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* [PATCH 1/1] dt-bindings: reg-io-width for SiFive CLINT
@ 2021-10-15 10:09 ` Heinrich Schuchardt
  0 siblings, 0 replies; 16+ messages in thread
From: Heinrich Schuchardt @ 2021-10-15 10:09 UTC (permalink / raw)
  To: Daniel Lezcano, Thomas Gleixner
  Cc: Guo Ren, Bin Meng, Xiang W, Samuel Holland, Atish Patra,
	Rob Herring, Palmer Dabbelt, Paul Walmsley, Anup Patel,
	linux-kernel, devicetree, linux-riscv, opensbi,
	Heinrich Schuchardt

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 <heinrich.schuchardt@canonical.com>
---
 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
+
   interrupts-extended:
     minItems: 1
 
-- 
2.32.0


^ permalink raw reply related	[flat|nested] 16+ messages in thread

end of thread, other threads:[~2021-10-19  6:10 UTC | newest]

Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
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2021-10-15 10:09 [PATCH 1/1] dt-bindings: reg-io-width for SiFive CLINT Heinrich Schuchardt
2021-10-15 10:09 ` Heinrich Schuchardt
2021-10-15 10:14 ` Bin Meng
2021-10-15 10:14   ` Bin Meng
2021-10-15 11:54   ` Heinrich Schuchardt
2021-10-15 11:54     ` Heinrich Schuchardt
2021-10-15 12:15     ` Jessica Clarke
2021-10-15 12:15       ` Jessica Clarke
2021-10-15 12:42       ` Heinrich Schuchardt
2021-10-15 12:42         ` Heinrich Schuchardt
2021-10-15 13:46       ` Bin Meng
2021-10-15 13:46         ` Bin Meng
2021-10-17  7:54 ` Xiang W
2021-10-17  7:54   ` Xiang W
2021-10-19  6:10 ` Guo Ren
2021-10-19  6:10   ` Guo Ren

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