[PATCH v1.1 4/7] dt-bindings: iommu: Add spacemit/t100 features
Conor Dooley
conor at kernel.org
Thu Jan 29 02:08:06 PST 2026
On Thu, Jan 29, 2026 at 02:09:13PM +0800, Lv Zheng wrote:
> Adds device tree bindings for SpacemiT T100 specific features.
>
> vendor-hpm-events: Allow vendor events to be customized in the device
> tree.
> global-filter: The feature saves silicon area by reducing filters to
> one and use it as a global filter across all events.
> This usually is sufficient for real applications.
Why can these not be determined from a device specific compatible?
> Signed-off-by: Lv Zheng <lv.zheng at spacemit.com>
> Signed-off-by: Jingyu Li <joey.li at spacemit.com>
> ---
> .../bindings/iommu/riscv,iommu.yaml | 60 ++++++++++++++++++-
> 1 file changed, 59 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml b/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> index d4838c3b3741..0378eef1f34e 100644
> --- a/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> +++ b/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> @@ -57,17 +57,42 @@ properties:
>
> interrupts:
> minItems: 1
> - maxItems: 4
> + maxItems: 68
> description:
> Wired interrupt vectors available for RISC-V IOMMU to notify the
> RISC-V HARTS. The cause to interrupt vector is software defined
> using IVEC IOMMU register.
> + Normally the number of interrupt vectors available is 4 for IOATS
> + civ/fiv/pmiv/piv interrupts. But for SpacemiT distributed IOMMU,
> + the number of interrupt vectors includes IOATC pmiv wired
> + interrupts and the maximum number of IOATCs can be up to 64.
The extension to 68 should only be permitted for a soc-specific
compatible.
> +
> + interrupt-names:
> + minItems: 1
> + maxItems: 68
>
> msi-parent: true
>
> power-domains:
> maxItems: 1
>
> + vendor-hpm-events:
> + minItems: 1
> + maxItems: 120
> + description:
> + Each item defines a vendor specific event using the format of
> + "eventId[:eventName]", where the eventId is an integer filling the
> + eventID field of the iohpmevt register and the eventName is an
> + optional string used as the annotation of the event instead of the
> + default name "eventId".
> + $ref: /schemas/types.yaml#/definitions/string-array
> +
> + global-filter:
> + type: boolean
> + description:
> + Indicate the filters programmed across iohpmevt registers are wired
> + together in hardware as a global filter applied to all HPM events.
> +
> required:
> - compatible
> - reg
> @@ -145,3 +170,36 @@ examples:
> };
> };
> };
> +
> + - |+
> + /* Example 5 (SpacemiT distributed IOMMU) */
> + #include <dt-bindings/interrupt-controller/irq.h>
> +
> + iommu4: iommu at 1bccd000 {
> + compatible = "qemu,riscv-iommu", "riscv,iommu";
You cannot use the qemu compatible for your device, you must use a
specific one for the spacemit k3.
Also, why is your version "v1.1"? That should just be "v1", and your
next version "v2" etc.
pw-bot: changes-requested
Cheers,
Conor.
> + reg = <0x1bccd000 0x1000>;
> + interrupts = <58 IRQ_TYPE_LEVEL_HIGH>, <58 IRQ_TYPE_LEVEL_HIGH>,
> + <58 IRQ_TYPE_LEVEL_HIGH>, <58 IRQ_TYPE_LEVEL_HIGH>,
> + <62 IRQ_TYPE_LEVEL_HIGH>, <63 IRQ_TYPE_LEVEL_HIGH>;
> + interrupt-names = "civ", "fiv", "ioats-pmiv", "piv",
> + "ioatc0-pmiv", "ioatc1-pmiv";
> + interrupt-parent = <&saplic>;
> + #iommu-cells = <0x01>;
> + /* SpacemiT T100 features */
> + global-filter;
> + vendor-hpm-events = "0x10:pri_page_reqs",
> + "0x11:ptw_cache_reqs",
> + "0x12:dtw_cache_reqs",
> + "0x15:all_trans_reqs",
> + "0x20:dtw_cache_lkps",
> + "0x28:s1l0_ptw_cache_lkps",
> + "0x2A:s1l1_ptw_cache_lkps",
> + "0x2C:s1l2_ptw_cache_lkps",
> + "0x2E:s1l3_ptw_cache_lkps",
> + "0x30:s2l0_ptw_cache_lkps",
> + "0x32:s2l1_ptw_cache_lkps",
> + "0x34:s2l2_ptw_cache_lkps",
> + "0x36:s2l3_ptw_cache_lkps",
> + "0x38:mtlb_lkps",
> + "0x3A:utlb_lkps";
> + };
> --
> 2.43.0
>
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