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path: root/drivers/tty/serial/sh-sci.c
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Diffstat (limited to 'drivers/tty/serial/sh-sci.c')
-rw-r--r--drivers/tty/serial/sh-sci.c45
1 files changed, 25 insertions, 20 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 6ff53b604ff6..ea35f5144237 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -834,19 +834,9 @@ static void sci_transmit_chars(struct uart_port *port)
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
- if (uart_circ_empty(xmit)) {
+ if (uart_circ_empty(xmit))
sci_stop_tx(port);
- } else {
- ctrl = serial_port_in(port, SCSCR);
-
- if (port->type != PORT_SCI) {
- serial_port_in(port, SCxSR); /* Dummy read */
- sci_clear_SCxSR(port, SCxSR_TDxE_CLEAR(port));
- }
- ctrl |= SCSCR_TIE;
- serial_port_out(port, SCSCR, ctrl);
- }
}
/* On SH3, SCIF may read end-of-break as a space->mark char */
@@ -1301,6 +1291,7 @@ static void work_fn_tx(struct work_struct *work)
struct uart_port *port = &s->port;
struct circ_buf *xmit = &port->state->xmit;
dma_addr_t buf;
+ int head, tail;
/*
* DMA is idle now.
@@ -1310,16 +1301,23 @@ static void work_fn_tx(struct work_struct *work)
* consistent xmit buffer state.
*/
spin_lock_irq(&port->lock);
- buf = s->tx_dma_addr + (xmit->tail & (UART_XMIT_SIZE - 1));
+ head = xmit->head;
+ tail = xmit->tail;
+ buf = s->tx_dma_addr + (tail & (UART_XMIT_SIZE - 1));
s->tx_dma_len = min_t(unsigned int,
- CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE),
- CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE));
- spin_unlock_irq(&port->lock);
+ CIRC_CNT(head, tail, UART_XMIT_SIZE),
+ CIRC_CNT_TO_END(head, tail, UART_XMIT_SIZE));
+ if (!s->tx_dma_len) {
+ /* Transmit buffer has been flushed */
+ spin_unlock_irq(&port->lock);
+ return;
+ }
desc = dmaengine_prep_slave_single(chan, buf, s->tx_dma_len,
DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
+ spin_unlock_irq(&port->lock);
dev_warn(port->dev, "Failed preparing Tx DMA descriptor\n");
/* switch to PIO */
sci_tx_dma_release(s, true);
@@ -1329,20 +1327,20 @@ static void work_fn_tx(struct work_struct *work)
dma_sync_single_for_device(chan->device->dev, buf, s->tx_dma_len,
DMA_TO_DEVICE);
- spin_lock_irq(&port->lock);
desc->callback = sci_dma_tx_complete;
desc->callback_param = s;
- spin_unlock_irq(&port->lock);
s->cookie_tx = dmaengine_submit(desc);
if (dma_submit_error(s->cookie_tx)) {
+ spin_unlock_irq(&port->lock);
dev_warn(port->dev, "Failed submitting Tx DMA descriptor\n");
/* switch to PIO */
sci_tx_dma_release(s, true);
return;
}
+ spin_unlock_irq(&port->lock);
dev_dbg(port->dev, "%s: %p: %d...%d, cookie %d\n",
- __func__, xmit->buf, xmit->tail, xmit->head, s->cookie_tx);
+ __func__, xmit->buf, tail, head, s->cookie_tx);
dma_async_issue_pending(chan);
}
@@ -1548,11 +1546,18 @@ static void sci_free_dma(struct uart_port *port)
static void sci_flush_buffer(struct uart_port *port)
{
+ struct sci_port *s = to_sci_port(port);
+
/*
* In uart_flush_buffer(), the xmit circular buffer has just been
- * cleared, so we have to reset tx_dma_len accordingly.
+ * cleared, so we have to reset tx_dma_len accordingly, and stop any
+ * pending transfers
*/
- to_sci_port(port)->tx_dma_len = 0;
+ s->tx_dma_len = 0;
+ if (s->chan_tx) {
+ dmaengine_terminate_async(s->chan_tx);
+ s->cookie_tx = -EINVAL;
+ }
}
#else /* !CONFIG_SERIAL_SH_SCI_DMA */
static inline void sci_request_dma(struct uart_port *port)