[Qemu-devel] [PATCH v2] Enable 8-byte wide MMIO for 16550 serial devices

[Qemu-devel] [PATCH v2] Enable 8-byte wide MMIO for 16550 serial devices

[Mike Nawrocki]

Some drivers for the PPMC7400 PowerPC evaluation board accesses the
serial registers through the floating point unit (stfd/ldfd), which is
an 8-byte wide access. This patch enables that behavior.

Signed-off-by: Mike Nawrocki <michael.nawrocki@gtri.gatech.edu>
---
 hw/char/serial.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/hw/char/serial.c b/hw/char/serial.c
index 376bd2f240..eb72191ee7 100644
--- a/hw/char/serial.c
+++ b/hw/char/serial.c
@@ -1005,7 +1005,7 @@ static void serial_mm_write(void *opaque, hwaddr addr,
                             uint64_t value, unsigned size)
 {
     SerialState *s = opaque;
-    value &= ~0u >> (32 - (size * 8));
+    value &= 255;
     serial_ioport_write(s, addr >> s->it_shift, value, 1);
 }
 
@@ -1014,16 +1014,22 @@ static const MemoryRegionOps serial_mm_ops[3] = {
         .read = serial_mm_read,
         .write = serial_mm_write,
         .endianness = DEVICE_NATIVE_ENDIAN,
+        .valid.max_access_size = 8,
+        .impl.max_access_size = 8,
     },
     [DEVICE_LITTLE_ENDIAN] = {
         .read = serial_mm_read,
         .write = serial_mm_write,
         .endianness = DEVICE_LITTLE_ENDIAN,
+        .valid.max_access_size = 8,
+        .impl.max_access_size = 8,
     },
     [DEVICE_BIG_ENDIAN] = {
         .read = serial_mm_read,
         .write = serial_mm_write,
         .endianness = DEVICE_BIG_ENDIAN,
+        .valid.max_access_size = 8,
+        .impl.max_access_size = 8,
     },
 };
 
-- 
2.14.2

Re: [Qemu-devel] [PATCH v2] Enable 8-byte wide MMIO for 16550 serial devices

[Paolo Bonzini]

On 06/11/2017 17:10, Mike Nawrocki wrote:
> Some drivers for the PPMC7400 PowerPC evaluation board accesses the
> serial registers through the floating point unit (stfd/ldfd), which is
> an 8-byte wide access. This patch enables that behavior.
> 
> Signed-off-by: Mike Nawrocki <michael.nawrocki@gtri.gatech.edu>

Queued for inclusion in 2.11, thanks.

Paolo

> ---
>  hw/char/serial.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/char/serial.c b/hw/char/serial.c
> index 376bd2f240..eb72191ee7 100644
> --- a/hw/char/serial.c
> +++ b/hw/char/serial.c
> @@ -1005,7 +1005,7 @@ static void serial_mm_write(void *opaque, hwaddr addr,
>                              uint64_t value, unsigned size)
>  {
>      SerialState *s = opaque;
> -    value &= ~0u >> (32 - (size * 8));
> +    value &= 255;
>      serial_ioport_write(s, addr >> s->it_shift, value, 1);
>  }
>  
> @@ -1014,16 +1014,22 @@ static const MemoryRegionOps serial_mm_ops[3] = {
>          .read = serial_mm_read,
>          .write = serial_mm_write,
>          .endianness = DEVICE_NATIVE_ENDIAN,
> +        .valid.max_access_size = 8,
> +        .impl.max_access_size = 8,
>      },
>      [DEVICE_LITTLE_ENDIAN] = {
>          .read = serial_mm_read,
>          .write = serial_mm_write,
>          .endianness = DEVICE_LITTLE_ENDIAN,
> +        .valid.max_access_size = 8,
> +        .impl.max_access_size = 8,
>      },
>      [DEVICE_BIG_ENDIAN] = {
>          .read = serial_mm_read,
>          .write = serial_mm_write,
>          .endianness = DEVICE_BIG_ENDIAN,
> +        .valid.max_access_size = 8,
> +        .impl.max_access_size = 8,
>      },
>  };
>  
>