diff options
| author | Fugang Duan <fugang.duan@nxp.com> | 2017-06-12 16:56:43 +0800 |
|---|---|---|
| committer | Jason Liu <jason.hui.liu@nxp.com> | 2019-02-12 10:26:50 +0800 |
| commit | 4d3bd1e2f9b14284aa8190ca28ac97e20935830a (patch) | |
| tree | 87da430970249860dee21abb1c6a83359fb799ee /drivers/tty/serial/imx.c | |
| parent | 28f34e086c871f34277e35f4cde3db16979cd03f (diff) | |
MLK-15093 tty: serial: imx: enable bit TDMAEN in each DMA transfer
In below case:
write() -> flush() -> write() -> flush() ...
.imx_flush_buffer() _MAY_ clear UCR1_TDMAEN bit if the callback is not
comming or DMA transfer is not completed, to ensure DMA trigger is enabled
for the new DMA prep_sg, enable the UCR1_TDMAEN bit in .dma_tx_work().
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: David Wolfe <david.wolfe@nxp.com>
Diffstat (limited to 'drivers/tty/serial/imx.c')
| -rw-r--r-- | drivers/tty/serial/imx.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 8f780974754d..53cd6b326740 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -508,16 +508,21 @@ static void dma_tx_callback(void *data) struct circ_buf *xmit = &sport->port.state->xmit; unsigned long flags; - dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); - - sport->dma_is_txing = 0; - /* update the stat */ spin_lock_irqsave(&sport->port.lock, flags); + /* user call .flush() before the code slice coming */ + if (!sport->dma_is_txing) { + spin_unlock_irqrestore(&sport->port.lock, flags); + return; + } + sport->dma_is_txing = 0; + xmit->tail = (xmit->tail + sport->tx_bytes) & (UART_XMIT_SIZE - 1); sport->port.icount.tx += sport->tx_bytes; spin_unlock_irqrestore(&sport->port.lock, flags); + dma_unmap_sg(sport->port.dev, sgl, sport->dma_tx_nents, DMA_TO_DEVICE); + dev_dbg(sport->port.dev, "we finish the TX DMA.\n"); clear_bit(DMA_TX_IS_WORKING, &sport->flags); @@ -543,6 +548,7 @@ static void dma_tx_work(struct work_struct *w) struct dma_chan *chan = sport->dma_chan_tx; struct device *dev = sport->port.dev; unsigned long flags; + unsigned long temp; int ret; if (test_and_set_bit(DMA_TX_IS_WORKING, &sport->flags)) @@ -584,6 +590,10 @@ static void dma_tx_work(struct work_struct *w) sport->dma_is_txing = 1; dmaengine_submit(desc); dma_async_issue_pending(chan); + + temp = readl(sport->port.membase + UCR1); + temp |= UCR1_TDMAEN; + writel(temp, sport->port.membase + UCR1); return; } spin_unlock_irqrestore(&sport->port.lock, flags); @@ -1448,7 +1458,9 @@ static void imx_flush_buffer(struct uart_port *port) temp = readl(sport->port.membase + UCR1); temp &= ~UCR1_TDMAEN; writel(temp, sport->port.membase + UCR1); - sport->dma_is_txing = false; + sport->dma_is_txing = 0; + clear_bit(DMA_TX_IS_WORKING, &sport->flags); + smp_mb__after_atomic(); } /* |