| Message ID | 20211116112036.96349-4-tudor.ambarus@microchip.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dmaengine: at_xdmac: Various fixes | expand |
Hi, Le 16/11/2021 à 12:20, Tudor Ambarus a écrit : > The driver wrongly assummed that tx_submit() will start the transfer, > which is not the case, now that the at_xdmac driver is fixed. tx_submit > is supposed to push the current transaction descriptor to a pending queue, > waiting for issue_pending to be called. issue_pending must start the > transfer, not tx_submit. While touching atmel_prepare_rx_dma(), introduce > a local variable for the RX dma channel. > > Fixes: 34df42f59a60 ("serial: at91: add rx dma support") > Fixes: 08f738be88bb ("serial: at91: add tx dma support") > Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> > --- > drivers/tty/serial/atmel_serial.c | 20 +++++++++++++------- > 1 file changed, 13 insertions(+), 7 deletions(-) > > diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c > index 376f7a9c2868..b3e593f3c17f 100644 > --- a/drivers/tty/serial/atmel_serial.c > +++ b/drivers/tty/serial/atmel_serial.c > @@ -1009,6 +1009,8 @@ static void atmel_tx_dma(struct uart_port *port) > atmel_port->cookie_tx); > return; > } > + > + dma_async_issue_pending(chan); > } > > if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) From this hunk... > @@ -1191,6 +1193,7 @@ static void atmel_rx_from_dma(struct uart_port *port) > static int atmel_prepare_rx_dma(struct uart_port *port) > { > struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); > + struct dma_chan *chan_rx; > struct device *mfd_dev = port->dev->parent; > struct dma_async_tx_descriptor *desc; > dma_cap_mask_t mask; > @@ -1203,11 +1206,13 @@ static int atmel_prepare_rx_dma(struct uart_port *port) > dma_cap_zero(mask); > dma_cap_set(DMA_CYCLIC, mask); > > - atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx"); > - if (atmel_port->chan_rx == NULL) > + chan_rx = dma_request_slave_channel(mfd_dev, "rx"); > + if (chan_rx == NULL) > goto chan_err; > + atmel_port->chan_rx = chan_rx; > + > dev_info(port->dev, "using %s for rx DMA transfers\n", > - dma_chan_name(atmel_port->chan_rx)); > + dma_chan_name(chan_rx)); > > spin_lock_init(&atmel_port->lock_rx); > sg_init_table(&atmel_port->sg_rx, 1); > @@ -1239,8 +1244,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port) > config.src_addr = port->mapbase + ATMEL_US_RHR; > config.src_maxburst = 1; > > - ret = dmaengine_slave_config(atmel_port->chan_rx, > - &config); > + ret = dmaengine_slave_config(chan_rx, &config); > if (ret) { > dev_err(port->dev, "DMA rx slave configuration failed\n"); > goto chan_err; > @@ -1249,7 +1253,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port) > * Prepare a cyclic dma transfer, assign 2 descriptors, > * each one is half ring buffer size > */ > - desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx, > + desc = dmaengine_prep_dma_cyclic(chan_rx, > sg_dma_address(&atmel_port->sg_rx), > sg_dma_len(&atmel_port->sg_rx), > sg_dma_len(&atmel_port->sg_rx)/2, ...to here : I think this should go in another patch since these hunks only introduce "chan_rx". And in this other patch, maybe add a little note on why "atmel_port->chan_rx = chan_rx;" is after "chan_rx = dma_request_slave_channel(mfd_dev, "rx");" > @@ -1269,12 +1273,14 @@ static int atmel_prepare_rx_dma(struct uart_port *port) > goto chan_err; > } > > + dma_async_issue_pending(chan_rx); > + > return 0; > > chan_err: > dev_err(port->dev, "RX channel not available, switch to pio\n"); > atmel_port->use_dma_rx = false; > - if (atmel_port->chan_rx) > + if (chan_rx) > atmel_release_rx_dma(port); > return -EINVAL; > } > The rest seems ok. Thanks ! Richard.
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 376f7a9c2868..b3e593f3c17f 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -1009,6 +1009,8 @@ static void atmel_tx_dma(struct uart_port *port) atmel_port->cookie_tx); return; } + + dma_async_issue_pending(chan); } if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) @@ -1191,6 +1193,7 @@ static void atmel_rx_from_dma(struct uart_port *port) static int atmel_prepare_rx_dma(struct uart_port *port) { struct atmel_uart_port *atmel_port = to_atmel_uart_port(port); + struct dma_chan *chan_rx; struct device *mfd_dev = port->dev->parent; struct dma_async_tx_descriptor *desc; dma_cap_mask_t mask; @@ -1203,11 +1206,13 @@ static int atmel_prepare_rx_dma(struct uart_port *port) dma_cap_zero(mask); dma_cap_set(DMA_CYCLIC, mask); - atmel_port->chan_rx = dma_request_slave_channel(mfd_dev, "rx"); - if (atmel_port->chan_rx == NULL) + chan_rx = dma_request_slave_channel(mfd_dev, "rx"); + if (chan_rx == NULL) goto chan_err; + atmel_port->chan_rx = chan_rx; + dev_info(port->dev, "using %s for rx DMA transfers\n", - dma_chan_name(atmel_port->chan_rx)); + dma_chan_name(chan_rx)); spin_lock_init(&atmel_port->lock_rx); sg_init_table(&atmel_port->sg_rx, 1); @@ -1239,8 +1244,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port) config.src_addr = port->mapbase + ATMEL_US_RHR; config.src_maxburst = 1; - ret = dmaengine_slave_config(atmel_port->chan_rx, - &config); + ret = dmaengine_slave_config(chan_rx, &config); if (ret) { dev_err(port->dev, "DMA rx slave configuration failed\n"); goto chan_err; @@ -1249,7 +1253,7 @@ static int atmel_prepare_rx_dma(struct uart_port *port) * Prepare a cyclic dma transfer, assign 2 descriptors, * each one is half ring buffer size */ - desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx, + desc = dmaengine_prep_dma_cyclic(chan_rx, sg_dma_address(&atmel_port->sg_rx), sg_dma_len(&atmel_port->sg_rx), sg_dma_len(&atmel_port->sg_rx)/2, @@ -1269,12 +1273,14 @@ static int atmel_prepare_rx_dma(struct uart_port *port) goto chan_err; } + dma_async_issue_pending(chan_rx); + return 0; chan_err: dev_err(port->dev, "RX channel not available, switch to pio\n"); atmel_port->use_dma_rx = false; - if (atmel_port->chan_rx) + if (chan_rx) atmel_release_rx_dma(port); return -EINVAL; }
The driver wrongly assummed that tx_submit() will start the transfer, which is not the case, now that the at_xdmac driver is fixed. tx_submit is supposed to push the current transaction descriptor to a pending queue, waiting for issue_pending to be called. issue_pending must start the transfer, not tx_submit. While touching atmel_prepare_rx_dma(), introduce a local variable for the RX dma channel. Fixes: 34df42f59a60 ("serial: at91: add rx dma support") Fixes: 08f738be88bb ("serial: at91: add tx dma support") Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> --- drivers/tty/serial/atmel_serial.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-)