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

[Mattijs Korpershoek]

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.

Huh. Ok. I will do some more debugging on my end. Thank you for your
patience.

>
>>
>> > 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