From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Tamseel Shams <m.shams@samsung.com>,
gregkh@linuxfoundation.org, jirislaby@kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org, alim.akhtar@samsung.com,
ajaykumar.rs@samsung.com, robin.murphy@arm.com
Subject: Re: [PATCH v5] serial: samsung: use dma_ops of DMA if attached
Date: Tue, 29 Jun 2021 11:44:51 +0200 [thread overview]
Message-ID: <8569ce54-26ef-e36a-b3a9-2d31e2575bd2@canonical.com> (raw)
In-Reply-To: <20210629045902.48912-1-m.shams@samsung.com>
On 29/06/2021 06:59, Tamseel Shams wrote:
> When DMA is used for TX and RX by serial driver, it should
> pass the DMA device pointer to DMA API instead of UART device
> pointer. DMA device should be used for DMA API because only
> the DMA device is aware of how the device connects to the memory.
> There might be an extra level of address translation due to a
> SMMU attached to the DMA device. When serial device is used for
> DMA API, the DMA API will have no clue of the SMMU attached to
> the DMA device.
>
> This patch is necessary to fix the SMMU page faults
> which is observed when a DMA(with SMMU enabled) is attached
> to UART for transfer.
>
> Signed-off-by: Tamseel Shams <m.shams@samsung.com>
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> ---
> Changes since v1:
> 1. Rebased the patch on "tty-next" branch of TTY driver tree
>
> Changes since v2:
> 1. Updated the commit message.
> 2. Changed the comment description
>
> Changes since v3:
> 1. Removed the null pointer check for "dma", "dma->tx_chan" and
> "dma->rx_chan" and instead sending DMA device pointer while calling
> DMA API.
>
> Changes since v4:
> 1. Fixed the alignments of arguments.
>
> drivers/tty/serial/samsung_tty.c | 46 +++++++++++++++++---------------
> 1 file changed, 25 insertions(+), 21 deletions(-)
>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Best regards,
Krzysztof
WARNING: multiple messages have this Message-ID (diff)
From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Tamseel Shams <m.shams@samsung.com>,
gregkh@linuxfoundation.org, jirislaby@kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org, alim.akhtar@samsung.com,
ajaykumar.rs@samsung.com, robin.murphy@arm.com
Subject: Re: [PATCH v5] serial: samsung: use dma_ops of DMA if attached
Date: Tue, 29 Jun 2021 11:44:51 +0200 [thread overview]
Message-ID: <8569ce54-26ef-e36a-b3a9-2d31e2575bd2@canonical.com> (raw)
In-Reply-To: <20210629045902.48912-1-m.shams@samsung.com>
On 29/06/2021 06:59, Tamseel Shams wrote:
> When DMA is used for TX and RX by serial driver, it should
> pass the DMA device pointer to DMA API instead of UART device
> pointer. DMA device should be used for DMA API because only
> the DMA device is aware of how the device connects to the memory.
> There might be an extra level of address translation due to a
> SMMU attached to the DMA device. When serial device is used for
> DMA API, the DMA API will have no clue of the SMMU attached to
> the DMA device.
>
> This patch is necessary to fix the SMMU page faults
> which is observed when a DMA(with SMMU enabled) is attached
> to UART for transfer.
>
> Signed-off-by: Tamseel Shams <m.shams@samsung.com>
> Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
> ---
> Changes since v1:
> 1. Rebased the patch on "tty-next" branch of TTY driver tree
>
> Changes since v2:
> 1. Updated the commit message.
> 2. Changed the comment description
>
> Changes since v3:
> 1. Removed the null pointer check for "dma", "dma->tx_chan" and
> "dma->rx_chan" and instead sending DMA device pointer while calling
> DMA API.
>
> Changes since v4:
> 1. Fixed the alignments of arguments.
>
> drivers/tty/serial/samsung_tty.c | 46 +++++++++++++++++---------------
> 1 file changed, 25 insertions(+), 21 deletions(-)
>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Best regards,
Krzysztof
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next prev parent reply other threads:[~2021-06-29 9:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210629045610epcas5p4fa9d2a217b351a950899073d6b7d3dfd@epcas5p4.samsung.com>
2021-06-29 4:59 ` [PATCH v5] serial: samsung: use dma_ops of DMA if attached Tamseel Shams
2021-06-29 4:59 ` Tamseel Shams
2021-06-29 8:31 ` Marek Szyprowski
2021-06-29 8:31 ` Marek Szyprowski
2021-06-29 9:44 ` Krzysztof Kozlowski [this message]
2021-06-29 9:44 ` Krzysztof Kozlowski
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