Hello Michael, On 22.03.22 09:19, Michael Grzeschik wrote: > On Tue, Mar 22, 2022 at 06:35:22AM +0100, Ahmad Fatoum wrote: >> On 21.03.22 23:17, Michael Grzeschik wrote: >>> On Wed, Jan 06, 2021 at 11:05:43AM +0100, Sascha Hauer wrote: >>>> On Mon, Dec 21, 2020 at 01:32:50AM +0100, Ahmad Fatoum wrote: >>>>> Linux doesn't seem to enforce a fixed order between phy_init and >>>>> phy_power_on. The Linux dwc2 driver does power_on and then phy_init, >>>>> which is the inverse of what barebox is currently doing. >>>>> >>>>> The PHYs normally used with dwc2 are written with this in mind. >>>>> For example, our stm32-usbphyc driver fails to disable: >>>>> >>>>> ERROR: stm32-usbphyc 5a006000.usbphyc@xxxxxxxxxxx: PLL not reset >>>>> ERROR: phy1: phy exit failed --> -5 >>>>> >>>>> Because Linux does exit -> power_off, but barebox does power_off -> >>>>> exit. >>>>> >>>>> Issue was raised upstream: >>>>> https://lore.kernel.org/lkml/6cd01e79-fdc0-3bd4-32b5-a85142533f8a@xxxxxxxxxxxxxx/T/#t >>>>> >>>>> Until this is settled, swap the order to follow what Linux does. >>>>> This is suboptimal, because it means controller drivers have different >>>>> order of the operations and that you can't combine arbitrary PHYs and >>>>> controllers, but it seems unlikely we will support combinations that >>>>> aren't supported by Linux in the first place anyway. >>>> >>>> This is valuable information and I don't want it to be lost, so instead >>>> of applying this as a fixup I rewrote the subject to: >>>> >>>> usb: dwc2: swap order of phy_init and phy_power_on to what Linux does >>>> >>>> and applied it as a separate patch. >>> >>> With this patch applied, some stm32mp1 do seem to timeout when >>> addressing the core. >>> >>> WARNING: dwc2 49000000.usb-otg@xxxxxxxxxxx: dwc2_core_reset: Timeout! Waiting for Core Soft Reset >>> ERROR: dwc2 49000000.usb-otg@xxxxxxxxxxx: probe failed: Connection timed out >>> >>> When I revert this patch. Everything works fine again. >>> >>> Is it possible that we can revert it in mainline now? >> >> Since 0e37f94fbe1b ("phy: stm32: sync with upstream"), the phy-stm32-usbphyc now >> has no poweron/poweroff callbacks, so a revert seems to only slightly change >> timing. I'd suggest you dig some more. > > That is not true. phy_power_on also enables the phy_regulator. Changing > this order has the effect that the regulator is enabled after or before > phy_init call. Oh, good point. >>> How can I reproduce the case this was fixing in the first place? >> >> The case was that barebox calls poweron/init in a different order than Linux. >> This point is moot now though because poweron is no longer provided by the >> driver. > > Still not true, though. Isn't this the same order Linux uses? Powering on regulator and then phy_init? Why does it lead to issues in barebox, but not in Linux? Cheers, Ahmad > > Regards, > Michael > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
