I've been fighting for a week with trying to get the IPU booted over 
remoteproc on an OMAP4470. I feel like I've got most of the way there 
but I don't get a response from the first kick after boot. Has anyone 
ever had the IPU booted on mainline? Dmesg from remoteproce boot is as 
below:

[   47.430084]  remoteproc0: ipu_c0 is available
[   47.431274]  remoteproc0: Note: remoteproc is still under development 
and considered experimental.
[   47.445312]  remoteproc0: THE BINARY FORMAT IS NOT YET FINALIZED, and 
backward compatibility isn't yet guaranteed.
[   47.869476]  remoteproc0: unsupported resource 5
[   47.876831]  remoteproc0: registered virtio0 (type 7)
[   47.882385]  remoteproc0: unsupported resource 5
[   47.888244] cma: cma_alloc(cma c1211f98, count 3, align 2)
[   47.897613] cma: cma_alloc(): returned deda7990
[   47.902465] cma: cma_alloc(cma c1211f98, count 3, align 2)
[   47.908813] cma: cma_alloc(): returned deda7a20
[   47.913604]  remoteproc0: powering up ipu_c0
[   47.967895]  remoteproc0: Booting fw image ducati-m3-core0.xem3, size 
14862876
[   47.983947] omap-iommu 55082000.mmu: 55082000.mmu: version 2.1
[   47.990112] cma: cma_alloc(cma c1211f98, count 1536, align 8)
[   47.997894] cma: cma_alloc(): returned deda9400
[   48.022949] cma: cma_alloc(cma c1211f98, count 58880, align 8)
[   48.047454] cma: cma_alloc(): returned dedb6c00
[   48.762756] cma: cma_alloc(cma c1211f98, count 256, align 8)
[   48.769165] cma: cma_alloc(): returned defbc400
[   48.779113]  remoteproc0: unsupported resource 5
[   48.887756] omap-rproc omap-rproc.1: JACK1
[   48.893157] omap-rproc omap-rproc.1: JACK2
[   48.893157] omap-rproc omap-rproc.1: JACK3
[   48.901794] omap-rproc omap-rproc.1: JACK4
[   48.906097]  remoteproc0: remote processor ipu_c0 is now up
[   48.912231] cma: cma_alloc(cma c1211f98, count 64, align 6)
[   48.922851] cma: cma_alloc(): returned deda8200
[   48.929321] virtio_rpmsg_bus virtio0: rpmsg host is online

What I would expect next (as is the case on my 3.4 TI vendor kernel) is 
something like:

[   13.647338] virtio_rpmsg_bus virtio0: rpmsg host is online
[   15.996520] omap-rproc omap-rproc.1: received echo reply from ipu_c0
[   15.996887] virtio_rpmsg_bus virtio0: creating channel rpmsg-dce addr 
0x2a
[   16.000335] virtio_rpmsg_bus virtio0: creating channel rpmsg-omx1 
addr 0x3c
[   16.000732] rpmsg_omx rpmsg-omx1: new OMX connection srv channel: 
1025 -> 60!
[   16.000915] virtio_rpmsg_bus virtio0: creating channel omaprpc addr 0x3b

I imagine the echo reply is remoteproc, but the other stuff is maybe 
omapdce?

The patch that I've hacked together to get this far is attached. I had 
to comment out some of the zero checking parts as it was failing, saying 
that the reserved memory was not zeroed; could this be the iommu that 
isn't translating properly?

Any input at all on the subject would be much appreciated!

Cheers,
Jack.