Messages in this thread | | | From | Philippe Schenker <> | Subject | Re: [RFC PATCH 0/2] Reset PHY in fec_resume if it got powered down | Date | Fri, 10 Dec 2021 13:51:00 +0000 |
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On Tue, 2021-12-07 at 01:58 +0000, Joakim Zhang wrote: > > Hi Philippe, > > > -----Original Message----- > > From: Philippe Schenker <philippe.schenker@toradex.com> > > Sent: 2021年12月6日 18:13 > > To: netdev@vger.kernel.org; Joakim Zhang <qiangqing.zhang@nxp.com>; > > Fabio Estevam <festevam@gmail.com>; Fugang Duan > > <fugang.duan@nxp.com>; David S . Miller <davem@davemloft.net>; > > Russell > > King <linux@armlinux.org.uk>; Andrew Lunn <andrew@lunn.ch>; Jakub > > Kicinski <kuba@kernel.org> > > Cc: Philippe Schenker <philippe.schenker@toradex.com>; > > linux-kernel@vger.kernel.org > > Subject: [RFC PATCH 0/2] Reset PHY in fec_resume if it got powered > > down > > > > > > If a hardware-design is able to control power to the Ethernet PHY > > and relying > > on software to do a reset, the PHY does no longer work after > > resuming from > > suspend, given the PHY does need a hardware-reset. > > The Freescale fec driver does currently control the reset-signal of > > a phy but > > does not issue a reset on resume. > > > > On Toradex Apalis iMX8 board we do have such a design where we also > > don't > > place the RC circuit to delay the reset-line by hardware. Hence we > > fully rely > > on software to do so. > > Since I didn't manage to get the needed parts of Apalis iMX8 working > > with > > mainline this patchset was only tested on the downstream kernel > > toradex_5.4-2.3.x-imx. [1] This kernel is based on NXP's release > > imx_5.4.70_2.3.0. [2] The affected code is still the same on > > mainline kernel, > > which would actually make me comfortable merging this patch, but due > > to > > this fact I'm sending this as RFC maybe someone else is able to test > > this code. > > > > This patchset aims to change the behavior by resetting the ethernet > > PHY in > > fec_resume. A short description of the patches can be found below, > > please > > find a detailed description in the commit-messages of the respective > > patches. > > > > [PATCH 2/2] net: fec: reset phy in resume if it was powered down > > > > This patch calls fec_reset_phy just after regulator enable in > > fec_resume, > > when the phy is resumed > > > > [PATCH 1/2] net: fec: make fec_reset_phy not only usable once > > > > This patch prepares the function fec_reset_phy to be called multiple > > times. It > > stores the data around the reset-gpio in fec_enet_private. > > This patch aims to do no functional changes. > > > > [1] > > https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fgit.tor > > adex.com%2Fcgit%2Flinux-toradex.git%2Flog%2F%3Fh%3Dtoradex_5.4-2.3.x > > -imx&data=04%7C01%7Cqiangqing.zhang%40nxp.com%7Cf3c138ed9232 > > 4a8d75e708d9b8a11b9a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0% > > 7C637743824364193423%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAw > > MDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sda > > ta=Bw%2BZdqhAjPXqKJFZCXp0mtId1x9mkX6f6MW2ky6U1ww%3D&res > > erved=0 > > [2] > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fsourc > > e.codeaurora.org%2Fexternal%2Fimx%2Flinux-imx%2Flog%2F%3Fh%3Dimx_ > > 5.4.70_2.3.0&data=04%7C01%7Cqiangqing.zhang%40nxp.com%7Cf3c13 > > 8ed92324a8d75e708d9b8a11b9a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C > > 0%7C0%7C637743824364193423%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiM > > C4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000 > > &sdata=of9z9hfVhHakVScLxCdEo%2BXmd2B9Ad9X8Rry6GjEZE4%3D&a > > mp;reserved=0 > > > > In fec driver, it has supported hardware reset for PHY when MAC resume > back, > > fec_resume() -> phy_init_hw() -> phy_device_reset() de-assert the > reset signal, you only need implement > the properties which PHY core provided. > > I think you should not use deprecated reset properties provided by fec > driver, instead the common > reset properties provided by PHY core. > > Please check the dt-bindings for more details: > Documentation/devicetree/bindings/net/fsl,fec.yaml > Documentation/devicetree/bindings/net/ethernet-phy.yaml > > Best Regards, > Joakim Zhang
Hi Joakim and many thanks for that hint! I tried that out but unfortunately it still does not work due to phy_init_hw() only deasserting the reset. For that to work, for example a call of phy_device_reset(ndev->phydev, 1); in fec_suspend or in fec_resume before enabling the supply would work, in order to assert that reset.
I see now two ways to go to fix our issue:
1. Assert the phy-reset gpio in fec_suspend() or fec_resume()
2. Add support for regulators in drivers/net/phy/phy-core.c and handle the phy-reset properly in there with assert-us and deassert-us delays.
As you probably have a much better overview: Do you see another possibility to handle phy-reset after resuming? Or which way shall I choose to go forward?
Thanks in advance for any advice Philippe
> > Philippe Schenker (2): > > net: fec: make fec_reset_phy not only usable once > > net: fec: reset phy in resume if it was powered down > > > > drivers/net/ethernet/freescale/fec.h | 6 ++ > > drivers/net/ethernet/freescale/fec_main.c | 98 ++++++++++++++++---- > > --- > > 2 files changed, 73 insertions(+), 31 deletions(-) > > > > -- > > 2.34.0 >
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