+Arnd On 13 January 2017 at 08:26, Marek Szyprowski <m.szyprowski@xxxxxxxxxxx> wrote: > Hello, > > This patchset changes the way the runtime PM is implemented in the PL330 DMA > engine driver. The main goal of such change is to add support for the audio > power domain to Exynos5 SoCs (5250, 542x, 5433, probably others) and let > it to be properly turned off, when no audio is being used. Switching to > non-irq-safe runtime PM is required to properly let power domain to be > turned off (irq-safe runtime PM keeps power domain turned on all the time) > and to integrate with clock controller's runtime PM (this cannot be > workarounded any other way, PL330 uses clocks from the controller, which > belongs to the same power domain). > > For more details of the proposed change to the PL330 driver see patch #4. > > Audio power domain on Exynos5 SoCs contains following hardware modules: > 1. clock controller > 2. pin controller > 3. PL330 DMA controller > 4. I2S audio controller > > Patches for adding or fixing runtime PM for each of the above devices is > handled separately. > > Runtime PM patches for clock controllers is possible and has been proposed > in the following thread (pending review): "[PATCH v4 0/4] Add runtime PM > support for clocks (on Exynos SoC example)", > http://www.spinics.net/lists/arm-kernel/msg550747.html > > Runtime PM support for Exynos pin controller has been posted in the > following thread: "[PATCH 0/9] Runtime PM for Exynos pin controller driver", > http://www.spinics.net/lists/arm-kernel/msg550161.html > > Exynos I2S driver supports runtime PM, but some fixes were needed for it > and they are already queued to linux-next. > > This patchset is based on linux-next from 13th January 2017 with "dmaengine: > pl330: fix double lock" patch applied. > > Best regards > Marek Szyprowski > Samsung R&D Institute Poland Marek, this is great work! It's been on my TODO list forever, so I really appreciate your work here. I did only a brief review so far, particularly concentrating on the changes for device links and runtime PM. I like it! Perhaps we can get someone like Arnd/Vinod to comment in general idea from a DT and DMA slave channel point of view. I don't know that stuff good enough to give good opinion. A couple of things that crosses my mind so far: 1) I have planned to extend pm_runtime_force_suspend|resume() to cover also device links. Seems like that becomes really useful together with these changes. 2) I think there will be some corner cases during system suspend/resume for pl330. Not sure yet though. However, fixing 1) and converting the driver to use pm_runtime_force_suspend|resume() should probably work anyway. Allow me to help out looking into 1) and 2). If not for pl330, I am pretty sure it will be useful for other DMA controllers that implements device links and runtime PM. [...] Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
