| Message ID | 20180905131125.12635-1-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [qemu,v2] hw/char/sh_serial: Add timeout handling to unbreak serial input | expand |
On 05/09/2018 15:11, Geert Uytterhoeven wrote: > As of commit 18e8cf159177100e ("serial: sh-sci: increase RX FIFO trigger > defaults for (H)SCIF") in Linux v4.11-rc1, the serial console on the > QEMU SH4 target is broken: it delays serial input until enough data has > been received. > > Since aforementioned commit, the Linux SCIF driver programs the Receive > FIFO Data Count Trigger bits in the FIFO Control Register, to postpone > generating a receive interrupt until: > 1. At least the receive trigger count of bytes of data are available > in the receive FIFO, OR > 2. No further data has been received for at least 15 etu after the > last received data. > > While QEMU implements the former, it does not implement the latter. > Hence the receive interrupt is not generated until the former condition > is met. > > Fix this by adding basic timeout handling. As the QEMU SCIF emulation > ignores any serial speed programming, the timeout value used conforms to > a default speed of 9600 bps, which is fine for any interactive console. > > Reported-by: Rob Landley <rob@landley.net> > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > Tested-by: Ulrich Hecht <uli@fpond.eu> > Tested-by: Rob Landley <rob@landley.net> > Tested-by: Rich Felker <dalias@libc.org> > --- > v2: > - Add Tested-by, > - Fix spelling in patch description. > --- > hw/char/sh_serial.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/hw/char/sh_serial.c b/hw/char/sh_serial.c > index 373a40595fd975d1..12831561a6c8b137 100644 > --- a/hw/char/sh_serial.c > +++ b/hw/char/sh_serial.c > @@ -29,6 +29,7 @@ > #include "hw/sh4/sh.h" > #include "chardev/char-fe.h" > #include "qapi/error.h" > +#include "qemu/timer.h" > > //#define DEBUG_SERIAL > > @@ -63,6 +64,8 @@ typedef struct { > int rtrg; > > CharBackend chr; > + QEMUTimer *fifo_timeout_timer; > + uint64_t etu; /* Elementary Time Unit (ns) */ > > qemu_irq eri; > qemu_irq rxi; > @@ -314,6 +317,16 @@ static int sh_serial_can_receive1(void *opaque) > return sh_serial_can_receive(s); > } > > +static void sh_serial_timeout_int(void *opaque) > +{ > + sh_serial_state *s = opaque; > + > + s->flags |= SH_SERIAL_FLAG_RDF; > + if (s->scr & (1 << 6) && s->rxi) { > + qemu_set_irq(s->rxi, 1); > + } > +} > + > static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size) > { > sh_serial_state *s = opaque; > @@ -330,8 +343,12 @@ static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size) > if (s->rx_cnt >= s->rtrg) { > s->flags |= SH_SERIAL_FLAG_RDF; > if (s->scr & (1 << 6) && s->rxi) { > + timer_del(s->fifo_timeout_timer); > qemu_set_irq(s->rxi, 1); > } > + } else { > + timer_mod(s->fifo_timeout_timer, > + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 15 * s->etu); > } > } > } > @@ -402,6 +419,9 @@ void sh_serial_init(MemoryRegion *sysmem, > sh_serial_event, NULL, s, NULL, true); > } > > + s->fifo_timeout_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, > + sh_serial_timeout_int, s); > + s->etu = NANOSECONDS_PER_SECOND / 9600; > s->eri = eri_source; > s->rxi = rxi_source; > s->txi = txi_source; > Queued, thanks. Paolo
Hi Paolo, On Tue, Sep 11, 2018 at 3:11 PM Paolo Bonzini <pbonzini@redhat.com> wrote: > On 05/09/2018 15:11, Geert Uytterhoeven wrote: > > As of commit 18e8cf159177100e ("serial: sh-sci: increase RX FIFO trigger > > defaults for (H)SCIF") in Linux v4.11-rc1, the serial console on the > > QEMU SH4 target is broken: it delays serial input until enough data has > > been received. > > > > Since aforementioned commit, the Linux SCIF driver programs the Receive > > FIFO Data Count Trigger bits in the FIFO Control Register, to postpone > > generating a receive interrupt until: > > 1. At least the receive trigger count of bytes of data are available > > in the receive FIFO, OR > > 2. No further data has been received for at least 15 etu after the > > last received data. > > > > While QEMU implements the former, it does not implement the latter. > > Hence the receive interrupt is not generated until the former condition > > is met. > > > > Fix this by adding basic timeout handling. As the QEMU SCIF emulation > > ignores any serial speed programming, the timeout value used conforms to > > a default speed of 9600 bps, which is fine for any interactive console. > > > > Reported-by: Rob Landley <rob@landley.net> > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > > Tested-by: Ulrich Hecht <uli@fpond.eu> > > Tested-by: Rob Landley <rob@landley.net> > > Tested-by: Rich Felker <dalias@libc.org> > Queued, thanks. Does that mean it should show up in qemu.git anytime soon? Thanks, and have a nice weekend! Gr{oetje,eeting}s, Geert
On 28/09/2018 14:36, Geert Uytterhoeven wrote: > Hi Paolo, > > On Tue, Sep 11, 2018 at 3:11 PM Paolo Bonzini <pbonzini@redhat.com> wrote: >> On 05/09/2018 15:11, Geert Uytterhoeven wrote: >>> As of commit 18e8cf159177100e ("serial: sh-sci: increase RX FIFO trigger >>> defaults for (H)SCIF") in Linux v4.11-rc1, the serial console on the >>> QEMU SH4 target is broken: it delays serial input until enough data has >>> been received. >>> >>> Since aforementioned commit, the Linux SCIF driver programs the Receive >>> FIFO Data Count Trigger bits in the FIFO Control Register, to postpone >>> generating a receive interrupt until: >>> 1. At least the receive trigger count of bytes of data are available >>> in the receive FIFO, OR >>> 2. No further data has been received for at least 15 etu after the >>> last received data. >>> >>> While QEMU implements the former, it does not implement the latter. >>> Hence the receive interrupt is not generated until the former condition >>> is met. >>> >>> Fix this by adding basic timeout handling. As the QEMU SCIF emulation >>> ignores any serial speed programming, the timeout value used conforms to >>> a default speed of 9600 bps, which is fine for any interactive console. >>> >>> Reported-by: Rob Landley <rob@landley.net> >>> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >>> Tested-by: Ulrich Hecht <uli@fpond.eu> >>> Tested-by: Rob Landley <rob@landley.net> >>> Tested-by: Rich Felker <dalias@libc.org> > >> Queued, thanks. > > Does that mean it should show up in qemu.git anytime soon? Yes, I'm testing the pull request now. (I went to Kernel Recipes and forgot at home my ssh private key, otherwise I'd have sent it last week!) Paolo
diff --git a/hw/char/sh_serial.c b/hw/char/sh_serial.c index 373a40595fd975d1..12831561a6c8b137 100644 --- a/hw/char/sh_serial.c +++ b/hw/char/sh_serial.c @@ -29,6 +29,7 @@ #include "hw/sh4/sh.h" #include "chardev/char-fe.h" #include "qapi/error.h" +#include "qemu/timer.h" //#define DEBUG_SERIAL @@ -63,6 +64,8 @@ typedef struct { int rtrg; CharBackend chr; + QEMUTimer *fifo_timeout_timer; + uint64_t etu; /* Elementary Time Unit (ns) */ qemu_irq eri; qemu_irq rxi; @@ -314,6 +317,16 @@ static int sh_serial_can_receive1(void *opaque) return sh_serial_can_receive(s); } +static void sh_serial_timeout_int(void *opaque) +{ + sh_serial_state *s = opaque; + + s->flags |= SH_SERIAL_FLAG_RDF; + if (s->scr & (1 << 6) && s->rxi) { + qemu_set_irq(s->rxi, 1); + } +} + static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size) { sh_serial_state *s = opaque; @@ -330,8 +343,12 @@ static void sh_serial_receive1(void *opaque, const uint8_t *buf, int size) if (s->rx_cnt >= s->rtrg) { s->flags |= SH_SERIAL_FLAG_RDF; if (s->scr & (1 << 6) && s->rxi) { + timer_del(s->fifo_timeout_timer); qemu_set_irq(s->rxi, 1); } + } else { + timer_mod(s->fifo_timeout_timer, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 15 * s->etu); } } } @@ -402,6 +419,9 @@ void sh_serial_init(MemoryRegion *sysmem, sh_serial_event, NULL, s, NULL, true); } + s->fifo_timeout_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, + sh_serial_timeout_int, s); + s->etu = NANOSECONDS_PER_SECOND / 9600; s->eri = eri_source; s->rxi = rxi_source; s->txi = txi_source;
As of commit 18e8cf159177100e ("serial: sh-sci: increase RX FIFO trigger defaults for (H)SCIF") in Linux v4.11-rc1, the serial console on the QEMU SH4 target is broken: it delays serial input until enough data has been received. Since aforementioned commit, the Linux SCIF driver programs the Receive FIFO Data Count Trigger bits in the FIFO Control Register, to postpone generating a receive interrupt until: 1. At least the receive trigger count of bytes of data are available in the receive FIFO, OR 2. No further data has been received for at least 15 etu after the last received data. While QEMU implements the former, it does not implement the latter. Hence the receive interrupt is not generated until the former condition is met. Fix this by adding basic timeout handling. As the QEMU SCIF emulation ignores any serial speed programming, the timeout value used conforms to a default speed of 9600 bps, which is fine for any interactive console. Reported-by: Rob Landley <rob@landley.net> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Tested-by: Ulrich Hecht <uli@fpond.eu> Tested-by: Rob Landley <rob@landley.net> Tested-by: Rich Felker <dalias@libc.org> --- v2: - Add Tested-by, - Fix spelling in patch description. --- hw/char/sh_serial.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)