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. Mit freundlichen Grüßen / Kind regards Michael Heimpold -- Software Engineer I2SE GmbH Tel: +49 (0) 341 355667-00 Friedrich-Ebert-Str. 61 Fax: +49 (0) 341 355667-02 04109 Leipzig Germany Web: http://www.i2se.com/ Mail: i...@i2se.com VAT No.: DE 811528334 Amtsgericht Leipzig HRB 23784 Geschäftsführer/CEO: Carsten Ziermann *** Diese E-Mail ist allein für den bezeichneten Adressaten bestimmt. Sie kann rechtlich vertrauliche Informationen enthalten. Wenn Sie diese E-Mail irrtümlich erhalten haben, informieren Sie bitte unverzüglich den Absender per E-Mail und löschen Sie diese E-Mail von Ihrem Computer, ohne Kopien anzufertigen. Vielen Dank. *** *** This email is for the exclusive use of the addressee. It may contain legally privileged information. If you have received this message in error, please notify the sender by email immediately and delete the message from your computer without making any copies. Thank you. *** -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
