Messages in this thread | | | Date | Wed, 24 Aug 2016 17:05:21 -0700 | From | Bjorn Andersson <> | Subject | Re: [PATCH 3/4] dt-binding: remoteproc: venus rproc dt binding document |
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On Wed 24 Aug 08:36 PDT 2016, Stanimir Varbanov wrote:
> Hi Rob, > > On 08/23/2016 08:32 PM, Rob Herring wrote: > > On Fri, Aug 19, 2016 at 06:53:19PM +0300, Stanimir Varbanov wrote: > >> Add devicetree binding document for Venus remote processor. > >> > >> Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org> > >> --- > >> .../devicetree/bindings/remoteproc/qcom,venus.txt | 33 ++++++++++++++++++++++ > >> 1 file changed, 33 insertions(+) > >> create mode 100644 Documentation/devicetree/bindings/remoteproc/qcom,venus.txt > >> > >> diff --git a/Documentation/devicetree/bindings/remoteproc/qcom,venus.txt b/Documentation/devicetree/bindings/remoteproc/qcom,venus.txt > >> new file mode 100644 > >> index 000000000000..06a2db60fa38 > >> --- /dev/null > >> +++ b/Documentation/devicetree/bindings/remoteproc/qcom,venus.txt > >> @@ -0,0 +1,33 @@ > >> +Qualcomm Venus Peripheral Image Loader > >> + > >> +This document defines the binding for a component that loads and boots firmware > >> +on the Qualcomm Venus remote processor core. > > > > This does not make sense to me. Venus is the video encoder/decoder h/w, > > right? Why is the firmware loader separate from the codec block? Why > > rproc is used? Are there multiple clients? Naming it rproc_venus implies > > there aren't. And why does the firmware loading need 8MB of memory at a > > fixed address? > > > > The firmware for Venus case is 5MB. And here is 8MB because of > dma_alloc_from_coherent size restriction. >
Then you should specify it 5MB large and we'll have to deal with this implementation issue in the code. I've created a JIRA ticket for the dma_alloc_from_coherent() behavior.
> The address is not really fixed, cause the firmware could support > relocation. In this example I just picked up the next free memory region > in memory-reserved from msm8916.dtsi. >
In 8974 we do have a physical region where it's expected to be loaded.
So in line with upcoming remoteproc work we should support referencing a reserved-memory node with either reg or size.
In the case of spotting a "reg" we're currently better off using ioremap. We're looking at getting the remoteproc core to deal with this mess.
So, on 8916 I think you should use the form:
venus_mem: venus { size = <0x500000>; };
And I don't think you should use the shared-dma-pool compatible, because this is not a region for multiple devices to allocate dma memory out of.
Regards, Bjorn
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