On 10/15/21 12:14, Bin Meng wrote:

On Fri, Oct 15, 2021 at 6:09 PM Heinrich Schuchardt
[off-list ref] wrote:

quoted

The CLINT in the T-HEAD 9xx processors do not support 64bit mmio access to
the MTIMER device. The current schema does not allow to specify this.

OpenSBI currently uses a property 'clint,has-no-64bit-mmio' to indicate the
restriction. Samuael Holland suggested in
lib: utils/timer: Use standard property to specify 32-bit I/O
https://github.com/smaeul/opensbi/commit/b95e9cf7cf93b0af16fc89204378bc59ff30008e
to use "reg-io-width = <4>;" as the reg-io-width property is generally used
in the devicetree schema for such a condition.

A release candidate of the ACLINT specification is available at
https://github.com/riscv/riscv-aclint/releases

Add reg-io-width as optional property to the SiFive Core Local Interruptor.

Signed-off-by: Heinrich Schuchardt <redacted>
---
  Documentation/devicetree/bindings/timer/sifive,clint.yaml | 7 +++++++
  1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
index a35952f48742..266012d887b5 100644
--- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml

@@ -41,6 +41,13 @@ properties:
    reg:
      maxItems: 1

+  reg-io-width:
+    description: |
+      Some CLINT implementations, e.g. on the T-HEAD 9xx, only support
+      32bit access for MTIMER.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 4

But this is not a "sifive,clint" anyway. Should there be a new
dt-bindings for T-Head clint variant?

I assume by new dt-bindings variant you mean: Add a new compatible 
string in Documentation/devicetree/bindings/timer/sifive,clint.yaml.

The vendor Debian image uses:
compatible = "{allwinner,sun20i-d1-clint", "sifive,clint0"};

We could add this diff in a future version of the patch:

--- a/Documentation/devicetree/bindings/timer/sifive,clint.yaml
+++ b/Documentation/devicetree/bindings/timer/sifive,clint.yaml

@@ -26,6 +26,7 @@ properties:
        - enum:
            - sifive,fu540-c000-clint
            - canaan,k210-clint
+          - allwinner,sun20i-d1-clint
        - const: sifive,clint0

      description:

@@ -33,10 +34,10 @@ properties:
        Supported compatible strings are -
        "sifive,fu540-c000-clint" for the SiFive CLINT v0 as integrated
        onto the SiFive FU540 chip, "canaan,k210-clint" for the SiFive
-      CLINT v0 as integrated onto the Canaan Kendryte K210 chip, and
+      CLINT v0 as integrated onto the Canaan Kendryte K210 chip,
        "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
-      integration tweaks.
-      Please refer to sifive-blocks-ip-versioning.txt for details
+      integration tweaks, and "allwinner,sun20i-d1-clint" for the Allwinner
+      D1. Please refer to sifive-blocks-ip-versioning.txt for details

    reg:
      maxItems: 1

Best regards

Heinrich

quoted

+
    interrupts-extended:
      minItems: 1

Regards,
Bin