diff options
Diffstat (limited to 'drivers/tty/serial/sh-sci.c')
| -rw-r--r-- | drivers/tty/serial/sh-sci.c | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 66c8bbea06c4..333de7d3fe86 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1319,6 +1319,7 @@ 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. @@ -1328,16 +1329,23 @@ 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); @@ -1347,20 +1355,20 @@ 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); } @@ -1571,11 +1579,18 @@ 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) |