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Re: [PATCH v2 7/7] hw/arm/exynos4210: Connect serial port DMA busy signa


From: Peter Maydell
Subject: Re: [PATCH v2 7/7] hw/arm/exynos4210: Connect serial port DMA busy signals with pl330
Date: Mon, 20 Jan 2020 13:59:41 +0000

On Sat, 18 Jan 2020 at 16:42, Guenter Roeck <address@hidden> wrote:
>
> The Exynos4210 serial driver uses an interrupt line to signal if receive
> data is available. Connect that interrupt with the DMA controller's
> 'peripheral busy' gpio pin to stop the DMA if there is no more receive
> data available. Without this patch, receive DMA runs wild and fills the
> entire receive DMA buffer with invalid data.
>
> Signed-off-by: Guenter Roeck <address@hidden>
> ---
> v2: Context changes; improved description
>     This patch has an outstanding review comment, suggesting that
>     uart and pl330 device states should be kept in Exynos4210State.
>     I did not address this comment for a number of reasons.
>     It looks like the problem is hypothetical, the problem may
>     apply to all devices created in exynos4210_realize(), and I am
>     not sure I understand what would need to be done to fix
>     the problem for good (ie for all devices created in the same
>     function which have the same problem). Overall, I think that
>     handling this situation would be better left for a separate patch.
>
>  hw/arm/exynos4210.c | 42 +++++++++++++++++++++++++++++-------------
>  1 file changed, 29 insertions(+), 13 deletions(-)

Reviewed-by: Peter Maydell <address@hidden>

thanks
-- PMM



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