Re: [PATCH 1/6] dt-bindings: remoteproc: qcom,pas-common: Introduce iommus and qcom,devmem property

[Dmitry Baryshkov]

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.

> +
> +      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.

> +
>    qcom,smem-states:
>      $ref: /schemas/types.yaml#/definitions/phandle-array
>      description: States used by the AP to signal the Hexagon core
> diff --git a/Documentation/devicetree/bindings/remoteproc/qcom,sa8775p-pas.yaml b/Documentation/devicetree/bindings/remoteproc/qcom,sa8775p-pas.yaml
> index 7fe401a06805..503c5c9d8ea7 100644
> --- a/Documentation/devicetree/bindings/remoteproc/qcom,sa8775p-pas.yaml
> +++ b/Documentation/devicetree/bindings/remoteproc/qcom,sa8775p-pas.yaml
> @@ -139,6 +139,26 @@ examples:
>          power-domains = <&rpmhpd RPMHPD_LCX>, <&rpmhpd RPMHPD_LMX>;
>          power-domain-names = "lcx", "lmx";
>  
> +        iommus = <&apps_smmu 0x3000 0x0>;
> +        qcom,devmem = <0x00110000 0x00110000 0x4000 0x1>,
> +                      <0x00123000 0x00123000 0x1000 0x3>,
> +                      <0x00124000 0x00124000 0x3000 0x3>,
> +                      <0x00127000 0x00127000 0x2000 0x3>,
> +                      <0x0012a000 0x0012a000 0x3000 0x3>,
> +                      <0x0012e000 0x0012e000 0x1000 0x3>,
> +                      <0x0012f000 0x0012f000 0x1000 0x1>,
> +                      <0x00144000 0x00144000 0x1000 0x1>,
> +                      <0x00148000 0x00148000 0x1000 0x1>,
> +                      <0x00149000 0x00149000 0xe000 0x3>,
> +                      <0x00157000 0x00157000 0x1000 0x3>,
> +                      <0x00158000 0x00158000 0xd000 0x3>,
> +                      <0x00165000 0x00165000 0x1000 0x3>,
> +                      <0x00172000 0x00172000 0x1000 0x3>,
> +                      <0x00173000 0x00173000 0x8000 0x3>,
> +                      <0x0017b000 0x0017b000 0x2000 0x3>,
> +                      <0x0017f000 0x0017f000 0x1000 0x3>,
> +                      <0x00184000 0x00184000 0x1000 0x1>;
> +
>          interconnects = <&lpass_ag_noc MASTER_LPASS_PROC 0 &mc_virt SLAVE_EBI1 0>;
>  
>          memory-region = <&pil_adsp_mem>;
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry