[PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Bjorn Andersson]

In the olden days the Qualcomm shared memory (SMEM) region consisted of
multiple chunks of memory, so SMEM was described as a standalone node
with references to its various memory regions.

But practically all modern Qualcomm platforms has a single reserved memory
region used for SMEM. So rather than having to use two nodes to describe
the one SMEM region, update the binding to allow the reserved-memory
region alone to describe SMEM.

The olden format is preserved as valid, as this is widely used already.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
index f7e17713b3d8..4149cf2b66be 100644
--- a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
+++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
@@ -10,14 +10,18 @@ maintainers:
   - Andy Gross <agross@kernel.org>
   - Bjorn Andersson <bjorn.andersson@linaro.org>
 
-description: |
-  This binding describes the Qualcomm Shared Memory Manager, used to share data
-  between various subsystems and OSes in Qualcomm platforms.
+description:
+  This binding describes the Qualcomm Shared Memory Manager, a region of
+  reserved-memory used to share data between various subsystems and OSes in
+  Qualcomm platforms.
 
 properties:
   compatible:
     const: qcom,smem
 
+  reg:
+    maxItems: 1
+
   memory-region:
     maxItems: 1
     description: handle to memory reservation for main SMEM memory region.
@@ -29,11 +33,19 @@ properties:
     $ref: /schemas/types.yaml#/definitions/phandle
     description: handle to RPM message memory resource
 
+  no-map: true
+
 required:
   - compatible
-  - memory-region
   - hwlocks
 
+oneOf:
+  - required:
+      - reg
+      - no-map
+  - required:
+      - memory-region
+
 additionalProperties: false
 
 examples:
@@ -43,6 +55,20 @@ examples:
         #size-cells = <1>;
         ranges;
 
+        smem@fa00000 {
+            compatible = "qcom,smem";
+            reg = <0xfa00000 0x200000>;
+            no-map;
+
+            hwlocks = <&tcsr_mutex 3>;
+        };
+    };
+  - |
+    reserved-memory {
+        #address-cells = <1>;
+        #size-cells = <1>;
+        ranges;
+
         smem_region: smem@fa00000 {
             reg = <0xfa00000 0x200000>;
             no-map;
-- 
2.29.2

[PATCH 2/3] soc: qcom: smem: Support reserved-memory description

[Bjorn Andersson]

Practically all modern Qualcomm platforms has a single reserved-memory
region for SMEM. So rather than having to describe SMEM in the form of a
node with a reference to a reserved-memory node, allow the SMEM device
to be instantiated directly from the reserved-memory node.

The current means of falling back to dereferencing the "memory-region"
is kept as a fallback, if it's determined that the SMEM node is a
reserved-memory node.

The "qcom,smem" compatible is added to the reserved_mem_matches list, to
allow the reserved-memory device to be probed.

In order to retain the readability of the code, the resolution of
resources is split from the actual ioremapping.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 drivers/of/platform.c   |  1 +
 drivers/soc/qcom/smem.c | 57 ++++++++++++++++++++++++++++-------------
 2 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 32d5ff8df747..07813fb1ef37 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -505,6 +505,7 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate);
 static const struct of_device_id reserved_mem_matches[] = {
 	{ .compatible = "qcom,rmtfs-mem" },
 	{ .compatible = "qcom,cmd-db" },
+	{ .compatible = "qcom,smem" },
 	{ .compatible = "ramoops" },
 	{ .compatible = "nvmem-rmem" },
 	{}
diff --git a/drivers/soc/qcom/smem.c b/drivers/soc/qcom/smem.c
index 4fb5aeeb0843..c7e519bfdc8a 100644
--- a/drivers/soc/qcom/smem.c
+++ b/drivers/soc/qcom/smem.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/sizes.h>
 #include <linux/slab.h>
@@ -240,7 +241,7 @@ static const u8 SMEM_INFO_MAGIC[] = { 0x53, 0x49, 0x49, 0x49 }; /* SIII */
  * @size:	size of the memory region
  */
 struct smem_region {
-	u32 aux_base;
+	phys_addr_t aux_base;
 	void __iomem *virt_base;
 	size_t size;
 };
@@ -499,7 +500,7 @@ static void *qcom_smem_get_global(struct qcom_smem *smem,
 	for (i = 0; i < smem->num_regions; i++) {
 		region = &smem->regions[i];
 
-		if (region->aux_base == aux_base || !aux_base) {
+		if ((u32)region->aux_base == aux_base || !aux_base) {
 			if (size != NULL)
 				*size = le32_to_cpu(entry->size);
 			return region->virt_base + le32_to_cpu(entry->offset);
@@ -664,7 +665,7 @@ phys_addr_t qcom_smem_virt_to_phys(void *p)
 		if (p < region->virt_base + region->size) {
 			u64 offset = p - region->virt_base;
 
-			return (phys_addr_t)region->aux_base + offset;
+			return region->aux_base + offset;
 		}
 	}
 
@@ -863,12 +864,12 @@ qcom_smem_enumerate_partitions(struct qcom_smem *smem, u16 local_host)
 	return 0;
 }
 
-static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
-				const char *name, int i)
+static int qcom_smem_resolve_mem(struct qcom_smem *smem, const char *name,
+				 struct smem_region *region)
 {
+	struct device *dev = smem->dev;
 	struct device_node *np;
 	struct resource r;
-	resource_size_t size;
 	int ret;
 
 	np = of_parse_phandle(dev->of_node, name, 0);
@@ -881,13 +882,9 @@ static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
 	of_node_put(np);
 	if (ret)
 		return ret;
-	size = resource_size(&r);
 
-	smem->regions[i].virt_base = devm_ioremap_wc(dev, r.start, size);
-	if (!smem->regions[i].virt_base)
-		return -ENOMEM;
-	smem->regions[i].aux_base = (u32)r.start;
-	smem->regions[i].size = size;
+	region->aux_base = r.start;
+	region->size = resource_size(&r);
 
 	return 0;
 }
@@ -895,12 +892,14 @@ static int qcom_smem_map_memory(struct qcom_smem *smem, struct device *dev,
 static int qcom_smem_probe(struct platform_device *pdev)
 {
 	struct smem_header *header;
+	struct reserved_mem *rmem;
 	struct qcom_smem *smem;
 	size_t array_size;
 	int num_regions;
 	int hwlock_id;
 	u32 version;
 	int ret;
+	int i;
 
 	num_regions = 1;
 	if (of_find_property(pdev->dev.of_node, "qcom,rpm-msg-ram", NULL))
@@ -914,13 +913,35 @@ static int qcom_smem_probe(struct platform_device *pdev)
 	smem->dev = &pdev->dev;
 	smem->num_regions = num_regions;
 
-	ret = qcom_smem_map_memory(smem, &pdev->dev, "memory-region", 0);
-	if (ret)
-		return ret;
+	rmem = of_reserved_mem_lookup(pdev->dev.of_node);
+	if (rmem) {
+		smem->regions[0].aux_base = rmem->base;
+		smem->regions[0].size = rmem->size;
+	} else {
+		/*
+		 * Fall back to the memory-region reference, if we're not a
+		 * reserved-memory node.
+		 */
+		ret = qcom_smem_resolve_mem(smem, "memory-region", &smem->regions[0]);
+		if (ret)
+			return ret;
+	}
 
-	if (num_regions > 1 && (ret = qcom_smem_map_memory(smem, &pdev->dev,
-					"qcom,rpm-msg-ram", 1)))
-		return ret;
+	if (num_regions > 1) {
+		ret = qcom_smem_resolve_mem(smem, "qcom,rpm-msg-ram", &smem->regions[1]);
+		if (ret)
+			return ret;
+	}
+
+	for (i = 0; i < num_regions; i++) {
+		smem->regions[i].virt_base = devm_ioremap_wc(&pdev->dev,
+							     smem->regions[i].aux_base,
+							     smem->regions[i].size);
+		if (!smem->regions[i].virt_base) {
+			dev_err(&pdev->dev, "failed to remap %pa\n", &smem->regions[i].aux_base);
+			return -ENOMEM;
+		}
+	}
 
 	header = smem->regions[0].virt_base;
 	if (le32_to_cpu(header->initialized) != 1 ||
-- 
2.29.2

[PATCH 3/3] arm64: dts: qcom: sdm845: Drop standalone smem node

[Bjorn Andersson]

Now that the SMEM binding and driver allows the SMEM node to be
described in the reserved-memory region directly, move the compatible
and hwlock properties to the reserved-memory node and drop the
standadlone node.

Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---
 arch/arm64/boot/dts/qcom/sdm845.dtsi | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sdm845.dtsi b/arch/arm64/boot/dts/qcom/sdm845.dtsi
index beee57087d05..2800eae61910 100644
--- a/arch/arm64/boot/dts/qcom/sdm845.dtsi
+++ b/arch/arm64/boot/dts/qcom/sdm845.dtsi
@@ -99,9 +99,11 @@ aop_cmd_db_mem: memory@85fe0000 {
 			no-map;
 		};
 
-		smem_mem: memory@86000000 {
+		memory@86000000 {
+			compatible = "qcom,smem";
 			reg = <0x0 0x86000000 0 0x200000>;
 			no-map;
+			hwlocks = <&tcsr_mutex 3>;
 		};
 
 		tz_mem: memory@86200000 {
@@ -941,12 +943,6 @@ tcsr_mutex: hwlock {
 		#hwlock-cells = <1>;
 	};
 
-	smem {
-		compatible = "qcom,smem";
-		memory-region = <&smem_mem>;
-		hwlocks = <&tcsr_mutex 3>;
-	};
-
 	smp2p-cdsp {
 		compatible = "qcom,smp2p";
 		qcom,smem = <94>, <432>;
-- 
2.29.2

Re: [PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Stephan Gerhold]

On Mon, Sep 27, 2021 at 09:45:44PM -0700, Bjorn Andersson wrote:
> In the olden days the Qualcomm shared memory (SMEM) region consisted of
> multiple chunks of memory, so SMEM was described as a standalone node
> with references to its various memory regions.
> 
> But practically all modern Qualcomm platforms has a single reserved memory
> region used for SMEM. So rather than having to use two nodes to describe
> the one SMEM region, update the binding to allow the reserved-memory
> region alone to describe SMEM.
> 
> The olden format is preserved as valid, as this is widely used already.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
>  1 file changed, 30 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> index f7e17713b3d8..4149cf2b66be 100644
> --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> [...]
> @@ -43,6 +55,20 @@ examples:
>          #size-cells = <1>;
>          ranges;
>  
> +        smem@fa00000 {

I think this is a good opportunity to make a decision which node name
should be used here. :)

You use smem@ here but mentioned before that you think using the generic
memory@ would be better [1]. And you use memory@ in PATCH 3/3:

-		smem_mem: memory@86000000 {
+		memory@86000000 {
+			compatible = "qcom,smem";
 			reg = <0x0 0x86000000 0 0x200000>;
 			no-map;
+			hwlocks = <&tcsr_mutex 3>;
 		};

However, if you would use memory@ as example in this DT schema,
Rob's bot would complain with the same error that I mentioned earlier [2]:

soc/qcom/qcom,smem.example.dt.yaml: memory@fa00000: 'device_type' is a required property
        From schema: dtschema/schemas/memory.yaml

We should either fix the error when using memory@ or start using some
different node name (Stephen Boyd suggested shared-memory@ for example).
Otherwise we'll just keep introducing more and more dtbs_check errors
for the Qualcomm device trees.

Thanks,
Stephan

[1]: https://lore.kernel.org/linux-arm-msm/YUo0suaIugOco1Vu@builder.lan/
[2]: https://lore.kernel.org/linux-arm-msm/YUo2ZzQktf2iSec%2F@gerhold.net/

Re: [PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Rob Herring]

On Mon, 27 Sep 2021 21:45:44 -0700, Bjorn Andersson wrote:
> In the olden days the Qualcomm shared memory (SMEM) region consisted of
> multiple chunks of memory, so SMEM was described as a standalone node
> with references to its various memory regions.
> 
> But practically all modern Qualcomm platforms has a single reserved memory
> region used for SMEM. So rather than having to use two nodes to describe
> the one SMEM region, update the binding to allow the reserved-memory
> region alone to describe SMEM.
> 
> The olden format is preserved as valid, as this is widely used already.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---
>  .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
>  1 file changed, 30 insertions(+), 4 deletions(-)
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/soc/qcom/qcom,smem.example.dt.yaml:0:0: /example-1/soc/sram@fc428000: failed to match any schema with compatible: ['qcom,rpm-msg-ram']

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/patch/1533702

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.

Re: [PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Rob Herring]

On Tue, Sep 28, 2021 at 5:22 AM Stephan Gerhold <stephan@gerhold.net> wrote:
>
> On Mon, Sep 27, 2021 at 09:45:44PM -0700, Bjorn Andersson wrote:
> > In the olden days the Qualcomm shared memory (SMEM) region consisted of
> > multiple chunks of memory, so SMEM was described as a standalone node
> > with references to its various memory regions.
> >
> > But practically all modern Qualcomm platforms has a single reserved memory
> > region used for SMEM. So rather than having to use two nodes to describe
> > the one SMEM region, update the binding to allow the reserved-memory
> > region alone to describe SMEM.
> >
> > The olden format is preserved as valid, as this is widely used already.
> >
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > ---
> >  .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
> >  1 file changed, 30 insertions(+), 4 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > index f7e17713b3d8..4149cf2b66be 100644
> > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > [...]
> > @@ -43,6 +55,20 @@ examples:
> >          #size-cells = <1>;
> >          ranges;
> >
> > +        smem@fa00000 {
>
> I think this is a good opportunity to make a decision which node name
> should be used here. :)

reserved-memory node names are kind of a mess, so I haven't tried for
any standard... It needs to be solved globally.

>
> You use smem@ here but mentioned before that you think using the generic
> memory@ would be better [1]. And you use memory@ in PATCH 3/3:
>
> -               smem_mem: memory@86000000 {
> +               memory@86000000 {
> +                       compatible = "qcom,smem";
>                         reg = <0x0 0x86000000 0 0x200000>;
>                         no-map;
> +                       hwlocks = <&tcsr_mutex 3>;
>                 };
>
> However, if you would use memory@ as example in this DT schema,
> Rob's bot would complain with the same error that I mentioned earlier [2]:
>
> soc/qcom/qcom,smem.example.dt.yaml: memory@fa00000: 'device_type' is a required property
>         From schema: dtschema/schemas/memory.yaml
>
> We should either fix the error when using memory@ or start using some
> different node name (Stephen Boyd suggested shared-memory@ for example).
> Otherwise we'll just keep introducing more and more dtbs_check errors
> for the Qualcomm device trees.

A different node name. A node name should only have 1 meaning and
'memory' is already defined.

The main issue here is what to name nodes with only a size and no address.

Rob

Re: [PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Bjorn Andersson]

On Tue 28 Sep 12:34 CDT 2021, Rob Herring wrote:

> On Tue, Sep 28, 2021 at 5:22 AM Stephan Gerhold <stephan@gerhold.net> wrote:
> >
> > On Mon, Sep 27, 2021 at 09:45:44PM -0700, Bjorn Andersson wrote:
> > > In the olden days the Qualcomm shared memory (SMEM) region consisted of
> > > multiple chunks of memory, so SMEM was described as a standalone node
> > > with references to its various memory regions.
> > >
> > > But practically all modern Qualcomm platforms has a single reserved memory
> > > region used for SMEM. So rather than having to use two nodes to describe
> > > the one SMEM region, update the binding to allow the reserved-memory
> > > region alone to describe SMEM.
> > >
> > > The olden format is preserved as valid, as this is widely used already.
> > >
> > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > ---
> > >  .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
> > >  1 file changed, 30 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > index f7e17713b3d8..4149cf2b66be 100644
> > > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > [...]
> > > @@ -43,6 +55,20 @@ examples:
> > >          #size-cells = <1>;
> > >          ranges;
> > >
> > > +        smem@fa00000 {
> >
> > I think this is a good opportunity to make a decision which node name
> > should be used here. :)
> 
> reserved-memory node names are kind of a mess, so I haven't tried for
> any standard... It needs to be solved globally.
> 

I'd be happy to paint the shed any color you decide :)

That said, the binding itself doesn't mandate any node name, so it's
just the example here that would be "wrong" - and just as wrong as it
currently is.

> >
> > You use smem@ here but mentioned before that you think using the generic
> > memory@ would be better [1]. And you use memory@ in PATCH 3/3:
> >
> > -               smem_mem: memory@86000000 {
> > +               memory@86000000 {
> > +                       compatible = "qcom,smem";
> >                         reg = <0x0 0x86000000 0 0x200000>;
> >                         no-map;
> > +                       hwlocks = <&tcsr_mutex 3>;
> >                 };
> >
> > However, if you would use memory@ as example in this DT schema,
> > Rob's bot would complain with the same error that I mentioned earlier [2]:
> >
> > soc/qcom/qcom,smem.example.dt.yaml: memory@fa00000: 'device_type' is a required property
> >         From schema: dtschema/schemas/memory.yaml
> >
> > We should either fix the error when using memory@ or start using some
> > different node name (Stephen Boyd suggested shared-memory@ for example).
> > Otherwise we'll just keep introducing more and more dtbs_check errors
> > for the Qualcomm device trees.
> 
> A different node name. A node name should only have 1 meaning and
> 'memory' is already defined.
> 
> The main issue here is what to name nodes with only a size and no address.
> 

This particular node has both address and size (as does all of the other
reserved-memory regions we use upstream today)...

Regards,
Bjorn

Re: [PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Rob Herring]

On Tue, Sep 28, 2021 at 12:49 PM Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
>
> On Tue 28 Sep 12:34 CDT 2021, Rob Herring wrote:
>
> > On Tue, Sep 28, 2021 at 5:22 AM Stephan Gerhold <stephan@gerhold.net> wrote:
> > >
> > > On Mon, Sep 27, 2021 at 09:45:44PM -0700, Bjorn Andersson wrote:
> > > > In the olden days the Qualcomm shared memory (SMEM) region consisted of
> > > > multiple chunks of memory, so SMEM was described as a standalone node
> > > > with references to its various memory regions.
> > > >
> > > > But practically all modern Qualcomm platforms has a single reserved memory
> > > > region used for SMEM. So rather than having to use two nodes to describe
> > > > the one SMEM region, update the binding to allow the reserved-memory
> > > > region alone to describe SMEM.
> > > >
> > > > The olden format is preserved as valid, as this is widely used already.
> > > >
> > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > > ---
> > > >  .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
> > > >  1 file changed, 30 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > > index f7e17713b3d8..4149cf2b66be 100644
> > > > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > > [...]
> > > > @@ -43,6 +55,20 @@ examples:
> > > >          #size-cells = <1>;
> > > >          ranges;
> > > >
> > > > +        smem@fa00000 {
> > >
> > > I think this is a good opportunity to make a decision which node name
> > > should be used here. :)
> >
> > reserved-memory node names are kind of a mess, so I haven't tried for
> > any standard... It needs to be solved globally.
> >
>
> I'd be happy to paint the shed any color you decide :)

I didn't ask for it to be painted. Unless it is for everyone, I don't
care unless there's some clear pattern used already.

> That said, the binding itself doesn't mandate any node name, so it's
> just the example here that would be "wrong" - and just as wrong as it
> currently is.

The example is right. The dts is wrong.

Perhaps we need a schema for 'any node name that doesn't match already
defined ones'.

> > > You use smem@ here but mentioned before that you think using the generic
> > > memory@ would be better [1]. And you use memory@ in PATCH 3/3:
> > >
> > > -               smem_mem: memory@86000000 {
> > > +               memory@86000000 {
> > > +                       compatible = "qcom,smem";
> > >                         reg = <0x0 0x86000000 0 0x200000>;
> > >                         no-map;
> > > +                       hwlocks = <&tcsr_mutex 3>;
> > >                 };
> > >
> > > However, if you would use memory@ as example in this DT schema,
> > > Rob's bot would complain with the same error that I mentioned earlier [2]:
> > >
> > > soc/qcom/qcom,smem.example.dt.yaml: memory@fa00000: 'device_type' is a required property
> > >         From schema: dtschema/schemas/memory.yaml
> > >
> > > We should either fix the error when using memory@ or start using some
> > > different node name (Stephen Boyd suggested shared-memory@ for example).
> > > Otherwise we'll just keep introducing more and more dtbs_check errors
> > > for the Qualcomm device trees.
> >
> > A different node name. A node name should only have 1 meaning and
> > 'memory' is already defined.
> >
> > The main issue here is what to name nodes with only a size and no address.
> >
>
> This particular node has both address and size (as does all of the other
> reserved-memory regions we use upstream today)...

I'm not talking about *just* QCom. If we define something here, it's
got to cover everyone.

In summary, you can't use 'memory' or anything other established,
standard node name.

Rob

Re: [PATCH 1/3] dt-bindings: soc: smem: Make indirection optional

[Bjorn Andersson]

On Tue 28 Sep 14:51 CDT 2021, Rob Herring wrote:

> On Tue, Sep 28, 2021 at 12:49 PM Bjorn Andersson
> <bjorn.andersson@linaro.org> wrote:
> >
> > On Tue 28 Sep 12:34 CDT 2021, Rob Herring wrote:
> >
> > > On Tue, Sep 28, 2021 at 5:22 AM Stephan Gerhold <stephan@gerhold.net> wrote:
> > > >
> > > > On Mon, Sep 27, 2021 at 09:45:44PM -0700, Bjorn Andersson wrote:
> > > > > In the olden days the Qualcomm shared memory (SMEM) region consisted of
> > > > > multiple chunks of memory, so SMEM was described as a standalone node
> > > > > with references to its various memory regions.
> > > > >
> > > > > But practically all modern Qualcomm platforms has a single reserved memory
> > > > > region used for SMEM. So rather than having to use two nodes to describe
> > > > > the one SMEM region, update the binding to allow the reserved-memory
> > > > > region alone to describe SMEM.
> > > > >
> > > > > The olden format is preserved as valid, as this is widely used already.
> > > > >
> > > > > Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> > > > > ---
> > > > >  .../bindings/soc/qcom/qcom,smem.yaml          | 34 ++++++++++++++++---
> > > > >  1 file changed, 30 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > > > index f7e17713b3d8..4149cf2b66be 100644
> > > > > --- a/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > > > +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smem.yaml
> > > > > [...]
> > > > > @@ -43,6 +55,20 @@ examples:
> > > > >          #size-cells = <1>;
> > > > >          ranges;
> > > > >
> > > > > +        smem@fa00000 {
> > > >
> > > > I think this is a good opportunity to make a decision which node name
> > > > should be used here. :)
> > >
> > > reserved-memory node names are kind of a mess, so I haven't tried for
> > > any standard... It needs to be solved globally.
> > >
> >
> > I'd be happy to paint the shed any color you decide :)
> 
> I didn't ask for it to be painted. Unless it is for everyone, I don't
> care unless there's some clear pattern used already.
> 

As Stephan indicated, I feel that I'll set precedence when I change
"memory" -> "smem" in the last patch.

> > That said, the binding itself doesn't mandate any node name, so it's
> > just the example here that would be "wrong" - and just as wrong as it
> > currently is.
> 
> The example is right. The dts is wrong.
> 

But I can't both not paint the node and resolve the fact that the dts is
wrong. So which one should I go with?

Should we leave the node name as is until we've decided what to do with
the reserved-memory children? Or should I start accepting patches that
changes "memory" to a list of non-generic names?

> Perhaps we need a schema for 'any node name that doesn't match already
> defined ones'.
> 
> > > > You use smem@ here but mentioned before that you think using the generic
> > > > memory@ would be better [1]. And you use memory@ in PATCH 3/3:
> > > >
> > > > -               smem_mem: memory@86000000 {
> > > > +               memory@86000000 {
> > > > +                       compatible = "qcom,smem";
> > > >                         reg = <0x0 0x86000000 0 0x200000>;
> > > >                         no-map;
> > > > +                       hwlocks = <&tcsr_mutex 3>;
> > > >                 };
> > > >
> > > > However, if you would use memory@ as example in this DT schema,
> > > > Rob's bot would complain with the same error that I mentioned earlier [2]:
> > > >
> > > > soc/qcom/qcom,smem.example.dt.yaml: memory@fa00000: 'device_type' is a required property
> > > >         From schema: dtschema/schemas/memory.yaml
> > > >
> > > > We should either fix the error when using memory@ or start using some
> > > > different node name (Stephen Boyd suggested shared-memory@ for example).
> > > > Otherwise we'll just keep introducing more and more dtbs_check errors
> > > > for the Qualcomm device trees.
> > >
> > > A different node name. A node name should only have 1 meaning and
> > > 'memory' is already defined.
> > >
> > > The main issue here is what to name nodes with only a size and no address.
> > >
> >
> > This particular node has both address and size (as does all of the other
> > reserved-memory regions we use upstream today)...
> 
> I'm not talking about *just* QCom. If we define something here, it's
> got to cover everyone.
> 
> In summary, you can't use 'memory' or anything other established,
> standard node name.
> 

I know that "memory" is wrong, but I'm not sure about what you're asking
me to do.

Regards,
Bjorn