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

Mattijs Korpershoek mkorpershoek at baylibre.com
Tue Jan 10 09:29:07 CET 2023


Hi Dario,

On Sat, Jan 07, 2023 at 17:45, Dario Binacchi <dario.binacchi at amarulasolutions.com> wrote:

> 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?

Yes it's ok 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


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