From: Peter Maydell <peter.maydell@linaro.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Igor Mitsyanko <i.mitsyanko@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>,
qemu-arm <qemu-arm@nongnu.org>,
QEMU Developers <qemu-devel@nongnu.org>
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 [thread overview]
Message-ID: <CAFEAcA9ADoUh+eKXKMTv2x=ubqTiyENNdKxuwVHfP3t6=dZXUg@mail.gmail.com> (raw)
In-Reply-To: <20200118164229.22539-8-linux@roeck-us.net>
On Sat, 18 Jan 2020 at 16:42, Guenter Roeck <linux@roeck-us.net> 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 <linux@roeck-us.net>
> ---
> 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 <peter.maydell@linaro.org>
thanks
-- PMM
prev parent reply other threads:[~2020-01-20 14:02 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-18 16:42 [PATCH v2 0/7] Fix Exynos4210 DMA support Guenter Roeck
2020-01-18 16:42 ` [PATCH v2 1/7] dma/pl330: Convert to support tracing Guenter Roeck
2020-01-20 13:28 ` Peter Maydell
2020-01-18 16:42 ` [PATCH v2 2/7] hw/arm/exynos4210: Fix DMA initialization Guenter Roeck
2020-01-20 13:35 ` Peter Maydell
2020-01-20 14:30 ` Guenter Roeck
2020-01-20 14:46 ` Peter Maydell
2020-01-20 15:11 ` Guenter Roeck
2020-01-18 16:42 ` [PATCH v2 3/7] hw/char/exynos4210_uart: Convert to support tracing Guenter Roeck
2020-01-18 16:42 ` [PATCH v2 4/7] hw/char/exynos4210_uart: Implement post_load function Guenter Roeck
2020-01-20 13:29 ` Peter Maydell
2020-01-18 16:42 ` [PATCH v2 5/7] hw/char/exynos4210_uart: Implement Rx FIFO level triggers and timeouts Guenter Roeck
2020-01-20 13:58 ` Peter Maydell
2020-01-20 15:04 ` Guenter Roeck
2020-01-18 16:42 ` [PATCH v2 6/7] hw/char/exynos4210_uart: Add receive DMA support Guenter Roeck
2020-01-18 16:42 ` [PATCH v2 7/7] hw/arm/exynos4210: Connect serial port DMA busy signals with pl330 Guenter Roeck
2020-01-20 13:59 ` Peter Maydell [this message]
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