[Qemu-devel] [PATCH] i8257: fix Terminal Count status

[Qemu-devel] [PATCH] i8257: fix Terminal Count status

[Hervé Poussineau]

When a DMA transfer is done (ie all bytes have been transfered), the corresponding
Terminal Count bit must be set in the status register.
This bit is already cleared in i8257_read_cont and i8257_write_cont when required.

This fixes (at least) floppy transfer in IBM 40p firmware, which checks in DMA
controller if everything went fine.

Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
---
 hw/dma/i8257.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/dma/i8257.c b/hw/dma/i8257.c
index 5a52707..6078893 100644
--- a/hw/dma/i8257.c
+++ b/hw/dma/i8257.c
@@ -342,6 +342,10 @@ static void i8257_channel_run(I8257State *d, int ichan)
                              r->now[COUNT], (r->base[COUNT] + 1) << ncont);
     r->now[COUNT] = n;
     ldebug ("dma_pos %d size %d\n", n, (r->base[COUNT] + 1) << ncont);
+    if (n == (r->base[COUNT] + 1) << ncont) {
+        ldebug("transfer done\n");
+        d->status |= (1 << ichan);
+    }
 }
 
 static void i8257_dma_run(void *opaque)
-- 
2.1.4

Re: [Qemu-devel] [PATCH] i8257: fix Terminal Count status

[John Snow]

On 02/25/2016 07:45 AM, Hervé Poussineau wrote:
> When a DMA transfer is done (ie all bytes have been transfered), the corresponding
> Terminal Count bit must be set in the status register.
> This bit is already cleared in i8257_read_cont and i8257_write_cont when required.
> 
> This fixes (at least) floppy transfer in IBM 40p firmware, which checks in DMA
> controller if everything went fine.
> 
> Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
> ---
>  hw/dma/i8257.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/hw/dma/i8257.c b/hw/dma/i8257.c
> index 5a52707..6078893 100644
> --- a/hw/dma/i8257.c
> +++ b/hw/dma/i8257.c
> @@ -342,6 +342,10 @@ static void i8257_channel_run(I8257State *d, int ichan)
>                               r->now[COUNT], (r->base[COUNT] + 1) << ncont);
>      r->now[COUNT] = n;
>      ldebug ("dma_pos %d size %d\n", n, (r->base[COUNT] + 1) << ncont);
> +    if (n == (r->base[COUNT] + 1) << ncont) {
> +        ldebug("transfer done\n");
> +        d->status |= (1 << ichan);
> +    }
>  }
>  
>  static void i8257_dma_run(void *opaque)
> 

As best as I can tell from the i8257 data sheet I found this seems to be
correct, assuming the size calculation is correct (looks right, based on
that existing ldebug print.)

Reviewed-by: John Snow <jsnow@redhat.com>

Re: [Qemu-devel] [PATCH] i8257: fix Terminal Count status

[Paolo Bonzini]

On 25/02/2016 13:45, Hervé Poussineau wrote:
> When a DMA transfer is done (ie all bytes have been transfered), the corresponding
> Terminal Count bit must be set in the status register.
> This bit is already cleared in i8257_read_cont and i8257_write_cont when required.
> 
> This fixes (at least) floppy transfer in IBM 40p firmware, which checks in DMA
> controller if everything went fine.
> 
> Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
> ---
>  hw/dma/i8257.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/hw/dma/i8257.c b/hw/dma/i8257.c
> index 5a52707..6078893 100644
> --- a/hw/dma/i8257.c
> +++ b/hw/dma/i8257.c
> @@ -342,6 +342,10 @@ static void i8257_channel_run(I8257State *d, int ichan)
>                               r->now[COUNT], (r->base[COUNT] + 1) << ncont);
>      r->now[COUNT] = n;
>      ldebug ("dma_pos %d size %d\n", n, (r->base[COUNT] + 1) << ncont);
> +    if (n == (r->base[COUNT] + 1) << ncont) {
> +        ldebug("transfer done\n");
> +        d->status |= (1 << ichan);
> +    }
>  }
>  
>  static void i8257_dma_run(void *opaque)
> 

Queued, thanks!

Paolo