Re: [PATCH v3 01/19] dt-bindings: crypto: add Rambus CryptoManager Hub
From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2026-08-10 08:16:38
Also in:
linux-crypto, linux-devicetree, linux-doc, linux-kselftest, linux-riscv, lkml
On 06/08/2026 21:55, Saravanakrishnan Krishnamoorthy wrote:
From: Alex Ousherovitch <redacted> Add device tree binding schema for the Rambus CryptoManager Hub (CMH) hardware crypto accelerator. The binding describes the parent SoC-level node with its SIC register region and one mailbox@N child node per mailbox the host owns, each carrying a reg (mailbox instance index), an optional interrupt, VCQ ring geometry (rambus,slots-log2 / rambus,strides-log2) and a rambus,cores affinity list. Which crypto cores are present is discovered from the SIC CORE_ENABLE register at probe, not described in the device tree. Register the 'rambus' vendor prefix for Rambus Inc. Co-developed-by: Saravanakrishnan Krishnamoorthy <redacted> Signed-off-by: Saravanakrishnan Krishnamoorthy <redacted>
Completely messed order of tags.
Signed-off-by: Alex Ousherovitch <redacted>
How Alex could sign after you?
Reviewed-by: Joel Wittenauer <redacted> Reviewed-by: Thi Nguyen <redacted>
Your SoB is the last. Are you sure these people reviewed THIS code instead of blanket-review for everything? Did they find any issues in the schema which you fixed?
quoted hunk ↗ jump to hunk
--- .../bindings/crypto/rambus,cmh.yaml | 207 ++++++++++++++++++ .../devicetree/bindings/vendor-prefixes.yaml | 2 + 2 files changed, 209 insertions(+) create mode 100644 Documentation/devicetree/bindings/crypto/rambus,cmh.yamldiff --git a/Documentation/devicetree/bindings/crypto/rambus,cmh.yaml b/Documentation/devicetree/bindings/crypto/rambus,cmh.yaml new file mode 100644 index 000000000000..2709e20fb76f --- /dev/null +++ b/Documentation/devicetree/bindings/crypto/rambus,cmh.yaml@@ -0,0 +1,207 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/crypto/rambus,cmh.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Rambus CryptoManager Hub (CMH) Hardware Crypto Accelerator + +maintainers: + - Alex Ousherovitch <aousherovitch@rambus.com> + - Saravanakrishnan Krishnamoorthy <skrishnamoorthy@rambus.com> + - Joel Wittenauer <Joel.Wittenauer@cryptography.com> + +description: | + The Rambus CryptoManager Hub (CMH) is a hardware cryptographic accelerator + accessed via a mailbox-based VCQ (Virtual Command Queue) interface. The + host writes VCQ command sequences into per-mailbox DMA queue buffers and + rings a doorbell; the CMH eSW processes them and signals completion via + interrupt. + + The management host statically partitions the hardware mailboxes across + the SoC's host interfaces at integration time; the set of mailboxes a + given host owns is therefore fixed and not runtime-discoverable (a + mailbox locked to a host reads as unavailable in the SIC availability + register). Each owned mailbox is described by a child node. Which + crypto cores are present, by contrast, is a fixed silicon-build property + the driver reads from the hardware at probe (the SIC CORE_ENABLE + register), so cores are not described in the device tree. + + CMH identifies the host that owns a mailbox by a hardware HOST ID + presented on the bus with every access, and permits only that HOST ID + to access a mailbox while it is locked. An integration must therefore + present a single, stable HOST ID for all accesses to a given mailbox, + independent of which CPU issues them. On SMP hosts whose interconnect + encodes the issuing CPU in the HOST ID, the integration must provide a + single consistent HOST ID for the set of CPUs that share a mailbox; the + driver neither selects nor can override the HOST ID presented by the + hardware. + + Supported algorithm families: SHA-2, SHA-3, SM3, AES, SM4, + ChaCha20-Poly1305, RSA, ECDSA, EdDSA, ECDH, SM2, ML-KEM, ML-DSA, + SLH-DSA, LMS, XMSS, DRBG. + +properties: + compatible: + const: rambus,cmh-v1030 + description: + Identifies the CryptoManager Hub v1.030 IP revision (register map and + command ABI). A specific SoC integration should list its own + "<vendor>,<soc>-cmh" compatible first with "rambus,cmh-v1030" as a + fallback; that extended form will be added when such a platform is + upstreamed.
Considering how variable the binding looks like, this needs real SoC compatibles.
+> + reg: + maxItems: 1 + description: + SIC (System Interface Controller) MMIO region. The registers of + mailbox instance N are at offset N * 0x1000 within this region. + + clocks: + minItems: 1 + maxItems: 3 + description: + Functional clocks driving the CryptoManager Hub. The block gates its + clocks internally (integrated clock-gating cell); the host does not + gate them, so these describe the input pins only. The names, in + order, are "core" (the main functional clock), "core-div2" (a + half-rate clock present only on configurations with + side-channel-protected cores) and "rt" (the real-time tick clock
Don't repeat constraints in free form text.
+ for the internal timer). Absent on integrations where a separate + management/power controller owns the clocks and Linux has no clock + handle.
List the items instead with description. minItems stays.
+ + clock-names: + minItems: 1 + items: + - const: core + - const: core-div2 + - const: rt + + reset-gpios: + maxItems: 1 + description: + Optional host-driven reset for the CryptoManager Hub. The hub has + two external, active-low reset inputs -- a power-on reset and a hard + reset; where a board routes one of them to a host-controlled GPIO, + that line is described here. Present only on integrations where the + Linux host is the management host; where a separate management + controller owns reset (the usual case) it is absent and Linux does + not drive reset. + + "#address-cells": + const: 1 + + "#size-cells": + const: 0 + +patternProperties: + "^mailbox@[0-9a-f]+$": + type: object + description: + One node per hardware mailbox owned by this host. The mailboxes a + host owns are assigned by the management host at integration time
So they are SoC-deducible.
+ and cannot be probed, so they are enumerated here.
Where are mbox-cells?
+ properties: + reg: + maxItems: 1 + description: + 0-based mailbox instance index. The instance's registers are + at reg * 0x1000 within the SIC region. + + interrupts: + maxItems: 1 + description: + Completion/error interrupt for this mailbox. Optional; when no
Don't repeat constraints in free form text. The schema tells if something is optional or not.
+ mailbox has an interrupt the driver falls back to polling.
Driver is usually irrelevant here and that internal review which supposedly happen for this code should tell you this.
+ + rambus,slots-log2: + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 1 + maximum: 15 + description: + log2 of the number of VCQ ring slots the driver provisions for
Driver stuff does not belong to DT.
+ this mailbox in host DMA memory. This is a per-board, + per-mailbox host-memory layout choice programmed into the + mailbox QUEUE/SLOTS registers, not a silicon constant -- + boards built around the same SoC (hence the same compatible) + may provision different ring geometry, so it is described per + mailbox here rather than derived from the compatible. The + upper bound is imposed by the hardware. Optional; defaults to + 6 (64 slots).
Missing default. Anyway, I do not understand why standard number you express as log. slots-num is a number. Number is 1, 2 or 4 etc. Not logarithm of something. Do you say: I have log-8 dollars in my wallet?
+ + rambus,strides-log2: + $ref: /schemas/types.yaml#/definitions/uint32 + minimum: 7 + maximum: 10 + description: + log2 of the per-slot stride in bytes for this mailbox's VCQ + ring. Like rambus,slots-log2 this is a per-board layout + choice, not derived from the compatible. The range is imposed + by the hardware. Optional; defaults to 9 (512 bytes per slot). +
Best regards, Krzysztof