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[PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst

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  [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst Shawn Lin <shawn.lin@rock-chips.com> - 2016-08-05 05:00 +0200
    Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of  arm,pl330-periph-burst Vinod Koul <vinod.koul@intel.com> - 2016-08-05 05:30 +0200
      Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of  arm,pl330-periph-burst Shawn Lin <shawn.lin@rock-chips.com> - 2016-08-05 09:30 +0200
        Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of  arm,pl330-periph-burst Lars-Peter Clausen <lars@metafoo.de> - 2016-08-09 10:50 +0200
          Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of  arm,pl330-periph-burst Shawn Lin <shawn.lin@rock-chips.com> - 2016-08-09 11:20 +0200

#1456854 — [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst

This patch adds the "arm,pl330-periph-burst" for arm-pl330 to
support busrt mode.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

---

 Documentation/devicetree/bindings/dma/arm-pl330.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/dma/arm-pl330.txt b/Documentation/devicetree/bindings/dma/arm-pl330.txt
index db7e226..262e97a 100644
--- a/Documentation/devicetree/bindings/dma/arm-pl330.txt
+++ b/Documentation/devicetree/bindings/dma/arm-pl330.txt
@@ -16,6 +16,7 @@ Optional properties:
   - dma-channels: contains the total number of DMA channels supported by the DMAC
   - dma-requests: contains the total number of DMA requests supported by the DMAC
   - arm,pl330-broken-no-flushp: quirk for avoiding to execute DMAFLUSHP
+  - arm,pl330-periph-burst: set peripheral dma request type as burst mode
 
 Example:
 
-- 
2.3.7

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#1456859 — Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst

On Fri, Aug 05, 2016 at 10:53:20AM +0800, Shawn Lin wrote:
> This patch adds the "arm,pl330-periph-burst" for arm-pl330 to
> support busrt mode.

why should this be DT property. Only reason I can think of if some hw
versions support this and some won't.

If all are supporting, please enable it everywhere for obvious reasons.

-- 
~Vinod

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#1456911 — Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst

Hi Vinod,

在 2016/8/5 11:34, Vinod Koul 写道:
> On Fri, Aug 05, 2016 at 10:53:20AM +0800, Shawn Lin wrote:
>> This patch adds the "arm,pl330-periph-burst" for arm-pl330 to
>> support busrt mode.
>
> why should this be DT property. Only reason I can think of if some hw
> versions support this and some won't.

yes, if we want to support burst mode, both of the master(pl330) and
client(several peripherals) should implement it, otherwise it will
be broken when enabling.

So I mentioned it on my cover letter as the reason to introduce this
optional property. If people add this property and find it's ok for
their platform, they could land new dt-patch to add it. But we could
*not* presume that we could get all users involved in testing this
patchet. I don't wanna to break any other platforms, so it's needed.


Thanks.

>
> If all are supporting, please enable it everywhere for obvious reasons.
>


-- 
Best Regards
Shawn Lin

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#1458520 — Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst

On 08/05/2016 09:25 AM, Shawn Lin wrote:
> Hi Vinod,
> 
> 在 2016/8/5 11:34, Vinod Koul 写道:
>> On Fri, Aug 05, 2016 at 10:53:20AM +0800, Shawn Lin wrote:
>>> This patch adds the "arm,pl330-periph-burst" for arm-pl330 to
>>> support busrt mode.
>>
>> why should this be DT property. Only reason I can think of if some hw
>> versions support this and some won't.
> 
> yes, if we want to support burst mode, both of the master(pl330) and
> client(several peripherals) should implement it, otherwise it will
> be broken when enabling.

As you said, it is up to the consumer peripheral whether it supports BURST,
SINGLE or both. So this is a per client property, but you specify this as a
a global property on the producer side.

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#1458537 — Re: [PATCH 1/3] dt/bindings: arm-pl330: add description of arm,pl330-periph-burst

Hi Lars-Peter,

在 2016/8/9 16:39, Lars-Peter Clausen 写道:
> On 08/05/2016 09:25 AM, Shawn Lin wrote:
>> Hi Vinod,
>>
>> 在 2016/8/5 11:34, Vinod Koul 写道:
>>> On Fri, Aug 05, 2016 at 10:53:20AM +0800, Shawn Lin wrote:
>>>> This patch adds the "arm,pl330-periph-burst" for arm-pl330 to
>>>> support busrt mode.
>>>
>>> why should this be DT property. Only reason I can think of if some hw
>>> versions support this and some won't.
>>
>> yes, if we want to support burst mode, both of the master(pl330) and
>> client(several peripherals) should implement it, otherwise it will
>> be broken when enabling.
>
> As you said, it is up to the consumer peripheral whether it supports BURST,
> SINGLE or both. So this is a per client property, but you specify this as a
> a global property on the producer side.

Thanks for comment.

yup, but what is the proper way to add it ? :)


a) If pl330 support BURST as well as all the peripherals, we could
enable it.

b) If pl300 support BURST, but all the peripherals don't support it,
we could not enable it.

c) If pl300 support BURST, but not all the peripherals support it,
we also could not enable it.

the burst feature of peripheral IP may be vendor-specific, but the
common driver for this peripheral are used for many many vendors which
means we could not check all of this info. It's very likely to break
them... I couldn't figure out how many upstreamed peripheral drivers
who are using pl300 either.

So this check should be done by all this vendors but we could make
sure we don't break them before they check a), b), c), right?


>
>
>
>


-- 
Best Regards
Shawn Lin

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