From: Marek Szyprowski <m.szyprowski@samsung.com> To: Tamseel Shams <m.shams@samsung.com>, krzysztof.kozlowski@canonical.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 10:31:19 +0200 [thread overview] Message-ID: <2f3a7337-6349-0638-b126-183a57d0da6c@samsung.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> Acked-by: Marek Szyprowski <m.szyprowski@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(-) > > diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c > index 9fbc61151c2e..0cf4dfe77c32 100644 > --- a/drivers/tty/serial/samsung_tty.c > +++ b/drivers/tty/serial/samsung_tty.c > @@ -305,8 +305,9 @@ static void s3c24xx_serial_stop_tx(struct uart_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->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); > async_tx_ack(dma->tx_desc); > count = dma->tx_bytes_requested - state.residue; > xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); > @@ -338,8 +339,9 @@ static void s3c24xx_serial_tx_dma_complete(void *args) > count = 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); > > spin_lock_irqsave(&port->lock, flags); > > @@ -443,8 +445,9 @@ static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport, > dma->tx_size = count & ~(dma_get_cache_alignment() - 1); > dma->tx_transfer_addr = dma->tx_addr + xmit->tail; > > - dma_sync_single_for_device(ourport->port.dev, dma->tx_transfer_addr, > - dma->tx_size, DMA_TO_DEVICE); > + dma_sync_single_for_device(dma->tx_chan->device->dev, > + dma->tx_transfer_addr, dma->tx_size, > + DMA_TO_DEVICE); > > dma->tx_desc = dmaengine_prep_slave_single(dma->tx_chan, > dma->tx_transfer_addr, dma->tx_size, > @@ -515,7 +518,7 @@ static void s3c24xx_uart_copy_rx_to_tty(struct s3c24xx_uart_port *ourport, > if (!count) > return; > > - dma_sync_single_for_cpu(ourport->port.dev, dma->rx_addr, > + dma_sync_single_for_cpu(dma->rx_chan->device->dev, dma->rx_addr, > dma->rx_size, DMA_FROM_DEVICE); > > ourport->port.icount.rx += count; > @@ -636,8 +639,8 @@ static void s3c64xx_start_rx_dma(struct s3c24xx_uart_port *ourport) > { > struct s3c24xx_uart_dma *dma = ourport->dma; > > - dma_sync_single_for_device(ourport->port.dev, dma->rx_addr, > - dma->rx_size, DMA_FROM_DEVICE); > + dma_sync_single_for_device(dma->rx_chan->device->dev, dma->rx_addr, > + dma->rx_size, DMA_FROM_DEVICE); > > dma->rx_desc = dmaengine_prep_slave_single(dma->rx_chan, > dma->rx_addr, dma->rx_size, DMA_DEV_TO_MEM, > @@ -1102,18 +1105,19 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > goto err_release_tx; > } > > - dma->rx_addr = dma_map_single(p->port.dev, dma->rx_buf, > - dma->rx_size, DMA_FROM_DEVICE); > - if (dma_mapping_error(p->port.dev, dma->rx_addr)) { > + dma->rx_addr = dma_map_single(dma->rx_chan->device->dev, dma->rx_buf, > + dma->rx_size, DMA_FROM_DEVICE); > + if (dma_mapping_error(dma->rx_chan->device->dev, dma->rx_addr)) { > reason = "DMA mapping error for RX buffer"; > ret = -EIO; > goto err_free_rx; > } > > /* TX buffer */ > - dma->tx_addr = dma_map_single(p->port.dev, p->port.state->xmit.buf, > - UART_XMIT_SIZE, DMA_TO_DEVICE); > - if (dma_mapping_error(p->port.dev, dma->tx_addr)) { > + dma->tx_addr = dma_map_single(dma->tx_chan->device->dev, > + p->port.state->xmit.buf, UART_XMIT_SIZE, > + DMA_TO_DEVICE); > + if (dma_mapping_error(dma->tx_chan->device->dev, dma->tx_addr)) { > reason = "DMA mapping error for TX buffer"; > ret = -EIO; > goto err_unmap_rx; > @@ -1122,8 +1126,8 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > return 0; > > err_unmap_rx: > - dma_unmap_single(p->port.dev, dma->rx_addr, dma->rx_size, > - DMA_FROM_DEVICE); > + dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr, > + dma->rx_size, DMA_FROM_DEVICE); > err_free_rx: > kfree(dma->rx_buf); > err_release_tx: > @@ -1142,8 +1146,8 @@ static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) > > if (dma->rx_chan) { > dmaengine_terminate_all(dma->rx_chan); > - dma_unmap_single(p->port.dev, dma->rx_addr, > - dma->rx_size, DMA_FROM_DEVICE); > + dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr, > + dma->rx_size, DMA_FROM_DEVICE); > kfree(dma->rx_buf); > dma_release_channel(dma->rx_chan); > dma->rx_chan = NULL; > @@ -1151,8 +1155,8 @@ static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) > > if (dma->tx_chan) { > dmaengine_terminate_all(dma->tx_chan); > - dma_unmap_single(p->port.dev, dma->tx_addr, > - UART_XMIT_SIZE, DMA_TO_DEVICE); > + dma_unmap_single(dma->tx_chan->device->dev, dma->tx_addr, > + UART_XMIT_SIZE, DMA_TO_DEVICE); > dma_release_channel(dma->tx_chan); > dma->tx_chan = NULL; > } Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
WARNING: multiple messages have this Message-ID (diff)
From: Marek Szyprowski <m.szyprowski@samsung.com> To: Tamseel Shams <m.shams@samsung.com>, krzysztof.kozlowski@canonical.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 10:31:19 +0200 [thread overview] Message-ID: <2f3a7337-6349-0638-b126-183a57d0da6c@samsung.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> Acked-by: Marek Szyprowski <m.szyprowski@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(-) > > diff --git a/drivers/tty/serial/samsung_tty.c b/drivers/tty/serial/samsung_tty.c > index 9fbc61151c2e..0cf4dfe77c32 100644 > --- a/drivers/tty/serial/samsung_tty.c > +++ b/drivers/tty/serial/samsung_tty.c > @@ -305,8 +305,9 @@ static void s3c24xx_serial_stop_tx(struct uart_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->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); > async_tx_ack(dma->tx_desc); > count = dma->tx_bytes_requested - state.residue; > xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); > @@ -338,8 +339,9 @@ static void s3c24xx_serial_tx_dma_complete(void *args) > count = 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); > > spin_lock_irqsave(&port->lock, flags); > > @@ -443,8 +445,9 @@ static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport, > dma->tx_size = count & ~(dma_get_cache_alignment() - 1); > dma->tx_transfer_addr = dma->tx_addr + xmit->tail; > > - dma_sync_single_for_device(ourport->port.dev, dma->tx_transfer_addr, > - dma->tx_size, DMA_TO_DEVICE); > + dma_sync_single_for_device(dma->tx_chan->device->dev, > + dma->tx_transfer_addr, dma->tx_size, > + DMA_TO_DEVICE); > > dma->tx_desc = dmaengine_prep_slave_single(dma->tx_chan, > dma->tx_transfer_addr, dma->tx_size, > @@ -515,7 +518,7 @@ static void s3c24xx_uart_copy_rx_to_tty(struct s3c24xx_uart_port *ourport, > if (!count) > return; > > - dma_sync_single_for_cpu(ourport->port.dev, dma->rx_addr, > + dma_sync_single_for_cpu(dma->rx_chan->device->dev, dma->rx_addr, > dma->rx_size, DMA_FROM_DEVICE); > > ourport->port.icount.rx += count; > @@ -636,8 +639,8 @@ static void s3c64xx_start_rx_dma(struct s3c24xx_uart_port *ourport) > { > struct s3c24xx_uart_dma *dma = ourport->dma; > > - dma_sync_single_for_device(ourport->port.dev, dma->rx_addr, > - dma->rx_size, DMA_FROM_DEVICE); > + dma_sync_single_for_device(dma->rx_chan->device->dev, dma->rx_addr, > + dma->rx_size, DMA_FROM_DEVICE); > > dma->rx_desc = dmaengine_prep_slave_single(dma->rx_chan, > dma->rx_addr, dma->rx_size, DMA_DEV_TO_MEM, > @@ -1102,18 +1105,19 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > goto err_release_tx; > } > > - dma->rx_addr = dma_map_single(p->port.dev, dma->rx_buf, > - dma->rx_size, DMA_FROM_DEVICE); > - if (dma_mapping_error(p->port.dev, dma->rx_addr)) { > + dma->rx_addr = dma_map_single(dma->rx_chan->device->dev, dma->rx_buf, > + dma->rx_size, DMA_FROM_DEVICE); > + if (dma_mapping_error(dma->rx_chan->device->dev, dma->rx_addr)) { > reason = "DMA mapping error for RX buffer"; > ret = -EIO; > goto err_free_rx; > } > > /* TX buffer */ > - dma->tx_addr = dma_map_single(p->port.dev, p->port.state->xmit.buf, > - UART_XMIT_SIZE, DMA_TO_DEVICE); > - if (dma_mapping_error(p->port.dev, dma->tx_addr)) { > + dma->tx_addr = dma_map_single(dma->tx_chan->device->dev, > + p->port.state->xmit.buf, UART_XMIT_SIZE, > + DMA_TO_DEVICE); > + if (dma_mapping_error(dma->tx_chan->device->dev, dma->tx_addr)) { > reason = "DMA mapping error for TX buffer"; > ret = -EIO; > goto err_unmap_rx; > @@ -1122,8 +1126,8 @@ static int s3c24xx_serial_request_dma(struct s3c24xx_uart_port *p) > return 0; > > err_unmap_rx: > - dma_unmap_single(p->port.dev, dma->rx_addr, dma->rx_size, > - DMA_FROM_DEVICE); > + dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr, > + dma->rx_size, DMA_FROM_DEVICE); > err_free_rx: > kfree(dma->rx_buf); > err_release_tx: > @@ -1142,8 +1146,8 @@ static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) > > if (dma->rx_chan) { > dmaengine_terminate_all(dma->rx_chan); > - dma_unmap_single(p->port.dev, dma->rx_addr, > - dma->rx_size, DMA_FROM_DEVICE); > + dma_unmap_single(dma->rx_chan->device->dev, dma->rx_addr, > + dma->rx_size, DMA_FROM_DEVICE); > kfree(dma->rx_buf); > dma_release_channel(dma->rx_chan); > dma->rx_chan = NULL; > @@ -1151,8 +1155,8 @@ static void s3c24xx_serial_release_dma(struct s3c24xx_uart_port *p) > > if (dma->tx_chan) { > dmaengine_terminate_all(dma->tx_chan); > - dma_unmap_single(p->port.dev, dma->tx_addr, > - UART_XMIT_SIZE, DMA_TO_DEVICE); > + dma_unmap_single(dma->tx_chan->device->dev, dma->tx_addr, > + UART_XMIT_SIZE, DMA_TO_DEVICE); > dma_release_channel(dma->tx_chan); > dma->tx_chan = NULL; > } Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-06-29 8:31 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 [this message] 2021-06-29 8:31 ` Marek Szyprowski 2021-06-29 9:44 ` Krzysztof Kozlowski 2021-06-29 9:44 ` Krzysztof Kozlowski
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