Currently using kernel 3.7.1 with mpc8315e, I am observing instability during the usb initialisation. The usb controller is set as a host controller with internal PHY defined in UTMI mode. This issue appears sometimes after a warm reset. The kernel hangs and the log buffer contents shows that a machine check exception is detected when execution is located into ehci_fsl_setup_phy function. The latest messages available from the console are: ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver uhci_hcd: USB Universal Host Controller Interface driver /immr@e0000000/usb@23000: Invalid 'dr_mode' property, fallback to host mode fsl-ehci fsl-ehci.0: Freescale On-Chip EHCI Host Controller fsl-ehci fsl-ehci.0: new USB bus registered, assigned bus number 1
By adding multiple printk into the ehci-fsl, I found that the issue happens when executing the write to the portsc register nearly at the end of the function (ehci_writel(ehci, portsc, &ehci->regs->port_status[port_offset]);) This issue appears either with or without external usb devices connected. I didn't find any restrictions to access this register and/or explanation from freescale doc and usb2 & ehci specification. This issue has been also seen with older kernel release like 2.6.39. Applying a warn reset, then the processor boot correctly and the usb interface is now fully functional and really stable with intensive activities. The processor is based on the latest 1.2 mask revision. Hope that someone has some suggestions about this strange behaviour. Thanks for your help, Regards Guy Yribarren ACTIS Computer - 42 Route de Satigny - CH-1217 Meyrin - Switzerland Tel +41 (22) 706 1830 - Fax +41 (22) 794 4391 guy.yribarren <at> actis-computer.com _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
