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Message-ID: <ebb4927c-2194-4224-b8f0-274a181b2bcd@ixit.cz>
Date: Tue, 19 Dec 2023 21:26:57 +0100
From: David Heidelberg <david@...t.cz>
To: Robin Murphy <robin.murphy@....com>, Joerg Roedel <joro@...tes.org>,
Will Deacon <will@...nel.org>, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>, Andy Gross <agross@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>
Cc: iommu@...ts.linux.dev, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v5] dt-bindings: iommu: Convert msm,iommu-v0 to yaml
On 19/12/2023 16:25, Robin Murphy wrote:
> On 2023-12-16 12:22 am, David Heidelberg wrote:
>> Convert Qualcomm IOMMU v0 implementation to yaml format.
>>
>> Signed-off-by: David Heidelberg <david@...t.cz>
>> ---
>> v5:
>> - updated example (thx @Konrad)
>> - ordering of requirements + dropped > and | and reformatted (thx
>> @Konrad)
>> v4:
>> - renamed to qcom,apq8064-iommu as Rob requested
>> - changed title to Qualcomm APQ8064 IOMMU
>> - dropped quotes around URLs
>> - dropped mdp node
>> - dropped unused mdp_port0 label
>>
>> v3:
>> - I kept the name as -v0, since we have other binding -v1 and it look
>> good, I can change thou in v4 if requested.
>> - dropped non-existent smmu_clk part (and adjusted example, which was
>> using it)
>> - dropped iommu description
>> - moved iommu-cells description to the property #iommu-cells
>>
>> v2:
>> - fix wrong path in binding $id
>> - comment qcom,mdp4 node example (we don't want to validate it yet)
>>
>> .../bindings/iommu/msm,iommu-v0.txt | 64 ---------------
>> .../bindings/iommu/qcom,apq8064-iommu.yaml | 82 +++++++++++++++++++
>> 2 files changed, 82 insertions(+), 64 deletions(-)
>> delete mode 100644
>> Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
>> create mode 100644
>> Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
>> b/Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
>> deleted file mode 100644
>> index 20236385f26e..000000000000
>> --- a/Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
>> +++ /dev/null
>> @@ -1,64 +0,0 @@
>> -* QCOM IOMMU
>> -
>> -The MSM IOMMU is an implementation compatible with the ARM VMSA short
>> -descriptor page tables. It provides address translation for bus
>> masters outside
>> -of the CPU, each connected to the IOMMU through a port called
>> micro-TLB.
>> -
>> -Required Properties:
>> -
>> - - compatible: Must contain "qcom,apq8064-iommu".
>> - - reg: Base address and size of the IOMMU registers.
>> - - interrupts: Specifiers for the MMU fault interrupts. For
>> instances that
>> - support secure mode two interrupts must be specified, for
>> non-secure and
>> - secure mode, in that order. For instances that don't support
>> secure mode a
>> - single interrupt must be specified.
>> - - #iommu-cells: The number of cells needed to specify the stream
>> id. This
>> - is always 1.
>> - - qcom,ncb: The total number of context banks in the IOMMU.
>> - - clocks : List of clocks to be used during SMMU register
>> access. See
>> - Documentation/devicetree/bindings/clock/clock-bindings.txt
>> - for information about the format. For each clock specified
>> - here, there must be a corresponding entry in clock-names
>> - (see below).
>> -
>> - - clock-names : List of clock names corresponding to the clocks
>> specified in
>> - the "clocks" property (above).
>> - Should be "smmu_pclk" for specifying the interface clock
>> - required for iommu's register accesses.
>> - Should be "smmu_clk" for specifying the functional clock
>> - required by iommu for bus accesses.
>> -
>> -Each bus master connected to an IOMMU must reference the IOMMU in
>> its device
>> -node with the following property:
>> -
>> - - iommus: A reference to the IOMMU in multiple cells. The first
>> cell is a
>> - phandle to the IOMMU and the second cell is the stream id.
>> - A single master device can be connected to more than one iommu
>> - and multiple contexts in each of the iommu. So multiple entries
>> - are required to list all the iommus and the stream ids that the
>> - master is connected to.
>> -
>> -Example: mdp iommu and its bus master
>> -
>> - mdp_port0: iommu@...0000 {
>> - compatible = "qcom,apq8064-iommu";
>> - #iommu-cells = <1>;
>> - clock-names =
>> - "smmu_pclk",
>> - "smmu_clk";
>> - clocks =
>> - <&mmcc SMMU_AHB_CLK>,
>> - <&mmcc MDP_AXI_CLK>;
>> - reg = <0x07500000 0x100000>;
>> - interrupts =
>> - <GIC_SPI 63 0>,
>> - <GIC_SPI 64 0>;
>> - qcom,ncb = <2>;
>> - };
>> -
>> - mdp: qcom,mdp@...0000 {
>> - compatible = "qcom,mdp";
>> - ...
>> - iommus = <&mdp_port0 0
>> - &mdp_port0 2>;
>> - };
>> diff --git
>> a/Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
>> b/Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
>> new file mode 100644
>> index 000000000000..5af59305d277
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
>> @@ -0,0 +1,82 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +
>> +$id: http://devicetree.org/schemas/iommu/qcom,apq8064-iommu.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm APQ8064 IOMMU
>> +
>> +maintainers:
>> + - Will Deacon <will@...nel.org>
>> +
>> +description:
>> + The MSM IOMMU is an implementation compatible with the ARM VMSA short
>> + descriptor page tables. It provides address translation for bus
>> masters
>> + outside of the CPU, each connected to the IOMMU through a port
>> called micro-TLB.
>> +
>> +properties:
>> + compatible:
>> + const: qcom,apq8064-iommu
>> +
>> + clocks:
>> + items:
>> + - description: interface clock for register accesses
>> + - description: functional clock for bus accesses
>> +
>> + clock-names:
>> + items:
>> + - const: smmu_pclk
>> + - const: iommu_clk
>> +
>> + reg:
>> + maxItems: 1
>> +
>> + interrupts:
>> + description: Specifiers for the MMU fault interrupts.
>> + minItems: 1
>> + items:
>> + - description: non-secure mode interrupt
>> + - description: secure mode interrupt (for instances which
>> supports it)
>> +
>> + "#iommu-cells":
>> + const: 1
>> + description:
>> + The first cell is a phandle to the IOMMU and the second cell
>> + is the stream id.
>> + A single master device can be connected to more than one iommu
>> + and multiple contexts in each of the iommu.
>> + So multiple entries are required to list all the iommus and
>> + the stream ids that the master is connected to.
>
> This seems pretty confusing since it's the description for some other
> property, not this one. FWIW I'd just put this as something like "Each
> IOMMU specifier describes a single Stream ID.", and if you think it's
> really worth calling out that clients can have multiple IOMMU
> specifiers, I'd stick that in the overall description.
>
> Thanks,
> Robin.
Good catch, I must do wrong copy-paste here. I would think that the
description you wrote is good enough and I can drop the rest :) Sending v6.
Thanks
David
>
>> +
>> + qcom,ncb:
>> + $ref: /schemas/types.yaml#/definitions/uint32
>> + description: The total number of context banks in the IOMMU.
>> +
>> +required:
>> + - reg
>> + - interrupts
>> + - clocks
>> + - clock-names
>> + - qcom,ncb
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> + - |
>> + #include <dt-bindings/clock/qcom,mmcc-msm8960.h>
>> + #include <dt-bindings/interrupt-controller/irq.h>
>> + #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> + iommu@...0000 {
>> + compatible = "qcom,apq8064-iommu";
>> + reg = <0x07500000 0x100000>;
>> + interrupts = <GIC_SPI 63 IRQ_TYPE_LEVEL_HIGH>,
>> + <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
>> + clocks = <&clk SMMU_AHB_CLK>,
>> + <&clk MDP_AXI_CLK>;
>> + clock-names = "smmu_pclk",
>> + "iommu_clk";
>> + #iommu-cells = <1>;
>> + qcom,ncb = <2>;
>> + };
--
David Heidelberg
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