[PATCH 03/13] tty: serial: atmel: Call dma_async_issue_pending()
From: Tudor Ambarus <hidden>
Date: 2021-11-16 11:21:54
Also in:
dmaengine, linux-arm-kernel, lkml
Subsystem:
microchip at91 serial driver, the rest, tty layer and serial drivers · Maintainers:
Richard Genoud, Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
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 <redacted>
---
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)
@@ -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; }
--
2.25.1