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| Started by | Jose Abreu <Jose.Abreu@synopsys.com> |
|---|---|
| First post | 2016-12-30 12:40 +0100 |
| Last post | 2017-01-02 15:00 +0100 |
| Articles | 7 — 4 participants |
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dmaengine: dw-dmac: Custom cyclic API (Why?) Jose Abreu <Jose.Abreu@synopsys.com> - 2016-12-30 12:40 +0100
Re: dmaengine: dw-dmac: Custom cyclic API (Why?) Jose Abreu <Jose.Abreu@synopsys.com> - 2016-12-30 13:10 +0100
Re: dmaengine: dw-dmac: Custom cyclic API (Why?) Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2017-01-02 09:40 +0100
Re: dmaengine: dw-dmac: Custom cyclic API (Why?) Vinod Koul <vinod.koul@intel.com> - 2017-01-02 11:20 +0100
Re: dmaengine: dw-dmac: Custom cyclic API (Why?) Viresh Kumar <viresh.kumar@linaro.org> - 2017-01-02 12:00 +0100
Re: dmaengine: dw-dmac: Custom cyclic API (Why?) Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2017-01-02 12:40 +0100
Re: dmaengine: dw-dmac: Custom cyclic API (Why?) Jose Abreu <Jose.Abreu@synopsys.com> - 2017-01-02 15:00 +0100
| From | Jose Abreu <Jose.Abreu@synopsys.com> |
|---|---|
| Date | 2016-12-30 12:40 +0100 |
| Subject | dmaengine: dw-dmac: Custom cyclic API (Why?) |
| Message-ID | <sU3Hs-3Ks-23@gated-at.bofh.it> |
Hi All, I am going to work with dw-dmac AHB controller and I wanted to use SND_DMAENGINE_PCM. In order to use this, a standard DMA driver with cyclic support is needed. I found out that dw-dmac is capable of cyclic transfers but instead of using the DMA engine standard cyclic API it uses a custom API. Is there any specific reason for this? What is the effort to change the custom API to a standard DMA engine cyclic API? Best regards, Jose Miguel Abreu
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| From | Jose Abreu <Jose.Abreu@synopsys.com> |
|---|---|
| Date | 2016-12-30 13:10 +0100 |
| Message-ID | <sU4at-4aa-9@gated-at.bofh.it> |
| In reply to | #1548556 |
++dw-dmac Maintainers On 30-12-2016 11:32, Jose Abreu wrote: > Hi All, > > > I am going to work with dw-dmac AHB controller and I wanted to > use SND_DMAENGINE_PCM. In order to use this, a standard DMA > driver with cyclic support is needed. I found out that dw-dmac is > capable of cyclic transfers but instead of using the DMA engine > standard cyclic API it uses a custom API. Is there any specific > reason for this? What is the effort to change the custom API to a > standard DMA engine cyclic API? > > > Best regards, > > Jose Miguel Abreu >
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| From | Andy Shevchenko <andriy.shevchenko@linux.intel.com> |
|---|---|
| Date | 2017-01-02 09:40 +0100 |
| Message-ID | <sV6jU-4bE-9@gated-at.bofh.it> |
| In reply to | #1548566 |
On Fri, 2016-12-30 at 12:05 +0000, Jose Abreu wrote: > ++dw-dmac Maintainers > > > On 30-12-2016 11:32, Jose Abreu wrote: > > Hi All, > > > > > > I am going to work with dw-dmac AHB controller and I wanted to > > use SND_DMAENGINE_PCM. In order to use this, a standard DMA > > driver with cyclic support is needed. I found out that dw-dmac is > > capable of cyclic transfers but instead of using the DMA engine > > standard cyclic API it uses a custom API. Is there any specific > > reason for this? What is the effort to change the custom API to a > > standard DMA engine cyclic API? > > Because it was a predecessor of generic implementation. I used to have some semi-finished patch to switch to generic API, though at that point I had no means to test it. Since I eventually got iDMA 32-bit, which is used as LPE Audio DMA engine, support in my branch I might test it in the future, though I think someone else would be much faster than me. So, I can share whatever I have to the topic with someone who is really interested to do that task. -- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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| From | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| Date | 2017-01-02 11:20 +0100 |
| Message-ID | <sV7SF-5kc-13@gated-at.bofh.it> |
| In reply to | #1549024 |
On Mon, Jan 02, 2017 at 10:38:00AM +0200, Andy Shevchenko wrote: > On Fri, 2016-12-30 at 12:05 +0000, Jose Abreu wrote: > > ++dw-dmac Maintainers > > > > > > On 30-12-2016 11:32, Jose Abreu wrote: > > > Hi All, > > > > > > > > > I am going to work with dw-dmac AHB controller and I wanted to > > > use SND_DMAENGINE_PCM. In order to use this, a standard DMA > > > driver with cyclic support is needed. I found out that dw-dmac is > > > capable of cyclic transfers but instead of using the DMA engine > > > standard cyclic API it uses a custom API. Is there any specific > > > reason for this? What is the effort to change the custom API to a > > > standard DMA engine cyclic API? > > > > > Because it was a predecessor of generic implementation. And we don't have an implementation that uses this. > I used to have some semi-finished patch to switch to generic API, though > at that point I had no means to test it. > > Since I eventually got iDMA 32-bit, which is used as LPE Audio DMA > engine, support in my branch I might test it in the future, though I > think someone else would be much faster than me. no we can't, since the DSP is involved and takes control, so unless we do lots of nasty hacks, it won't be testable. I don't see the ROI for such an effort. not sure about non intel ones, viresh? btw, feel free to test and send patches if you have such a h/w -- ~Vinod
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| From | Viresh Kumar <viresh.kumar@linaro.org> |
|---|---|
| Date | 2017-01-02 12:00 +0100 |
| Message-ID | <sV8vn-5CQ-21@gated-at.bofh.it> |
| In reply to | #1549096 |
On 02-01-17, 15:48, Vinod Koul wrote: > not sure about non intel ones, viresh? Not sure really :( -- viresh
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| From | Andy Shevchenko <andriy.shevchenko@linux.intel.com> |
|---|---|
| Date | 2017-01-02 12:40 +0100 |
| Message-ID | <sV985-6ct-9@gated-at.bofh.it> |
| In reply to | #1549096 |
On Mon, 2017-01-02 at 15:48 +0530, Vinod Koul wrote: > On Mon, Jan 02, 2017 at 10:38:00AM +0200, Andy Shevchenko wrote: > > On Fri, 2016-12-30 at 12:05 +0000, Jose Abreu wrote: > > > ++dw-dmac Maintainers > > I used to have some semi-finished patch to switch to generic API, > > though > > at that point I had no means to test it. > > > > Since I eventually got iDMA 32-bit, which is used as LPE Audio DMA > > engine, support in my branch I might test it in the future, though I > > think someone else would be much faster than me. > > no we can't, since the DSP is involved and takes control, so unless we > do > lots of nasty hacks, it won't be testable. I don't see the ROI for > such an > effort. Thanks for clarification > btw, feel free to test and send patches if you have such a h/w Actually we have AVR32 connected to our lab. So, I can test it there, but I rather need a patch to use some dummy stub instead of codec (it has no codec connected). -- Andy Shevchenko <andriy.shevchenko@linux.intel.com> Intel Finland Oy
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| From | Jose Abreu <Jose.Abreu@synopsys.com> |
|---|---|
| Date | 2017-01-02 15:00 +0100 |
| Message-ID | <sVbjA-7wa-17@gated-at.bofh.it> |
| In reply to | #1549127 |
Hi, On 02-01-2017 11:30, Andy Shevchenko wrote: > On Mon, 2017-01-02 at 15:48 +0530, Vinod Koul wrote: >> On Mon, Jan 02, 2017 at 10:38:00AM +0200, Andy Shevchenko wrote: >>> On Fri, 2016-12-30 at 12:05 +0000, Jose Abreu wrote: >>>> ++dw-dmac Maintainers >>> I used to have some semi-finished patch to switch to generic API, >>> though >>> at that point I had no means to test it. >>> >>> Since I eventually got iDMA 32-bit, which is used as LPE Audio DMA >>> engine, support in my branch I might test it in the future, though I >>> think someone else would be much faster than me. >> no we can't, since the DSP is involved and takes control, so unless we >> do >> lots of nasty hacks, it won't be testable. I don't see the ROI for >> such an >> effort. > Thanks for clarification > >> btw, feel free to test and send patches if you have such a h/w > Actually we have AVR32 connected to our lab. So, I can test it there, > but I rather need a patch to use some dummy stub instead of codec (it > has no codec connected). > Thank you all for the info. I don't have the HW ready to test yet (I was collecting some info first), but when I do I can test on my side using Designware I2S and ALSA SoC DMA engine. Best regards, Jose Miguel Abreu
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