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

[Dario Binacchi]

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.

>
> > 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