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Mon, 28 Jun 2021 22:43:56 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas5p3.samsung.com (KnoxPortal) with ESMTPA id 20210628133713epcas5p3f4d801f37d32bef752e5fb19252a786c~MwoLyknx60058100581epcas5p3V; Mon, 28 Jun 2021 13:37:13 +0000 (GMT) Received: from epsmgms1p2.samsung.com (unknown [182.195.42.42]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20210628133713epsmtrp2cf6f298c5e9d0526f59848eb071d30c3~MwoLxrOub1775117751epsmtrp29; Mon, 28 Jun 2021 13:37:13 +0000 (GMT) X-AuditID: b6c32a4b-43fff700000024ec-66-60d9d21ceee5 Received: from epsmtip1.samsung.com ( [182.195.34.30]) by epsmgms1p2.samsung.com (Symantec Messaging Gateway) with SMTP id C8.08.08289.980D9D06; Mon, 28 Jun 2021 22:37:13 +0900 (KST) Received: from mshams01 (unknown [107.122.12.94]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20210628133711epsmtip12e4d3b9ec28bdf5df78606ee1a6969d7~MwoKTU_Bu1243412434epsmtip1W; Mon, 28 Jun 2021 13:37:11 +0000 (GMT) From: "M Tamseel Shams" To: "'Krzysztof Kozlowski'" , , Cc: , , , , , , In-Reply-To: <3aa88ee4-c662-8069-fb04-90df82038dbe@canonical.com> Subject: RE: [PATCH v4] serial: samsung: use dma_ops of DMA if attached Date: Mon, 28 Jun 2021 19:07:10 +0530 Message-ID: <022901d76c22$b3af0a80$1b0d1f80$@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQK2IkAgtIfCRGonZQvdeYnU2JkFyAHqIlofAj9D7r2pSnSzIA== Content-Language: en-us X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrGKsWRmVeSWpSXmKPExsWy7bCmlq7MpZsJBofusFsceH+QxeLBvG1s Fs2L17NZvJsrY7Hx7Q8mi02Pr7FaXN41h81ixvl9TBZnFveyWxz88ITVgctjzbw1jB6zGnrZ PDat6mTz2D93DbvH5iX1Hn1bVjF6fN4kF8AexWWTkpqTWZZapG+XwJXx+VZewTyxiiu3e5kb GHuEuhg5OSQETCR+nZ7A2MXIxSEksJtR4tHNIywQzidGiYvbfkBlPjNKHJ52G8jhAGtZ9jsK Ir6LUWLSrk9QRc8YJa4v72MBmcsmoCsx6WAbM4gtIlAucX7GbDYQm1ngCaPE2ffqIDangKPE 7zO/2UFsYQF3iTeTJoLVsAioSnRPuAo2h1fAUmJ7zxdWCFtQ4uTMJywQc7Qlli18zQzxg4LE z6fLWCF2OUkcX/AJqkZc4uXRI+wgx0kI7OGQ+HavmRWiwUVi4ufbLBC2sMSr41vYIWwpic/v 9rJB2PkS8+etglpQIbHywhso217iwJU5LKCQYBbQlFi/Sx8iLCsx9dQ6Joi9fBK9v58wQcR5 JXbMg7EVJf7v7odaJS7xbsUU1gmMSrOQvDYLyWuzkLwwC2HbAkaWVYySqQXFuempxaYFxnmp 5XrFibnFpXnpesn5uZsYwUlLy3sH46MHH/QOMTJxMB5ilOBgVhLhFau6liDEm5JYWZValB9f VJqTWnyIUZqDRUmcdyn7oQQhgfTEktTs1NSC1CKYLBMHp1QD0xl3fl79fdUqD3zCZBrfzf7+ mGGL5CPRrZ/OJyVeXLa2mTvg/bmUtVIb/k1jU9c4+v7VA88nQnP+HM5ce63gjNu9FwVusa9t 2MwljNeenKNw+an/wVCl6uMrYjIEwvN89uiYakhfN7yos9/wWsyzQ893Gs5+sKM9U/Zz9Obz XzyqF/r/qG/vvWaXGDY78UGQp3+cX6BpALc3M0/Y1xN2tqpOiks+H3r3sKtnfqpfBbPYL/fg omo9t4B5SZtCjW6wbdD7liQz4+P3oLzJT/86nyhM2jdhZYuF5VHGyw2/1goWXdlj7pCsGt8c xn1W5+zvnW2HZkxJn1Gk75558F6vjxdPwafzb8LXKMTct1JRVmIpzkg01GIuKk4EAMuT6trJ AwAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprFIsWRmVeSWpSXmKPExsWy7bCSnG7nhZsJBuv/clgceH+QxeLBvG1s Fs2L17NZvJsrY7Hx7Q8mi02Pr7FaXN41h81ixvl9TBZnFveyWxz88ITVgctjzbw1jB6zGnrZ PDat6mTz2D93DbvH5iX1Hn1bVjF6fN4kF8AexWWTkpqTWZZapG+XwJUx/cAapoJGsYoly2ax NjC+FOxi5OCQEDCRWPY7qouRi0NIYAejxP6Gu6xdjJxAcXGJab/2M0LYwhIr/z1nhyh6wijx bOsssCI2AV2JSQfbmEEGiQhUSixp0gOpYRZ4xSjx6dxtNoiG/YwSp7YeYQJp4BRwlPh95jc7 iC0s4C7xZtJENhCbRUBVonvCVRYQm1fAUmJ7zxdWCFtQ4uTMJ2BxZgFtid6HrYww9rKFr5kh rlOQ+Pl0GVi9iICTxPEFn6DqxSVeHj3CPoFReBaSUbOQjJqFZNQsJC0LGFlWMUqmFhTnpucW GxYY5aWW6xUn5haX5qXrJefnbmIER5+W1g7GPas+6B1iZOJgPMQowcGsJMIrVnUtQYg3JbGy KrUoP76oNCe1+BCjNAeLkjjvha6T8UIC6YklqdmpqQWpRTBZJg5OqQYmVtdpe20u3fpjs09M MY2TZ9Lq5B1Su46LnneatmLyYbM1l3b9PjFfjVFkZw/vCWdGrrDbzk4HJ83Q/Ln6b3jnqsNT zaQ0uusvlytx2Req5cvJ7qkXdF15fde3t5J8T0Sesl5u+Je8fl2wqExSy5V71yNUpv6auYmV fZOJ05mYd7yC/EHWq7d4t3bf5QzlC9eNcnXJE1wdeILfS+LgKxZhrX1XN9kuKHE0/S/f87xm 71Xj2TITf/m9fXxJ7U/5BHE21zmzONvfn2tS5tLksi7XdYpQ5ajmubSjhmvpA/NuT/Zm3S// d+1Y5nmiIakrP/oc/+6a/uasXyzb14qedDgpO2EJ2++42DcV/dcVOn4psRRnJBpqMRcVJwIA oO39eC0DAAA= X-CMS-MailID: 20210628133713epcas5p3f4d801f37d32bef752e5fb19252a786c X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P X-CMS-RootMailID: 20210625074751epcas5p125067e47c4ff1ad24a1e595d85f82540 References: <20210625075114.71155-1-m.shams@samsung.com> <3aa88ee4-c662-8069-fb04-90df82038dbe@canonical.com> Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org > > 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 > > Signed-off-by: Ajay Kumar > > --- > > Changes since v1: > > 1. Rebased the patch on =22tty-next=22 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 =22dma=22, =22dma->tx_chan=22 and > > =22dma->rx_chan=22 and instead sending DMA device pointer while calling > > DMA API. > > > > drivers/tty/serial/samsung_tty.c =7C 32 > > ++++++++++++++++---------------- > > 1 file changed, 16 insertions(+), 16 deletions(-) > > > > diff --git a/drivers/tty/serial/samsung_tty.c > > b/drivers/tty/serial/samsung_tty.c > > index 9fbc61151c2e..fa30aa20a13f 100644 > > --- a/drivers/tty/serial/samsung_tty.c > > +++ b/drivers/tty/serial/samsung_tty.c > > =40=40 -305,7 +305,7 =40=40 static void s3c24xx_serial_stop_tx(struct u= art_port > *port) > > dmaengine_pause(dma->tx_chan); > > dmaengine_tx_status(dma->tx_chan, dma->tx_cookie, &state); > > dmaengine_terminate_all(dma->tx_chan); > > - dma_sync_single_for_cpu(ourport->port.dev, > > + dma_sync_single_for_cpu(dma->tx_chan->device->dev, > > dma->tx_transfer_addr, dma->tx_size, > DMA_TO_DEVICE); > > async_tx_ack(dma->tx_desc); > > count =3D dma->tx_bytes_requested - state.residue; =40=40 -338,8 > +338,8 > > =40=40 static void s3c24xx_serial_tx_dma_complete(void *args) > > count =3D dma->tx_bytes_requested - state.residue; > > async_tx_ack(dma->tx_desc); > > > > - dma_sync_single_for_cpu(ourport->port.dev, dma->tx_transfer_addr, > > - dma->tx_size, DMA_TO_DEVICE); > > + dma_sync_single_for_cpu(dma->tx_chan->device->dev, > > + dma->tx_transfer_addr, dma->tx_size, > DMA_TO_DEVICE); >=20 > Looks like alignment is broken here. However even if the line was not ali= gned > before, please fix it up now - align the arguments like checkpatch sugges= ts. >=20 > This applies to other places as well. Thanks. >=20 > Best regards, > Krzysztof Hi Krzysztof, Will fix the alignments in the next version. Thanks & Regards, Tamseel Shams