From 2293c27faddf9547dd8b52423caa6e85844eec3a Mon Sep 17 00:00:00 2001 From: KONRAD Frederic Date: Tue, 14 Jun 2016 15:59:14 +0100 Subject: [PATCH] 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 Reviewed-by: Alistair Francis Reviewed-by: Peter Crosthwaite Tested-By: Hyun Kwon Message-id: 1465833014-21982-3-git-send-email-fred.konrad@greensocs.com Signed-off-by: Peter Maydell --- hw/i2c/core.c | 132 +++++++++++++++++++++++++++++--------------------- 1 file changed, 78 insertions(+), 54 deletions(-) diff --git a/hw/i2c/core.c b/hw/i2c/core.c index 013ff68593..1fa8268c30 100644 --- a/hw/i2c/core.c +++ b/hw/i2c/core.c @@ -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; -} - -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; + bus->saved_address = -1; + if (!QLIST_EMPTY(&bus->current_devs)) { + if (!bus->broadcast) { + bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address; + } + } } 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; - break; + 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); - /* 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); + 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. */ + if (sc->event) { + 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); - if (sc->event) { - sc->event(dev, I2C_FINISH); + QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) { + sc = I2C_SLAVE_GET_CLASS(node->elt); + if (sc->event) { + sc->event(node->elt, I2C_FINISH); + } + QLIST_REMOVE(node, next); + g_free(node); } - - bus->current_dev = NULL; + 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; + QLIST_FOREACH(node, &bus->current_devs, next) { + sc = I2C_SLAVE_GET_CLASS(node->elt); + if (sc->send) { + ret = ret || sc->send(node->elt, data); + } else { + ret = -1; + } } - - sc = I2C_SLAVE_GET_CLASS(dev); - if (sc->send) { - return sc->send(dev, data); - } - - 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); - if (sc->event) { - sc->event(dev, I2C_NACK); + QLIST_FOREACH(node, &bus->current_devs, next) { + sc = I2C_SLAVE_GET_CLASS(node->elt); + if (sc->event) { + 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; }