| Message ID | 20151127120919.66f2bfda@ipc1.ka-ro |
|---|---|
| State | RFC, archived |
| Delegated to: | David Miller |
| Headers | show |
Hi Lothar, Am 27.11.2015 um 12:09 schrieb Lothar Waßmann: > Hi, > >> we at I2SE have developed an i.MX28 based embedded device, called Duckbill. >> Regarding ethernet, it is very similar to the FSL mx28evk, i.e. we use the same >> phy (SMSC LAN8720), we use RMII mode, clock is provided by iMX (not via >> external crystal), we have a GPIO to reset the phy and an interrupt GPIO. >> >> At the moment, we are using vanilla kernel 4.2.5 with only a fetch patches - mainly >> patches to add the device tree stuff needed and some cherry-picked upstream >> patches. Nothing special IMO. You can find it here: >> https://github.com/I2SE/linux/tree/v4.2.5-duckbill >> >> After booting the device, we observe on a few devices the ethernet "swinging" >> or toggling: >> [ 15.830759] fec 800f0000.ethernet eth0: Freescale FEC PHY driver [SMSC LAN8710/LAN8720] (mii_bus:phy_addr=800f0000.etherne:00, irq=35) >> [ 15.843361] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready >> [ 17.112867] fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx >> [ 17.121746] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready >> [ 17.894416] fec 800f0000.ethernet eth0: Link is Down >> [ 19.506960] fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx >> [ 20.294398] fec 800f0000.ethernet eth0: Link is Down >> [ 21.932365] fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx >> [ 22.714410] fec 800f0000.ethernet eth0: Link is Down >> [ 24.357890] fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx >> [ 25.144400] fec 800f0000.ethernet eth0: Link is Down >> [ 26.783367] fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx >> [ 27.564357] fec 800f0000.ethernet eth0: Link is Down >> [ 29.208846] fec 800f0000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx >> >> However, in U-Boot I can transfer several hundreds of MB without any problem, >> I can attach the cable/reattach etc. as usual - no obvious problems. >> This is the reason, we think that the hardware is ok (and of course, we double-checked >> especially the soldering of the affected devices). >> >> This is what I tried so far: >> - changed the device tree to not use the interrupt line -> phy is polled periodically >> - reverted latest phy changes for LAN8720, i.e. >> d88ecb373bd1877acc43e13311a8e0e6daffc3d2 - "net: phy: smsc: disable energy detect mode" >> ff94c742dfeea3110f1e1d27399d728f8494d29e - "net: phy: fix semicolon.cocci warnings" >> 776829de90c5972895db398993ddfa9417ff8b01 - "net: phy: workaround for buggy cable detection by LAN8700 after cable plugging" >> - then I tried the following patch >> >> -snip- >> --- a/drivers/net/ethernet/freescale/fec_main.c >> +++ b/drivers/net/ethernet/freescale/fec_main.c >> @@ -936,7 +936,7 @@ fec_restart(struct net_device *ndev) >> if (fep->quirks & FEC_QUIRK_HAS_AVB) { >> writel(0, fep->hwp + FEC_ECNTRL); >> } else { >> - writel(1, fep->hwp + FEC_ECNTRL); >> + //writel(1, fep->hwp + FEC_ECNTRL); >> udelay(10); >> } >> -snap- >> The idea behind this patch is: when FEC is resetted, then registers are reset to initial values >> and thus FEC is configured for MII. When using ENET_CLK_OUT this results in 25 MHz clock >> to phy instead of 50 MHz as required by RMII. At least for a short time, there might be >> a "glitch". The concern was, that the phy might become stuck by this. >> >> However, nothing of the above improved anything. So, at the moment, I'm >> running out of ideas - any help/hint to debug this issue further is really appreciated. >> Please let me know if I missed some important information. >> > I faced the same problem on one of our i.MX6 modules recently but > haven't come around to send a proper patch yet. > > The problem is that the enet_out clock is disabled in > fec_enet_clk_enable() which leaves the PHY without a running clock. > Due to this the PHY loses its internal state and requires a reset to be > reactivated. > > The following patch should fix this problem: > diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c > index b2a3220..cfa70b5 100644 > --- a/drivers/net/ethernet/freescale/fec_main.c > +++ b/drivers/net/ethernet/freescale/fec_main.c > @@ -1857,11 +1857,6 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) > ret = clk_prepare_enable(fep->clk_ahb); > if (ret) > return ret; > - if (fep->clk_enet_out) { > - ret = clk_prepare_enable(fep->clk_enet_out); > - if (ret) > - goto failed_clk_enet_out; > - } > if (fep->clk_ptp) { > mutex_lock(&fep->ptp_clk_mutex); > ret = clk_prepare_enable(fep->clk_ptp); > @@ -1873,35 +1868,26 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) > } > mutex_unlock(&fep->ptp_clk_mutex); > } > - if (fep->clk_ref) { > - ret = clk_prepare_enable(fep->clk_ref); > - if (ret) > - goto failed_clk_ref; > - } > + ret = clk_prepare_enable(fep->clk_ref); > + if (ret) > + goto failed_clk_ref; > } else { > clk_disable_unprepare(fep->clk_ahb); > - if (fep->clk_enet_out) > - clk_disable_unprepare(fep->clk_enet_out); > if (fep->clk_ptp) { > mutex_lock(&fep->ptp_clk_mutex); > clk_disable_unprepare(fep->clk_ptp); > fep->ptp_clk_on = false; > mutex_unlock(&fep->ptp_clk_mutex); > } > - if (fep->clk_ref) > - clk_disable_unprepare(fep->clk_ref); > + clk_disable_unprepare(fep->clk_ref); > } > > return 0; > > failed_clk_ref: > - if (fep->clk_ref) > - clk_disable_unprepare(fep->clk_ref); > + clk_disable_unprepare(fep->clk_ref); > failed_clk_ptp: > - if (fep->clk_enet_out) > - clk_disable_unprepare(fep->clk_enet_out); > -failed_clk_enet_out: > - clk_disable_unprepare(fep->clk_ahb); > + clk_disable_unprepare(fep->clk_ahb); > > return ret; > } > @@ -3430,6 +3416,10 @@ fec_probe(struct platform_device *pdev) > if (ret) > goto failed_clk; > > + ret = clk_prepare_enable(fep->clk_enet_out); > + if (ret) > + goto failed_clk_enet_out; > + > ret = clk_prepare_enable(fep->clk_ipg); > if (ret) > goto failed_clk_ipg; > @@ -3514,6 +3504,8 @@ failed_init: > if (fep->reg_phy) > regulator_disable(fep->reg_phy); > failed_regulator: > + clk_disable_unprepare(fep->clk_enet_out); > +failed_clk_enet_out: > clk_disable_unprepare(fep->clk_ipg); > failed_clk_ipg: > fec_enet_clk_enable(ndev, false); > @@ -3536,6 +3528,8 @@ fec_drv_remove(struct platform_device *pdev) > fec_ptp_stop(pdev); > unregister_netdev(ndev); > fec_enet_mii_remove(fep); > + fec_enet_clk_enable(ndev, false); > + clk_disable_unprepare(fep->clk_enet_out); > if (fep->reg_phy) > regulator_disable(fep->reg_phy); > of_node_put(fep->phy_node); > > > > Lothar Waßmann thank you very much - your patch fixes our problem. Mit freundlichen Grüßen / Kind regards Michael Heimpold
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index b2a3220..cfa70b5 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1857,11 +1857,6 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) ret = clk_prepare_enable(fep->clk_ahb); if (ret) return ret; - if (fep->clk_enet_out) { - ret = clk_prepare_enable(fep->clk_enet_out); - if (ret) - goto failed_clk_enet_out; - } if (fep->clk_ptp) { mutex_lock(&fep->ptp_clk_mutex); ret = clk_prepare_enable(fep->clk_ptp); @@ -1873,35 +1868,26 @@ static int fec_enet_clk_enable(struct net_device *ndev, bool enable) } mutex_unlock(&fep->ptp_clk_mutex); } - if (fep->clk_ref) { - ret = clk_prepare_enable(fep->clk_ref); - if (ret) - goto failed_clk_ref; - } + ret = clk_prepare_enable(fep->clk_ref); + if (ret) + goto failed_clk_ref; } else { clk_disable_unprepare(fep->clk_ahb); - if (fep->clk_enet_out) - clk_disable_unprepare(fep->clk_enet_out); if (fep->clk_ptp) { mutex_lock(&fep->ptp_clk_mutex); clk_disable_unprepare(fep->clk_ptp); fep->ptp_clk_on = false; mutex_unlock(&fep->ptp_clk_mutex); } - if (fep->clk_ref) - clk_disable_unprepare(fep->clk_ref); + clk_disable_unprepare(fep->clk_ref); } return 0; failed_clk_ref: - if (fep->clk_ref) - clk_disable_unprepare(fep->clk_ref); + clk_disable_unprepare(fep->clk_ref); failed_clk_ptp: - if (fep->clk_enet_out) - clk_disable_unprepare(fep->clk_enet_out); -failed_clk_enet_out: - clk_disable_unprepare(fep->clk_ahb); + clk_disable_unprepare(fep->clk_ahb); return ret; } @@ -3430,6 +3416,10 @@ fec_probe(struct platform_device *pdev) if (ret) goto failed_clk; + ret = clk_prepare_enable(fep->clk_enet_out); + if (ret) + goto failed_clk_enet_out; + ret = clk_prepare_enable(fep->clk_ipg); if (ret) goto failed_clk_ipg; @@ -3514,6 +3504,8 @@ failed_init: if (fep->reg_phy) regulator_disable(fep->reg_phy); failed_regulator: + clk_disable_unprepare(fep->clk_enet_out); +failed_clk_enet_out: clk_disable_unprepare(fep->clk_ipg); failed_clk_ipg: fec_enet_clk_enable(ndev, false); @@ -3536,6 +3528,8 @@ fec_drv_remove(struct platform_device *pdev) fec_ptp_stop(pdev); unregister_netdev(ndev); fec_enet_mii_remove(fep); + fec_enet_clk_enable(ndev, false); + clk_disable_unprepare(fep->clk_enet_out); if (fep->reg_phy) regulator_disable(fep->reg_phy); of_node_put(fep->phy_node);