From: Jon Hunter <jonathanh@nvidia.com>
To: Dmitry Osipenko <digetx@gmail.com>,
Laxman Dewangan <ldewangan@nvidia.com>,
Vinod Koul <vkoul@kernel.org>,
Thierry Reding <thierry.reding@gmail.com>,
Ben Dooks <ben.dooks@codethink.co.uk>
Cc: <dmaengine@vger.kernel.org>, <linux-tegra@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] dmaengine: tegra-apb: Error out if DMA_PREP_INTERRUPT flag is unset
Date: Thu, 30 May 2019 13:01:35 +0100 [thread overview]
Message-ID: <9b0e0d20-6386-a38a-1347-4264d249cb44@nvidia.com> (raw)
In-Reply-To: <20190529214355.15339-1-digetx@gmail.com>
On 29/05/2019 22:43, Dmitry Osipenko wrote:
> Apparently driver was never tested with DMA_PREP_INTERRUPT flag being
> unset since it completely disables interrupt handling instead of skipping
> the callbacks invocations, hence putting channel into unusable state.
>
> The flag is always set by all of kernel drivers that use APB DMA, so let's
> error out in otherwise case for consistency. It won't be difficult to
> support that case properly if ever will be needed.
>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> drivers/dma/tegra20-apb-dma.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
> index cf462b1abc0b..2c84a660ba36 100644
> --- a/drivers/dma/tegra20-apb-dma.c
> +++ b/drivers/dma/tegra20-apb-dma.c
> @@ -988,8 +988,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg(
> csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> }
>
> - if (flags & DMA_PREP_INTERRUPT)
> + if (flags & DMA_PREP_INTERRUPT) {
> csr |= TEGRA_APBDMA_CSR_IE_EOC;
> + } else {
> + WARN_ON_ONCE(1);
> + return NULL;
> + }
>
> apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
>
> @@ -1131,8 +1135,12 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic(
> csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT;
> }
>
> - if (flags & DMA_PREP_INTERRUPT)
> + if (flags & DMA_PREP_INTERRUPT) {
> csr |= TEGRA_APBDMA_CSR_IE_EOC;
> + } else {
> + WARN_ON_ONCE(1);
> + return NULL;
> + }
>
> apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1;
Looks good to me.
Acked-by: Jon Hunter <jonathanh@nvidia.com>
Cheers
Jon
--
nvpublic
next prev parent reply other threads:[~2019-05-30 12:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 21:43 [PATCH v1] dmaengine: tegra-apb: Error out if DMA_PREP_INTERRUPT flag is unset Dmitry Osipenko
2019-05-30 12:01 ` Jon Hunter [this message]
2019-05-30 17:32 ` Dmitry Osipenko
2019-06-04 12:16 ` Vinod Koul
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9b0e0d20-6386-a38a-1347-4264d249cb44@nvidia.com \
--to=jonathanh@nvidia.com \
--cc=ben.dooks@codethink.co.uk \
--cc=digetx@gmail.com \
--cc=dmaengine@vger.kernel.org \
--cc=ldewangan@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=thierry.reding@gmail.com \
--cc=vkoul@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).