From: Erwan Le Ray erwan.leray@st.com
[ Upstream commit 64c32eab660386f9904bb295a104c9c425e9f8b2 ]
Adds a check on the Transmission Complete bit status before closing the com port. Prevents the port closure before the end of the transmission. TC poll loop is moved from stm32_tx_dma_complete to stm32_shutdown routine, in order to check TC before shutdown in both dma and PIO tx modes. TC clear is added in stm32_transmit_char routine, in order to be cleared before transmitting in both dma and PIO tx modes.
Fixes: 3489187204eb ("serial: stm32: adding dma support") Signed-off-by: Erwan Le Ray erwan.leray@st.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/tty/serial/stm32-usart.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 2e7757d..d603be9 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -290,21 +290,6 @@ static void stm32_tx_dma_complete(void *arg) struct uart_port *port = arg; struct stm32_port *stm32port = to_stm32_port(port); struct stm32_usart_offsets *ofs = &stm32port->info->ofs; - unsigned int isr; - int ret; - - ret = readl_relaxed_poll_timeout_atomic(port->membase + ofs->isr, - isr, - (isr & USART_SR_TC), - 10, 100000); - - if (ret) - dev_err(port->dev, "terminal count not set\n"); - - 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); stm32port->tx_dma_busy = false; @@ -396,7 +381,6 @@ static void stm32_transmit_chars_dma(struct uart_port *port) /* Issue pending DMA TX requests */ dma_async_issue_pending(stm32port->tx_ch);
- stm32_clr_bits(port, ofs->isr, USART_SR_TC); stm32_set_bits(port, ofs->cr3, USART_CR3_DMAT);
xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1); @@ -425,6 +409,11 @@ static void stm32_transmit_chars(struct uart_port *port) return; }
+ if (ofs->icr == UNDEF_REG) + stm32_clr_bits(port, ofs->isr, USART_SR_TC); + else + stm32_set_bits(port, ofs->icr, USART_ICR_TCCF); + if (stm32_port->tx_ch) stm32_transmit_chars_dma(port); else @@ -601,12 +590,21 @@ static void stm32_shutdown(struct uart_port *port) struct stm32_port *stm32_port = to_stm32_port(port); struct stm32_usart_offsets *ofs = &stm32_port->info->ofs; struct stm32_usart_config *cfg = &stm32_port->info->cfg; - u32 val; + u32 val, isr; + int ret;
val = USART_CR1_TXEIE | USART_CR1_RXNEIE | USART_CR1_TE | USART_CR1_RE; val |= BIT(cfg->uart_enable_bit); if (stm32_port->fifoen) val |= USART_CR1_FIFOEN; + + ret = readl_relaxed_poll_timeout(port->membase + ofs->isr, + isr, (isr & USART_SR_TC), + 10, 100000); + + if (ret) + dev_err(port->dev, "transmission complete not set\n"); + stm32_clr_bits(port, ofs->cr1, val);
dev_pm_clear_wake_irq(port->dev);