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authorHeikki Krogerus <heikki.krogerus@linux.intel.com>2013-04-10 16:58:24 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-04-11 13:17:56 -0700
commit5ea5b24da80322b8136cb000a7340cdc29a3d6dc (patch)
tree3ec6da8909165463d6f4f81cdb1c505e87823f60 /drivers/tty
parent84f57d9e3685500a7447fc09a6891ce218869174 (diff)
downloadblackbird-op-linux-5ea5b24da80322b8136cb000a7340cdc29a3d6dc.tar.gz
blackbird-op-linux-5ea5b24da80322b8136cb000a7340cdc29a3d6dc.zip
serial: 8250_dma: TX cleanup
Removing one unneeded uart_write_wakeup(). There is no need to start PIO transfer unless DMA fails, so this also changes serial8250_tx_dma() to return 0 unless that is the case. Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/8250/8250_dma.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index b9f7fd28112e..ce2518d5dfd1 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -33,10 +33,8 @@ static void __dma_tx_complete(void *param)
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&p->port);
- if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
+ if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port))
serial8250_tx_dma(p);
- uart_write_wakeup(&p->port);
- }
}
static void __dma_rx_complete(void *param)
@@ -67,12 +65,11 @@ int serial8250_tx_dma(struct uart_8250_port *p)
struct circ_buf *xmit = &p->port.state->xmit;
struct dma_async_tx_descriptor *desc;
- if (dma->tx_running)
- return -EBUSY;
+ if (uart_tx_stopped(&p->port) || dma->tx_running ||
+ uart_circ_empty(xmit))
+ return 0;
dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
- if (!dma->tx_size)
- return -EINVAL;
desc = dmaengine_prep_slave_single(dma->txchan,
dma->tx_addr + xmit->tail,
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