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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>
This commit is contained in:
Heikki Krogerus 2013-04-10 16:58:24 +03:00 committed by Greg Kroah-Hartman
parent 84f57d9e36
commit 5ea5b24da8
1 changed files with 4 additions and 7 deletions
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11
drivers/tty/serial/8250/8250_dma.c
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@ -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,