Hi Roger, On Monday 16 May 2016 04:01 PM, Roger Quadros wrote: > On 16/05/16 13:03, Kishon Vijay Abraham I wrote: >> Hi Roger, >> >> On Monday 16 May 2016 03:19 PM, Roger Quadros wrote: >>> On 16/05/16 12:26, Roger Quadros wrote: >>>> On 16/05/16 12:06, Roger Quadros wrote: >>>>> On 13/05/16 15:45, Marek Vasut wrote: >>>>>> On 05/13/2016 02:36 PM, Roger Quadros wrote: >>>>>>> Currently CONFIG_USB_DWC3 is not selected so doing a usb start >>>>>>> command results in a serious error [1]. >>>>>> >>>>>> Why does this error happen ? That is what should be fixed. Selecting >>>>>> some random options seems like papering over a bug. >>>>> >>>>> Agreed. I was lazy :P. >>>> >>>> OK. The issue is like this. >>>> >>>> CONFIG_CMD_USB and CONFIG_USB_XHCI is defined, so usb_init() calls >>>> usb_lowlevel_init() in xhci.c which calls xhci_hcd_init in xhci-omap.c >>>> which calls >>>> board_usb_init(). >> >> IIRC, board_usb_init for xhci (omap) is mostly a NOP. > > Then who will call board_usb_init() for host case? > >>>> >>>> But board_usb_init() in am57xx/board.c is defined only if CONFIG_USB_DWC3 >>>> is defined >>>> and that is missing in am57xx_evm.h leading to the serious error. We're >>>> trying to >>>> access the IP without turning on the necessary clocks. >> >> clocks are not turned on in board_usb_init() right? The board_usb_init() in >> am57xx/board.c is used only for gadget mode. >>>> >>>> So it looks like we need to define it based on CONFIG_USB_XHCI_OMAP or >>>> something else. >> >> right, but before that we might have to cleanup xhci-omap. >>>> >>>> But then again looking into the future, what if we want only gadget >>>> operation? >>>> That would not define XHCI, but we still need board_usb_init(). So >>>> board_usb_init() >>>> should be defined based on CONFIG_CMD_USB=y? >>>> >>>> What do you suggest? >>> >>> But board_usb_init() calls >>> >>> ti_usb_phy_uboot_init(&usb_phy1_device); >>> dwc3_omap_uboot_init(&usb_otg_ss1_glue); >>> dwc3_uboot_init(&usb_otg_ss1); >>> >>> which depend on CONFIG_USB_DWC3_PHY_OMAP, CONFIG_USB_DWC3_OMAP and >>> CONFIG_USB_DWC3 >>> respectively. >> >> IMO we should cleanup xhci-omap so that all the initializations are done >> using >> ti_usb_phy_uboot_init, dwc3_omap_uboot_init and dwc3_uboot_init. Then modify >> dwc3_uboot_init to initialize host or device based on CONFIG_*. >> > > I'm still trying to get a grip of how USB works in u-boot. > Is CONFIG_CMD_USB only meant for host mode or gadget mode as well?
IIRC it is only for host. Commands like usb start, usb stop are used to start and stop host. > Is dual-role even required in u-boot? probably it is not a good idea and we > just > ignore it for simplicity. yeah. > > What determines whether a USB port is meant for Host or device operation? Is > it > the CONFIG_ or caller of board_usb_init()? It should be the caller of board_usb_init(). The same port can be used as device or host based on command used (the command determines the caller of board_usb_init). Thanks Kishon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
