

    }



    sc = I2C_SLAVE_GET_CLASS(dev);

    sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);

    if (sc->recv) {

        return sc->recv(dev);

        return sc->recv(QLIST_FIRST(&bus->current_devs)->elt);

    }



    return -1;

}



void i2c_nack(I2CBus *bus)

{

    I2CSlave *dev = bus->current_dev;

    I2CSlaveClass *sc;

    I2CNode *node;



    if (!dev) {

    if (QLIST_EMPTY(&bus->current_devs)) {

        return;

    }



    sc = I2C_SLAVE_GET_CLASS(dev);

    QLIST_FOREACH(node, &bus->current_devs, next) {

        sc = I2C_SLAVE_GET_CLASS(node->elt);

        if (sc->event) {

        sc->event(dev, I2C_NACK);

            sc->event(node->elt, I2C_NACK);

        }

    }

}
@@ -182,9 +202,13 @@ 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->current_dev = dev;

    if ((bus->saved_address == dev->address) || (bus->broadcast)) {

        node = g_malloc(sizeof(struct I2CNode));

        node->elt = dev;

        QLIST_INSERT_HEAD(&bus->current_devs, node, next);

    }

    return 0;

}