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[PATCH 4/4] Update device tree Synopsys DW DMAC documentation

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  [PATCH 4/4] Update device tree Synopsys DW DMAC documentation Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> - 2016-11-16 15:00 +0100
    Re: [PATCH 4/4] Update device tree Synopsys DW DMAC documentation Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-11-16 16:20 +0100
      Re: [PATCH 4/4] Update device tree Synopsys DW DMAC documentation Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> - 2016-11-16 18:10 +0100
        Re: [PATCH 4/4] Update device tree Synopsys DW DMAC documentation Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-11-16 19:20 +0100
          Re: [PATCH 4/4] Update device tree Synopsys DW DMAC documentation Rob Herring <robh+dt@kernel.org> - 2016-11-16 19:20 +0100

#1523478 — [PATCH 4/4] Update device tree Synopsys DW DMAC documentation

 * Rename is_private to is-private as ordered by DT policy.
 The change leaves the support for the old format.

 * Add is-memcpu property, so it is possible to
 enable memory-to-memory transfers support via DT.

 * Add hw-llp property, so it is possible to enable
 hardware multi block transfers support via DT.

 Fix white spaces.

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
---
 Documentation/devicetree/bindings/dma/snps-dma.txt | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt b/Documentation/devicetree/bindings/dma/snps-dma.txt
index 0f55832..d41d960 100644
--- a/Documentation/devicetree/bindings/dma/snps-dma.txt
+++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
@@ -20,13 +20,19 @@ Required properties:
 Deprecated properties:
 - data_width: Maximum data width supported by hardware per AHB master
   (0 - 8bits, 1 - 16bits, ..., 5 - 256bits)
+- is_private: The device channels should be marked as private and not for by the
+  general purpose DMA channel allocator. False if not passed.
 
 
 Optional properties:
 - interrupt-parent: Should be the phandle for the interrupt controller
   that services interrupts for this device
-- is_private: The device channels should be marked as private and not for by the
+- is-private: The device channels should be marked as private and not for by the
   general purpose DMA channel allocator. False if not passed.
+- is-memcpu: The device channels do support memory-to-memory transfers. False
+  if not passed.
+- hw-llp: Multi block transfers supported by hardware per AHB master.
+  0 (default): not supported, 1: supported.
 
 Example:
 
@@ -56,7 +62,7 @@ The four cells in order are:
 4. Peripheral master for transfers on allocated channel
 
 Example:
-	
+
 	serial@e0000000 {
 		compatible = "arm,pl011", "arm,primecell";
 		reg = <0xe0000000 0x1000>;
-- 
2.5.5

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#1523570

On Wed, 2016-11-16 at 16:56 +0300, Eugeniy Paltsev wrote:
>  * Rename is_private to is-private as ordered by DT policy.
>  The change leaves the support for the old format.
> 
>  * Add is-memcpu property, so it is possible to
>  enable memory-to-memory transfers support via DT.
> 
>  * Add hw-llp property, so it is possible to enable
>  hardware multi block transfers support via DT.
> 
>  Fix white spaces.
> 
> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
> ---
>  Documentation/devicetree/bindings/dma/snps-dma.txt | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/dma/snps-dma.txt
> b/Documentation/devicetree/bindings/dma/snps-dma.txt
> index 0f55832..d41d960 100644
> --- a/Documentation/devicetree/bindings/dma/snps-dma.txt
> +++ b/Documentation/devicetree/bindings/dma/snps-dma.txt
> @@ -20,13 +20,19 @@ Required properties:
>  Deprecated properties:
>  - data_width: Maximum data width supported by hardware per AHB master
>    (0 - 8bits, 1 - 16bits, ..., 5 - 256bits)

> +- is_private: The device channels should be marked as private and not
> for by the
> +  general purpose DMA channel allocator. False if not passed.

This...

>  
>  
>  Optional properties:
>  - interrupt-parent: Should be the phandle for the interrupt
> controller
>    that services interrupts for this device

> -- is_private: The device channels should be marked as private and not
> for by the
> +- is-private: The device channels should be marked as private and not
> for by the
>    general purpose DMA channel allocator. False if not passed.

...and this is a part of patch 1.

> +- is-memcpu: The device channels do support memory-to-memory 

memcpy

> transfers. 

> False
> +  if not passed.
> +- hw-llp: Multi block transfers supported by hardware per AHB master.
> +  0 (default): not supported, 1: supported.

Overall, since we are going to expose some properties to the Device Tree
I would really think twice about naming. Better if we reuse something
existing already.

So, what I can see is

dmacap,private
dmacap,memcpy

Here is a selling point as well, i.e. standardization.

'hw-llp' sounds too tricky, perhaps 'multi-block' is better and could be
re-used.

>  
>  Example:
>  
> @@ -56,7 +62,7 @@ The four cells in order are:
>  4. Peripheral master for transfers on allocated channel
>  

>  Example:
> -	
> +

No, no need to touch this.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

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#1523667

Hi Andy,

On Wed, 2016-11-16 at 17:10 +0200, Andy Shevchenko wrote:
> Overall, since we are going to expose some properties to the Device
> Tree
> I would really think twice about naming. Better if we reuse something
> existing already.
> 
> So, what I can see is
> 
> dmacap,private
> dmacap,memcpy
> 
> Here is a selling point as well, i.e. standardization.
> 
As I can see these property name used only in "mv_xor" driver. And 
they are marked as deprecated.
So, I'm not sure if I should used these names.

I agree with other comments.
-- 
 Paltsev Eugeniy

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#1523720

On Wed, 2016-11-16 at 17:01 +0000, Eugeniy Paltsev wrote:
> On Wed, 2016-11-16 at 17:10 +0200, Andy Shevchenko wrote:
> > Overall, since we are going to expose some properties to the Device
> > Tree
> > I would really think twice about naming. Better if we reuse
> > something
> > existing already.
> > 
> > So, what I can see is
> > 
> > dmacap,private
> > dmacap,memcpy
> > 
> > Here is a selling point as well, i.e. standardization.
> > 
> 
> As I can see these property name used only in "mv_xor" driver. And 
> they are marked as deprecated.
> So, I'm not sure if I should used these names.

Oh, good catch! So, then I leave this to DT experienced guys to decide.
Rob?

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy

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#1523723

On Wed, Nov 16, 2016 at 12:08 PM, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> On Wed, 2016-11-16 at 17:01 +0000, Eugeniy Paltsev wrote:
>> On Wed, 2016-11-16 at 17:10 +0200, Andy Shevchenko wrote:
>> > Overall, since we are going to expose some properties to the Device
>> > Tree
>> > I would really think twice about naming. Better if we reuse
>> > something
>> > existing already.
>> >
>> > So, what I can see is
>> >
>> > dmacap,private
>> > dmacap,memcpy
>> >
>> > Here is a selling point as well, i.e. standardization.
>> >
>>
>> As I can see these property name used only in "mv_xor" driver. And
>> they are marked as deprecated.
>> So, I'm not sure if I should used these names.
>
> Oh, good catch! So, then I leave this to DT experienced guys to decide.
> Rob?

Well, maybe they were deprecated for a reason? This all seems like
user configuration to me. So either they don't belong in DT or should
be common if they do.

Rob

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