[PATCH v2] usb: gadget: fastboot: detach usb just before rebooting

Dario Binacchi dario.binacchi at amarulasolutions.com
Sat Jan 7 17:45:22 CET 2023


Hi Mattijs,

On Fri, Jan 6, 2023 at 5:42 PM Mattijs Korpershoek
<mkorpershoek at baylibre.com> wrote:
>
> On Thu, Jan 05, 2023 at 14:25, Dario Binacchi <dario.binacchi at amarulasolutions.com> wrote:
>
> > Hi Mattijs,
> >
> > On Thu, Jan 5, 2023 at 12:03 PM Mattijs Korpershoek
> > <mkorpershoek at baylibre.com> wrote:
> >>
> >> On Thu, Jan 05, 2023 at 10:10, Dario Binacchi <dario.binacchi at amarulasolutions.com> wrote:
> >>
> >> > Hi Mattijs,
> >> >
> >> > On Thu, Jan 5, 2023 at 10:06 AM Mattijs Korpershoek
> >> > <mkorpershoek at baylibre.com> wrote:
> >> >>
> >> >> On Wed, Jan 04, 2023 at 17:46, Dario Binacchi <dario.binacchi at amarulasolutions.com> wrote:
> >> >>
> >> >> > The patch fixes the following error when updating a BSH SMM S2 board:
> >> >> > 3:72>Start Cmd:FB[-t 8000]: ucmd nand write ${loadaddr} nanddtb ${filesize}
> >> >> > 3:72>Okay (0.023s)
> >> >> > 3:72>Start Cmd:FB: reboot
> >> >> > 3:72>Fail Bulk(R):LIBUSB_ERROR_IO(0s)
> >> >> >
> >> >> > The "fastboot reboot" command detaches the USB when it still needs to be
> >> >> > used. So let's detach the USB just before the reset.
> >> >> >
> >> >> > CC: Mattijs Korpershoek <mkorpershoek at baylibre.com>
> >> >> > Fixes: 5f7e01e9d5d800 ("usb: gadget: fastboot: detach usb on reboot commands")
> >> >> > Suggested-by: Michael Trimarchi <michael at amarulasolutions.com>
> >> >> > Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
> >> >>
> >> >> Hi Dario,
> >> >>
> >> >> Thank you for your patch and for reporting the problem.
> >> >>
> >> >> Unfortunately, applying it seems to break the problem I tried to
> >> >> solve with 5f7e01e9d5d800 ("usb: gadget: fastboot: detach usb on reboot commands")
> >> >>
> >> >> Does reverting 5f7e01e9d5d800 also solves your issue?
> >> >
> >> > Yes
> >> >
> >> >>
> >> >> I'll spend some time on this.
> >> >
> >> > Ok, thanks. So we can test on our hardware.
> >>
> >> So historically, I wanted to make this a "arch specific fix, as
> >> discussed in
> >> https://lore.kernel.org/u-boot/20220728-reset-usb-controller-v2-0-ef7657ce78b1@baylibre.com/
> >>
> >> To me, the problem with calling g_dnl_trigger_detach() in the
> >> fastboot_func->in_req->complete() handler is that it's called too late.
> >>
> >> In fact, the main fastboot loop is as following:
> >>
> >>     while (1) {
> >>             if (g_dnl_detach())
> >>                     break;
> >>             if (ctrlc())
> >>                     break;
> >>             schedule();
> >>             usb_gadget_handle_interrupts(controller_index);
> >>      }
> >>       ret = CMD_RET_SUCCESS;
> >>
> >>   exit:
> >>       usb_gadget_release(controller_index);
> >>       g_dnl_unregister();
> >>       g_dnl_clear_detach();
> >>
> >>       return ret;
> >>
> >> usb_gadget_handle_interrupts, will at some point, call complete() which will call compl_do_reset().
> >> But in compl_do_reset(), we already reset the board
> >> (without going through the exit: section from cmd/fastboot.c)
> >>
> >> For the BSH SMM S2 board, since it's being updated with uuu,
> >> I assume that the host PC also triggers a call of acmd_complete() afterwards?
> >>
> >> Can you try the following diff as well, on top of your change? (for testing purposes)
> >>
> >> --- a/drivers/usb/gadget/f_fastboot.c
> >> +++ b/drivers/usb/gadget/f_fastboot.c
> >> @@ -492,7 +492,7 @@ static void do_bootm_on_complete(struct usb_ep *ep, struct usb_request *req)
> >>
> >>  static void compl_do_reset(struct usb_ep *ep, struct usb_request *req)
> >>  {
> >> -       do_exit_on_complete(ep, req);
> >> +       usb_gadget_release(0);
> >>         do_reset(NULL, 0, 0, NULL);
> >>  }
> >>
> >> I suspect this will also break your flashing.
> >
> > No, I am able to flash and reset the board.
> > This change works.
>
> With some additional testing on my end, I can see that the final message
> (sending OKAY to the host) done on fastboot_func->in_ep is not done on
> my end. I think I am lucky that my controller driver (dwc2_udc_otg)
> delivers the message to my host anyways and calls done() even when
> messages are aborted.
>
> I think I have something that might be better.
>
> Dario, could you do another test for me, please?
> 1. Revert 5f7e01e9d5d800 ("usb: gadget: fastboot: detach usb on reboot commands")
>
> 2. Apply the following diff:
>
> diff --git a/drivers/usb/gadget/f_fastboot.c b/drivers/usb/gadget/f_fastboot.c
> index d0e92c7a071f..f4311328a2da 100644
> --- a/drivers/usb/gadget/f_fastboot.c
> +++ b/drivers/usb/gadget/f_fastboot.c
> @@ -421,6 +421,7 @@ static int fastboot_tx_write_str(const char *buffer)
>
>  static void compl_do_reset(struct usb_ep *ep, struct usb_request *req)
>  {
> +       g_dnl_unregister();
>         do_reset(NULL, 0, 0, NULL);
>  }
>
I applied your diff and it runs.
I changed my patch with your suggestion.
I'll submit v3.
The patch can be applied without reverting 5f7e01e9d5d800.
Can you re-test and apply your tested-by tag?
I added the Co-developed-by tag too.
Do you think it is correct to proceed like this?

Thanks and regards,
Dario

> The call to g_dnl_unregister() will end up calling
> g_dnl_unbind() which calls usb_gadget_disconnect()
> where each controller can implement a soft disconnect (which I can do
> for dwc2_udc_otg)
>
> >
> >>
> >> > Regards Dario
> >> >
> >> >>
> >> >> >
> >> >> > ---
> >> >> >
> >> >> > Changes in v2:
> >> >> > - Add 'Suggested-by' tag.
> >> >> >
> >> >> >  drivers/usb/gadget/f_fastboot.c | 12 ++++++------
> >> >> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >> >> >
> >> >> > diff --git a/drivers/usb/gadget/f_fastboot.c b/drivers/usb/gadget/f_fastboot.c
> >> >> > index 07b1681c8a9a..0b3fae564d0a 100644
> >> >> > --- a/drivers/usb/gadget/f_fastboot.c
> >> >> > +++ b/drivers/usb/gadget/f_fastboot.c
> >> >> > @@ -419,11 +419,6 @@ static int fastboot_tx_write_str(const char *buffer)
> >> >> >       return fastboot_tx_write(buffer, strlen(buffer));
> >> >> >  }
> >> >> >
> >> >> > -static void compl_do_reset(struct usb_ep *ep, struct usb_request *req)
> >> >> > -{
> >> >> > -     do_reset(NULL, 0, 0, NULL);
> >> >> > -}
> >> >> > -
> >> >> >  static unsigned int rx_bytes_expected(struct usb_ep *ep)
> >> >> >  {
> >> >> >       int rx_remain = fastboot_data_remaining();
> >> >> > @@ -495,6 +490,12 @@ static void do_bootm_on_complete(struct usb_ep *ep, struct usb_request *req)
> >> >> >       do_exit_on_complete(ep, req);
> >> >> >  }
> >> >> >
> >> >> > +static void compl_do_reset(struct usb_ep *ep, struct usb_request *req)
> >> >> > +{
> >> >> > +     do_exit_on_complete(ep, req);
> >> >> > +     do_reset(NULL, 0, 0, NULL);
> >> >> > +}
> >> >> > +
> >> >> >  #if CONFIG_IS_ENABLED(FASTBOOT_UUU_SUPPORT)
> >> >> >  static void do_acmd_complete(struct usb_ep *ep, struct usb_request *req)
> >> >> >  {
> >> >> > @@ -544,7 +545,6 @@ static void rx_handler_command(struct usb_ep *ep, struct usb_request *req)
> >> >> >               case FASTBOOT_COMMAND_REBOOT_FASTBOOTD:
> >> >> >               case FASTBOOT_COMMAND_REBOOT_RECOVERY:
> >> >> >                       fastboot_func->in_req->complete = compl_do_reset;
> >> >> > -                     g_dnl_trigger_detach();
> >> >> >                       break;
> >> >> >  #if CONFIG_IS_ENABLED(FASTBOOT_UUU_SUPPORT)
> >> >> >               case FASTBOOT_COMMAND_ACMD:
> >> >> > --
> >> >> > 2.32.0
> >> >
> >> >
> >> >
> >> > --
> >> >
> >> > Dario Binacchi
> >> >
> >> > Senior Embedded Linux Developer
> >> >
> >> > dario.binacchi at amarulasolutions.com
> >> >
> >> > __________________________________
> >> >
> >> >
> >> > Amarula Solutions SRL
> >> >
> >> > Via Le Canevare 30, 31100 Treviso, Veneto, IT
> >> >
> >> > T. +39 042 243 5310
> >> > info at amarulasolutions.com
> >> >
> >> > www.amarulasolutions.com
> >
> >
> >
> > --
> >
> > Dario Binacchi
> >
> > Senior Embedded Linux Developer
> >
> > dario.binacchi at amarulasolutions.com
> >
> > __________________________________
> >
> >
> > Amarula Solutions SRL
> >
> > Via Le Canevare 30, 31100 Treviso, Veneto, IT
> >
> > T. +39 042 243 5310
> > info at amarulasolutions.com
> >
> > www.amarulasolutions.com



-- 

Dario Binacchi

Senior Embedded Linux Developer

dario.binacchi at amarulasolutions.com

__________________________________


Amarula Solutions SRL

Via Le Canevare 30, 31100 Treviso, Veneto, IT

T. +39 042 243 5310
info at amarulasolutions.com

www.amarulasolutions.com


More information about the U-Boot mailing list