[PATCH v3 1/7] dt-bindings: iommu: riscv: Add bindings for RISC-V IOMMU
Tomasz Jeznach
tjeznach at rivosinc.com
Wed May 1 19:47:41 PDT 2024
On Wed, May 1, 2024 at 6:16 AM Rob Herring <robh at kernel.org> wrote:
>
> On Tue, Apr 30, 2024 at 01:01:51PM -0700, Tomasz Jeznach wrote:
> > Add bindings for the RISC-V IOMMU device drivers.
> >
> > Co-developed-by: Anup Patel <apatel at ventanamicro.com>
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > Signed-off-by: Tomasz Jeznach <tjeznach at rivosinc.com>
> > ---
> > .../bindings/iommu/riscv,iommu.yaml | 150 ++++++++++++++++++
> > MAINTAINERS | 7 +
> > 2 files changed, 157 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml b/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> > new file mode 100644
> > index 000000000000..16817525e157
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> > @@ -0,0 +1,150 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iommu/riscv,iommu.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: RISC-V IOMMU Architecture Implementation
> > +
> > +maintainers:
> > + - Tomasz Jeznach <tjeznach at rivosinc.com>
> > +
> > +description: |
> > + The RISC-V IOMMU provides memory address translation and isolation for
> > + input and output devices, supporting per-device translation context,
> > + shared process address spaces including the ATS and PRI components of
> > + the PCIe specification, two stage address translation and MSI remapping.
> > + It supports identical translation table format to the RISC-V address
> > + translation tables with page level access and protection attributes.
> > + Hardware uses in-memory command and fault reporting queues with wired
> > + interrupt or MSI notifications.
> > +
> > + Visit https://github.com/riscv-non-isa/riscv-iommu for more details.
> > +
> > + For information on assigning RISC-V IOMMU to its peripheral devices,
> > + see generic IOMMU bindings.
> > +
> > +properties:
> > + # For PCIe IOMMU hardware compatible property should contain the vendor
> > + # and device ID according to the PCI Bus Binding specification.
> > + # Since PCI provides built-in identification methods, compatible is not
> > + # actually required. For non-PCIe hardware implementations 'riscv,iommu'
> > + # should be specified along with 'reg' property providing MMIO location.
> > + compatible:
> > + oneOf:
> > + - items:
> > + - enum:
> > + - qemu,iommu
>
> 'qemu,iommu' is too broad. Could be other QEMU implementations of an
> IOMMU. So 'qemu,riscv-iommu'.
>
I'm ok with that. Any objections from others?
> > + - const: riscv,iommu
> > + - items:
> > + - enum:
> > + - pci1efd,edf1
> > + - const: riscv,pci-iommu
> > +
> > + reg:
> > + maxItems: 1
> > + description:
> > + For non-PCI devices this represents base address and size of for the
> > + IOMMU memory mapped registers interface.
> > + For PCI IOMMU hardware implementation this should represent an address
> > + of the IOMMU, as defined in the PCI Bus Binding reference. The reg
> > + property is a five-cell address encoded as (phys.hi phys.mid phys.lo
> > + size.hi size.lo), where phys.hi should contain the device's BDF as
> > + 0b00000000 bbbbbbbb dddddfff 00000000. The other cells should be zero.
>
> No need to describe what the PCI address looks like.
>
> > +
> > + '#iommu-cells':
> > + const: 1
> > + description:
> > + Has to be one. The single cell describes the requester id emitted
>
> Drop 'Has to be one'. You already said that with the schema.
>
> > + by a master to the IOMMU.
> > +
> > + interrupts:
> > + minItems: 1
> > + maxItems: 4
> > + 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.
> > +
> > + msi-parent: true
> > +
> > + power-domains:
> > + maxItems: 1
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - '#iommu-cells'
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |+
> > + /* Example 1 (IOMMU device with wired interrupts) */
> > + #include <dt-bindings/interrupt-controller/irq.h>
> > +
> > + iommu1: iommu at 1bccd000 {
> > + compatible = "qemu,iommu", "riscv,iommu";
> > + reg = <0x1bccd000 0x1000>;
> > + interrupt-parent = <&aplic_smode>;
> > + interrupts = <32 IRQ_TYPE_LEVEL_HIGH>,
> > + <33 IRQ_TYPE_LEVEL_HIGH>,
> > + <34 IRQ_TYPE_LEVEL_HIGH>,
> > + <35 IRQ_TYPE_LEVEL_HIGH>;
> > + #iommu-cells = <1>;
> > + };
> > +
> > + /* Device with two IOMMU device IDs, 0 and 7 */
> > + master1 {
> > + iommus = <&iommu1 0>, <&iommu1 7>;
> > + };
> > +
> > + - |+
> > + /* Example 2 (IOMMU device with shared wired interrupt) */
> > + #include <dt-bindings/interrupt-controller/irq.h>
> > +
> > + iommu2: iommu at 1bccd000 {
> > + compatible = "qemu,iommu", "riscv,iommu";
> > + reg = <0x1bccd000 0x1000>;
> > + interrupt-parent = <&aplic_smode>;
> > + interrupts = <32 IRQ_TYPE_LEVEL_HIGH>;
> > + #iommu-cells = <1>;
> > + };
> > +
> > + - |+
> > + /* Example 3 (IOMMU device with MSIs) */
> > + iommu3: iommu at 1bcdd000 {
> > + compatible = "qemu,iommu", "riscv,iommu";
> > + reg = <0x1bccd000 0x1000>;
> > + msi-parent = <&imsics_smode>;
> > + #iommu-cells = <1>;
> > + };
> > +
> > + - |+
> > + /* Example 4 (IOMMU PCIe device with MSIs) */
> > + bus {
> > + #address-cells = <2>;
> > + #size-cells = <2>;
> > +
> > + pcie at 30000000 {
> > + device_type = "pci";
> > + #address-cells = <3>;
> > + #size-cells = <2>;
> > + reg = <0x0 0x30000000 0x0 0x1000000>;
> > + ranges = <0x02000000 0x0 0x41000000 0x0 0x41000000 0x0 0x0f000000>;
> > +
> > + /*
> > + * The IOMMU manages all functions in this PCI domain except
> > + * itself. Omit BDF 00:01.0.
> > + */
> > + iommu-map = <0x0 &iommu0 0x0 0x8
> > + 0x9 &iommu0 0x9 0xfff7>;
>
> Bracket each entry.
>
> > +
> > + /* The IOMMU programming interface uses slot 00:01.0 */
> > + iommu0: iommu at 1,0 {
> > + compatible = "pci1efd,edf1", "riscv,pci-iommu";
> > + reg = <0x800 0 0 0 0>;
> > + #iommu-cells = <1>;
> > + };
> > + };
> > + };
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index f6dc90559341..7fcf7c27ef6b 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -18958,6 +18958,13 @@ F: arch/riscv/
> > N: riscv
> > K: riscv
> >
> > +RISC-V IOMMU
> > +M: Tomasz Jeznach <tjeznach at rivosinc.com>
> > +L: iommu at lists.linux.dev
> > +L: linux-riscv at lists.infradead.org
> > +S: Maintained
> > +F: Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> > +
> > RISC-V MICROCHIP FPGA SUPPORT
> > M: Conor Dooley <conor.dooley at microchip.com>
> > M: Daire McNamara <daire.mcnamara at microchip.com>
> > --
> > 2.34.1
> >
ack to other comments.
Thank you for review,
- Tomasz
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