> Date: Sun, 14 Aug 2016 14:02:21 +0200
> From: Marcus Glocker <[email protected]>
>
> On Sun, Aug 14, 2016 at 12:08:14AM +0200, Mark Kettenis wrote:
>
> > > Date: Sat, 13 Aug 2016 23:06:45 +0200
> > > From: Marcus Glocker <[email protected]>
> > >
> > > When I currently boot the allwinner,sun5i-r8 board with an UART cable
> > > connected for console but no terminal attached, the boot hangs as soon
> > > the driver switches from the console output routines to interrupts.
> > >
> > > I figured out that this is caused because at one place we set the
> > > FIFO RX interupt trigger to RXT2 (trigger on 1/2 full) instead of RXT0
> > > (trigger on 1 char). I guess it's a typo since everywhere else in the
> > > driver it gets set to RXT0.
> > >
> > > When setting it to RXT0 (which is the reset value) the boot doesn't
> > > hang anymore also when an UART cable is connected without a terminal
> > > attached.
> > >
> > > ok?
> >
> > Not sure if it is a typo, but if it fixes your issues, go ahead.
>
> Sigh. Doing further tests showed that the last diff didn't work
> reliable. I did steal the FIFO drain code as well now from com(4) and
> now it seems to work reliable. Still ok for you?
sure; ok kettenis@
> Index: sxiuart.c
> ===================================================================
> RCS file: /cvs/src/sys/arch/armv7/sunxi/sxiuart.c,v
> retrieving revision 1.12
> diff -u -p -r1.12 sxiuart.c
> --- sxiuart.c 12 Aug 2016 16:09:37 -0000 1.12
> +++ sxiuart.c 14 Aug 2016 11:56:49 -0000
> @@ -660,11 +660,18 @@ sxiuartopen(dev_t dev, int flag, int mod
> iot = sc->sc_iot;
> ioh = sc->sc_ioh;
>
> - bus_space_write_1(iot, ioh, SXIUART_FCR, FIFOE | FIFO_RXT2);
> - delay(100);
> - while (ISSET(bus_space_read_1(iot, ioh, SXIUART_LSR),
> - LSR_RXRDY))
> + /* (Re)enable and drain FIFOs. */
> + for (;;) {
> + bus_space_write_1(iot, ioh, SXIUART_FCR, 0);
> + delay(100);
> (void)bus_space_read_1(iot, ioh, SXIUART_RBR);
> + bus_space_write_1(iot, ioh, SXIUART_FCR,
> + FIFOE | FIFO_RXT0);
> + delay(100);
> + if (!ISSET(bus_space_read_1(iot, ioh, SXIUART_LSR),
> + LSR_RXRDY))
> + break;
> + }
>
> sc->sc_mcr = MCR_DTR | MCR_RTS | MCR_IENABLE;
> bus_space_write_1(iot, ioh, SXIUART_MCR, sc->sc_mcr);
>
