From: Bich Hemon <bich.hemon@xxxxxx>
tx_empty: poll TC (PIO mode) or DMAT (DMA mode) bit.
flush_buffer: terminate on going DMA tx transfer.
remove: terminate DMA rx and tx transfers.
Signed-off-by: Gerald Baeza <gerald.baeza@xxxxxx>
---
drivers/tty/serial/stm32-usart.c | 37 ++++++++++++++++++++++++++++++++++---
1 file changed, 34 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index ed2025b..266dc4f 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -408,8 +408,14 @@ static unsigned int stm32_tx_empty(struct uart_port *port)
{
struct stm32_port *stm32_port = to_stm32_port(port);
struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+ int ret;
+
+ if (!stm32_port->tx_ch)
+ ret = readl_relaxed(port->membase + ofs->isr) & USART_SR_TC;
+ else
+ ret = readl_relaxed(port->membase + ofs->cr3) & USART_CR3_DMAT;
- return readl_relaxed(port->membase + ofs->isr) & USART_SR_TXE;
+ return ret;
}
static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -449,6 +455,26 @@ static void stm32_start_tx(struct uart_port *port)
stm32_transmit_chars(port);
}
+/* Flush the transmit buffer. */
+static void stm32_flush_buffer(struct uart_port *port)
+{
+ struct stm32_port *stm32_port = to_stm32_port(port);
+ struct stm32_usart_offsets *ofs = &stm32_port->info->ofs;
+
+ if (stm32_port->tx_ch) {
+ spin_lock(&port->lock);
+ dmaengine_terminate_all(stm32_port->tx_ch);
+ spin_unlock(&port->lock);
+ if (ofs->icr == UNDEF_REG)
+ stm32_clr_bits(port, ofs->isr, USART_SR_TC);
+ else
+ stm32_set_bits(port, ofs->icr, USART_CR_TC);
+
+ stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
+ stm32_port->tx_dma_busy = false;
+ }
+}
+
/* Throttle the remote when input buffer is about to overflow. */
static void stm32_throttle(struct uart_port *port)
{
@@ -701,6 +727,7 @@ static void stm32_pm(struct uart_port *port, unsigned int state,
.break_ctl = stm32_break_ctl,
.startup = stm32_startup,
.shutdown = stm32_shutdown,
+ .flush_buffer = stm32_flush_buffer,
.set_termios = stm32_set_termios,
.pm = stm32_pm,
.type = stm32_type,
@@ -950,8 +977,10 @@ static int stm32_serial_remove(struct platform_device *pdev)
stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAR);
- if (stm32_port->rx_ch)
+ if (stm32_port->rx_ch) {
+ dmaengine_terminate_all(stm32_port->rx_ch);
dma_release_channel(stm32_port->rx_ch);
+ }
if (stm32_port->rx_dma_buf)
dma_free_coherent(&pdev->dev,
@@ -960,8 +989,10 @@ static int stm32_serial_remove(struct platform_device *pdev)
stm32_clr_bits(port, ofs->cr3, USART_CR3_DMAT);
- if (stm32_port->tx_ch)
+ if (stm32_port->tx_ch) {
+ dmaengine_terminate_all(stm32_port->tx_ch);
dma_release_channel(stm32_port->tx_ch);
+ }
if (stm32_port->tx_dma_buf)
dma_free_coherent(&pdev->dev,
--
1.9.1
--
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