Thread (5 messages) flat view 5 messages, 2 authors, 2020-02-28

Re: [PATCH v3 3/3] dt-bindings: pmem-region: Document memory-region

From: Rob Herring <robh@kernel.org>
Date: 2020-02-27 23:23:00
Also in: lkml, nvdimm

On Sun, Feb 23, 2020 at 06:10:29PM -0800, Alistair Delva wrote:
quoted hunk ↗ jump to hunk
From: Kenny Root <redacted>

Add documentation and example for memory-region in pmem.

Signed-off-by: Kenny Root <redacted>
Signed-off-by: Alistair Delva <redacted>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Dan Williams <redacted>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <redacted>
Cc: devicetree@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: kernel-team@android.com
---
[v3: adelva: remove duplicate "From:"]
 .../devicetree/bindings/pmem/pmem-region.txt  | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)
diff --git a/Documentation/devicetree/bindings/pmem/pmem-region.txt b/Documentation/devicetree/bindings/pmem/pmem-region.txt
index 5cfa4f016a00..0ec87bd034e0 100644
--- a/Documentation/devicetree/bindings/pmem/pmem-region.txt
+++ b/Documentation/devicetree/bindings/pmem/pmem-region.txt
@@ -29,6 +29,18 @@ Required properties:
 		in a separate device node. Having multiple address ranges in a
 		node implies no special relationship between the two ranges.
 
+		This property may be replaced or supplemented with a
+		memory-region property. Only one of reg or memory-region
+		properties is required.
+
+	- memory-region:
+		Reference to the reserved memory node. The reserved memory
+		node should be defined as per the bindings in
+		reserved-memory.txt
Though we've never enforced it, but /reserved-memory should be within 
the bounds of /memory node(s). Is that the intent here? If so, how does 
that work? Wouldn't all the memory be persistent then? Or some other 
system processor is preserving the contents?
quoted hunk ↗ jump to hunk
+
+		This property may be replaced or supplemented with a reg
+		property. Only one of reg or memory-region is required.
+
 Optional properties:
 	- Any relevant NUMA assocativity properties for the target platform.
 
@@ -63,3 +75,20 @@ Examples:
 		volatile;
 	};
 
+
+	/*
+	 * This example uses a reserved-memory entry instead of
+	 * specifying the memory region directly in the node.
+	 */
+
+	reserved-memory {
+		pmem_1: pmem@5000 {
+			no-map;
Just add 'compatible = "pmem-region";' here and be done with it. Why add 
a layer of indirection?
+			reg = <0x00005000 0x00001000>;
+		};
+	};
+
+	pmem@1 {
No 'reg', so shouldn't have a unit-address here.
+		compatible = "pmem-region";
+		memory-region = <&pmem_1>;
+	};
-- 
2.25.0.265.gbab2e86ba0-goog
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