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* [PATCH v2 1/1] dt-bindings: reg-io-width for SiFive CLINT
@ 2021-10-15 12:07 ` Heinrich Schuchardt
  0 siblings, 0 replies; 6+ messages in thread
From: Heinrich Schuchardt @ 2021-10-15 12:07 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.
Add a new compatible string "allwinner,sun20i-d1-clint" for the CLINT of
the Allwinner D1 SoC.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
---
 .../devicetree/bindings/timer/sifive,clint.yaml     | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/timer/sifive,clint.yaml b/Documentation/devicetree/bindings/timer/sifive,clint.yaml
index a35952f48742..d3b4c6844e2f 100644
--- 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:
@@ -33,14 +34,22 @@ 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
-      "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
+      CLINT v0 as integrated onto the Canaan Kendryte K210 chip,
+      "allwinner,sun20i-d1-clint" for the CLINT in the Allwinner D1 SoC,
+      and "sifive,clint0" for the SiFive CLINT v0 IP block with no chip
       integration tweaks.
       Please refer to sifive-blocks-ip-versioning.txt for details
 
   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] 6+ messages in thread

end of thread, other threads:[~2021-10-18  7:30 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2021-10-15 12:07 [PATCH v2 1/1] dt-bindings: reg-io-width for SiFive CLINT Heinrich Schuchardt
2021-10-15 12:07 ` Heinrich Schuchardt
2021-10-18  4:33 ` Anup Patel
2021-10-18  4:33   ` Anup Patel
2021-10-18  7:30   ` Heinrich Schuchardt
2021-10-18  7:30     ` Heinrich Schuchardt

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