[PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Geert Uytterhoeven]

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;
-- 
2.17.1

[PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Geert Uytterhoeven]

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;
-- 
2.17.1

[Qemu-devel] [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Geert Uytterhoeven]

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;
-- 
2.17.1

Re: [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Paolo Bonzini]

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

Re: [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Paolo Bonzini]

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

Re: [Qemu-devel] [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Paolo Bonzini]

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

Re: [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Geert Uytterhoeven]

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

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Geert Uytterhoeven]

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

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Paolo Bonzini]

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

Re: [PATCH qemu v2] hw/char/sh_serial: Add timeout handling to unbreak serial input

[Paolo Bonzini]

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