[4/5] dt-bindings: dma: ti-edma: Add option for reserved channel ranges
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Message ID 20190823125618.8133-5-peter.ujfalusi@ti.com
State Changes Requested
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Series
  • dmaengine: ti: edma: Multicore usage related fixes
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Commit Message

Peter Ujfalusi Aug. 23, 2019, 12:56 p.m. UTC
Similarly to paRAM slots, channels can be used by other cores.

Add optional property to configure the reserved channel ranges.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
---
 Documentation/devicetree/bindings/dma/ti-edma.txt | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Rob Herring Aug. 29, 2019, 10:47 p.m. UTC | #1
On Fri, Aug 23, 2019 at 03:56:17PM +0300, Peter Ujfalusi wrote:
> Similarly to paRAM slots, channels can be used by other cores.
> 
> Add optional property to configure the reserved channel ranges.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> ---
>  Documentation/devicetree/bindings/dma/ti-edma.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/dma/ti-edma.txt b/Documentation/devicetree/bindings/dma/ti-edma.txt
> index 4bbc94d829c8..1198682ada99 100644
> --- a/Documentation/devicetree/bindings/dma/ti-edma.txt
> +++ b/Documentation/devicetree/bindings/dma/ti-edma.txt
> @@ -42,6 +42,9 @@ Optional properties:
>  - ti,edma-reserved-slot-ranges: PaRAM slot ranges which should not be used by
>  		the driver, they are allocated to be used by for example the
>  		DSP. See example.
> +- ti,edma-reserved-chan-ranges: channel ranges which should not be used by
> +		the driver, they are allocated to be used by for example the
> +		DSP. See example.

Based on the other thread, I think extending dma-channel-mask to a 
uint32-array makes sense here.

Rob
Peter Ujfalusi Aug. 30, 2019, 5:37 a.m. UTC | #2
Rob,

On 30/08/2019 1.47, Rob Herring wrote:
> On Fri, Aug 23, 2019 at 03:56:17PM +0300, Peter Ujfalusi wrote:
>> Similarly to paRAM slots, channels can be used by other cores.
>>
>> Add optional property to configure the reserved channel ranges.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>> ---
>>  Documentation/devicetree/bindings/dma/ti-edma.txt | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/dma/ti-edma.txt b/Documentation/devicetree/bindings/dma/ti-edma.txt
>> index 4bbc94d829c8..1198682ada99 100644
>> --- a/Documentation/devicetree/bindings/dma/ti-edma.txt
>> +++ b/Documentation/devicetree/bindings/dma/ti-edma.txt
>> @@ -42,6 +42,9 @@ Optional properties:
>>  - ti,edma-reserved-slot-ranges: PaRAM slot ranges which should not be used by
>>  		the driver, they are allocated to be used by for example the
>>  		DSP. See example.
>> +- ti,edma-reserved-chan-ranges: channel ranges which should not be used by
>> +		the driver, they are allocated to be used by for example the
>> +		DSP. See example.
> 
> Based on the other thread, I think extending dma-channel-mask to a 
> uint32-array makes sense here.

Yes, that is the reason I have asked on that and I'm in progress of
converting the edma driver to use the dma-channel-mask.
Just need to do some shuffling in the driver to get the mask in a form
usable by the driver.

I'll send an updated series early next week.

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Peter Ujfalusi Sept. 3, 2019, 10:19 a.m. UTC | #3
Hi Rob,

On 30/08/2019 8.37, Peter Ujfalusi wrote:
> Rob,
> 
> On 30/08/2019 1.47, Rob Herring wrote:
>> On Fri, Aug 23, 2019 at 03:56:17PM +0300, Peter Ujfalusi wrote:
>>> Similarly to paRAM slots, channels can be used by other cores.
>>>
>>> Add optional property to configure the reserved channel ranges.
>>>
>>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
>>> ---
>>>  Documentation/devicetree/bindings/dma/ti-edma.txt | 5 +++++
>>>  1 file changed, 5 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/dma/ti-edma.txt b/Documentation/devicetree/bindings/dma/ti-edma.txt
>>> index 4bbc94d829c8..1198682ada99 100644
>>> --- a/Documentation/devicetree/bindings/dma/ti-edma.txt
>>> +++ b/Documentation/devicetree/bindings/dma/ti-edma.txt
>>> @@ -42,6 +42,9 @@ Optional properties:
>>>  - ti,edma-reserved-slot-ranges: PaRAM slot ranges which should not be used by
>>>  		the driver, they are allocated to be used by for example the
>>>  		DSP. See example.
>>> +- ti,edma-reserved-chan-ranges: channel ranges which should not be used by
>>> +		the driver, they are allocated to be used by for example the
>>> +		DSP. See example.
>>
>> Based on the other thread, I think extending dma-channel-mask to a 
>> uint32-array makes sense here.
> 
> Yes, that is the reason I have asked on that and I'm in progress of
> converting the edma driver to use the dma-channel-mask.
> Just need to do some shuffling in the driver to get the mask in a form
> usable by the driver.
> 
> I'll send an updated series early next week.

How should the dma-channel-mask uint31-array should be documented and used?

Basically some EDMA have 32, some 64 channels. This is fine.
Let's say I want to mask out channel 0-4 and 24-27

This would look like in case of EDMA with 32 channels:
&edma {
	/* channel 0-4 and 24-27 is not to be used */
	dma-channel-mask = <0xf0fffff0>;
};

How this should look like in case when I have 64 channels?
&edma {
	/* channel 0-4 and 24-27 is not to be used */
	dma-channel-mask = <0xf0fffff0>, <0xffffffff>;
};

When I read the u32s then
chan_mask[0] is for channel 0-31 (LSB is channel 0)
chan_maks[1] is for channel 32-63 (LSB is channel 32)

Or:
&edma {
	/* channel 0-4 and 24-27 is not to be used */
	dma-channel-mask = <0xffffffff>, <0xf0fffff0>;
};

chan_maks[0] is for channel 32-63 (LSB is channel 32)
chan_mask[1] is for channel 0-31 (LSB is channel 0)

Do you have pointer on already established notion on how to document and
handle this?

- Péter

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
Rob Herring Sept. 6, 2019, 1:10 p.m. UTC | #4
On Tue, Sep 3, 2019 at 11:19 AM Peter Ujfalusi <peter.ujfalusi@ti.com> wrote:
>
> Hi Rob,
>
> On 30/08/2019 8.37, Peter Ujfalusi wrote:
> > Rob,
> >
> > On 30/08/2019 1.47, Rob Herring wrote:
> >> On Fri, Aug 23, 2019 at 03:56:17PM +0300, Peter Ujfalusi wrote:
> >>> Similarly to paRAM slots, channels can be used by other cores.
> >>>
> >>> Add optional property to configure the reserved channel ranges.
> >>>
> >>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> >>> ---
> >>>  Documentation/devicetree/bindings/dma/ti-edma.txt | 5 +++++
> >>>  1 file changed, 5 insertions(+)
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/dma/ti-edma.txt b/Documentation/devicetree/bindings/dma/ti-edma.txt
> >>> index 4bbc94d829c8..1198682ada99 100644
> >>> --- a/Documentation/devicetree/bindings/dma/ti-edma.txt
> >>> +++ b/Documentation/devicetree/bindings/dma/ti-edma.txt
> >>> @@ -42,6 +42,9 @@ Optional properties:
> >>>  - ti,edma-reserved-slot-ranges: PaRAM slot ranges which should not be used by
> >>>             the driver, they are allocated to be used by for example the
> >>>             DSP. See example.
> >>> +- ti,edma-reserved-chan-ranges: channel ranges which should not be used by
> >>> +           the driver, they are allocated to be used by for example the
> >>> +           DSP. See example.
> >>
> >> Based on the other thread, I think extending dma-channel-mask to a
> >> uint32-array makes sense here.
> >
> > Yes, that is the reason I have asked on that and I'm in progress of
> > converting the edma driver to use the dma-channel-mask.
> > Just need to do some shuffling in the driver to get the mask in a form
> > usable by the driver.
> >
> > I'll send an updated series early next week.
>
> How should the dma-channel-mask uint31-array should be documented and used?
>
> Basically some EDMA have 32, some 64 channels. This is fine.
> Let's say I want to mask out channel 0-4 and 24-27
>
> This would look like in case of EDMA with 32 channels:
> &edma {
>         /* channel 0-4 and 24-27 is not to be used */
>         dma-channel-mask = <0xf0fffff0>;
> };
>
> How this should look like in case when I have 64 channels?
> &edma {
>         /* channel 0-4 and 24-27 is not to be used */
>         dma-channel-mask = <0xf0fffff0>, <0xffffffff>;
> };
>
> When I read the u32s then
> chan_mask[0] is for channel 0-31 (LSB is channel 0)
> chan_maks[1] is for channel 32-63 (LSB is channel 32)
>
> Or:
> &edma {
>         /* channel 0-4 and 24-27 is not to be used */
>         dma-channel-mask = <0xffffffff>, <0xf0fffff0>;
> };
>
> chan_maks[0] is for channel 32-63 (LSB is channel 32)
> chan_mask[1] is for channel 0-31 (LSB is channel 0)
>
> Do you have pointer on already established notion on how to document and
> handle this?

As far as word ordering, I guess you can do whatever order you want.
MSB first would make the most sense if this was only going to be up to
64-bit. But given it could be 96, 128, ... bits, probably the least
significant word first makes sense and is easier to parse for a
variable length.

The binding schema can be something like this:

items:
  - description: Mask of channels 0-31
  - description: Mask of channels 32-63

The length is implied by the number of list items.

Rob

Patch
diff mbox series

diff --git a/Documentation/devicetree/bindings/dma/ti-edma.txt b/Documentation/devicetree/bindings/dma/ti-edma.txt
index 4bbc94d829c8..1198682ada99 100644
--- a/Documentation/devicetree/bindings/dma/ti-edma.txt
+++ b/Documentation/devicetree/bindings/dma/ti-edma.txt
@@ -42,6 +42,9 @@  Optional properties:
 - ti,edma-reserved-slot-ranges: PaRAM slot ranges which should not be used by
 		the driver, they are allocated to be used by for example the
 		DSP. See example.
+- ti,edma-reserved-chan-ranges: channel ranges which should not be used by
+		the driver, they are allocated to be used by for example the
+		DSP. See example.
 
 ------------------------------------------------------------------------------
 eDMA3 Transfer Controller
@@ -91,6 +94,8 @@  edma: edma@49000000 {
 	ti,edma-memcpy-channels = <20 21>;
 	/* The following PaRAM slots are reserved: 35-44 and 100-109 */
 	ti,edma-reserved-slot-ranges = <35 10>, <100 10>;
+	/* The following channels are reserved: 35-44 */
+	ti,edma-reserved-chan-ranges = <35 10>;
 };
 
 edma_tptc0: tptc@49800000 {