[U-Boot] [PATCH v4 2/4] USB: host: Add the USB3 host driver
Sherry Sun
sherry.sun at nxp.com
Mon Sep 9 13:48:12 UTC 2019
Hi Jean,
>
> Hi Sherry,
>
> On 03/09/2019 14:44, Sherry Sun wrote:
> > Hi Jean,
> >
> >>
> >> On 02/09/2019 13:29, Sherry Sun wrote:
> >>> Hi Vignesh,
> >>>
> >>>> Hi Sherry,
> >>>>
> >>>> [...]
> >>>>>> AFAIK, U-Boot does not support runtime switching of USB port to
> >>>>>> host from device and vice versa. This is the case for existing
> >>>>>> driver like
> >>>> DWC3/MUSB etc.
> >>>>>> Ideally we would need a role switch driver that unbinds and
> >>>>>> rebinds host vs device driver as when required based on U-Boot
> >>>>>> cmd or via an API (if required to be done during SPL stage etc).
> >>>>> I wonder if we can add two subnodes under the wrapper node as
> >>>>> below,
> >>>> one bind to usb gadget driver and another bind to usb host driver.
> >>>>> So if we want to use usb device, just call the gadget driver, and
> >>>>> if want to
> >>>> use usb host, just call the host driver. The driver will probe
> >>>> correspond
> >> node.
> >>>>> I'm not sure if it is feasible, what do you think about it?
> >>>>>
> >>>>> usbss0: cdns_usb at 4104000 {
> >>>>> compatible = "ti,j721e-usb";
> >>>>> [....]
> >>>>> usb0: usb at 6010000 { /* xhci reg address*/
> >>>>> compatible = "cdns,usb3-1.0.1";
> >>>>> dr_mode = "host";
> >>>>> [....]
> >>>>> }
> >>>>> usb1: usb at 6020000 { /* dev reg address*/
> >>>>> compatible = "cdns,usb3-1.0.1";
> >>>>> dr_mode = "peripheral";
> >>>>> [....]
> >>>>> }
> >>>>> }
> >>>>>
> >>>> But this is not how DT would look in kernel. There will be single
> >>>> DT node representing both Host and Device node. DT repesentation
> >>>> should not be changed based on OS/bootloader, its HW description
> >>>> and must
> >> remain same.
> >>>> Unbinding host/gadget driver and rebinding with a different role
> >>>> should not be hard as the U-Boot core infrastructure exists.
> >>>>
> >>>> Moreover if xhci reg and dev reg are separated into different nodes
> >>>> dont we still need access to OTG register block to switch b/w host
> >>>> and
> >> device mode?
> >>> I think we may not need to access OTG register if we add two
> >>> subnodes for
> >> gadget and host.
> >>> But I see a for loop in dwc3_glue_bind() as follows, if there only
> >>> one single
> >> node representing both Host and Device node under usb wrapper node,
> >> why we need this for loop?
> >>> 212 for (node = fdt_first_subnode(fdt, dev_of_offset(parent)); node >
> 0;
> >>> 213 node = fdt_next_subnode(fdt, node)) {
> >> I believe this is a legacy from the code it was inspired from.
> >>
> >> Indeed the loop is not required.
> >>
> >> Like Vignesh I think we must stick with the dt-bindings used by the kernel.
> > Thanks for your reply, I understand now.
> >
> >> BTW we are working on the USB3 support right now that is lacking in our
> tree.
> >> I choose to keep the PHY drivers as close as possible to their linux
> >> version. I'll probably start posting preliminary patches this week.
> >>
> >> If you have the USB3 working in the kernel, can you point to a tree
> >> where I can have a look at the drivers and dt-bindings ?
> > Sure, you can see our downstream kernel code at my github, here is the
> link address:
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub
> .com%2Fsherrysun1%2Flinux-
> imx.git&data=02%7C01%7Csherry.sun%40nxp.com%7C368ba21c33c048
> fd137208d735199870%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7
> C637036256383501199&sdata=y4AB0RpG%2F7Skk34yccpkW9TQsDWpi
> 6OJhtlRWid1DM0%3D&reserved=0.
> > And look forward to seeing your patches in uboot maillist.
>
> It will take some times before I can post on the mailing list because I did the
> work on top TI's u-boot. But you can find the patches under
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub
> .com%2Fjjhiblot%2Fu-
> boot%2Ftree%2Fusb3_cleanup_v2&data=02%7C01%7Csherry.sun%40n
> xp.com%7C368ba21c33c048fd137208d735199870%7C686ea1d3bc2b4c6fa92c
> d99c5c301635%7C0%7C0%7C637036256383511193&sdata=ozU9gYDTO
> %2FkoB4NwU1R2omGw9%2F%2Fyf6MPxBz1%2FtQ8Lgg%3D&reserved=
> 0.
> <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithu
> b.com%2Fjjhiblot%2Fu-
> boot%2Ftree%2Fusb3_cleanup_v2&data=02%7C01%7Csherry.sun%40n
> xp.com%7C368ba21c33c048fd137208d735199870%7C686ea1d3bc2b4c6fa92c
> d99c5c301635%7C0%7C0%7C637036256383511193&sdata=ozU9gYDTO
> %2FkoB4NwU1R2omGw9%2F%2Fyf6MPxBz1%2FtQ8Lgg%3D&reserved=
> 0>
>
> The DTS bindings are the same as under Linux. The CDNS3 driver is a port of
> the iteration v11 of the linux driver that has just been merged in the linux usb
> tree
> (https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.ke
> rnel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fbalbi%2Fusb.git%2Flog
> %2F%3Fh%3Dnext&data=02%7C01%7Csherry.sun%40nxp.com%7C368b
> a21c33c048fd137208d735199870%7C686ea1d3bc2b4c6fa92cd99c5c301635%
> 7C0%7C0%7C637036256383511193&sdata=OxjRaHtDmkJBJ41qwfOtf2Zj
> WACskvcAuUUPDRuYDcA%3D&reserved=0)
>
> Care has been taken to keep the changes with linux minimal to ease the
> maintenance: the drivers are quite new and will probably evolve quite a bit in
> the next few months.
Thanks for your information, I will try to test your cdns3 patches on i.MX8 platform recently.
Best regards
Sherry Sun
>
> JJ
>
> >
> > Best regards
> > Sherry sun
> >
> >> JJ
> >>
> >>> Best regards
> >>> Sherry sun
> >>>
> >>>> Regards
> >>>> Vignesh
> >>>>
> >>>>> Best regards
> >>>>> Sherry sun
> >>>>>
> >>>>>> Regards
> >>>>>> Vignesh
> >>>>>>
> >>>>>>> Best regards
> >>>>>>> Sherry sun
> >>>>>>>
> >>>>>>>> JJ
> >>>>>>>>
> >>>>>>>>>> Then when binding the wrapper node, it will hard-coded the
> >>>>>>>>>> two
> >>>>>>>> subnodes
> >>>>>>>>>> to different driver(gadge/host driver) according to the
> >>>>>>>>>> dr_mode property
> >>>>>>>> in
> >>>>>>>>>> nodes.
> >>>>>>>>>>
> >>>>>>>>> Do you think I understand it right?
> >>>>>>>>> Best regards
> >>>>>>>>> Sherry sun
> >>>>>>>>>
> >>>>>>>>>> Best regards
> >>>>>>>>>> Sherry sun
> >>>>>>>>>>
> >>>>>>>>>>> JJ
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>>>>>>>> + { }
> >>>>>>>>>>>>>>>>> +};
> >>>>>>>>>> _______________________________________________
> >>>>>>>>>> U-Boot mailing list
> >>>>>>>>>> U-Boot at lists.denx.de
> >>>>>>>>>> https://l
> >>>>>>>>>>
> >>
> ists.d&data=02%7C01%7Csherry.sun%40nxp.com%7C7d1d76a7124f4c3f
> >>>>>> e9
> >>
> 9d08d72d3ddf82%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C63
> >>>>>> 70276
> >>
> 16080089878&sdata=70BPVQkomokcNpxsHRD3njfZQvuG51VSD1QKBjQ
> >>>>>> o1kA%3
> >>>>>>>>>> D&reserved=0
> >>>>>>>>>> enx.de%2Flistinfo%2Fu-
> >>>>>>>>>>
> >>
> boot&data=02%7C01%7Csherry.sun%40nxp.com%7C35f1d34da1ea4b7
> >>
> 670ba08d72b823e9a%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7
> >>
> C637025710721487079&sdata=Nfk0qWtSViz60wJHAOr2m5tgIwTWjNwI
> >>>>>>>>>> GrNOxDH6HC0%3D&reserved=0
> >>>>>> --
> >>>>>> Regards
> >>>>>> Vignesh
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