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authorPeter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>2012-07-24 10:55:15 +1000
committerPeter Crosthwaite <peter.crosthwaite@xilinx.com>2012-10-10 11:13:31 +1000
commitb4a76e84f4997392c9d2eb6f4373dc376d2ffd82 (patch)
treec86259bd728cddf0a9e67bc3b87802fe4981505e
parent4bb26682f70a5f626cad3e0ac82bf4b6252ea7a4 (diff)
ssi: Support for multiple attached devices
Removed assertion that only one device is attached to the SSI bus. When multiple devices are attached, all slaves have their transfer function called for transfers. Each device is responsible for knowing whether or not its CS is active, and if not returning 0. The returned data is the logical or of all responses from the (mulitple) devices. Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com> Acked-by: Peter Maydell <peter.maydell@linaro.org>
-rw-r--r--hw/ssi.c24
1 files changed, 9 insertions, 15 deletions
diff --git a/hw/ssi.c b/hw/ssi.c
index e5f14a0cef..35d0a04a08 100644
--- a/hw/ssi.c
+++ b/hw/ssi.c
@@ -2,6 +2,8 @@
* QEMU Synchronous Serial Interface support
*
* Copyright (c) 2009 CodeSourcery.
+ * Copyright (c) 2012 Peter A.G. Crosthwaite (peter.crosthwaite@petalogix.com)
+ * Copyright (c) 2012 PetaLogix Pty Ltd.
* Written by Paul Brook
*
* This code is licensed under the GNU GPL v2.
@@ -29,14 +31,6 @@ static int ssi_slave_init(DeviceState *dev)
{
SSISlave *s = SSI_SLAVE(dev);
SSISlaveClass *ssc = SSI_SLAVE_GET_CLASS(s);
- SSIBus *bus;
- BusChild *kid;
-
- bus = FROM_QBUS(SSIBus, qdev_get_parent_bus(dev));
- kid = QTAILQ_FIRST(&bus->qbus.children);
- if (kid->child != dev || QTAILQ_NEXT(kid, sibling) != NULL) {
- hw_error("Too many devices on SSI bus");
- }
return ssc->init(s);
}
@@ -74,16 +68,16 @@ SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
{
BusChild *kid;
- SSISlave *slave;
SSISlaveClass *ssc;
+ uint32_t r = 0;
- kid = QTAILQ_FIRST(&bus->qbus.children);
- if (!kid) {
- return 0;
+ QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
+ SSISlave *slave = SSI_SLAVE(kid->child);
+ ssc = SSI_SLAVE_GET_CLASS(slave);
+ r |= ssc->transfer(slave, val);
}
- slave = SSI_SLAVE(kid->child);
- ssc = SSI_SLAVE_GET_CLASS(slave);
- return ssc->transfer(slave, val);
+
+ return r;
}
static void ssi_slave_register_types(void)