Am 08.06.2012 06:23, schrieb Peter Crosthwaite: > Each of the two core has three interfaces (+interrupt pins): > > 1: Sysbus attachment for device control > 2: AXI stream TX link > 3: AXI stream RX link [...] > struct XilinxDMAConnection { > void *dma; > void *client; > > DMAPushFn to_dma; > DMAPushFn to_client; > }; > > So what im proposing is AXI stream is implemented as a unidirectional > point to point bus. The xilinx ethernet system would consist of two of > these buses one for tx, one for rx. [...] > A: Make AXI_STREAM_SLAVE an interface (not a sub-class of DEVICE). Its > kind of annoying though if someone in the future whats the create a > device thats only and axi stream slave, as they would have to > explicitly inherit from DEVICE as well. > > or > > B: Have the slave attachment be a device within a device. Hard part is > getting an accessor so machine models can retrieve the slave > attachment and hook it up.
If you dive into busses, note that Anthony has refactored QBus on qom-next branch. As Paul has already mentioned, the concept of tree-structured qdev busses is deprecated by QOM in favor of link<> properties. SysBus is also in the process of being deprecated, and Anthony is working on Pin objects for simple qemu_irq-style messaging. What you could try as option C today is deriving a type from SysBus with one added DMAPushFn and a link<> property of that type for unidirectional connection and form circular links for RX and TX... That would of course limit the number of channels to one. Otherwise you need a dedicated child<> object, of which a device can have multiple. Regards, Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg