[U-Boot] [PATCH 2/2] musb: sunxi: Implement dfu_usb_get_reset()

[Siarhei Siamashka]

On Sun, 25 Oct 2015 12:00:09 +0100
Marek Vasut <marex at denx.de> wrote:

> On Sunday, October 25, 2015 at 05:44:47 AM, Siarhei Siamashka wrote:
> > This is necessary to distinguish between the "dfu-util --detach" and
> > the "dfu-util --reset" requests.
> > 
> > The default weak implementation of dfu_usb_get_reset() unconditionally
> > reboots the device, but we want to be able to continue the boot.scr
> > execution after writing the kernel, fdt and ramdisk to RAM via DFU.
> > 
> > Signed-off-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>
> > ---
> >  drivers/usb/musb-new/sunxi.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/drivers/usb/musb-new/sunxi.c b/drivers/usb/musb-new/sunxi.c
> > index a146c08..5eb8d19 100644
> > --- a/drivers/usb/musb-new/sunxi.c
> > +++ b/drivers/usb/musb-new/sunxi.c
> > @@ -166,6 +166,17 @@ static void USBC_ConfigFIFO_Base(void)
> >  }
> > 
> >  /*************************************************************************
> > ***** + * Needed for the DFU polling magic
> > +
> > **************************************************************************
> > ****/ +
> > +static u8 last_int_usb;
> > +
> > +bool dfu_usb_get_reset(void)
> > +{
> > +	return !!(last_int_usb & MUSB_INTR_RESET);
> 
> The !! is not needed.

Thanks for your comment, I can surely change this in the updated
version of the patch.

But I'm more interested to know if the USB people are happy with the
current wacky way of interaction between the DFU code and the USB
drivers. Doing dfu_usb_get_reset() polling up to 1000 times in a loop
does not look exactly beautiful:

    https://github.com/u-boot/u-boot/blob/v2015.10/common/cmd_dfu.c#L64

It might be also a bit racy (the RESET interrupt could be potentially
missed sometimes).

-- 
Best regards,
Siarhei Siamashka