dma_map_single() provides much easier interface for simple mappings as
used for TX in atmel_serial. So switch to that, removing all the s-g
unnecessary handling.
Note that it is not easy (maybe impossible) to use kfifo_dma_* API for
atmel's serial purposes. It handles DMA very specially.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@xxxxxxxxxx>
Cc: Richard Genoud <richard.genoud@xxxxxxxxx>
Cc: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxx>
Cc: Claudiu Beznea <claudiu.beznea@xxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
drivers/tty/serial/atmel_serial.c | 35 +++++++++++++------------------
1 file changed, 14 insertions(+), 21 deletions(-)
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 5bb5e4303754..69ec80ffc97b 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -132,7 +132,7 @@ struct atmel_uart_port {
struct dma_async_tx_descriptor *desc_rx;
dma_cookie_t cookie_tx;
dma_cookie_t cookie_rx;
- struct scatterlist sg_tx;
+ dma_addr_t tx_phys;
struct scatterlist sg_rx;
struct tasklet_struct tasklet_rx;
struct tasklet_struct tasklet_tx;
@@ -904,8 +904,8 @@ static void atmel_release_tx_dma(struct uart_port *port)
if (chan) {
dmaengine_terminate_all(chan);
dma_release_channel(chan);
- dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1,
- DMA_TO_DEVICE);
+ dma_unmap_single(port->dev, atmel_port->tx_phys,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
}
atmel_port->desc_tx = NULL;
@@ -922,7 +922,7 @@ static void atmel_tx_dma(struct uart_port *port)
struct tty_port *tport = &port->state->port;
struct dma_chan *chan = atmel_port->chan_tx;
struct dma_async_tx_descriptor *desc;
- struct scatterlist sgl[2], *sg, *sg_tx = &atmel_port->sg_tx;
+ struct scatterlist sgl[2], *sg;
unsigned int tx_len, tail, part1_len, part2_len, sg_len;
dma_addr_t phys_addr;
@@ -955,7 +955,7 @@ static void atmel_tx_dma(struct uart_port *port)
sg_init_table(sgl, 2);
sg_len = 0;
- phys_addr = sg_dma_address(sg_tx) + tail;
+ phys_addr = atmel_port->tx_phys + tail;
if (part1_len) {
sg = &sgl[sg_len++];
sg_dma_address(sg) = phys_addr;
@@ -987,7 +987,8 @@ static void atmel_tx_dma(struct uart_port *port)
return;
}
- dma_sync_sg_for_device(port->dev, sg_tx, 1, DMA_TO_DEVICE);
+ dma_sync_single_for_device(port->dev, atmel_port->tx_phys,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
atmel_port->desc_tx = desc;
desc->callback = atmel_complete_tx_dma;
@@ -1014,7 +1015,7 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
dma_cap_mask_t mask;
struct dma_slave_config config;
struct dma_chan *chan;
- int ret, nent;
+ int ret;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
@@ -1029,26 +1030,18 @@ static int atmel_prepare_tx_dma(struct uart_port *port)
dma_chan_name(atmel_port->chan_tx));
spin_lock_init(&atmel_port->lock_tx);
- sg_init_table(&atmel_port->sg_tx, 1);
/* UART circular tx buffer is an aligned page. */
BUG_ON(!PAGE_ALIGNED(tport->xmit_buf));
- sg_set_page(&atmel_port->sg_tx,
- virt_to_page(tport->xmit_buf),
- UART_XMIT_SIZE,
- offset_in_page(tport->xmit_buf));
- nent = dma_map_sg(port->dev,
- &atmel_port->sg_tx,
- 1,
- DMA_TO_DEVICE);
+ atmel_port->tx_phys = dma_map_single(port->dev, tport->xmit_buf,
+ UART_XMIT_SIZE, DMA_TO_DEVICE);
- if (!nent) {
+ if (dma_mapping_error(port->dev, atmel_port->tx_phys)) {
dev_dbg(port->dev, "need to release resource of dma\n");
goto chan_err;
} else {
- dev_dbg(port->dev, "%s: mapped %d@%p to %pad\n", __func__,
- sg_dma_len(&atmel_port->sg_tx),
- tport->xmit_buf,
- &sg_dma_address(&atmel_port->sg_tx));
+ dev_dbg(port->dev, "%s: mapped %lu@%p to %pad\n", __func__,
+ UART_XMIT_SIZE, tport->xmit_buf,
+ &atmel_port->tx_phys);
}
/* Configure the slave DMA */
--
2.44.0
