dt-bindings: sifive: describe sifive-blocks versioning
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  • dt-bindings: sifive: describe sifive-blocks versioning
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Commit Message

Paul Walmsley Nov. 22, 2018, 1:06 a.m. UTC
For IP blocks that are generated from the public, open-source
sifive-blocks repository, describe the version numbering policy
that its maintainers intend to use, upon request from Rob
Herring <robh@kernel.org>.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Megan Wachs <megan@sifive.com>
Cc: Wesley Terpstra <wesley@sifive.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: devicetree@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
---

Hi Rob, please let me know if this document works with your
requirements, or if some changes are needed.  - Paul

 .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt

Comments

Atish Patra Nov. 22, 2018, 1:33 a.m. UTC | #1
On 11/21/18 5:07 PM, Paul Walmsley wrote:
> 
> For IP blocks that are generated from the public, open-source
> sifive-blocks repository, describe the version numbering policy
> that its maintainers intend to use, upon request from Rob
> Herring <robh@kernel.org>.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Palmer Dabbelt <palmer@sifive.com>
> Cc: Megan Wachs <megan@sifive.com>
> Cc: Wesley Terpstra <wesley@sifive.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> Signed-off-by: Paul Walmsley <paul@pwsan.com>
> ---
> 
> Hi Rob, please let me know if this document works with your
> requirements, or if some changes are needed.  - Paul
> 
>   .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
>   1 file changed, 38 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> 
> diff --git a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> new file mode 100644
> index 000000000000..b899e5c6e00c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt

It should be be under 
Documentation/devicetree/bindings/riscv/sifive/sifive-blocks-ip-versioning.txt 
?

> @@ -0,0 +1,38 @@
> +DT compatible string versioning for SiFive open-source IP blocks
> +
> +This document describes the version specification for DT "compatible"
> +strings for open-source SiFive IP blocks.  HDL for these IP blocks
> +can be found in this public repository:
> +
> +https://github.com/sifive/sifive-blocks
> +
> +IP block-specific DT compatible strings are contained within the HDL,
> +in the form "sifive,<ip-block-name><integer version number>".
> +
> +An example is "sifive,uart0" from:
> +
> +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
> +
> +Until these IP blocks (or IP integration) support version
> +autodiscovery, the maintainers of these IP blocks intend to increment

/s/autodiscovery/auto discovery

> +the suffixed number in the compatible string whenever the software
> +interface to these IP blocks changes, or when the functionality of the
> +underlying IP blocks changes in a way that software should be aware of.
> +
> +Driver developers can use compatible string "match" values such as
> +"sifive,uart0" to indicate that their driver is compatible with the
> +register interface and functionality associated with the relevant
> +upstream sifive-blocks commits.  It is expected that most drivers will
> +match on these IP block-specific compatible strings.
> +
> +DT data authors, when writing data for a particular SoC, should
> +continue to specify an SoC-specific compatible string value, such as
> +"sifive,fu540-c000-uart".  This way, if SoC-specific
> +integration-specific bug fixes or workarounds are needed, the kernel
> +or other system software can match on this string to apply them.  The
> +IP block-specific compatible string (such as "sifive,uart0") should
> +then be specified as a subsequent value.
> +
> +An example of this style:
> +
> +    compatible = "sifive,fu540-c000-uart", "sifive,uart0";
> 

Just for the sake of completion, should this document also specify what 
should be the style of any possible closed IP as well?

Regards,
Atish
Palmer Dabbelt Nov. 26, 2018, 7:02 p.m. UTC | #2
On Wed, 21 Nov 2018 17:06:56 PST (-0800), Paul Walmsley wrote:
>
> For IP blocks that are generated from the public, open-source
> sifive-blocks repository, describe the version numbering policy
> that its maintainers intend to use, upon request from Rob
> Herring <robh@kernel.org>.
>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Palmer Dabbelt <palmer@sifive.com>
> Cc: Megan Wachs <megan@sifive.com>
> Cc: Wesley Terpstra <wesley@sifive.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> Signed-off-by: Paul Walmsley <paul@pwsan.com>
> ---
>
> Hi Rob, please let me know if this document works with your
> requirements, or if some changes are needed.  - Paul
>
>  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
>  1 file changed, 38 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
>
> diff --git a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> new file mode 100644
> index 000000000000..b899e5c6e00c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> @@ -0,0 +1,38 @@
> +DT compatible string versioning for SiFive open-source IP blocks
> +
> +This document describes the version specification for DT "compatible"
> +strings for open-source SiFive IP blocks.  HDL for these IP blocks
> +can be found in this public repository:
> +
> +https://github.com/sifive/sifive-blocks
> +
> +IP block-specific DT compatible strings are contained within the HDL,
> +in the form "sifive,<ip-block-name><integer version number>".
> +
> +An example is "sifive,uart0" from:
> +
> +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
> +
> +Until these IP blocks (or IP integration) support version
> +autodiscovery, the maintainers of these IP blocks intend to increment
> +the suffixed number in the compatible string whenever the software
> +interface to these IP blocks changes, or when the functionality of the
> +underlying IP blocks changes in a way that software should be aware of.
> +
> +Driver developers can use compatible string "match" values such as
> +"sifive,uart0" to indicate that their driver is compatible with the
> +register interface and functionality associated with the relevant
> +upstream sifive-blocks commits.  It is expected that most drivers will
> +match on these IP block-specific compatible strings.
> +
> +DT data authors, when writing data for a particular SoC, should
> +continue to specify an SoC-specific compatible string value, such as
> +"sifive,fu540-c000-uart".  This way, if SoC-specific
> +integration-specific bug fixes or workarounds are needed, the kernel
> +or other system software can match on this string to apply them.  The
> +IP block-specific compatible string (such as "sifive,uart0") should
> +then be specified as a subsequent value.
> +
> +An example of this style:
> +
> +    compatible = "sifive,fu540-c000-uart", "sifive,uart0";

Reviewed-by: Palmer Dabbelt <palmer@sifive.com>
Palmer Dabbelt Nov. 26, 2018, 7:02 p.m. UTC | #3
On Wed, 21 Nov 2018 17:33:02 PST (-0800), atish.patra@wdc.com wrote:
> On 11/21/18 5:07 PM, Paul Walmsley wrote:
>>
>> For IP blocks that are generated from the public, open-source
>> sifive-blocks repository, describe the version numbering policy
>> that its maintainers intend to use, upon request from Rob
>> Herring <robh@kernel.org>.
>>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Palmer Dabbelt <palmer@sifive.com>
>> Cc: Megan Wachs <megan@sifive.com>
>> Cc: Wesley Terpstra <wesley@sifive.com>
>> Cc: Mark Rutland <mark.rutland@arm.com>
>> Cc: devicetree@vger.kernel.org
>> Cc: linux-riscv@lists.infradead.org
>> Cc: linux-kernel@vger.kernel.org
>> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
>> Signed-off-by: Paul Walmsley <paul@pwsan.com>
>> ---
>>
>> Hi Rob, please let me know if this document works with your
>> requirements, or if some changes are needed.  - Paul
>>
>>   .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
>>   1 file changed, 38 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
>>
>> diff --git a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
>> new file mode 100644
>> index 000000000000..b899e5c6e00c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
>
> It should be be under
> Documentation/devicetree/bindings/riscv/sifive/sifive-blocks-ip-versioning.txt
> ?
>
>> @@ -0,0 +1,38 @@
>> +DT compatible string versioning for SiFive open-source IP blocks
>> +
>> +This document describes the version specification for DT "compatible"
>> +strings for open-source SiFive IP blocks.  HDL for these IP blocks
>> +can be found in this public repository:
>> +
>> +https://github.com/sifive/sifive-blocks
>> +
>> +IP block-specific DT compatible strings are contained within the HDL,
>> +in the form "sifive,<ip-block-name><integer version number>".
>> +
>> +An example is "sifive,uart0" from:
>> +
>> +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
>> +
>> +Until these IP blocks (or IP integration) support version
>> +autodiscovery, the maintainers of these IP blocks intend to increment
>
> /s/autodiscovery/auto discovery
>
>> +the suffixed number in the compatible string whenever the software
>> +interface to these IP blocks changes, or when the functionality of the
>> +underlying IP blocks changes in a way that software should be aware of.
>> +
>> +Driver developers can use compatible string "match" values such as
>> +"sifive,uart0" to indicate that their driver is compatible with the
>> +register interface and functionality associated with the relevant
>> +upstream sifive-blocks commits.  It is expected that most drivers will
>> +match on these IP block-specific compatible strings.
>> +
>> +DT data authors, when writing data for a particular SoC, should
>> +continue to specify an SoC-specific compatible string value, such as
>> +"sifive,fu540-c000-uart".  This way, if SoC-specific
>> +integration-specific bug fixes or workarounds are needed, the kernel
>> +or other system software can match on this string to apply them.  The
>> +IP block-specific compatible string (such as "sifive,uart0") should
>> +then be specified as a subsequent value.
>> +
>> +An example of this style:
>> +
>> +    compatible = "sifive,fu540-c000-uart", "sifive,uart0";
>>
>
> Just for the sake of completion, should this document also specify what
> should be the style of any possible closed IP as well?

Let's restrict ourselves to the open-source IP for now, as versioning the 
closed source stuff is a bit of a different problem -- when everyone can see 
the source it's easier because we can all agree on exactly what a version 
string means.

For the closed source stuff we currently have just the chip-specific strings, 
as all that stuff is very chip specific (all sorts of special clocking 
constraints).  Essentially you'll have to just trust us as to what's compatible 
with what -- FWIW, since this is mostly driven by the chip process we really 
just have to trust the hardware designers, so we're kind of in the same boat 
(though we can at least peek under the covers if we want to).  Any versioning 
scheme here is doubly complicated because it's closed source and it's chip 
specific, so trying to match this up with the open source stuff seems like too 
much work.

For now we can at least get everyone on the same page as to how we're 
versioning the open-source blocks, which is more important because anyone can 
build a chip with those so we need a well defined scheme.
Paul Walmsley Dec. 6, 2018, 2:30 a.m. UTC | #4
Hi Atish,

On Wed, 21 Nov 2018, Atish Patra wrote:

> On 11/21/18 5:07 PM, Paul Walmsley wrote:
> > 
> > For IP blocks that are generated from the public, open-source
> > sifive-blocks repository, describe the version numbering policy
> > that its maintainers intend to use, upon request from Rob
> > Herring <robh@kernel.org>.
> > 
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Palmer Dabbelt <palmer@sifive.com>
> > Cc: Megan Wachs <megan@sifive.com>
> > Cc: Wesley Terpstra <wesley@sifive.com>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-riscv@lists.infradead.org
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> > Signed-off-by: Paul Walmsley <paul@pwsan.com>
> > ---
> > 
> > Hi Rob, please let me know if this document works with your
> > requirements, or if some changes are needed.  - Paul
> > 
> >   .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
> >   1 file changed, 38 insertions(+)
> >   create mode 100644
> > Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> > b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> > new file mode 100644
> > index 000000000000..b899e5c6e00c
> > --- /dev/null
> > +++
> > b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> 
> It should be be under
> Documentation/devicetree/bindings/riscv/sifive/sifive-blocks-ip-versioning.txt
> ?

These IP blocks could be used with any CPU architecture - ARM, x86, MIPS, 
etc. - so it probably makes sense just to keep them under sifive/, rather 
than associating them with a specific CPU architecture.

> > @@ -0,0 +1,38 @@
> > +DT compatible string versioning for SiFive open-source IP blocks
> > +
> > +This document describes the version specification for DT "compatible"
> > +strings for open-source SiFive IP blocks.  HDL for these IP blocks
> > +can be found in this public repository:
> > +
> > +https://github.com/sifive/sifive-blocks
> > +
> > +IP block-specific DT compatible strings are contained within the HDL,
> > +in the form "sifive,<ip-block-name><integer version number>".
> > +
> > +An example is "sifive,uart0" from:
> > +
> > +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
> > +
> > +Until these IP blocks (or IP integration) support version
> > +autodiscovery, the maintainers of these IP blocks intend to increment
> 
> /s/autodiscovery/auto discovery

I've changed it to "auto-discovery" per your request.  Let me know if it's 
not OK for you

> > +the suffixed number in the compatible string whenever the software
> > +interface to these IP blocks changes, or when the functionality of the
> > +underlying IP blocks changes in a way that software should be aware of.
> > +
> > +Driver developers can use compatible string "match" values such as
> > +"sifive,uart0" to indicate that their driver is compatible with the
> > +register interface and functionality associated with the relevant
> > +upstream sifive-blocks commits.  It is expected that most drivers will
> > +match on these IP block-specific compatible strings.
> > +
> > +DT data authors, when writing data for a particular SoC, should
> > +continue to specify an SoC-specific compatible string value, such as
> > +"sifive,fu540-c000-uart".  This way, if SoC-specific
> > +integration-specific bug fixes or workarounds are needed, the kernel
> > +or other system software can match on this string to apply them.  The
> > +IP block-specific compatible string (such as "sifive,uart0") should
> > +then be specified as a subsequent value.
> > +
> > +An example of this style:
> > +
> > +    compatible = "sifive,fu540-c000-uart", "sifive,uart0";
> > 
> 
> Just for the sake of completion, should this document also specify what should
> be the style of any possible closed IP as well?


Let's handle those separately, as Palmer discussed.

Thanks for the review,

- Paul
Rob Herring Dec. 7, 2018, 12:01 a.m. UTC | #5
On Wed, Nov 21, 2018 at 05:06:56PM -0800, Paul Walmsley wrote:
> 
> For IP blocks that are generated from the public, open-source
> sifive-blocks repository, describe the version numbering policy
> that its maintainers intend to use, upon request from Rob
> Herring <robh@kernel.org>.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Palmer Dabbelt <palmer@sifive.com>
> Cc: Megan Wachs <megan@sifive.com>
> Cc: Wesley Terpstra <wesley@sifive.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> Signed-off-by: Paul Walmsley <paul@pwsan.com>
> ---
> 
> Hi Rob, please let me know if this document works with your
> requirements, or if some changes are needed.  - Paul

Looks pretty good to me.

>  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
>  1 file changed, 38 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt

Use the path that was suggested.

> diff --git a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> new file mode 100644
> index 000000000000..b899e5c6e00c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> @@ -0,0 +1,38 @@
> +DT compatible string versioning for SiFive open-source IP blocks
> +
> +This document describes the version specification for DT "compatible"
> +strings for open-source SiFive IP blocks.  HDL for these IP blocks
> +can be found in this public repository:
> +
> +https://github.com/sifive/sifive-blocks
> +
> +IP block-specific DT compatible strings are contained within the HDL,
> +in the form "sifive,<ip-block-name><integer version number>".

Really, my preference would be to add a '-v' in this:

sifive,<ip-block-name>-v<integer version number>

But given this ship has already sailed, I guess it is fine as is.

> +
> +An example is "sifive,uart0" from:
> +
> +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43

That's nice, but will be out of date as soon as someone adds or removes 
a line above it. Can you point to a tagged version?

> +
> +Until these IP blocks (or IP integration) support version
> +autodiscovery, the maintainers of these IP blocks intend to increment
> +the suffixed number in the compatible string whenever the software
> +interface to these IP blocks changes, or when the functionality of the
> +underlying IP blocks changes in a way that software should be aware of.
> +
> +Driver developers can use compatible string "match" values such as
> +"sifive,uart0" to indicate that their driver is compatible with the
> +register interface and functionality associated with the relevant
> +upstream sifive-blocks commits.  It is expected that most drivers will
> +match on these IP block-specific compatible strings.
> +
> +DT data authors, when writing data for a particular SoC, should
> +continue to specify an SoC-specific compatible string value, such as
> +"sifive,fu540-c000-uart".  This way, if SoC-specific
> +integration-specific bug fixes or workarounds are needed, the kernel
> +or other system software can match on this string to apply them.  The
> +IP block-specific compatible string (such as "sifive,uart0") should
> +then be specified as a subsequent value.
> +
> +An example of this style:
> +
> +    compatible = "sifive,fu540-c000-uart", "sifive,uart0";
> -- 
> 2.19.1
>
Paul Walmsley Dec. 7, 2018, 12:45 a.m. UTC | #6
On Thu, 6 Dec 2018, Rob Herring wrote:

> On Wed, Nov 21, 2018 at 05:06:56PM -0800, Paul Walmsley wrote:
> > 
> > For IP blocks that are generated from the public, open-source
> > sifive-blocks repository, describe the version numbering policy
> > that its maintainers intend to use, upon request from Rob
> > Herring <robh@kernel.org>.
> > 
> > Cc: Rob Herring <robh+dt@kernel.org>
> > Cc: Palmer Dabbelt <palmer@sifive.com>
> > Cc: Megan Wachs <megan@sifive.com>
> > Cc: Wesley Terpstra <wesley@sifive.com>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Cc: devicetree@vger.kernel.org
> > Cc: linux-riscv@lists.infradead.org
> > Cc: linux-kernel@vger.kernel.org
> > Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> > Signed-off-by: Paul Walmsley <paul@pwsan.com>
> > ---
> > 
> > Hi Rob, please let me know if this document works with your
> > requirements, or if some changes are needed.  - Paul
> 
> Looks pretty good to me.
> 
> >  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
> >  1 file changed, 38 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> 
> Use the path that was suggested.

Could you remind me which one that is?

> > +
> > +An example is "sifive,uart0" from:
> > +
> > +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
> 
> That's nice, but will be out of date as soon as someone adds or removes 
> a line above it. Can you point to a tagged version?

Will do

- Paul
Rob Herring Dec. 7, 2018, 1:55 p.m. UTC | #7
On Thu, Dec 6, 2018 at 6:46 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
>
>
> On Thu, 6 Dec 2018, Rob Herring wrote:
>
> > On Wed, Nov 21, 2018 at 05:06:56PM -0800, Paul Walmsley wrote:
> > >
> > > For IP blocks that are generated from the public, open-source
> > > sifive-blocks repository, describe the version numbering policy
> > > that its maintainers intend to use, upon request from Rob
> > > Herring <robh@kernel.org>.
> > >
> > > Cc: Rob Herring <robh+dt@kernel.org>
> > > Cc: Palmer Dabbelt <palmer@sifive.com>
> > > Cc: Megan Wachs <megan@sifive.com>
> > > Cc: Wesley Terpstra <wesley@sifive.com>
> > > Cc: Mark Rutland <mark.rutland@arm.com>
> > > Cc: devicetree@vger.kernel.org
> > > Cc: linux-riscv@lists.infradead.org
> > > Cc: linux-kernel@vger.kernel.org
> > > Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> > > Signed-off-by: Paul Walmsley <paul@pwsan.com>
> > > ---
> > >
> > > Hi Rob, please let me know if this document works with your
> > > requirements, or if some changes are needed.  - Paul
> >
> > Looks pretty good to me.
> >
> > >  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
> > >  1 file changed, 38 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> >
> > Use the path that was suggested.
>
> Could you remind me which one that is?

In this thread: bindings/riscv/sifive/

> > > +
> > > +An example is "sifive,uart0" from:
> > > +
> > > +https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
> >
> > That's nice, but will be out of date as soon as someone adds or removes
> > a line above it. Can you point to a tagged version?
>
> Will do
>
> - Paul
Paul Walmsley Dec. 7, 2018, 2:31 p.m. UTC | #8
On Fri, 7 Dec 2018, Rob Herring wrote:

> On Thu, Dec 6, 2018 at 6:46 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
> > On Thu, 6 Dec 2018, Rob Herring wrote:
> > > On Wed, Nov 21, 2018 at 05:06:56PM -0800, Paul Walmsley wrote:
> > >
> > > >  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
> > > >  1 file changed, 38 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> > >
> > > Use the path that was suggested.
> >
> > Could you remind me which one that is?
> 
> In this thread: bindings/riscv/sifive/

SiFive also produces ARM-based SoCs.  Some of those ARM SoCs may use these 
IP blocks from sifive-blocks as well.  As far as I know, there's nothing 
RISC-V-specific about most of these IP blocks.  (As an example, there's 
nothing CPU architecture-specific about a UART.)

I'm fine with putting these bindings under bindings/riscv/, if that's 
where you need them to go.  But I'd like to understand the rationale 
better - could you describe that?

thanks,

- Paul
Rob Herring Dec. 7, 2018, 3:19 p.m. UTC | #9
On Fri, Dec 7, 2018 at 8:31 AM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
>
> On Fri, 7 Dec 2018, Rob Herring wrote:
>
> > On Thu, Dec 6, 2018 at 6:46 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
> > > On Thu, 6 Dec 2018, Rob Herring wrote:
> > > > On Wed, Nov 21, 2018 at 05:06:56PM -0800, Paul Walmsley wrote:
> > > >
> > > > >  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
> > > > >  1 file changed, 38 insertions(+)
> > > > >  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
> > > >
> > > > Use the path that was suggested.
> > >
> > > Could you remind me which one that is?
> >
> > In this thread: bindings/riscv/sifive/
>
> SiFive also produces ARM-based SoCs.  Some of those ARM SoCs may use these
> IP blocks from sifive-blocks as well.  As far as I know, there's nothing
> RISC-V-specific about most of these IP blocks.  (As an example, there's
> nothing CPU architecture-specific about a UART.)

Fair enough. As-is is fine.

Rob
Rob Herring May 13, 2019, 8:47 p.m. UTC | #10
On Wed, Nov 21, 2018 at 7:06 PM Paul Walmsley <paul.walmsley@sifive.com> wrote:
>
>
> For IP blocks that are generated from the public, open-source
> sifive-blocks repository, describe the version numbering policy
> that its maintainers intend to use, upon request from Rob
> Herring <robh@kernel.org>.
>
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Palmer Dabbelt <palmer@sifive.com>
> Cc: Megan Wachs <megan@sifive.com>
> Cc: Wesley Terpstra <wesley@sifive.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: devicetree@vger.kernel.org
> Cc: linux-riscv@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
> Signed-off-by: Paul Walmsley <paul@pwsan.com>
> ---
>
> Hi Rob, please let me know if this document works with your
> requirements, or if some changes are needed.  - Paul
>
>  .../sifive/sifive-blocks-ip-versioning.txt    | 38 +++++++++++++++++++
>  1 file changed, 38 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt

I just noticed this was never re-spun and applied. We now have
bindings in tree referring to it though.

Rob
Paul Walmsley May 13, 2019, 9:07 p.m. UTC | #11
On Mon, 13 May 2019, Rob Herring wrote:

> I just noticed this was never re-spun and applied. We now have
> bindings in tree referring to it though.

Will send an updated version shortly.

- Paul

Patch
diff mbox series

diff --git a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
new file mode 100644
index 000000000000..b899e5c6e00c
--- /dev/null
+++ b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
@@ -0,0 +1,38 @@ 
+DT compatible string versioning for SiFive open-source IP blocks
+
+This document describes the version specification for DT "compatible"
+strings for open-source SiFive IP blocks.  HDL for these IP blocks
+can be found in this public repository:
+
+https://github.com/sifive/sifive-blocks
+
+IP block-specific DT compatible strings are contained within the HDL,
+in the form "sifive,<ip-block-name><integer version number>".
+
+An example is "sifive,uart0" from:
+
+https://github.com/sifive/sifive-blocks/blob/master/src/main/scala/devices/uart/UART.scala#L43
+
+Until these IP blocks (or IP integration) support version
+autodiscovery, the maintainers of these IP blocks intend to increment
+the suffixed number in the compatible string whenever the software
+interface to these IP blocks changes, or when the functionality of the
+underlying IP blocks changes in a way that software should be aware of.
+
+Driver developers can use compatible string "match" values such as
+"sifive,uart0" to indicate that their driver is compatible with the
+register interface and functionality associated with the relevant
+upstream sifive-blocks commits.  It is expected that most drivers will
+match on these IP block-specific compatible strings.
+
+DT data authors, when writing data for a particular SoC, should
+continue to specify an SoC-specific compatible string value, such as
+"sifive,fu540-c000-uart".  This way, if SoC-specific
+integration-specific bug fixes or workarounds are needed, the kernel
+or other system software can match on this string to apply them.  The
+IP block-specific compatible string (such as "sifive,uart0") should
+then be specified as a subsequent value.
+
+An example of this style:
+
+    compatible = "sifive,fu540-c000-uart", "sifive,uart0";