On Sun, Oct 06, 2024 at 10:38:01PM +0300, Dmitry Baryshkov wrote:
> On Sat, Oct 05, 2024 at 02:53:54AM GMT, Mukesh Ojha wrote:
> > From: Shiraz Hashim <quic_shashim@xxxxxxxxxxx>
> >
> > Qualcomm’s PAS implementation for remote processors only supports a
> > single stage of IOMMU translation and is presently managed by the
> > Qualcomm EL2 hypervisor (QHEE) if it is present. In the absence of QHEE,
> > such as with a KVM hypervisor, IOMMU translations need to be set up by
> > the KVM host. Remoteproc needs carveout memory region and its resource
> > (device memory) permissions to be set before it comes up, and this
> > information is presently available statically with QHEE.
> >
> > In the absence of QHEE, the boot firmware needs to overlay this
> > information based on SoCs running with either QHEE or a KVM hypervisor
> > (CPUs booted in EL2).
> >
> > The qcom,devmem property provides IOMMU devmem translation information
> > intended for non-QHEE based systems.
> >
> > Signed-off-by: Shiraz Hashim <quic_shashim@xxxxxxxxxxx>
> > Co-Developed-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>
> > Signed-off-by: Mukesh Ojha <quic_mojha@xxxxxxxxxxx>
> > ---
> > .../bindings/remoteproc/qcom,pas-common.yaml | 42 +++++++++++++++++++
> > .../bindings/remoteproc/qcom,sa8775p-pas.yaml | 20 +++++++++
> > 2 files changed, 62 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/remoteproc/qcom,pas-common.yaml b/Documentation/devicetree/bindings/remoteproc/qcom,pas-common.yaml
> > index 63a82e7a8bf8..068e177ad934 100644
> > --- a/Documentation/devicetree/bindings/remoteproc/qcom,pas-common.yaml
> > +++ b/Documentation/devicetree/bindings/remoteproc/qcom,pas-common.yaml
> > @@ -52,6 +52,48 @@ properties:
> > minItems: 1
> > maxItems: 3
> >
> > + iommus:
> > + maxItems: 1
> > +
> > + qcom,devmem:
> > + $ref: /schemas/types.yaml#/definitions/uint32-matrix
> > + description:
> > + Qualcomm’s PAS implementation for remote processors only supports a
> > + single stage of IOMMU translation and is presently managed by the
> > + Qualcomm EL2 hypervisor (QHEE) if it is present. In the absence of QHEE,
> > + such as with a KVM hypervisor, IOMMU translations need to be set up by
> > + the KVM host. Remoteproc might need some device resources and related
> > + access permissions to be set before it comes up, and this information is
> > + presently available statically with QHEE.
> > +
> > + In the absence of QHEE, the boot firmware needs to overlay this
> > + information based on SoCs running with either QHEE or a KVM hypervisor
> > + (CPUs booted in EL2).
> > +
> > + The qcom,devmem property provides IOMMU devmem translation information
> > + intended for non-QHEE based systems. It is an array of u32 values
> > + describing the device memory regions for which IOMMU translations need to
> > + be set up before bringing up Remoteproc. This array consists of 4-tuples
> > + defining the device address, physical address, size, and attribute flags
> > + with which it has to be mapped.
>
> I'd expect that this kind of information is hardware-dependent. As such
> it can go to the driver itself, rather than the device tree. The driver
> can use compatible string to select the correct table.
>
IIUC, are you saying that to move this into driver file and override the
compatible string via overlay ?
> > +
> > + remoteproc@3000000 {
> > + ...
> > +
> > + qcom,devmem = <0x82000 0x82000 0x2000 0x3>,
> > + <0x92000 0x92000 0x1000 0x1>;
> > + }
> > +
> > + items:
> > + items:
> > + - description: device address
> > + - description: physical address
> > + - description: size of mapping
> > + - description: |
> > + iommu attributes - IOMMU_READ, IOMMU_WRITE, IOMMU_CACHE, IOMMU_NOEXEC, IOMMU_MMIO
> > + enum: [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
> > + 25, 26, 27, 28, 29, 30, 31 ]
>
> Attributes should definitely be defined and then the DT should use
> defines rather than the raw values.
>
Ack.
-Mukesh
