Messages in this thread | | | From | Ohad Ben-Cohen <> | Date | Wed, 25 Jan 2012 15:45:48 +0200 | Subject | Re: remoteproc: Load coprocessor code to the specific main memory location |
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On Wed, Jan 25, 2012 at 2:41 PM, Michal Simek <monstr@monstr.eu> wrote: > First of all will be the best to describe what we want to achieve. > We have Zynq platform ARM Cortex-A9(which should be ARMv7 - 2cpus). > cpu0 runs Linux and cpu1 will be used for real-time os. We would like to use > remoteproc for loading any code(firmware if you like) for the cpu1 and start > it.
Sounds cool.
So you're not < ARMv6, and I now understand why you bumped into that code path: you're using a vanilla kernel, without CMA.
I suggest you merge Marek's CMA branch into your tree. Though 1MB isn't that much really, and you can easily get away even without CMA. You just won't have any non-CMA public example to use as a reference ;).
For details about the CMA tree and branches, see Marek's email:
https://lkml.org/lkml/2012/1/10/48
> Then in zynq_rproc_kick I copy content of this 1MB carveout to 0x0 physical
I recommend to keep the ->kick() handler as light as possible, as it may be frequently triggered (think of a network driver doing I/O).
Ideally you should do the minimum required to only wake up the other core when you are kicked. Copying a 1MB region every kick sounds excessive.
> The main my problem is that firmware base addr must be at the beginning of > address space > or selected address but it is fixed and known. .. > ok. How do you handle limitations if coprocessor expect code on any address?
Just make sure you reserve the CMA region at that fixed address.
For a reference how this can be done, look for OMAP_RPROC_CMA_BASE in my rpmsg_3.2_rc4 branch.
>> Looping in Mark, who did the davinci remoteproc support, and might >> have the code available to share. Hopefully we'd have the patches >> posted soon, and then no-iommu platforms could just use them for >> reference. > > > ok. great. Will look forward for that code and recommendation because I am > ARM newbie.
So I no longer think you need the davinci code, you can just follow the OMAP example.
> I am also interested in suggestions about DTS binding. Have someone tried to > describe it or use it?
No, AFAICT. And I'm not sure there are DTS binding for CMA regions yet. Feel free to take a stab at it though ;)
Regards, Ohad.
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