[PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Bjorn Andersson]

Add binding documentation for the Qualcomm Hardware Mutex.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---

I think the conclusion on the dt binding discussion for hwspinlocks was that
we're down to having the #hwlock-cells intact. So this version includes that,
but non of the other previously discussed properties.

Changes since v5:
- Extracted the dt binding documentation into a separate patch
- Moved the driver to consume a syscon
- Dropped previously suggested generic hwlock dt bindings

 .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt

diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
new file mode 100644
index 0000000..28ade7d
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
@@ -0,0 +1,39 @@
+Qualcomm Hardware Mutex Block:
+
+The hardware block provides mutexes utilized between different processors on
+the SoC as part of the communication protocol used by these processors.
+
+- compatible:
+	Usage: required
+	Value type: <string>
+	Definition: must be one of:
+		    "qcom,sfpb-mutex",
+		    "qcom,tcsr-mutex"
+
+- syscon:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: one cell containing:
+		    syscon phandle
+		    offset of the hwmutex block within the syscon
+		    stride of the hwmutex registers
+
+- #hwlock-cells:
+	Usage: required
+	Value type: <u32>
+	Definition: must be 1, the specified cell represent the lock id
+		    (hwlock standard property, see hwlock.txt)
+
+Example:
+
+        tcsr: syscon@1a400000 {
+		compatible = "qcom,tcsr-msm8974", "syscon";
+		reg = <0xfd484000 0x2000>;
+	};
+
+	hwlock@fd484000 {
+		compatible = "qcom,tcsr-mutex";
+		syscon = <&tcsr 0 0x80>;
+
+		#hwlock-cells = <1>;
+	};
-- 
1.8.2.2

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

Hi Mark, Rob,

On Sat, Feb 28, 2015 at 12:30 AM, Bjorn Andersson
<bjorn.andersson@sonymobile.com> wrote:
> Add binding documentation for the Qualcomm Hardware Mutex.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---
>
> I think the conclusion on the dt binding discussion for hwspinlocks was that
> we're down to having the #hwlock-cells intact. So this version includes that,
> but non of the other previously discussed properties.
>
> Changes since v5:
> - Extracted the dt binding documentation into a separate patch
> - Moved the driver to consume a syscon
> - Dropped previously suggested generic hwlock dt bindings
>
>  .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt

Could you please ack this one patch from Bjorn?

I'll need your Ack before I can this forward.

Thanks,
Ohad.

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Tim Bird]

On Thu, Mar 12, 2015 at 2:29 AM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> Hi Mark, Rob,
>
> On Sat, Feb 28, 2015 at 12:30 AM, Bjorn Andersson
> <bjorn.andersson@sonymobile.com> wrote:
>> Add binding documentation for the Qualcomm Hardware Mutex.
>>
>> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
>> ---
>>
>> I think the conclusion on the dt binding discussion for hwspinlocks was that
>> we're down to having the #hwlock-cells intact. So this version includes that,
>> but non of the other previously discussed properties.
>>
>> Changes since v5:
>> - Extracted the dt binding documentation into a separate patch
>> - Moved the driver to consume a syscon
>> - Dropped previously suggested generic hwlock dt bindings
>>
>>  .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
>>  1 file changed, 39 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
>
> Could you please ack this one patch from Bjorn?
>
> I'll need your Ack before I can this forward.

I didn't see an Ack from Mark or Rob.  But I did see a question from
Mark and response from Bjorn.

Ohad - did you take this or are you still waiting for something?

Who should I pester about this? :-)
 -- Tim

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

On Thu, Apr 2, 2015 at 12:32 AM, Tim Bird <tbird20d@gmail.com> wrote:
> I didn't see an Ack from Mark or Rob.  But I did see a question from
> Mark and response from Bjorn.
>
> Ohad - did you take this or are you still waiting for something?
>
> Who should I pester about this? :-)

Sorry, I can't take this without a DT ack.

Ohad.

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Tim Bird]

On Wed, Apr 1, 2015 at 9:40 PM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> On Thu, Apr 2, 2015 at 12:32 AM, Tim Bird <tbird20d@gmail.com> wrote:
>> I didn't see an Ack from Mark or Rob.  But I did see a question from
>> Mark and response from Bjorn.
>>
>> Ohad - did you take this or are you still waiting for something?
>>
>> Who should I pester about this? :-)
>
> Sorry, I can't take this without a DT ack.

Hmmm.

The policy seems to be:
     "For driver (not subsystem) bindings: If you are comfortable with the
     binding, and it hasn't received an Acked-by from the devicetree
     maintainers after a few weeks, go ahead and take it."

The syscon property is only relative to the qcom hwspinlock driver,
(unless I'm missing something) and both Qualcomm and Sony devs are
OK with it.  So while an ACK from the DT side would be nice, I don't
think it's required.  This is exactly the type of delay that is really
holding up a lot of out-of-tree code.

But, in case that doesn't convince you...

Mark or Rob (or someone, anyone, over on the DT side)...

Can you please ACK or NAK the following binding?   This particular driver
is at the bottom of a very large dependency tree for out-of-tree code
for Qualcomm.

Thanks,
  -- Tim

---

Add binding documentation for the Qualcomm Hardware Mutex.

Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
---

I think the conclusion on the dt binding discussion for hwspinlocks was that
we're down to having the #hwlock-cells intact. So this version includes that,
but none of the other previously discussed properties.

Changes since v5:
- Extracted the dt binding documentation into a separate patch
- Moved the driver to consume a syscon
- Dropped previously suggested generic hwlock dt bindings

 .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt

diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
new file mode 100644
index 0000000..28ade7d
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
@@ -0,0 +1,39 @@
+Qualcomm Hardware Mutex Block:
+
+The hardware block provides mutexes utilized between different processors on
+the SoC as part of the communication protocol used by these processors.
+
+- compatible:
+    Usage: required
+    Value type: <string>
+    Definition: must be one of:
+            "qcom,sfpb-mutex",
+            "qcom,tcsr-mutex"
+
+- syscon:
+    Usage: required
+    Value type: <prop-encoded-array>
+    Definition: one cell containing:
+            syscon phandle
+            offset of the hwmutex block within the syscon
+            stride of the hwmutex registers
+
+- #hwlock-cells:
+    Usage: required
+    Value type: <u32>
+    Definition: must be 1, the specified cell represent the lock id
+            (hwlock standard property, see hwlock.txt)
+
+Example:
+
+        tcsr: syscon@1a400000 {
+        compatible = "qcom,tcsr-msm8974", "syscon";
+        reg = <0xfd484000 0x2000>;
+    };
+
+    hwlock@fd484000 {
+        compatible = "qcom,tcsr-mutex";
+        syscon = <&tcsr 0 0x80>;
+
+        #hwlock-cells = <1>;
+    };
--

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

On Thu, Apr 2, 2015 at 9:11 PM, Tim Bird <tbird20d-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Wed, Apr 1, 2015 at 9:40 PM, Ohad Ben-Cohen <ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org> wrote:
>> Sorry, I can't take this without a DT ack.
>
> Hmmm.
>
> The policy seems to be:
>      "For driver (not subsystem) bindings: If you are comfortable with the
>      binding, and it hasn't received an Acked-by from the devicetree
>      maintainers after a few weeks, go ahead and take it."
>
> The syscon property is only relative to the qcom hwspinlock driver,
> (unless I'm missing something) and both Qualcomm and Sony devs are
> OK with it.  So while an ACK from the DT side would be nice, I don't
> think it's required.  This is exactly the type of delay that is really
> holding up a lot of out-of-tree code.

Sorry, I do prefer to make sure Mark is OK with this devicetree patch,
especially since it wasn't clear whether Mark is entirely comfortable
with it in his last response.

Thanks,
Ohad.
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Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Tim Bird]

On Fri, Apr 3, 2015 at 6:55 AM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> On Thu, Apr 2, 2015 at 9:11 PM, Tim Bird <tbird20d@gmail.com> wrote:
>> On Wed, Apr 1, 2015 at 9:40 PM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
>>> Sorry, I can't take this without a DT ack.
>>
>> Hmmm.
>>
>> The policy seems to be:
>>      "For driver (not subsystem) bindings: If you are comfortable with the
>>      binding, and it hasn't received an Acked-by from the devicetree
>>      maintainers after a few weeks, go ahead and take it."
>>
>> The syscon property is only relative to the qcom hwspinlock driver,
>> (unless I'm missing something) and both Qualcomm and Sony devs are
>> OK with it.  So while an ACK from the DT side would be nice, I don't
>> think it's required.  This is exactly the type of delay that is really
>> holding up a lot of out-of-tree code.
>
> Sorry, I do prefer to make sure Mark is OK with this devicetree patch,
> especially since it wasn't clear whether Mark is entirely comfortable
> with it in his last response.

Just to be clear - do you personally have any objections to the patch?
Are we now stuck in limbo until such time as the device tree maintainers
get around to us?

I'm worried about this status because my understanding is that the
DT maintainers are hugely backlogged and let a lot of stuff drop on the
floor.  In particular, see slide 21 of the following presentation:
http://www.elinux.org/images/0/0a/The_Device_Tree_as_a_Stable_ABI-_A_Fairy_Tale%3F.pdf
That graph shows that the DT maintainers are falling way behind in
their reviews and ACKs.

The policy of not waiting for an ACK from device tree maintainers
was specifically created to help the situation we are now in, and yet
you seem to be unwilling to follow it.  This is extremely frustrating.

One idea we discussed at a recent meeting on mainlining was to submit
SoC-blocking items to drivers/staging.  Then, stuff is at least in the tree
and can be tested by others pending some approval.  Do you have any
opinion on that?

Is there any way to move ahead?  Or are we doomed to just sit around
and wait indefinitely? For the record, after what amount of time without
a DT ACK would you consider accepting this (if ever)?

Another idea I'm considering is to write our own hwspinlock layer
and become the maintainer of that, so we're not blocked by you.
At this point, the value of using your hwspinlock framework
is vastly outweighed by the negative effect is has on our mainlining
effort.

Regards,

 -- Tim Bird
Senior Software Engineer, Sony Mobile
Architecture Group Chair, CE Workgroup, Linux Foundation

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

On Mon, Apr 6, 2015 at 7:22 PM, Tim Bird <tbird20d-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Fri, Apr 3, 2015 at 6:55 AM, Ohad Ben-Cohen <ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org> wrote:
>> On Thu, Apr 2, 2015 at 9:11 PM, Tim Bird <tbird20d-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>> On Wed, Apr 1, 2015 at 9:40 PM, Ohad Ben-Cohen <ohad-Ix1uc/W3ht7QT0dZR+AlfA@public.gmane.org> wrote:
>>>> Sorry, I can't take this without a DT ack.
>>>
>>> Hmmm.
>>>
>>> The policy seems to be:
>>>      "For driver (not subsystem) bindings: If you are comfortable with the
>>>      binding, and it hasn't received an Acked-by from the devicetree
>>>      maintainers after a few weeks, go ahead and take it."
>>>
>>> The syscon property is only relative to the qcom hwspinlock driver,
>>> (unless I'm missing something) and both Qualcomm and Sony devs are
>>> OK with it.  So while an ACK from the DT side would be nice, I don't
>>> think it's required.  This is exactly the type of delay that is really
>>> holding up a lot of out-of-tree code.
>>
>> Sorry, I do prefer to make sure Mark is OK with this devicetree patch,
>> especially since it wasn't clear whether Mark is entirely comfortable
>> with it in his last response.
>
> Just to be clear - do you personally have any objections to the patch?

No, but this patch is for a folder I don't maintain so I prefer
someone who does to take a look.

Mark did take a look, and said he's confused by this patch (see this thread).

Do you want me to ignore him and just send it to Linus anyway?
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Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Bjorn Andersson]

On Mon, Apr 6, 2015 at 9:31 AM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> On Mon, Apr 6, 2015 at 7:22 PM, Tim Bird <tbird20d@gmail.com> wrote:
>> On Fri, Apr 3, 2015 at 6:55 AM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
>>> On Thu, Apr 2, 2015 at 9:11 PM, Tim Bird <tbird20d@gmail.com> wrote:
>>>> On Wed, Apr 1, 2015 at 9:40 PM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
>>>>> Sorry, I can't take this without a DT ack.
>>>>
>>>> Hmmm.
>>>>
>>>> The policy seems to be:
>>>>      "For driver (not subsystem) bindings: If you are comfortable with the
>>>>      binding, and it hasn't received an Acked-by from the devicetree
>>>>      maintainers after a few weeks, go ahead and take it."
>>>>
>>>> The syscon property is only relative to the qcom hwspinlock driver,
>>>> (unless I'm missing something) and both Qualcomm and Sony devs are
>>>> OK with it.  So while an ACK from the DT side would be nice, I don't
>>>> think it's required.  This is exactly the type of delay that is really
>>>> holding up a lot of out-of-tree code.
>>>
>>> Sorry, I do prefer to make sure Mark is OK with this devicetree patch,
>>> especially since it wasn't clear whether Mark is entirely comfortable
>>> with it in his last response.
>>
>> Just to be clear - do you personally have any objections to the patch?
>
> No, but this patch is for a folder I don't maintain so I prefer
> someone who does to take a look.
>
> Mark did take a look, and said he's confused by this patch (see this thread).
>
> Do you want me to ignore him and just send it to Linus anyway?

Ohad, Tim,

For this patch to be useful to us we also need Suman's DT patch, so we
should try to get them both in asap.

Based on the long discussion we had on one of the previous iterations
of Suman's DT binding, with the DT maintainers I believe that it would
be fine to move along and sent Suman's patches to Linus - without an
explicit Ack from the DT guys (or did I just miss one?).

Regarding this patch I agree with Ohad that it would be good if we
verify that Mark's question is answered before moving on. So I will
reach out to him to see if he has any remaining concerns.

Regards,
Bjorn

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

On Mon, Apr 6, 2015 at 7:48 PM, Bjorn Andersson <bjorn@kryo.se> wrote:
> Based on the long discussion we had on one of the previous iterations
> of Suman's DT binding, with the DT maintainers I believe that it would
> be fine to move along and sent Suman's patches to Linus - without an
> explicit Ack from the DT guys (or did I just miss one?).

Thanks Bjorn.

Mark, are you OK with the latest iteration from Suman? it would be
nice to get your +1 just to make sure we don't merge stuff you're
uncomfortable with.

Thanks!
Ohad.

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

On Mon, Apr 6, 2015 at 10:04 PM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> Mark, are you OK with the latest iteration from Suman? it would be
> nice to get your +1 just to make sure we don't merge stuff you're
> uncomfortable with.

Quick update:

As Tim pointed out, we can move forward with the driver binding patch
according to the process described under II.2 of [1]. Both Bjorn and
myself would still prefer to make sure Mark is satisfied with the
response Bjorn sent to Mark's question, but we understand if Mark is
swamped and we eventually would proceed according to the DT's
submitting-patches guidance below. Tim, thanks for pointing that out
as I wasn't aware of this.

What we probably do need a DT ack on is the hwspinlock subsystem
binding submitted by Suman, again according to the process described
under II.2 of [1]: "Subsystem bindings (anything affecting more than a
single device): then getting a devicetree maintainer to review it is
required".

Mark and Rob: thanks so much for all your help so far as you have
substantially helped shaping the hwspinlock binding. Please let us
know if you are satisfied with Suman's latest iteration, still prefer
to take another look at it, or are too swamped. If the latter, then
maybe we can ask Kumar to take a look, as this seems to be blocking
Qualcomm's upstream roadmap.

Thanks,
Ohad.

[1] Documentation/devicetree/bindings/submitting-patches.txt

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Rob Herring]

On Mon, Apr 13, 2015 at 5:23 AM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
> On Mon, Apr 6, 2015 at 10:04 PM, Ohad Ben-Cohen <ohad@wizery.com> wrote:
>> Mark, are you OK with the latest iteration from Suman? it would be
>> nice to get your +1 just to make sure we don't merge stuff you're
>> uncomfortable with.
>
> Quick update:
>
> As Tim pointed out, we can move forward with the driver binding patch
> according to the process described under II.2 of [1]. Both Bjorn and
> myself would still prefer to make sure Mark is satisfied with the
> response Bjorn sent to Mark's question, but we understand if Mark is
> swamped and we eventually would proceed according to the DT's
> submitting-patches guidance below. Tim, thanks for pointing that out
> as I wasn't aware of this.
>
> What we probably do need a DT ack on is the hwspinlock subsystem
> binding submitted by Suman, again according to the process described
> under II.2 of [1]: "Subsystem bindings (anything affecting more than a
> single device): then getting a devicetree maintainer to review it is
> required".

Right, you can't really merge this driver binding until the binding is
done and acked. Your binding would be referring to a binding doc that
doesn't exist in the tree if you merge this.

> Mark and Rob: thanks so much for all your help so far as you have
> substantially helped shaping the hwspinlock binding. Please let us
> know if you are satisfied with Suman's latest iteration, still prefer
> to take another look at it, or are too swamped. If the latter, then
> maybe we can ask Kumar to take a look, as this seems to be blocking
> Qualcomm's upstream roadmap.

While I think the binding looks fine, I'm not going to go around Mark
either. He's invested the most thought in this (of DT maintainers) and
should be the one to ack it. The part I'm not clear what the purpose
of "pool-hwlock" was.

Rob

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Mark Rutland]

> The part I'm not clear what the purpose of "pool-hwlock" was.

One use-case was a set of hwlocks having no fixed purpose, and being
available for dynamic allocation between the OS and other entities (e.g.
some RTOS on another core).

The set of locks forming a reusable pool, and any information associated
with them (e.g. the logical IDs used by the other entity) are a property
of that interface rather than the hwlock provider.

So you'd describe those pools of locks in some interface-specific
manner, consuming hwlocks from a set of hwlock providers.

Hopefully that doesn't maek things less clear...

Mark.
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Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Mark Rutland]

On Fri, Feb 27, 2015 at 10:30:16PM +0000, Bjorn Andersson wrote:
> Add binding documentation for the Qualcomm Hardware Mutex.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---
> 
> I think the conclusion on the dt binding discussion for hwspinlocks was that
> we're down to having the #hwlock-cells intact. So this version includes that,
> but non of the other previously discussed properties.
> 
> Changes since v5:
> - Extracted the dt binding documentation into a separate patch
> - Moved the driver to consume a syscon

I'm a little confused here. Why are we now using a syscon? I thought the
set of registers for the block was well-defined.

If there's a link to some previous discussion on that point, it would be
helpful.

Mark.

> - Dropped previously suggested generic hwlock dt bindings
> 
>  .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
> 
> diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
> new file mode 100644
> index 0000000..28ade7d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
> @@ -0,0 +1,39 @@
> +Qualcomm Hardware Mutex Block:
> +
> +The hardware block provides mutexes utilized between different processors on
> +the SoC as part of the communication protocol used by these processors.
> +
> +- compatible:
> +	Usage: required
> +	Value type: <string>
> +	Definition: must be one of:
> +		    "qcom,sfpb-mutex",
> +		    "qcom,tcsr-mutex"
> +
> +- syscon:
> +	Usage: required
> +	Value type: <prop-encoded-array>
> +	Definition: one cell containing:
> +		    syscon phandle
> +		    offset of the hwmutex block within the syscon
> +		    stride of the hwmutex registers
> +
> +- #hwlock-cells:
> +	Usage: required
> +	Value type: <u32>
> +	Definition: must be 1, the specified cell represent the lock id
> +		    (hwlock standard property, see hwlock.txt)
> +
> +Example:
> +
> +        tcsr: syscon@1a400000 {
> +		compatible = "qcom,tcsr-msm8974", "syscon";
> +		reg = <0xfd484000 0x2000>;
> +	};
> +
> +	hwlock@fd484000 {
> +		compatible = "qcom,tcsr-mutex";
> +		syscon = <&tcsr 0 0x80>;
> +
> +		#hwlock-cells = <1>;
> +	};
> -- 
> 1.8.2.2
> 
> 

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Bjorn Andersson]

On Thu 12 Mar 02:51 PDT 2015, Mark Rutland wrote:

> On Fri, Feb 27, 2015 at 10:30:16PM +0000, Bjorn Andersson wrote:
> > Add binding documentation for the Qualcomm Hardware Mutex.
> > 
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> > ---
> > 
> > I think the conclusion on the dt binding discussion for hwspinlocks was that
> > we're down to having the #hwlock-cells intact. So this version includes that,
> > but non of the other previously discussed properties.
> > 
> > Changes since v5:
> > - Extracted the dt binding documentation into a separate patch
> > - Moved the driver to consume a syscon
> 
> I'm a little confused here. Why are we now using a syscon? I thought the
> set of registers for the block was well-defined.
> 

The sfpb-mutex registers make up a block (according to my
documentation), but after discussing tcsr with Andy Gross we concluded
that although the tcsr-mutex registers are layed out consecutively in
the tcsr, they are not alone in the block.

Further more Andy introduced the tcsr-syscon binding in his work to
support DMA on GSBI (uart/i2c/spi), so that's why I had to make this
change.

Preferrably this would have showed up before v6...

> If there's a link to some previous discussion on that point, it would be
> helpful.
> 

Unfortunately there isn't, as we discussed this mainly face to face a
few weeks back.

Regards,
Bjorn

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Jeffrey Hugo]

On 2/27/2015 3:30 PM, Bjorn Andersson wrote:
> Add binding documentation for the Qualcomm Hardware Mutex.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---

Reviewed-by: Jeffrey Hugo <jhugo@codeaurora.org>

-- 
Jeffrey Hugo
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
Forum, a Linux Foundation Collaborative Project

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Andy Gross]

On Fri, Feb 27, 2015 at 02:30:16PM -0800, Bjorn Andersson wrote:
> Add binding documentation for the Qualcomm Hardware Mutex.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson-/MT0OVThwyLZJqsBc5GL+g@public.gmane.org>
> ---

Looks fine.

Reviewed-by: Andy Gross <agross-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>

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a Linux Foundation Collaborative Project

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Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Kumar Gala]

> On Feb 27, 2015, at 4:30 PM, Bjorn Andersson <bjorn.andersson@sonymobile.com> wrote:
> 
> Add binding documentation for the Qualcomm Hardware Mutex.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson-/MT0OVThwyLZJqsBc5GL+g@public.gmane.org>
> —
> 

Acked-by: Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>

- k


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Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Ohad Ben-Cohen]

On Tue, Apr 14, 2015 at 10:18 PM, Kumar Gala <galak@codeaurora.org> wrote:
>> On Feb 27, 2015, at 4:30 PM, Bjorn Andersson <bjorn.andersson@sonymobile.com> wrote:
>>
>> Add binding documentation for the Qualcomm Hardware Mutex.
>>
>> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
>> —
>>
>
> Acked-by: Kumar Gala <galak@codeaurora.org>

Perfect, thanks a lot, Kumar.

Re: [PATCH v6 1/2] DT: hwspinlock: Add binding documentation for Qualcomm hwmutex

[Mark Rutland]

On Fri, Feb 27, 2015 at 10:30:16PM +0000, Bjorn Andersson wrote:
> Add binding documentation for the Qualcomm Hardware Mutex.
> 
> Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
> ---
> 
> I think the conclusion on the dt binding discussion for hwspinlocks was that
> we're down to having the #hwlock-cells intact. So this version includes that,
> but non of the other previously discussed properties.
> 
> Changes since v5:
> - Extracted the dt binding documentation into a separate patch
> - Moved the driver to consume a syscon
> - Dropped previously suggested generic hwlock dt bindings
> 
>  .../devicetree/bindings/hwlock/qcom-hwspinlock.txt | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
> 
> diff --git a/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
> new file mode 100644
> index 0000000..28ade7d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwlock/qcom-hwspinlock.txt
> @@ -0,0 +1,39 @@
> +Qualcomm Hardware Mutex Block:
> +
> +The hardware block provides mutexes utilized between different processors on
> +the SoC as part of the communication protocol used by these processors.
> +
> +- compatible:
> +	Usage: required
> +	Value type: <string>
> +	Definition: must be one of:
> +		    "qcom,sfpb-mutex",
> +		    "qcom,tcsr-mutex"
> +
> +- syscon:
> +	Usage: required
> +	Value type: <prop-encoded-array>
> +	Definition: one cell containing:
> +		    syscon phandle
> +		    offset of the hwmutex block within the syscon
> +		    stride of the hwmutex registers
> +
> +- #hwlock-cells:
> +	Usage: required
> +	Value type: <u32>
> +	Definition: must be 1, the specified cell represent the lock id
> +		    (hwlock standard property, see hwlock.txt)

I guess that this is a linear ID, matching some ID in a data sheet? It
would be nice to have something a little more explicit as to what the
valid values of the cell are.

Otherwise this looks fine, and seems to pair fine with the generic
bindings. The nit above can be corrected with a followup.

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> +
> +Example:
> +
> +        tcsr: syscon@1a400000 {
> +		compatible = "qcom,tcsr-msm8974", "syscon";
> +		reg = <0xfd484000 0x2000>;
> +	};
> +
> +	hwlock@fd484000 {
> +		compatible = "qcom,tcsr-mutex";
> +		syscon = <&tcsr 0 0x80>;
> +
> +		#hwlock-cells = <1>;
> +	};
> -- 
> 1.8.2.2
> 
>