Then that's a u-boot bug, usb should be on after USB start. On Jul 1, 2017 10:03 AM, "Sergey Manucharian" <[email protected]> wrote:
> Thanks, Robert! > > However, those "loads" just copy kernel/dtb into RAM for subsequent use, > they are not going to change the CPU configuration at u-boot level. They > cannot turn on the USB power until the control is passed to the kernel. > That way works: I load kernel and dtbs from eMMC, but tell them > "root=/dev/sda1 rootwait" (i.e. USB drive), so the kernel enables the USB > power, then mount the USB stick. With this approach you cannot load a > kernel *from* USB drive. > > On Saturday, July 1, 2017 at 8:50:01 AM UTC-6, RobertCNelson wrote: >> >> On Fri, Jun 30, 2017 at 11:04 PM, Sergey Manucharian <[email protected]> >> wrote: >> > Oh, thanks, William, I was inspired doing this by your post! >> > >> > The problem is that "usb start" starts u-boot's USB subsystem, it >> (probably) >> > has nothing to do with the CPU. >> > You explicitly mentioned that used a USB HDD with external power >> supply, but >> > I'm trying to boot off a USB flash drive. The CPU doesn't provide USB >> power >> > at early stage. If I provide power from an external source, everything >> works >> > fine. >> > >> > The latest u-boot supports loading overlays, I'm not sure whether it's >> > possible to load an overlays with the correct configuration of that pin >> and >> > then load kernel and stuff from USB flash drive. >> >> Why not? >> >> zImage: >> >> "loadimage=load ${devtype} ${bootpart} ${loadaddr} >> ${bootdir}/${bootfile}\0" \ >> >> https://github.com/eewiki/u-boot-patches/blob/master/v2017. >> 07-rc2/0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch#L507 >> >> overlay: >> >> "load ${devtype} ${bootpart} ${rdaddr} ${uboot_overlay}; " \ >> >> https://github.com/eewiki/u-boot-patches/blob/master/v2017. >> 07-rc2/0002-U-Boot-BeagleBone-Cape-Manager.patch#L800 >> >> both use the devtype & bootpart references.. Thus if the kernel/dtb >> are on the same partition of the usb flash drive as the overlays, >> everything just works.. >> >> But, you'll need to add the usb options here: >> >> https://github.com/eewiki/u-boot-patches/blob/master/v2017. >> 07-rc2/0001-am335x_evm-uEnv.txt-bootz-n-fixes.patch#L277 >> >> Regards, >> >> -- >> Robert Nelson >> https://rcn-ee.com/ >> > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/beagleboard/8fe903c1-9d73-42b5-888a-9b49653aaa56%40googlegroups.com > <https://groups.google.com/d/msgid/beagleboard/8fe903c1-9d73-42b5-888a-9b49653aaa56%40googlegroups.com?utm_medium=email&utm_source=footer> > . > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAOCHtYi%3DNOU%2BOEQ_0KOoj_pVAHJWcjCggJipm_amzsZTbpJ49A%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
