| Message ID | 20210625075114.71155-1-m.shams@samsung.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | [v4] serial: samsung: use dma_ops of DMA if attached | expand |
On 25/06/2021 09:51, 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. > > drivers/tty/serial/samsung_tty.c | 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 > @@ -305,7 +305,7 @@ 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_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; > @@ -338,8 +338,8 @@ 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); Looks like alignment is broken here. However even if the line was not aligned before, please fix it up now - align the arguments like checkpatch suggests. This applies to other places as well. Thanks. Best regards, Krzysztof
> > 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. > > > > drivers/tty/serial/samsung_tty.c | 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 > > @@ -305,7 +305,7 @@ 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_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; @@ -338,8 > +338,8 > > @@ 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); > > Looks like alignment is broken here. However even if the line was not aligned > before, please fix it up now - align the arguments like checkpatch suggests. > > This applies to other places as well. Thanks. > > Best regards, > Krzysztof Hi Krzysztof, Will fix the alignments in the next version. Thanks & Regards, Tamseel Shams
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 @@ -305,7 +305,7 @@ 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_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; @@ -338,8 +338,8 @@ 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 +443,8 @@ 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 +515,7 @@ 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; @@ -636,7 +636,7 @@ 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_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, @@ -1102,18 +1102,18 @@ 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_addr = dma_map_single(dma->rx_chan->device->dev, dma->rx_buf, dma->rx_size, DMA_FROM_DEVICE); - if (dma_mapping_error(p->port.dev, dma->rx_addr)) { + 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 +1122,8 @@ 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: @@ -1142,7 +1142,7 @@ 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_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); @@ -1151,7 +1151,7 @@ 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, + 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;