[PATCH v3 1/3] libnvdimm/of_pmem: factor out region registration

[PATCH v3 1/3] libnvdimm/of_pmem: factor out region registration

[Alistair Delva]

From: Kenny Root <kroot@google.com>

Factor out region registration for 'reg' node. A follow-up change will
use of_pmem_register_region() to handle memory-region nodes too.

Signed-off-by: Kenny Root <kroot@google.com>
Signed-off-by: Alistair Delva <adelva@google.com>
Reviewed-by: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: devicetree@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: kernel-team@android.com
---
[v3: adelva: remove duplicate "From:"]
 drivers/nvdimm/of_pmem.c | 60 +++++++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 25 deletions(-)

diff --git a/drivers/nvdimm/of_pmem.c b/drivers/nvdimm/of_pmem.c
index 8224d1431ea9..fdf54494e8c9 100644
--- a/drivers/nvdimm/of_pmem.c
+++ b/drivers/nvdimm/of_pmem.c
@@ -14,6 +14,39 @@ struct of_pmem_private {
 	struct nvdimm_bus *bus;
 };
 
+static void of_pmem_register_region(struct platform_device *pdev,
+				    struct nvdimm_bus *bus,
+				    struct device_node *np,
+				    struct resource *res, bool is_volatile)
+{
+	struct nd_region_desc ndr_desc;
+	struct nd_region *region;
+
+	/*
+	 * NB: libnvdimm copies the data from ndr_desc into it's own
+	 * structures so passing a stack pointer is fine.
+	 */
+	memset(&ndr_desc, 0, sizeof(ndr_desc));
+	ndr_desc.numa_node = dev_to_node(&pdev->dev);
+	ndr_desc.target_node = ndr_desc.numa_node;
+	ndr_desc.res = res;
+	ndr_desc.of_node = np;
+	set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
+
+	if (is_volatile)
+		region = nvdimm_volatile_region_create(bus, &ndr_desc);
+	else
+		region = nvdimm_pmem_region_create(bus, &ndr_desc);
+
+	if (!region)
+		dev_warn(&pdev->dev,
+			 "Unable to register region %pR from %pOF\n",
+			 ndr_desc.res, np);
+	else
+		dev_dbg(&pdev->dev, "Registered region %pR from %pOF\n",
+			ndr_desc.res, np);
+}
+
 static int of_pmem_region_probe(struct platform_device *pdev)
 {
 	struct of_pmem_private *priv;
@@ -46,31 +79,8 @@ static int of_pmem_region_probe(struct platform_device *pdev)
 			is_volatile ? "volatile" : "non-volatile",  np);
 
 	for (i = 0; i < pdev->num_resources; i++) {
-		struct nd_region_desc ndr_desc;
-		struct nd_region *region;
-
-		/*
-		 * NB: libnvdimm copies the data from ndr_desc into it's own
-		 * structures so passing a stack pointer is fine.
-		 */
-		memset(&ndr_desc, 0, sizeof(ndr_desc));
-		ndr_desc.numa_node = dev_to_node(&pdev->dev);
-		ndr_desc.target_node = ndr_desc.numa_node;
-		ndr_desc.res = &pdev->resource[i];
-		ndr_desc.of_node = np;
-		set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
-
-		if (is_volatile)
-			region = nvdimm_volatile_region_create(bus, &ndr_desc);
-		else
-			region = nvdimm_pmem_region_create(bus, &ndr_desc);
-
-		if (!region)
-			dev_warn(&pdev->dev, "Unable to register region %pR from %pOF\n",
-					ndr_desc.res, np);
-		else
-			dev_dbg(&pdev->dev, "Registered region %pR from %pOF\n",
-					ndr_desc.res, np);
+		of_pmem_register_region(pdev, bus, np, &pdev->resource[i],
+					is_volatile);
 	}
 
 	return 0;
-- 
2.25.0.265.gbab2e86ba0-goog

[PATCH v3 2/3] libnvdimm/of_pmem: handle memory-region in DT

[Alistair Delva]

From: Kenny Root <kroot@google.com>

Add support for parsing the 'memory-region' DT property in addition to
the 'reg' DT property. This enables use cases where the pmem region is
not in I/O address space or dedicated memory (e.g. a bootloader
carveout).

Signed-off-by: Kenny Root <kroot@google.com>
Signed-off-by: Alistair Delva <adelva@google.com>
Reviewed-by: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: devicetree@vger.kernel.org
Cc: linux-nvdimm@lists.01.org
Cc: kernel-team@android.com
---
[v3: adelva: remove duplicate "From:"]
 drivers/nvdimm/of_pmem.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/nvdimm/of_pmem.c b/drivers/nvdimm/of_pmem.c
index fdf54494e8c9..cff47cc5fc4a 100644
--- a/drivers/nvdimm/of_pmem.c
+++ b/drivers/nvdimm/of_pmem.c
@@ -49,11 +49,12 @@ static void of_pmem_register_region(struct platform_device *pdev,
 
 static int of_pmem_region_probe(struct platform_device *pdev)
 {
+	struct device_node *mr_np, *np;
 	struct of_pmem_private *priv;
-	struct device_node *np;
 	struct nvdimm_bus *bus;
+	struct resource res;
 	bool is_volatile;
-	int i;
+	int i, ret;
 
 	np = dev_of_node(&pdev->dev);
 	if (!np)
@@ -83,6 +84,21 @@ static int of_pmem_region_probe(struct platform_device *pdev)
 					is_volatile);
 	}
 
+	i = 0;
+	while ((mr_np = of_parse_phandle(np, "memory-region", i++))) {
+		ret = of_address_to_resource(mr_np, 0, &res);
+		if (ret) {
+			dev_warn(
+				&pdev->dev,
+				"Unable to acquire memory-region from %pOF: %d\n",
+				mr_np, ret);
+		} else {
+			of_pmem_register_region(pdev, bus, np, &res,
+						is_volatile);
+		}
+		of_node_put(mr_np);
+	}
+
 	return 0;
 }
 
-- 
2.25.0.265.gbab2e86ba0-goog

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

[Alistair Delva]

From: Kenny Root <kroot@google.com>

Add documentation and example for memory-region in pmem.

Signed-off-by: Kenny Root <kroot@google.com>
Signed-off-by: Alistair Delva <adelva@google.com>
Cc: "Oliver O'Halloran" <oohall@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
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
+
+		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;
+			reg = <0x00005000 0x00001000>;
+		};
+	};
+
+	pmem@1 {
+		compatible = "pmem-region";
+		memory-region = <&pmem_1>;
+	};
-- 
2.25.0.265.gbab2e86ba0-goog

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

[Rob Herring]

On Sun, Feb 23, 2020 at 06:10:29PM -0800, Alistair Delva wrote:
> From: Kenny Root <kroot@google.com>
> 
> Add documentation and example for memory-region in pmem.
> 
> Signed-off-by: Kenny Root <kroot@google.com>
> Signed-off-by: Alistair Delva <adelva@google.com>
> Cc: "Oliver O'Halloran" <oohall@gmail.com>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> 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?

> +
> +		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
> 

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

[Alistair Delva]

Hi Rob,

Thanks for reviewing.

On Thu, Feb 27, 2020 at 3:22 PM Rob Herring <robh@kernel.org> wrote:
>> On Sun, Feb 23, 2020 at 06:10:29PM -0800, Alistair Delva wrote:
> > From: Kenny Root <kroot@google.com>
> >
> > Add documentation and example for memory-region in pmem.
> >
> > Signed-off-by: Kenny Root <kroot@google.com>
> > Signed-off-by: Alistair Delva <adelva@google.com>
> > Cc: "Oliver O'Halloran" <oohall@gmail.com>
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Vishal Verma <vishal.l.verma@intel.com>
> > Cc: Dave Jiang <dave.jiang@intel.com>
> > Cc: Ira Weiny <ira.weiny@intel.com>
> > 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?

On the systems we're working with, the RAM remains refreshed across
reboots, but the contents of RAM could be changed by something outside
of Linux (i.e. the bootloader). By reserving this region in DT for
pmem we are saying "this is persistent like the rest of RAM on this
device, but it is also not going to be touched by anything besides
this Linux driver".

> > +
> > +             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?

Sure, I'll do that..

> > +                     reg = <0x00005000 0x00001000>;
> > +             };
> > +     };
> > +
> > +     pmem@1 {
>
> No 'reg', so shouldn't have a unit-address here.

..then I guess I can just delete this. v4 incoming.


> > +             compatible = "pmem-region";
> > +             memory-region = <&pmem_1>;
> > +     };
> > --
> > 2.25.0.265.gbab2e86ba0-goog
> >
>
> --
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>